Cessna 172N Aeromedical Factors (IFR) — Instrument Rating Oral Questions

DPE oral questions · aeromedical factors (ifr)

9 questions a DPE may ask in this section

1. Question 1 · IR.I.A.R3

   You depart on an IFR flight in a non-pressurized aircraft and climb to 15,000 feet MSL. It's a 2-hour flight. What oxygen requirements apply to you and your passengers?

   What a DPE expects to hear

   • At 15,000 feet MSL: supplemental oxygen is required for ALL occupants (crew AND passengers) at all times
   • §91.211(a)(3): at altitudes above 15,000 feet MSL, the required flight crew must use supplemental oxygen AND the pilot must provide it to passengers
   • At 14,001-15,000 feet: required crew must use oxygen; passengers are recommended but not legally required
   • At 12,501-14,000 feet: required crew must use oxygen when at that altitude for more than 30 minutes
   • You are required to have sufficient supplemental oxygen for all passengers at 15,000 feet

   Common wrong answers

   • Not knowing passengers must have oxygen above 15,000 (not just crew)
   • Confusing the 12,500/30-min rule with the 14,000/15,000 rules
   • Thinking the 30-minute rule applies at 15,000 (it applies at 12,501-14,000 only)

   Source14 CFR §91.211; PilotsCafe IFR Quick-Review p.25

2. Question 2 · IR.I.A.R3

   What is the IM SAFE personal checklist? What does each letter mean?

   What a DPE expects to hear

   • I — Illness: any symptoms of physical illness
   • M — Medication: prescription or OTC drugs that could impair judgment or reaction time
   • S — Stress: psychological pressure from work, family, finances
   • A — Alcohol: 'bottle to throttle' — 8 hours minimum; blood alcohol not to exceed 0.04% (§91.17)
   • F — Fatigue: adequate rest; not flying when impaired by fatigue
   • E — Emotion: emotional state that could affect decision-making or attention

   Common wrong answers

   • Forgetting the 8-hour rule AND the 0.04% BAC rule (both apply simultaneously)
   • Not including OTC medications in the medication check
   • Missing Emotion — often overlooked

   Source14 CFR §91.17; AIM 8-1-1; PHAK Chapter 17; PilotsCafe IFR Quick-Review p.4

3. Question 3 · IR.I.A.R3

   Describe the leans — what causes them and how do you correct?

   What a DPE expects to hear

   • The leans: a vestibular illusion where the pilot senses a bank that doesn't exist (or senses wings level during a banked turn)
   • Cause: if the aircraft rolls gradually below the threshold of the semicircular canals, the roll goes undetected. When leveled off, the pilot 'feels' banked in the opposite direction.
   • Or: during a prolonged constant-rate turn, the fluid stops moving (adaptation). When rolling out, the pilot feels as if banking in the opposite direction.
   • Correction: trust the flight instruments; do NOT follow the false physical sensation. Instruments are correct.
   • The leans are NOT resolved by leaning the body — this can worsen the illusion
   • Persistence of leans is normal and not dangerous if pilot maintains instrument scan discipline

   Common wrong answers

   • Thinking you should lean your body to resolve the sensation
   • Thinking the leans will correct themselves quickly (they can persist for minutes)
   • Not knowing the cause is the semicircular canal roll threshold

   SourceFAA-H-8083-25C PHAK Chapter 17; AIM 8-1-5; PilotsCafe IFR Quick-Review p.25-26

4. Question 4 · IR.I.A.R3

   What is the graveyard spiral and why is it dangerous in IMC?

   What a DPE expects to hear

   • Graveyard spiral: the most common fatal IMC accident sequence
   • A prolonged coordinated turn in IMC goes undetected by the vestibular system (semicircular canals adapt)
   • Pilot feels the aircraft is level — but it is actually in a descending spiral
   • When the pilot notices airspeed and altitude increasing/decreasing: tries to pull up — this only tightens the spiral and increases G-load
   • Correct recovery: level the wings FIRST using instruments, then adjust pitch
   • Prevention: rigorous instrument scan; use autopilot in actual IMC when workload is high
   • A 3° per second standard rate turn for 20 seconds = 60° — fully detected; but 1° per second takes 20+ seconds to reach threshold and is undetected

   Common wrong answers

   • Thinking pulling back will recover from a spiral
   • Not knowing to level wings before correcting pitch
   • Confusing graveyard spiral with graveyard spin

   SourceFAA-H-8083-25C PHAK Chapter 17; AIM 8-1-5; PilotsCafe IFR Quick-Review p.25

5. Question 5 · IR.I.A.R3

   Name at least four spatial disorientation illusions and describe each.

