When is an Instrument Rating Required?

• When acting as PIC under IFR or in weather conditions less than prescribed for VFR (§61.3)
• When carrying passengers for compensation or hire on cross-country flights in excess of 50 NM or at night (§61.133)
• For flight in Class A airspace (§91.135)
• For Special VFR (1 SM flight visibility, clear of clouds) between sunset and sunrise (§91.157)

Logging Instrument Time (§61.51)

• A person may log instrument time only for that flight time when the person operates the aircraft solely by reference to instruments under actual or simulated instrument flight conditions
• An authorized instructor may log instrument time when conducting instrument flight instruction in actual instrument flight conditions

Airplane – Instrument Rating Minimum Aeronautical Experience (§61.65)

• 50 hours XC PIC time
  
  • Of which, 10 hours in airplane
• 40 hours of actual or simulated instrument time
  
  • Of which, 15 hours with CFII
    
    • Including one XC flight of:
      
      • 250 NM along airways or by directed ATC routing
      • An instrument approach at each airport
      • 3 difference kinds of approaches using navigation systems
      • With a filed IFR flight plan
    • 3 hours instrument flight time training in last 2 calendar months prior to practical test
• Use of approved full flight simulator or FTD (flight training device), if trained by authorized instructor:
  
  • Max 30 hours if instrument time completed under part 142
  • Max 20 if not completed under part 142
• Use of FAA approved Aviation Training Device, if trained by an authorized instructor
  
  • Max 10 hours of instrument time if Basic ATD
  • Max 20 hours of instrument time if Advanced ATD
• No more than 20 hours of total instrument time can be credited in a full flight simulator, FTD or ATD, except the 30 hours exception under part 142 mentioned above

Recency of Experience (§61.56, §91.109, §61.57, Instrument-Airplane ACS)

• To act as PIC under IFR or in weather conditions less than the minimums for VFR – “6 HITS” (within 6 calendar months preceding the month of flight):
  
  • 6 instrument approaches
  • Holding procedures and tasks
  • Intercepting & Tracking courses through the use of navigational electronic systems
  • The above can be completed in an FFS, ATD, or FTD provided the device represents the category of aircraft for the instrument rating privileges to be maintained and the pilot performs the tasks and iterations in simulated instrument conditions. A flight instructor is not needed
• Not current looking back 6 months?
  
  • You can still log the required “6 HITS” with a safety pilot (under simulated conditions), examiner or instructor
    
    • Safety pilot requirements
      
      • At least a private pilot with appropriate category and class
      • Have adequate vision forward and to each side of the aircraft
      • Aircraft must have a dual control system
• Not current looking back 12 months?
  
  • Instrument Proficiency Check (IPC) by a CFII, examiner, or other approved person is required. Guidelines are in the ACS
  • Some IPC tasks, but not all, can be conducted in a FTD or ATD. (Refer to the ACS)
• To carry passengers as PIC
  
  • 3 takeoffs & landings in category, class, and type (if type rating req.) in the last 90 days
  • At periods between 1 hour after sunset to 1 hour before sunrise: 3 takeoffs & landings to full stop within 1 hour after sunset to 1 hour before sunrise
• To act as PIC – Flight Review in the last 24 calendar months (see FAR for exceptions)
• To meet recent instrument experience requirements, the following information must be recorded in the person’s logbook:
  
  • Location and type of each instrument approach accomplished, and
  • The name of the safety pilot, if required
• Use of full flight simulator, FTD, or ATD for acquiring instrument aeronautical experience:
  
  • For training towards a certificate or rating, an authorized instructor is present to observe and signs the person’s logbook to verify the time and content of the session
  • For IFR recency requirements, log:
    
    • Training device, time and content

Personal Documents Required for Flight

• Pilot Certificate
• Medical Certificate (or US Driver’s license as permitted by §61.113 & §61.23)
• Authorized photo ID (passport, driver’s license, etc)
• Restricted Radiotelephone Operator Permit (For flights outside the US)

Aircraft Documents Required for Flight – A.R.R.O.W (§21.5, §91.103, §91.9, §91.203, ICAO Article 29)

• Airworthiness Certificate
• Registration Certificate
• Radio station license (for flights outside the US)
• Operating Limitations and Information (in AFM)
• Weight and Balance data (aircraft specific)

Aircraft Maintenance Inspections Required for IFR: A.V.I.A.T.E.S

• Airworthiness Directive (AD) required inspections. (§39)
• VOR check every 30 days (For IFR; §91.171)
• Inspections: (§91.409)
  
  • Annual inspection – 12 Cal. Months (all aircraft)
  • 100-hour (time in service) inspection required if:
    
    • Carrying a person for hire (other than crew member), or
      
      • Flight instructing for hire in an aircraft provided by the person giving the instruction
      • “For hire” refers to the person, not the aircraft.
        
        • Flight school providing airplane + instructor for hire: 100-hour required
        • Student-owned aircraft: 100-hour not required
        • Rental (no pilot or instructor): 100-hour not required
      • The 100-hour inspection may be exceeded by up to 10 hours if aircraft is enroute to a place where it can be done. This additional time must be included in computers the next 100-hour inspection
      • An annual can be substituted for the 100-hour if done within 100 hours of time-in-service
    • A progressive inspection schedule, if specifically approved by the FAA, may replace the annual and 100 hour inspections.
  • Altimeter, automatic altitude reporting (used by transponder) & static system every 24 calendar months (for IFR in controlled airspace; §91.411)
  • Transponder every 24 calendar months (§91.413)
  • ELT (§91.207)
    
    • Inspected every 12 calendar months
    • Battery must be replaced after more than 1 hour of cumulative transmitter use of if 50% of its useful life has expired (or, for rechargeable batteries, 50% of the useful life of charge has expired)
  • Supplemental Type Certificate (STC) required inspections

Preflight Self-Assessment: I.M S.A.F.E (§91.17, AIM 8-1-1)

• Illness
• Medication
• Stress
• Alcohol – no drinking within 8 hours. No more than 0.04% of alcohol in blood.
• Fatigue
• Emotion

Preflight Info Required for IFR: N.W K.R.A.F.T (§91.103)

• NOTAMs
• Weather reports and forecasts 
• Known traffic delays as advised by ATC
• Runway length of intended use
• Alternatives available if flight cannot be completed as planned
• Fuel requirements
• Takeoff and landing performance data

Risk Management and Personal Minimums: P.A.V.E (Pilot’s Handbook of Aeronautical Knowledge)

• Pilot (general health, physical / mental / emotional state, proficiency, currency)
• Aircraft (airworthiness, equipment, performance)
• enVironment (weather hazards, terrain, airports/runways to be used & other conditions)
• External pressure (meetings, people waiting at destination, etc.)

Decision Making: D.E.C.I.D.E (Pilots Handbook of Aeronautical Knowledge)

• Detect that a change has occurred
• Estimate the need to counter the change
• Choose a desirable outcome
• Identify solutions
• Do the necessary actions
• Evaluate the effects of the actions 

Passenger Briefing: S.A.F.E.T.Y (Pilots Handbook of Aeronautical Knowledge)

• S
  
  • Seatbelts fastened for taxi, takeoff, landing
  • Shoulder harness fastened for takeoff, landing
  • Seat position adjusted and locked in place
• A
  
  • Air vents location and operation
  • All environmental controls (discussed)
  • Action in case of any passenger discomfort
• F
  
  • Fire extinguisher (location and operation)
• E
  
  • Exit doors (how to secure, how to open)
  • Emergency evacuation plan
  • Emergency survival kit (location and contents)
• T
  
  • Traffic (scanning, spotting, notifying pilot)
  • Talking, sterile flight deck expectations
• Y
  
  • Your questions? Speak up! 

Taxi Briefing: A.R.C.H

• Assigned/planned runway
• Route
• Crossings and hold short instructions
• Hot spots and hazards (e.g., NOTAMs, closed taxiways/runways, surface condition)

Takeoff Briefing: D.E.P.A.R.T.S

• Departure review (e.g. takeoff type, initial heading, first fix & course, clearance readout)
• Establish expectations (e.g. flying pilot, PIC, positive transfer of controls)
• Plan/special considerations (e.g. weather, visibility, terrain, unfamiliar field, inoperative equipment/MELs)
• Alternate (takeoff alternate, if needed, or return plan)
• Runway conditions and length
• Trouble/Tactics (e.g. rejected takeoff, engine failure)
• Speak up! Questions/concerns?

IFR Flight Plan (§91.173)

• Requirement: no person may operate an aircraft in controlled airspace under IFR unless that person has:
  
  • Filed an IFR flight plan; and
  • Received an appropriate ATC clearance
• It is legal to fly IFR in uncontrolled airspace (class G) without a flight plan or clearance. However, once airborne, you must remain in uncontrolled airspace until you file a flight plan and get an ATC clearance to enter to enter the controlled airspace 
• How to file an IFR flight plan?
  
  • FSS
    
    • By phone (1-800-WX-BRIEF)
    • Over the radio (GCO/RCO frequencies): in person
  • Online
    
    • www.1800wxbrief.com (leido)
    • www.fltplan.com (Garmin)
  • EFB (e.g. Foreflight)
  • With ATC (over radio, or phone if no other mean available)
• File at least 30 minutes prior to estimated departure. Non-scheduled flights above FL230 should be filed at least 4 hours before est. departure time (AIM 5-1-8)
• Flight plan cancelation (AIM 5-1-15)
  
  • Towered airports – automatically cancelled by ATC upon landing
  • Non-towered airports – pilot must contact ATC/FCC to cancel (by radio or phone)
  • Can cancel anytime in flight if out of IMC and out of class A airspace
• Preferred IFR routes are published in Chart Supplement U.S. It is to the pilot’s advantage to file a preferred route if available (AIM 5-1-8)

IFR Minimum Fuel Requirements (§91.167)

• Fuel from departure to destination airport + Fuel from destination to most distant alternate (if alternate required) + 45 minutes calculated at normal cruise
  
  • Other fuel requirements exist for 121, 135
    
    • Part 121: US-to-US is domestic, US-to-nonUS is a flag operation, and all cargo or “large aircraft charters” are a supplemental operation. These all have different fuel requirements, crew rest requirements, alternate airport requirements, etc.)

