And yet another thing
In a couple of places folks have made reference to a rate of 500'/min as being what ATC expects when a descent clearance is issued. It is not correct that anything over this rate is "gravy!" ATC expects you to descend at a rate that's optimal for the aircraft and they have a list of aircraft and what each will do to use as a guideline.
There are two viewpoints from shich this must be seen. First, there is AIM Para. 4-4-9 (d), which says:
"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 B, Class C, or Class D surface area), when required for speed reduction.
REFERENCE-
14 CFR Section 91.117.
NOTE-
Leveling off at 10,000 feet MSL on descent or 2,500 feet above airport elevation (prior to entering a Class B, Class C, or Class D surface area) to comply with 14 CFR Section 91.117 airspeed restrictions is commonplace. Controllers anticipate this action and plan accordingly. Leveling off at any other time on climb or descent may seriously affect air traffic handling by ATC. Consequently, it is imperative that pilots make every effort to fulfill the above expected actions to aid ATC in safely handling and expediting traffic."
Here's the link:
http://www.faa.gov/atpubs/AIM/Chap4/aim0404.html#4-4-9
The other viewpoint from which this must be understood is that of the controller who issues an altitude clearance. What a controller is told you will do when he issues a clearance is found in FAA Order 7110.65P - most often redferred to as the Controllers' Handbook. Para 4-5-7 (d) addresses he specific example of issuance of a clearance without any express or implied pilot discretion.
"EXAMPLE-
"United Four Seventeen, descend and maintain six thousand."
NOTE-
The pilot is expected to commence descent upon receipt of the clearance and to descend at the suggested rates specified in the AIM, para 4-4-9, Adherence to Clearance, until reaching the assigned altitude of 6,000 feet."
So, we're back to the AIM at least as far as we're concerned. However, that's not all that the controller has at his disposal. Appendix A of 7110.65P is packed full of aircraft information for controller reference. The figures are very enlightening since they are the only real guidance controllers have as to the performance of a particular aircraft type.
Here's a link to the page:
http://www.faa.gov/atpubs/ATC/Appendices/atcapda.html
Here's what it says a 737-300 can be expected to do in terms of performance:
Climb = 5,500'/min
Descent = 3,500'/min
Now, no matter what you think of these numbers they
ARE what controllers think you will do. This is what controllers feel is optimal - for AIM purposes.
The last thing I wanted to stress is that you can't just loung aournd up there. When ATC issues a descent or a speed restriction you are expectd to comply with the instruction promptly. Simply pulling the power back and waiting four or five minutes for the thing to slow from 270 to 210 isn't gonna cut it. That's not timely compliance and it could mess a thing or two up.
Here's the reference from AIM 4-4-9:
"Leveling off at 10,000 feet MSL on descent or 2,500 feet above airport elevation (prior to entering a Class B, Class C, or Class D surface area) to comply with 14 CFR Section 91.117 airspeed restrictions is commonplace. Controllers anticipate this action and plan accordingly. Leveling off at any other time on climb or descent may seriously affect air traffic handling by ATC. Consequently, it is imperative that pilots make every effort to fulfill the above expected actions to aid ATC in safely handling and expediting traffic."
There's a lot more to this but I'm outta time right now. I think I'll just sit back and see how this goes over.
TIS