The Rule Pilots Think They Know
FAR 91.185 is one of those regulations every instrument-rated pilot has memorized for their checkride — and then slowly misapplies in the real world. The framework is clean: if you lose two-way radio communication in IMC, you squawk 7600, follow the AVE F rule for route, and apply MEA/MCA/assigned/expected/filed logic for altitude. Simple enough on paper. In the oral portion of an airline interview, the gaps show up fast.
Here are the specific errors that trip up otherwise qualified pilots — both in actual lost comm situations and in the interview room.
Mistake #1: Confusing "Expected" vs. "Assigned" Altitude
The altitude to fly under 91.185(c)(2) is the highest of:
- The altitude or flight level assigned in the last ATC clearance
- The minimum altitude for IFR operations (MEA, MOCA, etc.)
- The altitude ATC has advised you to expect in a further clearance
The mistake: pilots assume "expect" altitudes are advisory only and default to their last assigned altitude. The regulation is explicit — if ATC told you to expect FL240 in 10 minutes and you lost comms before receiving it, you fly FL240 at the appropriate time. That "expect" advisory becomes operationally binding under lost comms.
The second-order mistake is forgetting that "expect" must come from ATC — not from a DP or STAR altitude restriction. Filed altitude on your flight plan is not the same as an expected altitude issued by a controller.
Mistake #2: Misapplying the AVE F Route Sequence
The route priority under 91.185(c)(1) is:
- A — Assigned route in last clearance
- V — Vectored: direct to the fix, route, or airway specified in the vector
- E — Expected route advised by ATC
- F — Filed route
You're on a vector to intercept the ILS. You lose comms mid-vector. What do you do? Most pilots say "fly the vector heading until intercepting the localizer." Wrong. You were vectored — per the V in AVE F, you proceed direct to the fix associated with that vector (the FAF or the approach fix), not indefinitely on the assigned heading. A heading is not a route; it's guidance toward a fix.
This distinction matters because flying an aimless heading while other IFR traffic operates on published routes creates a genuine conflict risk. ATC structures vectors with an endpoint in mind — lost comms procedure honors that intent.
Mistake #3: Getting the Approach Timing Wrong
91.185(c)(3) governs when to begin the approach. The pilot shall leave the IAF at the expect further clearance (EFC) time if one was received, or if no EFC was given, at the estimated time of arrival calculated from the filed or expected flight plan.
The error: pilots arrive at the IAF and hold indefinitely, waiting for something to change. Nothing will change — you've lost comms. The regulation requires you to commit to the approach at a defined time. Holding past your EFC or your ETA burns fuel, conflicts with the ATC sequencing assumption, and in an actual emergency, delays landing when the airplane may need to be on the ground.
If you were never given an EFC, do the math: filed departure time plus enroute estimate gets you to the IAF. Fly the approach. That's the system working as designed.
Why This Comes Up in Airline Interviews
Lost comms questions appear regularly across major and regional carrier orals precisely because they test systems thinking, not just rote memorization. Interviewers aren't looking for you to recite the regulation — they're watching how you reason through a non-standard scenario with partial information.
Pilots preparing for United Airlines interviews and Delta Air Lines interviews have flagged lost comms scenarios in recent gouge, often framed as "you're in the system and this happens — walk me through it" rather than a clean textbook question. The vector mid-approach scenario above is a real example of how it gets asked.
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The Bottom Line
FAR 91.185 is not ambiguous — but it requires precise application, not a general recollection of the concept. Know the altitude hierarchy cold, understand that vectors have implied endpoints, and never hold past your EFC or calculated ETA. Those three specifics separate pilots who pass the oral from pilots who get follow-up questions they weren't expecting.
For a deeper dive on IFR systems knowledge as it applies to the interview, see our IFR oral exam prep guide.