Need a Destination Alternate? “1-2-3” Rule (§91.169)

• A destination alternate is always required, unless:
  
  • An instrument approach is published and available for the destination, AND, 
  • For at least 1 hour before to 1 hour after ETA:
    
    • Ceiling will be at least 2000’ above airport elevation; and
    • Visibility will be at least 3 SM 
• If alternate is needed: (§91.169)
  
  • Min WX conditions required at an airport to list it as an alternate
    
    • The alternate airport minima published in the procedure charts, or, if none:
      
      • Precision approach: 600ft ceiling and 2SM visibility
      • Non-precision approach: 800ft ceiling and 2SM visibility
      • No instrument approach available at the alternate: ceiling and visibility must allow descent from MEA, approach and landing under VFR

Filing an alternate – GPS considerations (AIM 1-1-17b.5, 1-1-18c.9, 1-2-3d)

• Equipped with a non-WAAS GPS? You can flight plan based on GPS approaches at either the destination or the alternate, but not at both
• WAAS Without baro-VNAV? May base the flight plan on use of LNAV approaches at both the destination and alternate
• WAAS With baro-VNAV? May base the flight plan on use of LNAV/VNAV or RNP 0.3 at both the destination and the alternate

IFR Cruising Altitudes (§91.179)

• Uncontrolled Airspace
  
  • Based on magnetic course:
    
    • Below FL290
      
      • 0-179, ODD thousands (below 18000 ft) or Flight Levels (at or above FL180)
      • 180-359 EVEN thousands (below 18000 ft) or Flight Levels (at or above FL180)
    • Above FL290 (in non-RVSM)
      
      • 0-179 Flight Levels at 4000 ft increments starting at FL290 (e.g. 290, 330, 370)
      • 180-359 Flight Levels at 4000 ft increments starting at FL310 (e.g. 310, 350, 390)
    • Above FL290-FL410 (in RVSM)
      
      • 0-179 ODD Flight Levels at 2000 ft increments starting at FL290 (e.g. 290, 310, 330)
      • 180-359 EVEN Flight Levels at 2000 ft increments starting at FL300 (e.g. 300, 320, 340)
• Controlled Airspace
  
  • IFR cruising altitudes are as assigned by ATC

IFR Takeoff Minimums (§91.175)

• No takeoff minimums mandated for part 91 operations. Part 121, 125, 129, 135:
  
  • Prescribed T/O minimums for the runway, or, if none:
    
    • 1-2 engines airplanes: 1 SM visibility 
    • More than 2 engines: ½ SM visibility
• Non-standard TO mins/Departure Procedures 
•   Non-standard IFR alternate minimums exist 
•   Alternate minimums not authorized due to unmonitored facility of the absence of weather reporting service 

Departure Procedures (DP) (AIM 5-2-9)

• Ensures obstacle clearance, provided:
  
  • The airplane crossed the departure end of the runway at least 35 ft AGL
  • Reaches 400 ft AGL before turning, and 
  • Climbs at least 200 Feet per NM (FPNM), or as published otherwise on the chart. 
    
    • FPNM to feet-per-minute conversion:
      
      • fpm = FPNM * Groundspeed / 60
• Pilots are encouraged to file a DP at night, during marginal VMC or IMC.
• Two types of DP
  
  • Obstacle Departure Procedure (ODP) 
    
    • Provides only obstacle clearance. 
    • Graphic ODPs will have “(OBSTACLE)” printed in the chart title. 
    • Printed either textually or graphically. 
  • Standard Instrument Departure (SID) 
    
    • In addition to obstacle clearance it reduces pilot and controller workload by simplifying ATC clearances and minimizing radio communications. 
    • Some SIDs may depict special radio failure procedures. 
    • Always printed graphically.
• DP are also categorized by equipment required: 
  
  • Non-RNAV DP – for use by aircraft equipped with ground-based navigation (i.e., VOR, DME, NDB). 
  • RNAV DP – for aircraft equipped with RNAV equipment (e.g., GPS, VOR/DME, DME/DME). Require at least RNAV 1 performance. Identified with the word “RNAV” in the title. 
  • RADAR DP – ATC radar vectors to an ATS route, NAVAID, or fix are used after departure. RADAR DPs are annotated “RADAR REQUIRED.”
• You are not required to accept a DP. To avoid getting one, state “NO SIDs” in remarks section of flight plan. 
• Transition routes connect the end of the basic SID procedure to the en route structure.

IFR DEPARTURE CLEARANCE C.R.A.F.T (AIM 5-2-6)

• C – Clearance limit. 
• R – Route. 
• A – Altitude.
• F – Frequency (for departure). 
• T – Transponder code.

• Clearance void time – The time at which your clearance is void and after which you may not takeoff. You must notify ATC within 30 min after the void time if you did not depart. 
• “Hold for release” – You may not takeoff until being released for IFR departure. 
• Release time – The earliest time the aircraft may depart under IFR. 
• Expect Departure Clearance Time (EDCT) – A runway release time given under traffic management programs in busy airports. Aircraft are expected to depart no earlier and no later than 5 minutes from the EDCT. 
• Abbreviated departure clearance – “Cleared (…) as filed (…)”

STANDARD TERMINAL ARRIVAL (STAR) 

• Serves as a transition between the en route structure and a point from which an approach to landing can be made. 
• Transition routes connect en route fixes to the basic STAR procedure. 
• Usually named according to the fix at which the basic procedure begins. 
• As with a SID, you can state “NO STARs” in the remarks section of the flight plan, to avoid getting a clearance containing a STAR. 
• RNAV STARs require RNAV 1 performance.

IFR Altitudes (§91.177)

• MIN IFR Altitudes
  
  • Except for takeoff or landing, or otherwise authorized by the FAA, no person may operate an aircraft under IFR below 
    
    • Minimum altitudes prescribed for the flown segment, or if none: 
    • Mountainous areas: 2,000 ft above the highest obstacle within a horizontal distance of 4 NM from the course. 
    • Non-mountainous areas: 1,000 ft above the highest obstacle within 4 NM from the course.
• DA / H – Decision Altitude / Height: the Altitude (MSL) / Height (above runway threshold), on an instrument approach procedure at which the pilot must decide whether to continue the approach or go around. 
• MAA – Maximum Authorized Altitude. Annotated “MAA-17000” (17,000ft as an example) on IFR charts. 
  
  •  
• MCA – Minimum Crossing Altitude: lowest altitude at certain fixes at which the aircraft must cross when proceeding in the direction of a higher minimum enroute IFR altitude
  
  •  
• MDA / H – Minimum Decent Altitude / Height: The lowest Altitude (MSL) / Height (above runway threshold) to which descent is authorized on a non-precision approach until the pilot sees the visual references required for landing. 
• MEA – Minimum En route Altitude: The lowest published altitude between radio fixes which assures acceptable navigational signal coverage and meets obstacle clearance requirements. An MEA gap establishes an area of loss in navigational coverage and annotated “MEA GAP” on IFR charts. 
  
  •  
• MOCA – Minimum Obstruction Clearance Altitude: Provides obstacle clearance and navigation coverage only up to 22 NM of the VOR. 
  
  • If both an MEA and a MOCA are prescribed for a particular route segment, a person may operate an aircraft lower than the MEA down to, but not below the MOCA, provided the applicable navigation signals are available. For aircraft using VOR for navigation, this applies only when the aircraft is within 22 NM of the VOR. (§91.177) 
  •  
• MORA – Minimum Off Route Altitude (Jeppesen): 
  
  • Route MORA provides obstruction clearance within 10NM to either side of airway centerlines and within a 10NM radius at the ends of airways (2000’ of terrain clearance in mountainous areas, 1000’ in non-mountainous regions)
  • Grid MORA provide obstruction clearance within a latitude / longitude grid block (clears all terrain and man-made structures by 1000ft in areas where the highest elevations are 5000’ MSL or lower and by 2000’ in areas where the highest elevations are 5001’ MSL or higher)
• MRA – Minimum Reception Altitude: lowest altitude on an airway segment where an aircraft can be assured of receiving signals from off-course navigation aids like VOR that define a fix
  
  •  
• MTA – Minimum Turning Altitude: Provides vertical and lateral obstacle clearance in turns over certain fixes. Annotated with the MCA X icon and a note describing the restriction. 
  
  •  
• MVA – Minimum Vectoring Altitude: The lowest altitude at which an IFR aircraft will be vectored by a radar controller, except as otherwise authorized for radar approaches, departures, and missed approaches. MVAs may be lower than the minimum altitudes depicted on aeronautical charts, such as MEAs or MOCAs, because the ability to isolate specific obstacles
• OROCA – Off Route Obstruction Clearance Altitude: Provides obstruction clearance with a 1,000 ft buffer in non-mountainous terrain areas and 2,000 ft in mountainous areas. OROCA may not provide navigation or communication signal coverage. 
  
  •  

*Designated mountainous areas are defined in 14 CFR part 95 by lat / long coordinates.

Flight Instruments

• Gyroscopic Instruments
  
  • Two principles of a gyroscope: Rigidity in space (gyro has tendency to resist forces applied to it, it is stable on the axis it spins) and precession (when a force is applied perpendicular to a spinning rotor the rotor will resist the force where it is applied and the force will manifest 90 degrees later in the direction the rotor is spinning). 
  • Attitude indicator – operates on the principle of rigidity in space. Shows bank and pitch information. Older AIs may have a tumble limit. Should show correct attitude within 5 minutes of starting the engine. Normally vacuum-driven in GA aircraft, may be electrical in others. May have small acceleration/deceleration errors (accelerate-slight pitch up, decelerate- pitch down) and roll-out errors (following a 180 turn shows a slight turn to the opposite direction). 
  • Heading indicator – operates on the principle of rigidity in space. It only reflects changes in heading, but cannot measure the heading directly. You have to calibrate it with a magnetic compass in order for it to indicate correctly. HIs may be slaved to a magnetic heading source, such as a flux gate, and sync automatically to the present heading. Normally powered by the vacuum system in on GA aircraft. 
  • Turn indicators – operates on the principle of precession. 
    
    • Turn coordinators show rate-of-turn and rate of roll. 
      
