IFR Lost Coms (91.185) troubles
 

I've been teaching a lot of instrument students during my days as a flight instructor, and at some point we always get to the lost coms scenario discussion.

Basically 91.185 gives you your procedures to follow (we're talking no VFR conditions in sight here) for route, altitude and when to leave clearance limit.

Now, by talking to a lot of different ATC controllers, most of them will tell me that if I would ever lose coms in IMC close to the departure airport, they would rather see me just return and land asap, than follow 91.185, but i digress.

Onto the matter at hand here (lost coms scenarios):

1. Your clearance limit is your destination airport, for some reason your ETA was out of wack, and you arrive over your clearance limit 20 minutes before your ETA time.
Now by 91.185, you should now proceed to a fix from where an approach begins, and then descent as close as possible to your ETA.
Would you agree that the regulations in this instance tell you to hold at the IAF for an approach for an additional 20 minutes?

2. Say you're a jet operating under part 91 (don't know if these rules are different in regards to 135/121), and your enroute altitude is FL 410, you lose coms early in the flight, with only that altitude assigned to you.
Are you expected to arrive over the clearance limit (your destination airport) at FL 410, and then descend in a holding pattern over the IAF or somesuch?


Would be awesome if anyone has any reference material for different lost coms scenarios, especially those in regards to clearance limit and descending for the approach/airport !

- Photon

without looking at any regs in front of me, i would have to say that you would not stay at FL410 over the initial. most likely you would be assigned some type of arrival with crossing restrictions and speed restrictions. so i would think that you would plan your descents according to that. then plan on arriving at the minimum intercept altitude on the initial approach fix using a 3.0 descent ratio. also if you lost your coms early in the flight you would want to plan to arrive at your clearance limit as close to your eta as possible by adjusting cruise speed. but i know that may not always be possible giving winds/fuel burn.

so this is just a WAG (wild ass guess) on my part. thankfully we have 3 radios on my jet!

If you are in IMC at 410 and still in IMC when you get to ~3-9k then your biggest problem is that you are flying in a thunderstorm.

§ 91.185 IFR operations: Two-way radio communications failure.
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(a) General. 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) VFR conditions. 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) IFR conditions. 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:



Say you have an overcast layer at 12 000 feet then (AGL), you can't proceed VFR and land, so what do you do?

In regards to crossing restrictions:

http://www.faa.gov/about/office_org/...sselles_Jr.pdf

Quote from that letter:

I would stay at my highest altitude (of M-E-A) and proceed to the clearance limit and hold. Once my ETA hit I would start descent and then when I got to an altitude at which I was able to I would start the approach.

ok, so if your assigned altitude is FL410, you would go to your clearance limit, either hold there, or proceed to an IAF, and then descend from FL410 in the hold for the approach?

If the lost comm could be considered an emergency, could you not also start the approach upon arrival? I'm sure if squawking 7600 and under radar surveillence that ATC is clearing the way for you. I would not want to hold at altitude in hard IMC for instance and wonder what was going to possible fail next on my aircraft. Woodfinx - what are your thoughts about that?

USMCFLYR

That is certainly what ATC would LIKE for you to do, and you could probably justify it as PIC emergency authority under normal conditions. ATC will get everyone out of your way and they will annoyed if you hold at the IAF for 30 minutes, shutting down SFO for arrivals.

But there is a reason that you have an ETA/clearance limit and are supposed to comply with it ...what if the comms failure is not just YOUR airplane?

Say Jihad Johny takes out one or more ARTCCs or their comms systems...all of the OTHER airplanes are going to be arriving, on schedule, at the same fix YOU are going to :eek: In that scenario, it's probably best if you don't reach the IAF at the published ALT early. Hopefully your TCAS still works...

You would probably have some idea whether the comm failure was on your equipment or not.

Correct. However that is for an airport with no published arrival. If I am filed to be on an arrival I would descend to the crossing restriction and go from there.