FAR 91.185 — IFR Lost Comm Procedures
FAR 91.185 explains what IFR pilots must do after a two-way radio failure: route, altitude (MEA), and clearance limit rules. Memory aids AVEF and MEA.
In Plain English
FAR 91.185 tells you exactly what to do if you lose two-way radio communications while flying IFR. It's a critical rule because without it, ATC has no way to predict where you'll go or when you'll descend.
- VFR conditions: If the failure happens in VFR, or you encounter VFR after the failure, continue VFR and land as soon as practicable.
- IFR conditions: If you must continue IFR, fly the route in this priority (memory aid AVE-F):
- Assigned in your last clearance
- Vectored — direct to the fix/route/airway in the vector clearance
- Expected in a further clearance
- Filed flight plan route
- Fly at the highest of these altitudes for each segment (MEA):
- Minimum IFR altitude
- Expected altitude from ATC
- Assigned altitude in your last clearance
- Clearance limit: If it's a fix where an approach begins, start descent/approach at your EFC time, or if none, as close as possible to your ETA. If it isn't, leave at EFC (or upon arrival if no EFC), proceed to an approach fix, and descend at ETA.
Knowing this cold keeps you predictable to ATC and legal in the system.
Regulation Text
14 CFR § 91.185§ 91.185 IFR operations: Two-way radio communications failure.
(a)Unless otherwise authorized by ATC, each pilot who has two-way radio communications failure when operating under IFR shall comply with the rules of this section.
(b)If the failure occurs in VFR conditions, or if VFR conditions are encountered after the failure, each pilot shall continue the flight under VFR and land as soon as practicable.
(c)If the failure occurs in IFR conditions, or if paragraph (b) of this section cannot be complied with, each pilot shall continue the flight according to the following:
(1)(i) By the route assigned in the last ATC clearance received;
(ii) If being radar vectored, by the direct route from the point of radio failure to the fix, route, or airway specified in the vector clearance;
(iii) In the absence of an assigned route, by the route that ATC has advised may be expected in a further clearance; or
(iv) In the absence of an assigned route or a route that ATC has advised may be expected in a further clearance, by the route filed in the flight plan.
(2)At the highest of the following altitudes or flight levels for the route segment being flown:
(i) The altitude or flight level assigned in the last ATC clearance received;
(ii) The minimum altitude (converted, if appropriate, to minimum flight level as prescribed in § 91.121(c)) for IFR operations; or
(iii) The altitude or flight level ATC has advised may be expected in a further clearance.
(3)(i) When the clearance limit is a fix from which an approach begins, commence descent or descent and approach as close as possible to the expect-further-clearance time if one has been received, or if one has not been received, as close as possible to the estimated time of arrival as calculated from the filed or amended (with ATC) estimated time en route.
(ii) If the clearance limit is not a fix from which an approach begins, leave the clearance limit at the expect-further-clearance time if one has been received, or if none has been received, upon arrival over the clearance limit, and proceed to a fix from which an approach begins and commence descent or descent and approach as close as possible to the estimated time of arrival as calculated from the filed or amended (with ATC) estimated time en route.
[Docket 18334, 54 FR 34294, Aug. 18, 1989; Amdt. 91-211, 54 FR 41211, Oct. 5, 1989]
Oral Exam Questions a DPE Might Ask
Q1You lose two-way radio communications while in IMC on an IFR flight plan. What route do you fly?
Per FAR 91.185(c)(1), I follow the route in this order: the route assigned in my last ATC clearance; if being vectored, direct to the fix/route/airway in the vector clearance; the route ATC said to expect in a further clearance; or, lastly, the route I filed.
Q2What altitude should you fly after a lost-comm event in IMC?
FAR 91.185(c)(2) requires the highest of the assigned altitude in my last clearance, the minimum IFR altitude for the segment, or the altitude ATC said to expect in a further clearance.
Q3If your clearance limit is a fix from which an approach begins, when do you start the approach?
Under FAR 91.185(c)(3)(i), I begin descent or descent and approach as close as possible to my expect-further-clearance time, or if I didn't receive one, as close as possible to my ETA based on my filed or amended flight plan.
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Related Sections in Part 91