      • Standard Rate Turn (SRT) = 3deg/sec
      • SRT Angle of Bank = [True Airspeed in Knots/10] +5
    • Turn-and-slip indicators show rate-of-turn only.
• Pitot-Static Instruments
  
  • Altimeter
    
    • An aneroid barometer (instrument used for measuring pressure, does not involve liquid) that shows the height above a given pressure level, based on standard pressure lapse rate of 1000’ per inch of mercury. 
    • A stack of sealed aneroid wafers expand and contract with changes in atmospheric pressure received from the static port. 
    • A mechanical linkage between the aneroid and the display translates the sensed pressure to an altitude indication. 
    • An altimeter setting knob (on a “sensitive altimeter”, which are most aircraft altimeters) allows the pilot to adjust the current pressure to the current altimeter setting published locally (available from ATIS, METAR or ATC). 
    • The pressure setting is displayed in the “Kollsman Window” in mb and/or inches of mercury (Hg) 
    • In the US, when operating below 18,000’ MSL regularly set the altimeter to a station within 100 NM. Above 18,000’ MSL, the altimeter should be set to the standard sea level pressure of 29.92” Hg, and operate in Flight Levels (FL). 
    • “High to Low – Watch out below!”. Use caution when flying from high pressure to low pressure areas. If altimeter setting is not updated, altitude will indicate higher, causing the pilot to fly lower than desired. Flying from hot to cold areas results in the same error.
  • Types of Altitudes
    
    • Indicated altitude – Uncorrected altitude indicated on the dial when set to local pressure setting (QNH). 
    • Pressure altitude – Altitude above the standard 29.92. Hg plane. (QNE). Used when flying above the transition altitude (18,000’ in the US) 
    • Density altitude – Pressure alt. corrected for nonstandard temperature. Used for performance calculations. 
    • True altitude – Actual altitude above Mean Sea Level (MSL). 
    • Absolute altitude – Height above surface (QFE or AGL).
  • Vertical Speed Indicator (VSI)
    
    • Indicates rate-of-climb in fpm (accurate after a 6-9 sec. lag), and rate trend (immediately with rate change). 
    • A diaphragm inside the instrument is connected directly to the static source. 
    • The area outside the diaphragm also receives static pressure, but via a calibrated leak (a restricted orifice). 
    • This configuration essentially responds to static pressure change over time. 
    • As the diaphragm expands or contracts, a mechanical linkage moves the pointer needle to display the current rate of climb to the pilot. 
    • Instantaneous VSI (IVSI) solves the lag issue with the addition of vertical accelerometers
  • Airspeed Indicator (ASI)
    
    • The airspeed indicator measures the difference between impact (ram) air pressure from the pitot tube and ambient pressure from the static port. The result pressure is called dynamic pressure and corresponds to airspeed. 
      
      • Dynamic Pressure (airspeed) = Impact Pressure – Static pressure. 
    • A diaphragm in the instrument receives ram pressure from the pitot tube. The area outside the diaphragm is sealed and connected to the static port. A mechanical linkage converts the expansion and contraction of the diaphragm to airspeed shown on the display dial.
  • Types of Speeds
    
    • Indicated airspeed (IAS) – indicated on the airspeed indicator 
    • Calibrated airspeed (CAS) – IAS corrected for instrument & position errors. 
    • Equivalent airspeed (EAS) – CAS corrected for compressibility error. 
    • True airspeed (TAS) – Actual speed through the air. EAS corrected for nonstandard temperature and pressure 
    • Mach number – The ratio of TAS to the local speed of sound. 
    • Ground speed – Actual speed over the ground. TAS corrected for wind conditions.
  • Airspeed Indicator Markings
    
    • White arc – Flap operating range. Starts at Vs0; ends at Vfe 
    • Green arc – Normal operating range. Starts at Vs1; ends at Vno 
    • Yellow arc – Caution range. Fly only in smooth air and only with caution. 
    • Red line – Vne
  • V-SPEEDS 
    
    • Va – Design maneuvering speed 
    • Vs – Stall speed, clean config.
    • Vs0 – Stall speed landing config. 
    • Vs1 – Stall speed specific config. 
    • Vfe – Max flap extended speed. 
    • Vno – Max structural cruise speed 
    • Vne – Never Exceed Speed 
    • Vx – Best angle of climb 
    • Vy – Best rate of climb
  • Static Port Blockage
    
    • Airspeed indicator – Indicates correctly only at the blockage altitude. 
      
      • Higher altitudes → airspeed indicates lower than it should. 
      • Lower altitudes → Indicates higher than it should. 
    • Altimeter – will freeze on the altitude where it was blocked. 
    • VSI – freezes on zero. 
      
      • After verifying a blockage in the static port, you should use an alternate static source or break the VSI window (in which case, expect reverse VSI information). 
    • When using the alternate static source (a lower static pressure is measured):
      
      • Airspeed indicator – indicate a faster speed than it should. 
      • Altimeter – indicate higher than it should.
      • VSI – momentarily show a climb.
  • Pitot Tube Blockage
    
    • The only instrument affected is the airspeed indicator. 
    • Ram air inlet clogged and drain hole open? Airspeed drops to zero. 
    • Both air inlet and drain hole are clogged? The airspeed indicator will act as an altimeter, and will no longer be reliable. 
    • When suspecting a pitot blockage, consider the use of pitot heat to melt ice that may have formed in or on the pitot tube.
• General Instrument Taxi Check
  
  • Airspeed – 0 KIAS. 
  • Turn coordinator – ball centered and wings level when not turning. On turns: shows turn in correct direction, ball goes to opposite direction of the turn. 
  • Attitude – Correct pitch attitude and bank angle ±°5 within 5 minutes of engine start (if vacuum). 
  • Heading indicator – Set and shows correct headings. 
  • Altimeter – Set to local altimeter settings or to airport elevation (§91.121). Shows surveyed elevation ±75 ft (AIM 7-2-3). 
  • VSI – 0 fpm. 
  • Magnetic compass – swings freely, full of fluid, shows known headings and deviation card is installed. Marker beacons – Tested. 
  • NAV & Comm – Set. 
  • GPS – Checked and set. 
  • EFIS cockpits – Check PFD/MFD/EICAS for ‘X’s, messages, warnings and removed symbols.
• Magnetic Compass Errors and Limitations – D.V M.O.N.A
  
  • D- Deviation: error caused by electro-magnetic fields generated by the aircrafts electrical system and wiring. Mitigated with Deviation card
  • V- Variation: angular difference between True and Magnetic North
  • M- Magnetic dip: closer aircraft comes to North Pole, the less reliable it becomes
  • O- Oscillation: due to turbulence
  • N- North/south turn errors – Northern hemisphere: UNOS Undershoot North/ Overshoot South 
  • A- Acceleration errors – Northern hemisphere: ANDS Accelerate North/ Decelerate South
• Electronic Flight Instruments
  
  • Attitude Heading Reference Systems (AHRS) – Provides more accurate and reliable attitude and heading data than traditional separate gyro systems. The first AHRS units were very expensive and relied on laser gyros and flux valves. Today they are based on solid state technologies (no moving parts) and are cheaper, smaller and easier to maintain. 
  • Air Data Computers (ADC) – replaces the mechanical pitot-static instruments. The ADC receives inputs from the pitot, static and outside temperature ports and computes airspeed, true airspeed, vertical speed and altitude. 
  • Flight director – computes and displays command bars over the attitude indicator to assist the pilot in flying selected heading, course or vertical speed. 
  • Flight Management System (FMS) – Receives inputs from various sensors and provides guidance to the autopilot and flight director throughout the flight. The FMS also automatically monitors and selects the most appropriate navigation source for accurate positioning. (GPS, VOR/DME, INS etc.) 
  • Electronic Flight Instrument Systems (EFIS) – AKA “Glass cockpit”. 
  • Primary Flight Displays (PFD) – Displays flight data such as attitude, altitude, airspeed, VSI and heading as well as rate tapes. 
  • Multi-Function Displays (MFD) – Displays a variety of information such as moving maps, aircraft system status, weather and traffic. It may also be used as a backup for other displays, such as the PFD or EICAS.

Minimum Equipment Required for Flight (§91.205)

• For VFR day: A T.O.M.A.T.O F.L.A.M.E.S – 
  
  • A – Altimeter 
  • T – Tachometer for each engine
  • O – Oil temperature indicator for each engine
  • M – Manifold pressure gauge for each altitude engine
  • A – Airspeed indicator
  • T – Temperature gauge for each liquid cooled engine
  • O – Oil pressure gauge for each engine
  • F – Fuel quantity gauge for each tank
  • L – Landing gear position lights (if retractable gear)
  • A – Anticollision lights (for aircraft certified after March 11, 1996
  • M – Magnetic direction indicator (magnetic compass)
  • E – ELT, if required by §91.207
  • S – Safety belt / shoulder harness
• For VFR Night: All VFR Day Equipment + FLAPS
  
  • F – Fuses (spare set)
  • L – Landing light (if for hire)
  • A – Anticollision lights
  • P – Position lights (navigation lights)
  • S – Source of electrical power (i.e., battery)
• For IFR day: all VFR day equipment + GRABCARD; For IFR night: all VFR day + VFR night + GRABCARD 
  
  • G – Generator / alternator
  • R – Radios. Two-way radio communication & navigational equipment suitable for the route to be flown
  • A – Altimeter (sensitive, adjustable for barometric pressure) 
  • B – Ball (slip-skid indicator)
  • C – Clock. Shows hours, minutes and seconds with sweep-second pointer or digital representation. Installed as part of aircraft equipment
  • A – Attitude indicator
  • R – Rate-of-turn indicator 
  • D – Directional gyro (heading indicator)

Radio Navigation

• Distance Measuring Equipment (DME)
  
  • 962-1213 MHz (UHF).
  • Normally tuned automatically with a paired VHF station (VOR/LOC).
  • The Airborne DME unit transmits an interrogation signal.
  • The ground DME facility receives and replies to the interrogation. 
  • Airborne unit calculates the slant range distance to the station based on the reply time.
  • Due to slant range error, when flying overhead the station, DME indication is not “0”. 
  • Slant range error is negligible at 1 NM from the DME station per every 1000ft. For example, at 5000 ft, slant range error is negligible when further than 5 NM of the station.
• Non-Directional Beacon (NDB)
  
  • Operates at the 190-535 kHz range (can receive and point towards commercial radio AM station at 550 -1650 kHz). 
  • Low to medium frequency band. 
  • ADF (Automatic Direction Finder) in aircraft points towards the NDB station. 
  • Magnetic Bearing = Magnetic Heading + Relative Bearing
    
    • ADF needle gives Relative Bearing, compass gives Magnetic Heading, Magnetic Bearing is what you need to fly to reach the station
  • Minutes to Station = Time in Seconds / Degrees of Bearing Change 
  • Nautical Miles to the Station = TAS (kt) x Minutes to Station
    
    •  
  • Compass Locator: A low-powered NDB transmitter (at least 25 Watts and 15NM range) installed at the OM or the MM on some ILS approaches.
    
