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Rustee 05-11-2011 07:03 AM

Leaving the Clearance Limit (Lost Comms)
 
Lost Communications scenario in IFR conditions. We are already familiar with the Route and Altitude rules, so let's skip to the end.

Leaving the clearance limit. Based upon FAR 91.185, and without a lengthy citing of the FAR/AIM, here is what I believe to be a correct interpretation of the rule.

If you received an EFC time (this would also include holding instructions), hold until the EFC time, then proceed to the IAF and commence descent and approach as close as possible to your ETA.

If you did not receive an EFC, proceed to the IAF and commence descent and approach as close as possible to your ETA.

Here's where the answers tend to get muddy when asked about Lost Comms. The most common answer among pilots is, if you are early, you would hold until getting close to your ETA, then commence descent and approach close to the ETA. However, that doesn't make sense for a couple reasons.

1) As "close as possible to the ETA" definitely includes the possibility of being early

2) "Making up a hold" in no way assures obstruction clearance. The hold needs to be published for that to be garaunteed (or assigned by ATC)

3) It prolongs your NORDO flight in the National Airspace System, simply further complicating ATC's job of providing separation

So here's the question: Why does everyone say that, if early, they will hold?

It is understood that an EFC implies holding, and instructions would have been issued for that. But in the absence of an EFC, I see no logical explanation for holding at all, even if you are early.

Thoughts?

Cubdriver 05-11-2011 07:31 AM

Well I do think a hold is indicated by the wording of FAR 91.185, so the question it seems to me is why is it a requirement to hold when early to the fix. I will venture a guess it is for the situation where another airplane just got on final at the fix in question, perhaps they were late or simply on-time, and you are right on their tail due to being early to the fix. In IMC with no radio (NORDO) you would not know this and it could make for trouble if separation was compromised. There should be a minimum sector altitude on the approach plate to assure terrain clearance for a hold in case you need one. Do a standard hold at that fix until EFC arrives, and then fly the approach. The purpose of all the lost comm procedures is to maintain separation when only a prior clearance instruction exists for the NORDO aircraft.

TonyWilliams 05-11-2011 07:36 AM


Originally Posted by Rustee (Post 992129)

Here's where the answers tend to get muddy when asked about Lost Comms. The most common answer among pilots is, if you are early, you would hold until getting close to your ETA, then commence descent and approach close to the ETA. However, that doesn't make sense for a couple reasons.

Don't ever give this answer on an airline interview / type rating ride, etc, but yes, as a retired ATC guy who also holds an ATP (and flew airlines), yes, GET THE HECK OUT OF THE SKY !!!!

Call them on the phone, on the ground, or even in the air, if you can make it work.

The "made up" holds leave ATC wondering what you are doing (remember, few are pilots), if it's non-radar, they might assume you crashed when you didn't arrive at the airport.

Think about whether you passed an estimate for your ETA to ATC. I'm going to guess not (I don't think I ever did receive one in 20 years). So what actual info does ATC have that they would benefit from you flying holes randomly in the sky.

GET ON THE GROUND>

:D

Cubdriver 05-11-2011 07:40 AM

There is an obvious divergence between theory and practice here. A lot of these rules come from the days of yore when radios were crappy, computers and radars mostly did not exist either on the ground or in the airplane. They had to cover every hypothetical, because they were more likely than they are now with all these electronics.

rickair7777 05-11-2011 07:49 AM

Like the other guys said, the technically correct (checkride) answer is to hold at the clearance limit long enough to make your ETA at the airport match what was filed. The generally accepted real-world answer is to get out of the sky.

But if you are doing a checkride with a company (vice FAA) examiner, tell him the textbook answer so he knows that you know it, but then clarify what you would really do.

Rustee 05-11-2011 09:41 AM


Originally Posted by rickair7777 (Post 992160)
Like the other guys said, the technically correct (checkride) answer is to hold at the clearance limit long enough to make your ETA at the airport match what was filed. The generally accepted real-world answer is to get out of the sky.

But if you are doing a checkride with a company (vice FAA) examiner, tell him the textbook answer so he knows that you know it, but then clarify what you would really do.