   What a DPE expects to hear

   • 1. The Leans: illusion of bank after undetected roll — most common; pilot feels banked when wings level
   • 2. Graveyard Spin: during spin recovery, correcting the spin creates a sensation of spinning in the opposite direction — pilot re-enters the spin
   • 3. Coriolis Illusion: moving head during prolonged turn sends conflicting signals from multiple semicircular canals — violent tumbling sensation
   • 4. Elevator Illusion (Somatogravic): rapid acceleration creates illusion of nose-high attitude — pilot pitches down; common on takeoff
   • 5. Inversion Illusion: sudden pushover from climb creates illusion of tumbling backwards
   • 6. Graveyard Spiral: loss of feel for bank during prolonged turn; spiral goes undetected
   • 7. Autokinesis: in dark night conditions, a stationary light appears to move; pilot chases the phantom movement
   • Key fact from PilotsCafe: the only correct response to any disorientation is to trust and fly the instruments

   Common wrong answers

   • Thinking vestibular illusions can be overcome by concentrating harder on physical sensations
   • Not knowing Coriolis illusion — especially dangerous when reaching for charts in cockpit
   • Confusing somatogravic (acceleration/deceleration) with graveyard spiral

   SourceAIM 8-1-5; FAA-H-8083-25C PHAK Chapter 17; PilotsCafe IFR Quick-Review p.25-27

6. Question 6 · IR.I.A.R3

   What is hypoxia and at what altitude is supplemental oxygen required under Part 91?

   What a DPE expects to hear

   • Hypoxia: insufficient oxygen to the body tissues; particularly dangerous because the pilot may not be aware of impairment
   • Symptoms: headache, fatigue, euphoria, impaired judgment, blue lips/fingertips (cyanosis)
   • Part 91 oxygen requirements: §91.211
   • Cabin pressure altitude 12,500 to 14,000 feet MSL: required crew must use oxygen for any part of the flight at that altitude exceeding 30 minutes
   • Above 14,000 feet MSL: flight crew required to use oxygen at all times
   • Above 15,000 feet MSL: each occupant must be provided supplemental oxygen (passengers)
   • Non-pressurized aircraft effectively equals cabin altitude = aircraft altitude

   Common wrong answers

   • Saying 10,000 feet requires oxygen (it's 12,500 for 30+ minutes)
   • Thinking passengers require oxygen at 14,000 (it's 15,000)
   • Not knowing crew must use it continuously above 14,000

   Source14 CFR §91.211; FAA-H-8083-25C PHAK Chapter 17

7. Question 7 · IR.I.A.R3

   During a night IFR flight in IMC, you're staring at a single light ahead and it seems to be slowly drifting. You follow it with a slight heading change. What is happening and what should you do?

   What a DPE expects to hear

   • This is autokinesis: in dark visual conditions (no visual references), a stationary light appears to move
   • The pilot perceives movement where there is none — then makes heading inputs chasing the phantom motion
   • Correction: do NOT fixate on any single external light in dark IMC; return to instrument scan
   • Additional risk: other lights from other aircraft could be mistaken for ground features
   • The illusion resolves when you break fixation and use multiple visual references or return to instruments
   • Lesson: in dark/night IMC, the instrument scan is your only reliable reference — no external visual fixation

   Common wrong answers

   • Continuing to fixate and follow the apparent motion
   • Not knowing the term autokinesis
   • Thinking external visual references in dark IMC are reliable

   SourceAIM 8-1-5; FAA-H-8083-25C PHAK Chapter 17; PilotsCafe IFR Quick-Review p.27

8. Question 8 · IR.I.A.R3

   What is the somatogravic illusion and in what IFR situation is it most dangerous?

   What a DPE expects to hear

   • Somatogravic illusion: rapid linear acceleration is sensed by the otolith organs (utricle and saccule) as a nose-up pitch change — the pilot feels they are climbing
   • Most dangerous scenario: night takeoff or takeoff into IMC — after acceleration on the runway, the pilot may feel the nose is up and push forward on the controls, causing a nose-down attitude
   • Known as 'black hole' or 'dark night takeoff' accident scenario
   • The reverse (deceleration → feels like nose-down → pilot pulls back): can occur during approach on a deceleration to landing configuration
   • Correction: trust the instruments; use the attitude indicator to verify pitch on takeoff
   • The illusion is most pronounced when the transition from ground to airborne occurs in IMC or darkness with no visual horizon

   Common wrong answers

   • Confusing somatogravic with the leans
   • Not knowing it occurs during acceleration (not just turns)
   • Not knowing the dangerous takeoff scenario

   SourceAIM 8-1-5; FAA-H-8083-25C PHAK Chapter 17; PilotsCafe IFR Quick-Review p.27

9. Question 9 · IR.I.A.R3

   What is the Coriolis illusion and when does it occur in an IFR flight?

   What a DPE expects to hear

   • Coriolis illusion: occurs when a pilot has been in a prolonged turn at a constant rate (semicircular canals have adapted) and then MOVES THE HEAD — turning the head stimulates multiple semicircular canals simultaneously
   • Sensation: sudden violent tumbling or spinning sensation, often described as disorienting and terrifying
   • Most common scenario: reaching into the back seat, turning to look at a chart, or nodding the head while in a prolonged coordinated turn in IMC
   • Prevention: when flying in IMC, minimize head movements; do not turn to look at passengers or equipment
   • Correction: trust instruments; accept the discomfort; do not respond to the false sensation
   • The Coriolis illusion is one of the most intense vestibular illusions — it can be incapacitating for a moment

   Common wrong answers

   • Confusing with the leans (leans = bank sensation; Coriolis = tumbling from head movement)
   • Not knowing head movement triggers it
   • Thinking it only occurs during rapid turns

   SourceAIM 8-1-5; FAA-H-8083-25C PHAK Chapter 17; PilotsCafe IFR Quick-Review p.26