    •  
• VOR
  
  •  
  • 108.0 to 117.95 MHz, excluding 108.10-111.95 with odd tenths (reserved for LOC frequencies). 
  • If collocated with DME, then VOR/DME provides both azimuth (magnetic heading) and distance information
  • If collocated with military Tactical Air Navigation (TACAN) unit, then resultant “VORTAC” provides both azimuth and distance information
  • Full scale deflection: 10º
  • Standard service volumes (SSV) do not apply to published routes. You can find SSV’s in your AF/D. All heights are in AGL
  • Pilot must verify correct and usable VOR station with morse ID before using it. 
  • The VOR MON (VOR Minimum Operational Network) program ensures that as old VORs are decommissioned, a MON airport (i.e., equipped with legacy ILS or VOR approach) is available within 100 NM regardless of aircraft position in the CONUS
  • Limitations
    
    • Cone of confusion 
    • Reverse sensing (if used incorrectly) 
    • Requires line-of-sight between aircraft and station
  • VOR Receiver Checks (§91.171)
    
    • Perform every 30 calendar days 
      
      • VOT ±4º (180 TO or 360 FROM): check A/FD to see if airport has one
      • Repair Station ±4º 
      • VOR ground checkpoint ±4º: look for signs located near taxiway/ramp/runup area. Follow instructions on sign
      • VOR airborne checkpoint ±6º (within)
      • Dual VOR cross-check ±4º (against one another): tune both to same VOR facility, center the needles of each VOR receiver with a “TO” indication, note indicated bearings
      • Above a prominent ground landmark on a selected radial at least 20 NM from a VOR, flying at a “reasonable low altitude” ±6º  (within), notable landmark can be found on the chart supplement
    • VOR Check sign-off (§91.171) D.E.P.S 
      
      • D – Date 
      • E – Error (bearing error) 
      • P – Place 
      • S – Signature
• Area Navigation (RNAV)
  
  • Allows navigation on any desired path without the need to overfly ground-based facilities. 
  • Types: 
    
    • Global Navigation Satellite System (GNSS): general term describing any satellite constellation that provides positioning, navigation, and timing (PNT) data. Examples include: GPS (US), Galileo (EU), GLONASS (Russia), BeiDou (China) 
    • VOR/DME RNAV 
    • DME/DME RNAV 
    • Inertial Reference Unit / System (IRU/ IRS) 
  • RNAV VNAV – Vertical NAVigation guidance. 
  • BARO-VNAV – An RNAV system that uses the barometric altitude to compute vertical guidance for the pilot. 
  • Published RNAV routes include Q (FL180 to FL450) and T (1,200 AGL to 18,000 MSL) routes and are designated RNAV 2 unless charted otherwise. RNAV 1 for SIDs and STARs (RNAV 1: 1NM accuracy 95% of the time. RNAV 1: 2NM accuracy 95% of the time)
  • Magnetic Reference Bearing (MRB) – the published bearing between two waypoints on an RNAV route: calculated by applying magnetic variation at the waypoint to the calculated true course between two waypoints. Enhances situational awareness by indicating a reference bearing (no-wind heading) that a pilot should see on the compass/HSI/RMI etc. when turning prior to/over a waypoint enroute to another waypoint
• Required Navigation Performance (RNP)
  
  • RNP is: 
    
    • A statement of navigation equipment and service performance. 
    • RNAV with added requirement for onboard performance monitoring and alerting (OBPMA) 
  • All RNAV approaches are RNP approaches 
    
    • Most US RNP approaches are titled “RNAV (GPS)”. 
    • US Approaches with “RNAV (RNP)” in the title are “AR” (Authorization Required) approaches, which require special FAA approval for the crew, aircraft and operation. 
    • In other countries, all RNP approaches may have “RNP” in the title, even those that do not require special authorization. 
  • RNP approach minimas and equipment: 
    
    • GLS (GBAS Landing System) DA minimas using GBAS (Ground Based Augmentation System, formerly LAAS – Local Area Augmentation System, may see this in documentation still but the two are synonymous) 
      
      • Couple ground-based GPS receiver stations located around an airport with space-based GPS signals. They are available at a limited number of airports including Newark (EWR) and Houston (IAH)
    • LP MDA or LPV DA minimas require RNP achieved by WAAS. 
    • LNAV / VNAV DA achieved by VNAV-approved WAAS, or BARO-VNAV systems. 
    • LNAV MDA – achieved by a basic, unaugmented IFR-approved GPS

Global Positioning System (GPS)

• GPS is a Global Navigation Satellite System (GNSS) operated by the United States. 
• The constellation consists of a minimum of 24 satellites (with some spares) orbiting above the earth at 10,900 NM. The system is designed so that at least 5 satellites are in view at any given location on earth. 
• The Aircraft’s GPS receiver calculates the distance to a GPS satellite based on the time lapse since the broadcast timestamp (obtained from an atomic clock onboard the satellite) and the time it received the signal. 
• Using only one satellite, the aircraft could virtually be on any point on a sphere surrounding the satellite, with the calculated distance (“pseudo-range”) as the sphere’s radius. 
• The GPS receiver uses the intersection of spheres, from multiple satellites, to calculate the aircraft’s geographical position. Course and speed data are computed from aircraft position changes. 
• At least 3 satellites are required for 2D position. (latitude and longitude); at least 4 satellites are required for 3D position. (latitude, longitude and altitude). 
• Receiver Autonomous Integrity Monitoring (RAIM) is a function of GPS receivers that monitors the integrity of the satellite signals. 
  
  • RAIM (fault detection) requires a minimum of 5 satellites, or, 4 satellites + an altimeter input (baro-aided RAIM) 
  • To eliminate a corrupt satellite (fault exclusion), RAIM needs an additional satellite (total of 6 or 5 + baro-aid) 
• A database loaded into the receiver unit contains navigational data such as: airports, navaids, routes, waypoints and instrument procedures. 
• Airborne GPS units use great-circle navigation: shortest distance between points on a globe is not a straight line – its an arc called a great circle (i.e. LA to Dubai goes over north pole. A great circle is a circle that divides a sphere in two). 
• GPS CDI deflection shows distance, unlike a VOR’s CDI, which presents an angular distance off course in degrees. 
• Pilots may substitute IFR-certified GPS receivers for DME and ADF avionics for all operations except NDB approaches without a GPS overlay (“or GPS” in title). GPS can be used in lieu of DME and ADF on all localizer-type approaches as well as VOR/DME approaches, including when charted NDB or DME transmitters are temporarily out of service
• Check GPS NOTAMS before the flight and use RAIM prediction if available on your receiver.
• GPS Augmentation systems, or Differential GPS (DGPS) – Improves the accuracy of GPS by measuring errors received by reference stations at known geographical locations and then broadcasting those errors to supported GPS receivers. 
  
  • Satellite Based Augmentation System (SBAS) 
    
    • Wide Area Augmentation System (WAAS) in the US; EGNOS in Europe. 
    • Ground stations (Wide-area Reference Stations and Wide-area Master Stations) measure GPS errors and produce correction signals. These corrections are broadcasted back to the satellite segment from which they are bounced back to aircraft GPS WAAS receivers to improve accuracy, integrity and availability monitoring for GPS navigation. 
    • Covers a wide area. 
    • Facilitates APV approaches such as LPV and LNAV/VNAV and LP approaches. 
  • Ground Based Augmentation System (GBAS) 
    
    • Formerly named Local Area Augmentation System (LAAS) in the US. Now replaced with the ICAO term “GBAS.” 
    • Errors are broadcasted via VHF to GBAS-enabled GPS receivers. 
    • GBAS is more accurate than WAAS but covers a much smaller geographical area. 
    • Allows for category I and above approaches to GLS DA minima.

Understanding the Difference Between RNAV, GNSS, GPS, PBN, and RNP

• Area Navigation (RNAV) 
  
  • RNAV is a system that enables navigation between any two points without the need to overfly ground-based stations. 
• GNSS is a broad term for satellite-based RNAV systems. 
  
  • GPS is the GNSS operated by the USA. Other examples are GLONASS by Russia and Galileo by the EU. 
• Performance Based Navigation (PBN) 
  
  • PBN is a general basis for navigation equipment standards, in terms of accuracy, integrity, continuity, availability and functionality for specific operation contexts (e.g., final approach, enroute, missed approach). 
• Required Navigation Performance (RNP) 
  
  • RNP is a specific statement of PBN for the flight segment and aircraft capability. 
  • RNP is also defined as RNAV + navigation monitoring and alerting functionality. 
    
    • Receiver Autonomous Integrity Monitoring (RAIM) or built-in monitoring in WAAS provide this capability. 
  • En route – RNP 2.0 (2 NM accuracy 95% of the flight time) Terminal & Departure – RNP 1.0 (1 NM accuracy 95% of the flight time) 
  • Final Approach – RNP 0.3 (0.3 NM accuracy 95% of flight time) 
  • Advanced RNP (A-RNP) – is a higher RNP standard mandatory for RNP AR, that require capability for: (AIM 1-2-2) 
    
    • Radius-to-Fix (RF) legs 
    • Scaleable RNP (meaning RNP accuracy can change value), and 
    • Parallel offset flight path generation

Instrument Landing System (ILS)

• LOCALIZER (AIM 1-1-9) 
  
  • Provides lateral course guidance. 
  • Frequencies: 108.1 – 111.95 MHz with odd tenths only. 90 and 150 Hz signals are carried over the VHF frequency and used by the receiver interpret the aircraft’s lateral position. 
  • Width: Between 3°-6° so that the width at the threshold would be 700 feet. Usually 5° total width. (2.5 full deflection to each side, 4 times more sensitive than a VOR). 
  • Coverage range: 35° to each side of the centerline for the first 10NM and 10° up to 18NM from the antenna and up to an altitude of 4500′.
  •  
• GLIDE SLOPE (AIM 1-1-9) 
  
  • Provides vertical course guidance. 
  • Frequencies: 329.3 to 335 MHz (UHF) ,automatically tuned with the localizer. Vertical position is interpreted by the intensity of 90 and 150 Hz signals carried over the UHF frequency and directed above and under the slope. 
  • Width: 1.4º (full deflection is 0.7º either direction). 
  • Range: typically up to 10 NM. 
  • Slope: typically 3°. 
  • Errors: False glide slope above normal glide slope
  •  
• MARKER BEACONS 
  
  • Provide range information over specific points along the approach. Transmits at 75 MHz. 
  • Outer marker: 4-7 miles out. Indicate the position at which the aircraft should intercept the GS at the appropriate interception altitude ±50ft. BLUE. “- – -“ 
  • Middle marker: ~3500ft from the runway. Indicates the approximate point where the GS meets the decision height. Usually 200ft above the touchdown zone elevation. AMBER. “. – . -” 
  • Inner marker: between the MM and runway threshold. Indicates the point where the glide slope meets the DH on a CAT II ILS approach. WHITE. “. . .” 
  • Back course marker: Indicates the FAF on selected back course approaches. Not a part of the ILS approach. WHITE. “.. ..”
  •  
• APPROACH LIGHT SYSTEMS (ALS) (AIM 2-1-1) 
  
  • Provides basic visible means to transition between instrument-guided flight into a visual approach. 
  • ALS extends from the landing threshold into the approach area up to: 
    
    • 2,400-3,000 feet for precision instrument runways, and 
    • 1,400-1,500 feet for non-precision instrument runways. 
  • May include sequenced flashing lights, which appear to the pilot as a ball of light traveling towards the runway at twice a second (AKA “The Rabbit”). 
  • The visible parts of the ALS configuration can help the pilot estimate flight visibility.
  •  

Attitude Instrument Flying

• Basic attitude instrument flying skills: Cross Check, Instrument Interpretation, Aircraft Control
• Common Errors: Fixation, Omission, Emphasis
• Control & Performance Method – Divides the cockpit panel by control instruments and performance instruments. First, set the power and attitude, then monitor the performance and make adjustments. 
  
