descend at pilot's discretion?

cessnajockey454

cessnajockey454

Well-Known Member
If I'm over the Gulf and am gliding distance to the shoreline and want to remain so, can I just stay up at altitude until ATC calls again? How soon is ATC expecting me to come down? Or can I just tell them I am 'unable' to descend for safety reasons?

This happens at night also - I want to stay within gliding distance to an airport but am cleared down to 3,000 or so at my discretion but my discretion tells me I need to stay up high.

I'm a tad concerned that flying low at night or over water will eventually get me- I'd rather just stay up high until I get really close and then come down fast.

In the past, when I've asked to remain at my original altitude, they tell me they need me lower for traffic - traffic coming into IAH or HOU. If I were VFR, it probably wouldn't be a problem because I would be higher than the nearby Class B airspace that I'm transiting anyway and I wouldn't be over the Gulf of Mexico but since I'm IFR, it seems as if I've got to put myself in possible jeopardy by descending down from a comfortable 12k down to an altitude that would cause a splash if the engine quit.

Granted, I'd rather roll the dice on the engine not quitting than run the risk of getting knocked out of the sky by a 757 - but in a perfect world, I'd rather try to avoid both.

Anyway, I guess my question is: Can or should I use the "unable" response to keep from descending below what I consider to be a comfortable altitude?
 
Well...I don't think it's that you're "unable" to descend, you're choosing not to. You can always ask for a different altitude, and you may get it...but when you're IFR and they ask you to descend, it's usually for a reason. I'm not sure if it would be a legitimate reason for you to ask for a higher altitude in case of engine failure. Just my opinion..
 
The word descend at pilot's discretion has always confused me. To me, I it means "stay where I want, until I want lower" however to most ATC that I come in contact with, they want me to start my decent fairly soon despite their kind words of "pilots discretion." I believe technically it is like a cruise clnc where the pilot may start his decent when he wishes, decend at any speed, temporarly level off at an altitude if desired and then decend some more. However, once an altitude has been vacated, the pilot may not return to that altitude.

Technically, the pilot in command my do what he deems necessary for the safety of the flight. However, if ATC tells you to decend, it may be for several reasons like prep you for the approach, service volumns of VORs, traffic etc. If ATC wants to help you get ready for an approach, they'll probably have no problem with you staying where you are, but if they want/ need you to descend (then they probably won't use at pilots discretion either) and you don't feel comfortable, then I'd tell ATC why you don't want to decend and offer solutions like climbs, turns, have conflicting traffic move etc.
 
"Pilot's Discretion" means just that... you do it when you are ready to. In this case, they are basically saying, 'we don't want to have the resposibility of reminding you when to descend because we really don't care WHEN you do it.'

If something comes up and they need you to get down (or stay up), they will tell you.

You might also hear, "Descend at pilots discretion to cross XYZ at 10,000". Which again, basically means that they don't care when you do it, as long as you hit the fix at the prescribed altitude.

An "unable" response to a PD directive can certainly be given, but usually because you couldn't make the altitude restriction even if you went down now, which is certainly an acceptable answer.

Regardless, if you don't like it or it seems strange to you (ie, maybe too far out), ask them about it. They'll either have a very good reason or change it to a PD.

Rereading your post, here's a better answer... don't let ATC crash your airplane!

What I mean is, if you can't accept a clearance for safety reasons, then you can't accept a clearance. Tell them that you can't and tell them why. You might even give them a possible solution, "We can take a turn to the N/E/W/S to get closer to land, then descend". They WILL find a solution. Just be aware that you might find yourself in the way with no where to go as you buzz along east of Galveston with storms sending all IAH traffic over Scholes. It's their job to deal with you, but the solution may be to send you WAY out of your way.

Jeremy
 
Hey, Merlin, like your signature.

The only question - is your wife acting like ATC at home? :p "right turn heading 270, and take out of trash." :insane:
 
AlexF said:
The word descend at pilot's discretion has always confused me. To me, I it means "stay where I want, until I want lower" however to most ATC that I come in contact with, they want me to start my decent fairly soon despite their kind words of "pilots discretion." I believe technically it is like a cruise clnc where the pilot may start his decent when he wishes, decend at any speed, temporarly level off at an altitude if desired and then decend some more. However, once an altitude has been vacated, the pilot may not return to that altitude.
Click to expand...

Not really correct. Pilot's Discretion means 'start the descent whenever you want to, but once you start it, descend down to what I assigned you.' It doesn't mean you can level off when you feel like it. That is a cruise or a block altitude. True though, once vacated you can't return.

I never say it unless I really mean it. Hell, stay up as long as you like. If we get to a point where you can't make the descent, that's a little on you and a little on me. However, I don't use it unless I mean it. Clear sky. Nothing between you and the runway. Come on down when you want. You have to understand that most controllers are not pilots. As such, performance characteristics and the idiosyncracies of wanting to stay up versus come down, fuel consumption, etc sometimes get lost on us.
 
daveatc said:
Not really correct. Pilot's Discretion means 'start the descent whenever you want to, but once you start it, descend down to what I assigned you.' It doesn't mean you can level off when you feel like it. .
Click to expand...

Dave,

During a PD descent a pilot can descend at any rate and level off at intermediate altitudes enroute to the assigned altitude. So, sure, you can level off on the way down. I agree that once you vacate an altitude...you can't go back up. That would be part of a cruize clearance.
 
Just pulled this out of the Pilot/Controller Dictionary on AOPA...

PILOT'S DISCRETION- When used in conjunction with altitude assignments, means that ATC has offered the pilot the option of starting climb or descent whenever he/she wishes and conducting the climb or descent at any rate he/she wishes. He/she may temporarily level off at any intermediate altitude. However, once he/she has vacated an altitude, he/she may not return to that altitude.
source: http://www.aopa.org/members/files/aim/glossary.html
 
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