Slowing at/by 10K

[AdlerDriver]

I got into a discussion with another pilot about descending and slowing by 10K. He was dumbfounded the first time he saw someone select altitude hold or roll the v/s to 0 at 10K, let the aircraft slow to 250 and then continue descending to the cleared altitude below 10K feet. He had been told/taught that doing that was illegal. He feels you must maintain the minimum descent rate ATC expects AND slow to 250 by 10K. He came from a purely civilian background.
Somewhere in my training, I ended up with the impression that ATC expects you to level off and slow at 10K prior to descending. I don't think I got that from the military because we didn't do it in fighters but I can't remember. I've done it and seen it done at the 3 airlines I've worked at and this is the first time I've even heard it mentioned as an issue.

Does anyone have a valid reference that would indicate if the level off technique is illegal? Thanks.

 

[banned username 2]

I got into a discussion with another pilot about descending and slowing by 10K. He was dumbfounded the first time he saw someone select altitude hold or roll the v/s to 0 at 10K, let the aircraft slow to 250 and then continue descending to the cleared altitude below 10K feet. He had been told/taught that doing that was illegal. He feels you must maintain the minimum descent rate ATC expects AND slow to 250 by 10K. He came from a purely civilian background.
Somewhere in my training, I ended up with the impression that ATC expects you to level off and slow at 10K prior to descending. I don't think I got that from the military because we didn't do it in fighters but I can't remember. I've done it and seen it done at the 3 airlines I've worked at and this is the first time I've even heard it mentioned as an issue.

Does anyone have a valid reference that would indicate if the level off technique is illegal? Thanks.

A level off at 10k to slow to 250 is allowed by ATC without asking for further permission... They expect it if you are going faster than 250 when reaching 10k...

 

[xtwapilot]

When I was based in STL with TWA, in an effort to make departures and arrivals efficient, we held routine meetings with the ATC. This topic came up, and ATC stated that they expect us to slow in the descend, not level off at 10K and then slow if given an altitude below 10k. There is also a reference to this in the AIM about optimum climb/descend until within 1000 ft of level off altitude. In STL we were asked by ATC to climb and descend on the sids/arrivals at 320 kts, on the MD80 one could do a 320 kts IAS descend and at 12600 ft, select IAS 250, and you would hit 250 on the nose as you went through 10k.

Xtwapilot

 

[81Horse]

From the AIM:​

4-4-9. Adherence to Clearance
...
d. When ATC has not used the term "AT PILOT'S DISCRETION" nor imposed any climb or descent restrictions, pilots should initiate climb or descent promptly on acknowledgement of the clearance. Descend or climb at an optimum rate consistent with the operating characteristics of the aircraft to 1,000 feet above or below the assigned altitude, and then attempt to descend or climb at a rate of between 500 and 1,500 fpm until the assigned altitude is reached. If at anytime the pilot is unable to climb or descend at a rate of at least 500 feet a minute, advise ATC. If it is necessary to level off at an intermediate altitude during climb or descent, advise ATC, except when leveling off at 10,000 feet MSL on descent, or 2,500 feet above airport elevation (prior to entering a Class C or Class D surface area), when required for speed reduction.

​

 

[xtwapilot]

Thanks for looking up the reference in the AIM, as I said before, ATC told us they expect us to slow while descending, not level off reduce to 250 and then continue the descend. If I'm given a level off at 10k, I keep the speed up until give lower, then slowdown and descend, however, if I'm given an altitude below 10k, then I start slowing in the descend, and have never seen anyone at any of the airlines I have been with descend to 10k, level off, slowdown, and then continue the descend.

Xtwapilot

 

[81Horse]

Thanks for looking up the reference in the AIM, as I said before, ATC told us they expect us to slow while descending, not level off reduce to 250 and then continue the descend. If I'm given a level off at 10k, I keep the speed up until give lower, then slowdown and descend, however, if I'm given an altitude below 10k, then I start slowing in the descend, and have never seen anyone at any of the airlines I have been with descend to 10k, level off, slowdown, and then continue the descend.

Well then, your local ATC facility was requesting that you operate contrary to the AIM. It's common procedure to level at 10000, slow to 250, then continue the descent; I'm amazed you've never seen it done this way. That said, nothing precludes a speed reduction during descent, if practical.

 

[Fox-Tree]

Thanks, I'd say the AIM reference says it all. You can level off if you need or want to.

 

[Holding Short]

I like this...you learn something new everyday.

 

[FL420]

When making a managed or VNAV descent the box will roll the speed bug back one to two thousand feet(depending on speed, weight, rate of descent, etc.) above 10K so as to be at 250 KIAS(plus zero, minus ten knots) as you descend through 10K. When hand flying or manually controlling the descent(e. g. - FLCH) you should try to do the same but, as others have said, it is not mandatory nor is it really expected.

 

[Flyerjosh]

Wait... we have to slow below 10,000'? I thought everybody decided that ATC could waive that for us.