  • Control instruments 
    
    • Power – Tachometer, Manifold pressure, EPR, N1, etc. 
    • Attitude – Attitude Indicator 
  • Performance Instruments 
    
    • Pitch: altimeter, airspeed and VSI 
    • Bank: Heading Indicator, Turn Coordinator, and magnetic compass 
  • Primary & Supporting Method – Divides the cockpit panel by Pitch, Bank, and Power instruments. 
    
    • Pitch instruments: Attitude Indicator, Altimeter, Airspeed Ind., and VSI. 
    • Bank instruments: Attitude ind., Heading ind., Mag. Compass, and Turn Coordinator. 
    • Power instruments: Airspeed, Tachometer, Manifold pressure 
    • For a specific maneuver, primary instruments provide the most essential information for pitch, bank and power while supporting Instruments back up and supplement the information presented by the primary instruments.
    • Example, for a constant rate climb with a standard rate turn – 
      
      • Primary: Pitch – VSI; Bank – Turn Coordinator; Power – RPM / MP
      • Secondary: Pitch – ASI; attitude, Bank – AI, HI, Mag. Compass; Power – ASI

MANDATORY REPORTS UNDER IFR 

• M.A.R.V.E.L.O.U.S. V.F.R. C.500 – (AIM 5-3-3, §91.183, §91.187 ) 
  
  • Missed approach 
  • Airspeed ±10 kts / 5% change of filed TAS (whichever is greater) 
  • Reaching a holding fix (report time & altitude) 
  • VFR on top when an altitude change will be made. 
  • ETA changed ±2 min, or ±3 min in North Atlantic (NAT) * 
  • Leaving a holding fix/point 
  • Outer marker (or fix used in lieu of it) * 
  • Un-forecasted weather 
  • Safety of flight (any other information related to safety of flight) 
  • Vacating an altitude/FL 
  • Final Approach fix * 
  • Radio/Nav/approach equipment failure (§91.187) 
  • Compulsory reporting points ▲ * (§91.183)
  • 500 – unable climb/descent 500 fpm 

* Required only in non-radar environments (including ATC radar failure)

POSITION REPORT ITEMS REQUIRED IN NON-RADAR ENVIRONMENT (§91.183, AIM 5-3-2) 

• Aircraft ID. 
• Position. 
• Time. 
• Altitude. 
• Type of flight plan (except when communicating with ARTCC / Approach control). 
• ETA and name of next reporting fix. 
• Name only of the next succeeding point along the route of flight. 
• Any pertinent remarks. 

Holding Patterns (AIM 5-3-8)

• ATC may assign holding instructions to delay or separate traffic in the air for reasons such as weather or airport closures. Non-charted holding clearance items: 
  
  • Direction of hold from the fix (e.g., N, W, S, NE) 
  • Holding Fix 
  • Radial, course, airway, or route on which to hold. 
  • Leg length in miles (if DME or RNAV) or minutes otherwise. 
  • Direction of turns (if left). Otherwise, right turns are standard. 
  • Expect Further Clearance (EFC) time 
• Charted holding clearance items 
  
  • Holding Fix 
  • Direction of hold from fix (e.g., N, W, S, E) 
  • EFC 
• Start speed reduction 3 minutes before reaching the hold fix. 
• Actions at hold fix and each turn point 5 Ts 
  
  • Turn 
  • Time 
  • Twist 
  • Throttle 
  • Talk 
• MAKE ALL HOLD TURNS: 
  
  • 3º per second, or 
  • 30º bank angle, or 
  • 25º bank angle if using a Flight Director system

*Whichever uses the least bank angle

• Holding Pattern Timing
  
  • Start timing outbound abeam/over the fix (whichever is later). Or, if the abeam point cannot be determined, start the time at the completion of the outbound turn. 
  • Adjust the outbound leg so the inbound leg takes: 
    
    • At or below 14,000’ MSL – 1 minute 
    • Above 14,000’ MSL – 1.5 minutes 
    • DME/GPS holds – fly the outbound leg to the specified distance from the fix/waypoint.
• HOLDING SPEEDS 
  
  • May be restricted to 175 kts on some instrument approach procedures
  •  
• HOLDING ENTRY 
  
  • Direct – Upon crossing the fix turn to follow the holding pattern 
  • Parallel – Upon crossing the fix, turn to a heading parallel to the holding course outbound for 1 minute. Then turn into the hold pattern to intercept the inbound course. 
  • Teardrop – Upon crossing the fix, turn outbound to a heading 30º into the pattern. Fly it for 1 minute, then turn in the direction of the hold turns to intercept the inbound course. 
  • AT THE HOLD FIX, REPORT TO ATC: “ Over at ”
  •  

LOST COMMUNICATIONS PROCEDURE (§91.185)

• Altitude to fly
  
  • Fly the highest of: M.E.A
    
    • M – Minimum altitude prescribed for IFR 
    • E – Expected (as in: “Expect 5000 10 min after departure”) 
    • A – Assigned. Last altitude assigned by ATC.
• Route to Fly
  
  • Select the Route by this order: A.V.E.F
    
    • A – Assigned route, if none: 
    • V – Vectored (fly to fix/route/airway last vectored to), if none: 
    • E – Last Expected route by ATC, if none: 
    • F – Filed route

Leaving the Clearance Limit (§91.185)

• Is the clearance limit a fix from which an approach begins?
  
  • Yes: Start descent and approach as close as possible to the EFC (expect further clearance time), or ETA (if no EFC given)
  • No: At EFC or clearance limit (if no EFC given), proceed to a fix from which an approach begins and start the approach

Procedure Turn (§91.175, AIM 5-4-9)

• A PT is a maneuver that enables: 
  
  • Course reversal. 
  • A descent from IAF (Initial Approach Fix) 
  • Inbound course interception. 
• Max speed – 200 kts. 
• Remain within the charted distance (“Remain within _ NM” note), typically 10 NM, and comply with published altitudes for obstacle clearance. 
• The shape of the maneuver is mandatory if a teardrop or holding-in-lieu of a PT is published. Otherwise, only the direction of the turn is mandatory. 
• A teardrop procedure may be published in lieu of a PT. In that case: 
  
  • No IF (intermediate fix) published? Intermediate segment begins 10 miles prior to the final approach fix. 
  • Nav facility located on the airport? Final approach starts at completion of the teardrop turn. However, the final approach segment begins on the final approach course 10 miles from the facility. 
• A PT or hold-in-lieu-of-PT is mandatory when depicted on the approach chart. However, it is not permitted when: No PT depicted on the chart, radar vectors to final or when conducting a timed approach from a holding fix.
• DO NOT FLY A PROCEDURE TURN WHEN: S.H.A.R.P.T.T – 
  
  • Straight-in approach clearance. 
  • Holding in lieu of a procedure turn. 
  • DME Arc. 
  • Radar vectors to final. 
  • No PT depicted on chart. 
  • Timed approach from a hold fix. 
  • Teardrop course reversal. 

Instrument approach types 

• Precision 
  
  • Lateral + vertical guidance to a DA. 
    
    • ILS – Instrument Landing System 
    • MLS – Microwave Landing System 
    • PAR – Precision Approach Radar 
    • GLS – GBAS Landing System 
    • TLS – Transponder Landing System 
• Non-Precision lateral guidance only. Flown to MDA. 
  
  • VOR 
  • NDB 
  • RNAV / RNP to LNAV or LP Minima 
  • LOC – Localizer 
  • LDA – Localizer-type Directional Aid. Identical to a LOC but not aligned with the runway. 
  • SDF – Simplified Directional Facility. Similar to a LOC with 6º or 12º width. May be aligned or not with the runway. 
  • ASR – Approach Surveillance Radar 
• Approach with Vertical Guidance (APV). A precision-like approach, flown to a DA with lateral + vertical guidance, but does not meet precision approach standards.
  
  • RNAV / GNSS (i.e, LNAV/VNAV and LPV minima) 
  • LDA with Glide Slope

Approach Clearances

• When can you descend to the next instrument approach segment? 
  
  • When cleared for the approach and established on a segment of a published approach or route. (AIM 5-5-4) 
• Contact approach (AIM 5-5-3) 
  
  • Requested by the pilot in lieu of an instrument approach. (Cannot be initiated by ATC) 
  • Requires at least 1SM ground visibility and remain clear of clouds. 
  • Only at airports with approved instrument approach procedures. 
  • Pilot assumes responsibility for obstruction clearance. 
• Visual approach (AIM 5-5-11) 
  
  • Initiated by either ATC or the pilot. 
  • Requires at least 1000’ ceiling and 3SM visibility. (IFR under VMC) 
  • Pilot must have either the airport or the traffic to follow in sight. 
  • Pilot is responsible for visual separation from traffic to follow.

Missed Approach (AIM 5-5-5) 

• Execute a missed approach when: 
  
  • Arrival at MAP or DH with insufficient visual reference to runway environment. 
  • A safe approach is not possible. 
  • Instructed to do so by ATC.

When can you descend below MDA / DA? (§91.175) 

1. The aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers. 
2. The flight visibility (or the enhanced flight visibility, if equipped) is not less than the visibility prescribed in the standard instrument approach being used. 
3. At least one of the following visual references for the intended runway is distinctly visible and identifiable to the pilot: (except for CAT II & III approaches) 
   
   1. The approach light system, except that the pilot may not descend below 100 feet above the touchdown zone elevation using the approach lights as a reference unless the red terminating bars or the red side row bars are also distinctly visible and identifiable. 
   2. The threshold. 
   3. The threshold markings. 
   4. The threshold lights. 
   5. The runway end identifier lights. 
   6. The visual glideslope indicator. 
   7. The touchdown zone or touchdown zone markings. 
   8. The touchdown zone lights. 
   9. The runway or runway markings. 
   10. The runway lights.

