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Instrument Rating — Airplane & Helicopter
Instrument Checkride Oral: Lost Comms (91.185) Questions & Answers
Lost communications is the most rehearsed scenario on every instrument oral because it tests whether you can run a rule-based procedure under uncertainty. 91.185 gives you a complete decision tree, and the examiner will walk you down every branch: What if you hit VFR? What route do you fly? What altitude? When do you start the approach?
Two principles organize everything: if you encounter VFR conditions, stay VFR and land — the IFR procedures only apply in IMC; and in IMC, fly what ATC most recently told you to expect, falling back to what you filed. Master the AVEF and MEA-highest memory aids, then practice applying them to a real clearance, because that's exactly how the DPE will frame it.
Route and altitude: AVEF and the 'highest of three'
Route (in order): Assigned — the route in your last clearance; Vectored — if being radar vectored, fly direct to the fix, route, or airway you were being vectored to; Expected — what ATC told you to expect in a further clearance; Filed — your flight-plan route. Work down the list only as far as needed.
Altitude — the highest of three, evaluated for each route segment: the altitude last assigned, the minimum IFR altitude (MEA or equivalent) for the segment, and the altitude ATC told you to expect. 'For each segment' is the part examiners hammer: if you were assigned 5,000 and a later segment's MEA is 7,000, you climb to 7,000 for that segment and may descend back to 5,000 when the MEA drops — the rule continuously re-evaluates. The logic: ATC is protecting airspace for you at the highest of what they promised, what you were given, and what terrain requires.
When to descend and land — and the practical layer
Clearance-limit rules (91.185(c)(3)): if the clearance limit is a fix from which an approach begins, hold as needed and commence descent/approach as close as possible to the EFC time — or, if no EFC was given, as close as possible to your filed/amended ETA. If the clearance limit is not an approach fix, leave it at the EFC, or upon arrival proceed to a fix from which an approach begins and start the approach as close as possible to the ETA. In plain language: the system expects you over the approach environment at a predictable time so ATC can sterilize the airspace.
The practical layer the examiner also wants: squawk 7600; try everything before declaring yourself NORDO — the other radio/com2, different frequencies (previous frequency, center, FSS, 121.5), the audio panel and headset jacks, transmitting blind with position reports, listening over VOR voice frequencies, and a cell phone call to ATC as a real-world backstop. And the umbrella answer: 91.3 emergency authority — if fuel, weather, or safety argue against the textbook procedure, deviate and land; the AIM itself acknowledges the regulation can't cover every situation. Saying 'I'd fly the rule, but I won't fly it into a thunderstorm or fuel exhaustion' is a feature, not a hedge.
Practice questions with answers & rationales
Q1. You lose comms in IMC, and ten minutes later you break out into solid VMC. What does 91.185 require?
Answer: Continue the flight under VFR and land as soon as practicable — not 'as soon as possible at the nearest field,' but at a suitable airport without unnecessary continuation of IFR flight. This branch outranks everything else: the route/altitude/clearance-limit procedures apply only if you remain in IMC. Examiners often start here because so many applicants jump straight to AVEF and forget the VFR branch.
Q2. You were being vectored to the final approach course when comms failed in IMC. What route do you fly?
Answer: The 'V' of AVEF: proceed direct from the point of failure to the fix, route, or airway specified in the vector clearance — for vectors to final, that means proceeding direct to the fix/route you were told ('vectors to BREMR, expect ILS 24') and flying the approach from there. You don't re-fly the filed route; the vector clearance defined where ATC intends you to be.
Q3. Your last assigned altitude was 6,000. The next airway segment has an MEA of 8,000, and ATC had said 'expect 10,000 ten minutes after departure.' What altitude do you fly on that segment?
Answer: 10,000 — the highest of assigned (6,000), minimum IFR altitude for the segment (8,000), and expected (10,000), and the expected altitude applies once its condition (ten minutes after departure) has been met. On a later segment where the MEA falls and nothing higher applies, you'd fly the highest of the remaining values. Work it segment by segment out loud — that's what the examiner is grading.
Q4. When may you begin your descent and approach at the destination?
Answer: If your clearance limit is a fix from which the approach begins: start descent/approach as close as possible to the EFC if you received one, otherwise as close as possible to the ETA from your filed or amended flight plan. If the clearance limit isn't an approach fix: leave the limit at the EFC (or upon arrival if none), proceed to an approach fix, and begin the approach as close as possible to the ETA. The intent: arrive over the approach structure when ATC expects you, because they're clearing that airspace around your ETA.
Q5. Which approach do you fly at the destination with no comms?
Answer: Any suitable instrument approach at the destination — pick based on weather, equipment, and the runway you can use; ATC is protecting the airspace for your arrival rather than a specific procedure. A complete answer adds: fly the full published procedure from an initial approach fix (no vectors are coming), comply with published altitudes, and continue squawking 7600 throughout.
Q6. What should you actually try before accepting that you're NORDO?
Answer: A systematic troubleshoot: volume/squelch, audio panel selections, both radios, swap headset or use the speaker and hand mic, check jacks and connectors, try the previous frequency and the next sector, guard (121.5), FSS, and listening for ATC over VOR voice. Transmit in the blind with position and intentions (your transmitter may work while the receiver doesn't), watch for light-gun signals if it ends at a towered field, and use a phone if you have signal. Most 'lost comms' events are a knob, a jack, or one dead radio.
Q7. Fuel is getting tight and the 91.185 gymnastics would add 30 minutes. What's your call?
Answer: Exercise 91.3 emergency authority: squawk 7700, proceed directly to a suitable approach and land. The lost-comm rule exists to make you predictable to ATC, but it explicitly yields to emergencies, and the AIM acknowledges pilots must use good judgment where the rule doesn't fit. Examiners want to hear that you know the procedure cold and know when to set it aside — in that order.
Common mistakes to avoid
- Forgetting the VFR branch entirely and flying the full IFR procedure past good VMC. 'VFR — land as soon as practicable' comes first.
- Applying the highest-of-three altitude once for the whole flight instead of re-evaluating each segment.
- Confusing 'practicable' with 'practical' or 'possible' — and getting led into defending a 200-mile IMC continuation.
- Ignoring the EFC/ETA timing rules at the clearance limit — descending early is exactly what ATC's protected-airspace model assumes you won't do.
- Answering only with the regulation and never mentioning 7600, troubleshooting, or blind transmissions.
- Being unwilling to invoke emergency authority in the low-fuel variant. The examiner is offering you the out — take it.