Well part of the point of this discussion is that I believe it is incorrect to hold unless, as previously stated, you were given an EFC. I understand that it has been taught over the years to "hold if early," but just because that's what CFII's have passed on to their students doesn't necessarily make it correct. (And to be fair, I've had DPE's lack critical knowledge of the PTS requirements on checkrides, so just because a DPE says so, that doesn't make it correct either.)

If you look at the wording of FAR 91.185, it states "commence descent or descent and approach as close as possible to the estimated time of arrival". That does not preclude being early, should that situation occur, it just indicates that the pilot should make a best effort attempt to meet this criterion. (i.e., that could simply mean adjusting speed if it became known that they would arrive significantly early.)

In a radar environment, there are no surprises as to where the aircraft is. The only possible surprise would be an aircraft making a seemingly (to ATC) random orbit somewhere for possibly an unknown amount of turns/time. In a nonradar environment, seperation still needs to be provided, which means I doubt ATC would clear an aircraft who may only be several miles (or minutes) ahead of you unless they were absolutely sure you were not close enough for there to be a loss of seperation. I'd imagine the seperation standards would be such that there is consideration for an aircraft being early to the airport (since, again, 91.185 simply states as close as possible to ETA), thus again holding would not be correct.

If you were making up a hold, would you utilize the MSA to maintain obstruction clearance? No. That doesn't make sense because the altitude rules do not include MSA/TAA depicted altitudes until an aircraft is utilizing the procedure. In fact, you may be flying at an MEA or assigned altitude that is below the MSA for the procedure you intend to do... would you climb to the MSA for your made-up hold, then come back down to complete the procedure? Or do you stay at the MEA and then risk leaving the 4nm protected area for the airway during your hold? Do you then fly the OROCA for your made-up hold? You can see I'm simply pointing out obvious problems with this train of thought. The common answer does not make sense, in fact, it seems to violate IFR rules.

I'm just looking for a good answer to the "hold when early" answer.

Cubdriver 05-11-2011 10:07 AM

MSA would be safe as a last resort, but since you may have a lower altitude choice according to the altitude rules for lost comms, you can use one of those altitudes and do standard holding on the right side of the airway making right turns. Ref. Jeppesen Instrument Commercial pg. 5-50. I don't see what your issue is with this. Less than a few minutes either way and I doubt I would bother with it. You aren't going to hit anything unless you fly some really large turns because you have 4 miles to hold laterally from the centerline of a typical victor airway.

NoyGonnaDoIt 05-11-2011 10:26 AM

What is the context of the question?

So far, anyway, I've never been issued an initial clearance to anywhere other than the destination airport - that's the clearance limit, not some IAF or other point in space.

Or, are you talking about your clearance being changed while en route that changes your clearance limit to a holding fix, etc, with only an EFC to go by?

Cubdriver 05-11-2011 10:32 AM

This question could only apply if you did not have a clearance to the airport, found yourself stuck at a fix nearby and had no radios on top of all that. It's pretty remote that it would ever happen except for the fact that we need something to argue about here occasionally. :)

Rustee 05-11-2011 10:49 AM


Originally Posted by Cubdriver (Post 992234)
MSA would be safe as a last resort, but since you may have a lower altitude choice according to the altitude rules for lost comms, you can use one of those altitudes and do standard holding on the right side of the airway making right turns. Ref. Jeppesen Instrument Commercial pg. 5-50. I don't see what your issue is with this. Less than a few minutes either way and I doubt I would bother with it. You aren't going to hit anything unless you fly some really large turns because you have 4 miles to hold laterally from the centerline of a typical victor airway.

The main issue is just that it doesn't seem to make sense to hold (unless you have an EFC), especially when you apply it to a scenario. And the "hold if early" answer is what is being taught. It's nice to have clear, reasonable answers, that's all. It's the abstract and indefinite answers that just propogate a poor understanding of things that should be very clear and understood.

Scenario is this: flight plan is from Departure direct ABCDE V1 VWXYZ direct Destination. Your ETA to Destination is 1300. You arrive at VWXYZ 1240. What do you do?

Common answer: hold at VWXYZ until ~1300 then go to IAF for Destination airport.

What I disagree with is that "hold" answer. You should simply go to IAF and commence descent and approach as close as possible to ETA. If you end up 10 min early, that is still acceptable (assuming the IAP took 10 min). The "hold" answer seems to complicate the situation. To my understanding, 91.185 does not prohibit this, and it does not impose unnecessary complications on ATC.


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