VISUAL DESCENT POINT (VDP) (AIM 5-4-5) 

• A defined point on the final approach course of a non-precision straight-in approach procedure from which normal descent from the MDA to the runway touchdown point may begin, provided adequate visual reference is established. 
• Identified by a ‘V’ symbol on the descent profile.
• If not equipped to identify the VDP, fly the approach as if no VDP was published. 
• Do not descend below the MDA prior to reaching the VDP. 
• Calculate VDP, when not published: 
  
  • By distance: VDP (in NM from threshold) = MDH / 300
    
    • Example: Given MDH is 600 ft, how far is the VDP from the threshold? VDP = 600 / 300 = 2 NM Start the descent 2 NM from the threshold. 
  • By time: MDH / 10 = seconds to subtract from time between FAF and MAP 
    
    • Example: Given MDH is 500 ft, FAF to MAP is 4:00, when would you be over the VDP and start the descent from MDA/H? 500 / 10 = 50 seconds. 4:00 – 0:50 = 3:10 Start the descent at 3:10 (time from FAF)

VISUAL DESCENT ANGLE (VDA) (AIM 5-4-5) 

• A computed glide path from the FAF to the runway’s TCH published for non-precision approaches. Typically 3º
• FAA policy is to publish a VDA/TCH on all non-precision approaches except those published in conjunction with vertically guided minimums (i.e., ILS or LOC RWY XX) or no FAF procedures without a stepdown fix (i.e., on-airport VOR or NDB). A VDA does not guarantee obstacle protection below the MDA in the visual segment. The presence of a VDA does not change any non-precision approach requirements. 
• VDAs are advisory only, pilots must still comply with all published altitudes on the procedure.

Rate of Descent for a 3º Glide Path 

• VS (fpm) = Ground Speed X (10 / 2), or VS (fpm) = Ground Speed X 5 
  
  • Example: 120 kts X (10 / 2) = 120 kts X 5 = 600 fpm 
• How Far to Start a Descent for a 3º Glide Path? TOD = Altitude to lose (ft) / 300 
  
  • Example, on approach 800 ft to lose MDA to TCH: 800/300 = 2.67 NM Start descent 2.67 NM from the runway threshold. 
  • Example Cruising at FL350, ATC: “…cross LGA VOR at FL240”: Altitude to lose = 35,000 – 24,000 = 11,000 ft 11000/300 = 36.67 NM Start descent 36.67 NM from LGA VOR

Other Glide Path Angles 

• Descent gradient (%) = tan(descent angle) X 100
  
  •  
  • VS (fpm) = Groundspeed X Descent Gradient (%) 
  • TOD = Altitude to lose / (glidepath angle *100) 
    
    • Example At FL350, ATC:”…cross LGA OR at FL240”, pilot elects a steep 4º slope, 380 kts GS: VS = 380 X 7 = 2660 fpm TOD = 11000 / 400 = 27.5 NM Start the descent 27.5NM from LGA at 2800 fpm

Airspace

• Victor Airways
• Class A (AIM 3-2-2) 
  
  • Controlled airspace from 18,000′ MSL to FL600 within the 48 contiguous states and Alaska. Includes the airspace within 12 NM of the shoreline as well as designated international airspace beyond the 12 NM distance. 
  • IFR only unless otherwise authorized. 
• Class B (AIM 3-2-3, §91.126) 
  
  • Controlled airspace surrounding the nation’s busiest airports. 
  • Usually extends from the surface up to 10,000′ MSL. 
  • The shape of each class B is specifically tailored for its environment. 
  • Consist of a surface area and two or more layers (resembling an upside-down wedding cake). 
  • Requires two-way radio communications. 
  • ATC separates both VFR and IFR traffic. 
  • Requires ATC clearance to enter. VFR pilots must make sure they hear a clearance to “Enter Class B”. IFR pilots will typically already have this clearance as part of their ATC clearance picked up before or after takeoff. 
  • A Mode-C transponder and ADS-B Out equipment are required within a 30 NM radius (the “Mode-C Veil”). 
• Class C (AIM 3-2-4) 
  
  • Controlled airspace around towered airports with certain number of IFR operations or passenger volume. 
  • Typical inner area is a 5 NM radius surrounding its primary airport, extending up to 4,000′ above airport height. 
  • A 10 NM radius shelf area typically extends from no lower than 1,200′ up to 4,000′ above airport height. 
  • A non-charted outer area extends up to 20 NM from the primary airport.
  • ATC Provides VFR/ IFR traffic separation in the outer area if two-way radio communication is established and in the Class C airspace itself. 
  • Requires two-way radio communication, a Mode-C transponder and ADS-B Out equipment. 
• Class D (AIM 3-2-5) 
  
  • Controlled airspace extending from the surface to 2,500′ above airport height. 
  • Usually shaped as a cylinder with a 4 NM radius from the primary airport. 
  • Requires two-way radio communication. 
• Class E (AIM 3-2-6) 
  
  • Controlled airspace not designated as A, B, C, or D. 
  • May or may not be associated with an airport. 
  • Requires Mode-C transponder and ADS-B Out equipment at and above 10,000′ MSL within the 48 contiguous states and D.C, excluding at or below 2,500′ AGL. 
  • Requires ADS-B Out at and above 3,000′ MSL over the Gulf of Mexico from the U.S. coast out to 12 NM. 
  • Types of Class E: 
    
    • Surface area designated for an airport. 
    • Extension to a surface area of Class B, C, or D. 
    • Transition area. Class E beginning at 700′ or 1200′ AGL used to transition to/from a terminal or en-route environment. 
    • En-route domestic areas 
• Class G (AIM 3-3) 
  
  • Uncontrolled airspace. Class G airspace is generally any airspace that has not been designated as Class A, B, C, D, or E.

BASIC VFR WEATHER MINIMUMS (§91.155)

• Except as provided in §91.157 (SVFR), no person may operate an aircraft beneath the ceiling under VFR within the lateral boundaries of controlled airspace designated to the surface for an airport when the ceiling is less than 1,000 feet. 
• Except as provided in §91.157 (SVFR), no person may take off or land an aircraft, or enter the traffic pattern of an airport, under VFR, within the lateral boundaries of the surface areas of Class B, C, D, or E airspace designated for an airport: 
  
  • Unless ground visibility at the airport is at least 3 SM, or 
  • If ground visibility is not reported at that airport, unless flight visibility during takeoff or landing, or while operating in the traffic pattern is at least 3 SM. 
• For the purpose of this section, an aircraft operating at the base altitude of a Class E airspace area is considered to be within the airspace directly below that area.

Special Use Airspace

• Prohibited Areas (§91.133, AIM 3-4-2) 
  
  • Flight is prohibited unless permission is granted by the using or controlling agency, as appropriate. 
  • Prohibited airspace exists due to security or other reasons associated with the national welfare. 
    
    • Example: Prohibited airspace P-56A over the White House. 
• Restricted Areas (§91.133, AIM 3-4-3) 
  
  • Flight is not completely prohibited, but is subject to restrictions due to hazards to aircraft such as artillery firing, aerial gunnery, or guided missiles. 
  • No person may operate an aircraft within a restricted area contrary to the restrictions imposed, unless that person has the permission of the using or controlling agency. 
  • If the restricted airspace is not active and has been released to the controlling agency (FAA), ATC will allow the aircraft to operate in the restricted airspace without a specific clearance to do so. 
  • If the restricted airspace is active, and has not been released to the controlling agency (FAA), ATC will issue a clearance which will ensure the aircraft avoids the restricted airspace unless it is on an approved altitude reservation mission or has obtained its own permission to operate in the airspace and so informs the controlling agency. 
• Warning Areas (AIM 3-4-4) 
  
  • Extends 3 NM outward from the coast of the U.S. 
  • Contains activity that may be hazardous to aircraft. 
  • The purpose of warning areas is to warn nonparticipating aircraft of the potential hazard. 
  • May be located on domestic or international water, or both. 
• Military Operating Areas (MOA) (AIM 3-4-5) 
  
  • Established for the purpose of separating certain military training activities from IFR traffic.
  • When a MOA is in use, nonparticipating IFR aircraft may be cleared through it if IFR separation can be provided. Otherwise, ATC will reroute or restrict the traffic. 
  • Example activities in an MOA: air combat tactics, air intercepts, aerobatics, formation training, and low-altitude tactics. 
  • Pilots operating under VFR should exercise extreme caution when operating within an active MOA. Therefore, pilots should contact any FSS within 100 miles of the area to obtain accurate real-time information concerning the MOA hours of operation. Prior to entering an active MOA, pilots should contact the controlling agency for traffic advisories. 
• Alert Areas (AIM 3-4-6) 
  
  • Depicted on charts to inform pilots of high volume of pilot training or an unusual type of aerial activity. 
  • Pilots transitioning the area are equally responsible for collision avoidance. 
• Controlled Firing Areas (AIM 3-4-7) 
  
  • Contain activities that, if not conducted in a controlled environment, may be hazardous to nonparticipating aircraft. 
  • Activities are suspended immediately when a spotter aircraft, radar or ground lookout positions indicate an aircraft might be approaching the area. 
  • CFAs are not charted because they do not cause a nonparticipating aircraft to change its flight path.
• Military Training Routes (MTR) (AIM 3-5-2) 
  
  • IFR MTRs (IR) are typically above 1,500′ AGL, while VFR MTRs (VR) are below 1,500′ AGL. 
  • Generally, MTRs are established below 10,000 ft at speeds in excess of 250 knots. However, route segments may exist at higher altitudes. 
  • Route identification 
    
    • MTRs with no segments above 1,500′ AGL are identified by 4 digits; e.g., IR1206, VR1207. 
    • MTRs that include one or more segments above 1,500′ AGL are identified by three digits; e.g., IR206, VR207. 
• Air Defense Identification Zone (ADIZ) (AIM 5-6) 
  
  • An area of airspace over land or water, in which the ready identification, location, and control of all aircraft (except DoD and law enforcement aircraft) is required in the interest of national security. 
  • Requirements to operate within an ADIZ: 
    
    • An operable Transponder with altitude encoding. 
    • Two-way radio communication with the appropriate aeronautical facility. 
    • File an IFR or Defense VFR (DVFR) Flight Plan 
    • Depart within 5 minutes of flight plan’s estimated departure time (exempt in Alaska info facility exists for filing, file immediately after departure or when within range of an appropriate facility). 
• Temporary Flight Restrictions (TFR) (AIM 3-5-3) 
  
  • Defined in Flight Data Center (FDC) NOTAMs 
  • TFR NOTAMs begin with the phrase: “FLIGHT RESTRICTIONS.” 
  • Current TFRs are found at: www.tfr.faa.gov. 
  • Some reasons the FAA may establish a TFR: 
    
    • Protect persons or property in the air or on the surface from hazards by low flying aircraft. 
    • Provide a safe environment for disaster relief aircraft. 
    • Prevent an unsafe congestion of sightseeing aircraft around an event of high public interest. 
    • Protect declared national disasters for humanitarian reasons in the State of Hawaii. 
    • Protect the President, Vice President, or other public figures. 
    • Provide a safe environment for space agency operations. 
• Special Flight Rules Area (SFRA) (AIM 3-5-7) 
  
  • An airspace of defined dimensions above land areas or territorial waters, where special air traffic rules have been established for. 
  • Each person operating in a SATR (Special Air Traffic Rules) or SFRA must adhere to the special air traffic rules in 14 CFR Part 93, unless otherwise authorized or required by ATC. 
    
