Suppose I lost my radio communication while en-route, I am following the cleared route to the last fix. I am flying the higher of my last assigned altitude and MEA. Then, I am holding at my last en-route fix and the filed expected arrival time is coming. In this case, how may I start to descent and commerce an approach? regarding which IAP to use and which IAF to head for, provided that the last en-route fix is none of IAFs in any IAPs and my last altitude is much higher than the minimums prescribed in the IAPs.


  1. Transponder is on 7600
  2. No VMC within the range of fuel
  3. Destination airport is tower-controlled
  • $\begingroup$ If you know that far in advance, I'd hope you're squawking 7600 by then. My guess is that ATC would then clear the way for you on your filed flight plan knowing they can't tell you to do anything else. $\endgroup$
    – FreeMan
    Feb 16, 2016 at 21:50

3 Answers 3


The FAA says (per 14 CFR 91.185):

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.

This seems to answer your question unless you have a more specific one. You can descend to an IAF as you see fit and commence any approach. ATC will clear the way.

  • $\begingroup$ So it is reasonable to make a VPATH from the last en-route fix to an IAF on approach plate? $\endgroup$ Feb 17, 2016 at 2:51
  • 1
    $\begingroup$ @skyoasis You cannot start descent until your ETA, so if you are proceeding from your last enroute fix because no approaches start there, and you have not reached your ETA yet, then you should not start descending yet, and should not use VPATH there. Instead, you remain level until your ETA (while proceeding to your IAF) and only start your descent at your ETA, holding at the IAF if needed. $\endgroup$
    – Lnafziger
    Feb 17, 2016 at 19:53

Let's extract some abbreviations from 14 CFR 91.185 (c) (3),

  • ECL: En-route clearance limit
  • EFC: Expected further clearance
  • IAF: Initial approach fix, a fix from which an approach
  • ETA: Estimated time of arrival, adjusted by departure time offset and superseded by most recent ATC amendment.

and expand the four possible concrete scenarios regarding how to commence the approach to the destination airport.

  1. ECL is a IAF with EFC:

    En-Route → ECL/IAF (Hold until EFC) → Descent and approach

  2. ECL is a IAF without EFC:

    En-Route → ECL/IAF (Hold until ETA) → Descent and approach

  3. ECL is not a IAF with EFC:

    En-Route → ECL (Hold until EFC) → IAF (Hold until ETA) → Descent and approach

  4. ECL is not a IAF without EFC:

    En-Route → ECL → IAF (Hold until ETA) → Descent and approach


Comm failure questions are always interesting.

Flying at a significantly higher altitude because of a comm failure, and then having to get down, I would chose an approach procedure that has a procedure turn or course reversal, and commence descent in a holding pattern over that procedure turn/reversal fix, at my ETA. If there is no such approach, I would shuttle-descend over the chosen IAF on my inbound track to that IAF, making sure to go no lower than any minimum IFR altitude, and always remaining within the area of coverage of that minimum IFR altitude. I might tweak my inbound track a bit to avoid too sharp turns onto the intermediate or final approach course.

This could take quite some time if the flight plan was filed for FL410 and you suffer a total comm failure. While shuttling down from FL410, I might try to whip out a cellphone (and an ATC phone number).

Luckily comm failures, especially in the worst-case circumstances assumed here, don't happen too often.

  • $\begingroup$ What about the expected cellular signal strength and voice quality for cellphones at FL410? $\endgroup$ Feb 19, 2016 at 5:37
  • $\begingroup$ @skyoasis I would not expect a cellular signal at FL410. But depending where you are, you might get a usable signal as high as FL200. I would only do this as an emergency measure, for example if low IMC prevailed everywhere along my route. In that case, I consider getting wx info to be absolutely critical. Again, this is all very hypothetical. $\endgroup$
    – Ugo
    Feb 19, 2016 at 8:04
  • $\begingroup$ Also note that we have near universal radar over conus so they are probably watching you anyway. $\endgroup$
    – rbp
    Apr 4, 2016 at 0:02
  • $\begingroup$ @Ugo, 41,000 ft is not all that far. Just 12.5 km or 7¾ mi which should be well within range of GSM stations. The main problem with phone calls from aircraft is that the phone would be hopping from one tower to the next quickly, draining a lot of battery in the process. There may be actually more problem down low due to closure rate as that GSM has limit on that; 3G and 4G should be better off in this regard. $\endgroup$
    – Jan Hudec
    Apr 4, 2016 at 7:52

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