    • Example: The Washington DC Metropolitan SFRA.

MAX AIRCRAFT AIRSPEEDS IN THE U.S. (§91.117)

• Mach 1.0 (speed of sound): above 10,000′ MSL. (§91.817) 
• 250 kts: below 10,000′ MSL. 
• 200 kts: under Class B, or within a VFR corridor through Class B. 
• 200 kts: at or below 2,500′ within 4 NM of the primary airport of a Class C or D airspace. 
• If the aircraft minimum safe airspeed for any particular operation is greater than the max speed prescribed above, the aircraft may be operated at that minimum speed.

Weather

• WEATHER INFORMATION SOURCES 
  
  • Flight Service Station (FSS) 
  • NOAA’s Aviation Weather Center Website https:// www.aviationweather.gov/ 
  • Flight planning websites such as www.1800wxbrief.com and www.fltplan.com 
  • EFB software (i.e., ForeFlight, Jeppesen FlightDeck Pro) 
  • Transcribed Weather Broadcast (TWEB) – Available in Alaska only. A recorded broadcast over selected L/MF and VOR facilities of weather information for the local area. 
  • Flight Information Services-Broadcast (FIS-B) – A ground information data link service, provided through the ADS-B service network over 978 UAT MHz. Provides aviation weather and aeronautical information on cockpit displays. Some information available on FIS-B: 
    
    • METAR, TAF, NEXRAD, AIRMET, SIGMETs and convective SIGMETs 
    • TFR, Special Use Airspace updates and NOTAMs (FDC and distant) 
    • PIREPs 
  • Automatic Terminal Information Service (ATIS) – A continuous broadcast of local airport weather and NOTAMs. Updated hourly, normally at 55 minutes passed the hour. Special updates issued outside the regular hourly cycle when needed. ATIS is published over the radio and, in locations with D-ATIS, via data link (ACARS). 
  • Automated Surface Observation System (ASOS) – Typically update hourly 
  • Automated Weather Observation System (AWOS) – Update every minute 
  • ATC – Center weather advisories are issued by ARTCC to alert pilots of existing or anticipated adverse weather conditions. ARTCC will also broadcast severe forecast alerts (AWW), convective SIGMETs and SIGMETs on all of its frequencies except for the emergency frequency (121.5 MHz). 
  • Onboard weather radar 
  • Onboard lightning detector 
  • XM Satellite weather service 
  • ACARS
• Weather Products
  
  • AIRMET (WA) 
    
    • An advisory of significant weather phenomena at lower intensities than those which require the issuance of SIGMETs. These conditions may affect all aircraft but are potentially hazardous to aircraft with limited capability. 
    • Valid for 6 hours. 
    • AIRMET (T) – describes moderate turbulence, sustained surface winds of 30 knots or greater, and/or non-convective low-level wind shear. 
    • AIRMET (Z) – describes moderate icing and provides freezing level heights.
    • AIRMET (S) – describes IFR conditions and/or extensive mountain obscurations. 
    • Graphical AIRMETs (AIRMET G) – found at www.aviationweather.gov
  • SIGMET (WS)
    
    • A non-scheduled inflight advisory with a maximum forecast period of 4 hours. Advises of non-convective weather potentially hazardous to all types of aircraft. A SIGMET is issued when the following is expected to occur: 
      
      • Severe icing not associated with thunderstorms 
      • Severe or extreme turbulence or Clear Air Turbulence (CAT) not associated with thunderstorms. 
      • Dust storms, sandstorms lowering surface visibility below 3 miles.
  • Convective SIGMET (WST) 
    
    • An inflight advisory of convective weather significant to the safety of all aircraft. 
    • Issued hourly at 55 minutes past the hour for the western (W), eastern (E) and central (C) USA. 
      
      • Not issued for Alaska or Hawaii. 
    • Valid for 2 hours. 
    • Contains either an observation and a forecast or only a forecast. 
    • Issued for any of the following: 
      
      • Severe thunderstorms due to: 
        
        • Surface winds greater or equal to 50 knots 
        • Hail at the surface greater than 3/4 inch in diameter 
      • Tornadoes 
      • Embedded thunderstorms of any intensity level 
      • A line of thunderstorms at least 60 miles long with thunderstorms affecting at least 40% of its length 
      • Thunderstorms producing heavy or greater precipitation (VIP level 4) affecting at least 40% of an area of at least 3000 square miles. 
    • Any Convective SIGMET implies severe or greater turbulence, severe icing, and low-level wind shear. 
  • International SIGMET 
    
    • Issued outside the Contiguous USA and follow ICAO coding standards
    • In the US, international SIGMETs are issued for areas that include Alaska, Hawaii, portions of the Atlantic and Pacific Oceans, and the Gulf of Mexico. 
    • Criteria for international SIGMETs: 
      
      • Thunderstorms occurring in lines, embedded in clouds, or in large areas producing tornadoes or large hail. 
      • Tropical cyclones 
      • Severe icing 
      • Severe or extreme turbulence 
      • Dust storms and sandstorms lowering surface visibility to less than 3 miles 
      • Volcanic ash 
  • PIREP (UA) & Urgent PIREP (UUA) – pilot weather reports. 
  • METAR – Aviation routine weather show surface weather observations in a standard international format. Scheduled METARs are published every hour. Non-scheduled METARS (SPECI) are issued when there is a significant change in one or more reported element since the last scheduled METAR. 
  • TAF – Terminal Aerodrome Forecast. Weather forecast for 5SM radius area around the station. Issued 4 times a day, every six hours and normally covers a 24 or 30 hour forecast period. TAF amendments (TAF AMD) supersede previous TAFs. 
  • Surface analysis chart –Generated from surface station reports. Shows pressure systems, isobars, fronts, airmass boundaries (e.g,: dry lines and outflow boundaries) and station information (e.g,: wind, temperature/dew point, sky coverage, and precipitation). Issued every 3 hours. (or every 6 hours in Hawaii and tropical and Oceanic regions). A Unified Surface Analysis Chart is produced every 6 hours and combines the analysis from the 4 centers (OPC, WPC, NHC and HFO) 
  • Radar summary chart (SD) – Depicts precipitation type, intensity, coverage, movement, echoes, and maximum tops. Issued hourly 
  • Wind & temp aloft forecasts (FB) – Issued 4 times daily for various altitudes and flight levels. Winds at altitude up to 1500’ AGL and temperatures at up to 2500’ AGL are not shown. Format: DDff±tt, where DD = wind direction; ff = wind speed; tt = temperature. Light and variable winds: 9900. Winds between 100-199 Kt are coded by adding 5 to the first digit of the wind direction. Above FL240 temperatures are negative and the minus sign (-) is omitted. Examples: 1312+05: winds 130 / 12 kt, 5°C. 7525-02: winds 250 / 125 kt, -2° C. 
  • Low level significant weather chart – Forecasts significant weather conditions for a 12 and 24 hour period from the surface to 400 mb level (24,000 ft). Issued 4 times a day. Depicts weather categories (IFR, MVFR and VFR), turbulence and freezing levels. 
  • Mid-level significant weather chart – Forecasts of significant weather at various altitudes and flight levels from 10,000’ MSL to FL450. Shows: thunderstorms, jet streams, tropopause height, tropical cyclones, moderate and severe icing conditions, moderate or severe turbulence, cloud coverage and type, volcanic ash and areas of released radioactive materials. Issued 4 times a day for the North Atlantic Region.
  • High-level significant weather charts – Depicts forecasts of significant weather phenomena for FL250 to FL630. Shows: coverage bases and tops of thunderstorms and CB clouds, moderate and severe turbulence, jet streams, tropopause heights, tropical cyclones, severe squall lines, volcanic eruption sites, widespread sand and dust storms. Issued 4 times a day. 
  • Convective outlook (AC) – Available in both graphical and textual format. A 3-day forecast of convective activity. Convective areas are classified as marginal (MRGL), slight (SLGT), enhanced (ENH), moderate (MDT), and high (HIGH) risk for severe weather. Issuance: day 1 – 5 times a day, day 2 – twice a day, day 3 – once a day. Available on www.spc.noaa.gov. 
  • Weather satellite images: 
    
    • Visible 
      
      • Helps in identifying cloud coverage based on visible light reflection. 
      • Not useful for identifying cloud height. 
    • Infrared (Color or B/W) 
      
      • Measure cloud top temperature 
      • Highest clouds appear bright white. 
      • Middle clouds are in shades of gray 
      • Low clouds and fog are dark gray, 
    • Water vapor 
      
      • Shows areas of moist and dry air in shades of gray from white to black. 
      • Moist air areas are depicted as bright white 
      • Dry air is depicted in black. 
  • Next Generation Weather Radar (NEXRAD) products. Examples:
    
    • Base reflectivity – echo intensities in dBZ. Available for several elevation tilt angles. 
    • Echo tops – color coded echo top heights. 
    • Composite reflectivity – Reveals highest reflectivity of all echos, helps in examining storm structure features and the intensity of storms. 
    • 1 and 3-hour precipitation 
  • Ceiling & Visibility Charts- Shows ceiling based on surface observations. This online tool phased out the older weather depiction chart and is now replaced with the HEMS tool at www.aviationweather.gov/hemst 
  • Graphical turbulence Guidance (GTG) tool at www.aviationweather.gov/turbulence/gtg – Shows color coded turbulence forecast based on aircraft category, altitude and time.

Weather Hazards

• THUNDERSTORMS 
  
  • The Three Conditions Required for the formation of Thunderstorms: 
    
    1. Sufficient water vapor (moisture). 
    2. An unstable temperature lapse rate. Stability is the resistance of the atmosphere to upwards or downwards displacement. An unstable lapse rate allows any air mass displacement to further grow vertically. 
    3. An initial uplifting force (e.g., front passages, orthographic lifting by typography, heating from below, etc.). 
  • Three Stages in Thunderstorm Lifecycle: 

• • 1. Cumulus (3-5 mile height) – The lifting action of the air begins, growth rate may exceed 3000 fpm.
    2. Mature (5-10 miles height) – Begins when precipitation starts falling from the cloud base. Updraft at this stage may exceed 6000 fpm. Downdrafts may exceed 2500 fpm. All thunderstorm hazards are at their greatest intensity at the mature stage. 
    3. Dissipating (5-7 miles height) – Characterized by strong downdrafts and the cell dying rapidly.

• • Thunderstorm Hazards: 
    
    • Limited visibility 
    • Wind shear 
    • Strong updrafts / downdrafts 
    • Icing 
    • Hailstones 
    • Heavy rain 
    • Severe turbulence 
    • Lightning strikes and tornadoes.
• FOG
  
  • A cloud that begins within 50 ft of the surface. Fog occurs when: 
    
    • The air temperature near the ground reaches its dew point, or 
    • when the dew point is raised to the existing temperature by added moisture to the air. 
  • Types of fog 
    
    • Radiation fog – Occurs at calm, clear nights when the ground cools rapidly due to the release of ground radiation. 
    • Advection fog – Warm, moist air moves over a cold surface. Winds are required for advection fog to form. 
    • Ice fog – Forms when the temperature is much below freezing and water vapor turns directly into ice crystals. Ice fog is common in the arctic regions, but also occurs in mid-latitudes. 
    • Upslope fog – Moist, stable air is forced up a terrain slope and cooled down to its dew point by adiabatic cooling. 
    • Steam fog – Cold, dry air moves over warm water. Moisture is added to the airmass and steam fog forms.
• ICING
  
  • Structural Ice. Two conditions for formation: 1. Visible moisture (i.e., rain, cloud droplets), and 2. Aircraft surface temperature below freezing. 
    
    • Clear ice– The most dangerous type. Heavy, hard and difficult to remove. Forms when water drops freeze slowly as a smooth sheet of solid ice. Usually occurs at temperatures close to the freezing point (-10° to 0° C) by large supercooled drops of water 
    • Rime ice – Opaque, white, rough ice formed by small supercooled water drops freezing quickly. Occurs at lower temperatures than clear ice. 
    • Mixed ice – Clear and rime ice formed simultaneously. 
  • Instrument ice – Structural ice forming over aircraft instruments and sensors, such as pitot and static. 
  • Induction ice – ice reducing the amount of air for the engine intake. 
  • Intake ice – Blocks the engine intake. 
  • Carburetor ice – May form due to the steep temperature drop in the carburetor Venturi. Typical conditions are outside air temperatures of -7° to 21° C and a high relative humidity (above 80%). 
  • Frost – Ice crystals caused by sublimation when both the temperature and the dew point are below freezing.

AEROMEDICAL (Pilot Handbook of Aeronautical Knowledge)

• Hypoxia – Insufficient supply of oxygen to the body cells. 
  
  • Hypoxic hypoxia – Insufficient supply of O2 to the body as a whole. As altitude increases, O2 percentage of the atmosphere is constant, but its pressure decreases. The reduced pressure becomes insufficient for the O2 molecules to pass through the respiratory system’s membranes. 
  • Hypemic hypoxia – Inability of the blood to carry the O2 molecules. It may be a result of insufficient blood (bleeding or blood donation), anemia or CO poisoning. 
  • Histotoxic hypoxia – Inability of the body cells to affectively use the O2 supplied by the blood. This can be caused by use of alcohol or drugs. 
  • Stagnant hypoxia – Caused by the blood not flowing efficiently. Can be caused by heart problems, excessive acceleration (Gs), shock or a constricted blood vessel. Cold temperatures can restrict circulation and decrease blood supplied to the extremities.
• Hyperventilation – A condition which occurs when excessive amount of CO2 is eliminated from the body as a result of breathing too rapidly. Symptoms may be similar to those of hypoxia. Breathing into a paper bag or talking aloud helps recovery from hyperventilation.
• Decompression sickness – Inert gasses (mainly nitrogen) are released rapidly from solution in the body tissues and fluids as a result of low barometric pressure. The gasses form bubbles that may harm the body in several ways. The most common result of decompression sickness is joint pain (“the bends”). To help prevent the bends after SCUBA diving: wait at least 12 hours after diving that does not require a controlled ascent (non-decompression stop diving) for flights up to 8000 ft MSL; wait 24 hours for flights above 8000 ft or after any diving that required a controlled ascent (decompression stop diving). 
• Oxygen requirements (§91.211, Note: see §121.327-121.333 & §135.89, §135.157 for 121/135 operations O2 rules) 
  
  • Unpressurized cabins 
    
    • Cabin pressure altitudes above 12,500 to 14,000’ MSL (including) – The required minimum flight crew must be provided with and must use supplemental O2 for periods of flight over 30 minutes at these altitudes. 
    • Cabin pressure altitudes above 14,000’ – The required minimum flight crew must be provided with and must use supplemental O2 the entire flight time at these altitudes. 
    • Cabin pressure altitudes above 15,000’ MSL – Each occupant must be provided with supplemental O2. 
  • Pressurized cabins 
    
    • Above FL250 – an addition of at least 10 minutes of supplemental O2 for each occupant is required. 
    • Above FL350 – one pilot at the controls must wear and use an O2 mask unless two pilots are at the control with quick-donning masks and the aircraft is at or below FL410. 
    • If one pilot leaves the controls above FL350, the other pilot must wear and use his O2 mask regardless if it’s a quick donning type. 
• Middle Ear & Sinus blockage 
  
  • Air pressure in the middle ear and sinuses normally equalizes with external air through the nasal passages. 
  • Allergies, colds or sinus infections may block these small opening and prevent the pressure from equalizing. 
  • If the air gets trapped, it may cause extreme pain, reduction in hearing or damage to the ear drums. This effect is usually most severe during descend. 
  • To relieve this condition, try the “Valsalva Maneuver“: pinch your nostrils and gently try to blow air out of your nose. This forces air through the Eustachian tube into the middle ear. It may not work if the pilot has a cold, sinus or ear infection, or a sore throat.
  • Consider seeing a physician if the condition doesn’t clear after the flight. 
• Spatial disorientation and illusions 
  
  • 3 systems the body uses for spatial orientation 
    
    • Vestibular System – Consists of organs in the inner ear 
      
      • 3 semicircular canals sense movement in 3 axes: pitch, roll and yaw. The canals are filled with fluid, which moves against tiny sensory hairs as the head is moved. The brain gets these signals and interprets a sensation of movement. 
      • 2 otolith organs, the utricle and saccule, sense acceleration in the horizontal and vertical planes. 
    • Somatosensory System – Consists of nerves in the skin, muscles and joints.
    • Visual System – Visual cues from our eyes help the brain figure out spatial orientation. 
  • Vestibular Illusions 
    
    • The leans – After leveling the wings following a prolonged turn, pilot may feel that the aircraft is banked in the opposite direction of the turn. 
    • Coriolis Illusion – After a prolonged turn, the fluid in the ear canal moves at same speed as the canal. A head movement on a different plane will cause the fluid to start moving and result in a false sensation of acceleration or turning on a different axis. 
    • Graveyard Spiral – A pilot in a prolonged, coordinated constant-rate turn may experience the illusion of not turning. After leveling the wings, the pilot may feel the sensation of turning to the other direction (“the leans”), causing the pilot to turn back in the original direction. Since a higher angle of attack is required during a turn to remain level, the pilot may notice a loss of altitude and apply back force on the elevator. This may tighten the spiral and increase the loss of altitude. 
    • Somatogravic Illusion – Rapid acceleration stimulates the inner ear otolith organs in the same way as tilting the head backwards. This may create the illusion of a higher pitch angle. Deceleration causes the opposite illusion – the sensation of tilting the head forward and the aircraft being in a nose-low attitude.
    • Inversion Illusion – An abrupt change from climb to straight and level may create the illusion of tumbling backwards due to the fluid movement in the otolith organs. 
    • Elevator Illusion – An abrupt upward vertical acceleration may create the illusion a climb, due to fluid movement in the otolith organs. 
  • Visual Illusions 
    
    • False Horizon – An illusion in which the pilot may misidentify the horizon line. May be caused by sloping cloud formation, an obscured horizon, an aurora borealis, dark night with scattered lights and stars or the geometry of the ground 
    • Autokinesis – Staring at a stationary point of light in a dark or featureless scene for a prolonged period of time may cause the light to appear to be moving. A pilot may attempt to align the aircraft with the perceived moving light, resulting in loss of control. 
  • Optical Illusions 
    
    • Runway Width Illusion – A narrow runway may create the illusion that the aircraft is higher than it actually is. A wide runway may cause the opposite effect of the aircraft flying too low. 
    • Runway and Terrain Slope Illusion – An upsloping terrain or runway may create the illusion that the aircraft is at a higher altitude than it actually is.
    • Featureless Terrain Illusion – Also known as “black hole approach.” Flying over featureless or dark areas, such as in an overwater approach, can create the illusion that the aircraft is at a higher altitude than it actually is and may lead the pilot to fly at a lower altitude than desired. 
    • Water Refraction – Rain on the windscreen can create an illusion of being at a higher altitude due to the horizon appearing lower than it is. This can result in the pilot flying a lower approach. 
    • Haze – Shooting an approach in haze may create the illusion that the runway is further that it actually is, or that the aircraft is higher than it actually is. 
    • Fog – Flying into fog may create an illusion of a nose-up motion. 
    • Ground Lighting Illusion – Lights along a straight path, such as a road or lights on moving trains, can be mistaken for runway and approach lights. Bright runway and approach lighting systems, especially where few lights illuminate the surrounding terrain, may create the illusion that the runway is closer than it actually is. This may result in the pilot flying a higher approach than desired.
• Coping with spatial disorientation (Pilot Handbook of Aeronautical Knowledge) 
  
  • Understand the causes of the illusions that may affect you as a pilot and stay alert for them when flying. 
  • Obtain and understand relevant preflight weather information. 
  • Maintain instrument proficiency and obtain training if needed before flying in marginal or instrument conditions. 
  • Do not fly into adverse weather conditions or into adverse weather conditions, dark or featureless areas unless instrument proficient. 
  • When using outside visual references, ensure they are reliable, fixed points on the earth’s surface. 
  • Avoid sudden head movements, particularly during takeoff, turns, and approaches to landing. 
  • Be physically tuned for flight into reduced visibility. Ensure proper rest, adequate diet, and, if flying at night, allow for night adaptation. Remember that illness, medication, alcohol, fatigue, sleep loss, and mild hypoxia are likely to increase susceptibility to spatial disorientation. 
  • Most importantly, become proficient in the use of flight instruments and rely upon them. Trust the instruments and disregard your sensory perceptions.