ATC expected descent rates
01-18-2009, 06:39 PM
#1
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ATC expected descent rates
What rate of descent does ATC normally expect from aircraft?
Do they differentiate between a cruise descent, descent into the terminal area or a descent on vectors to final?
I've heard plenty of opinions on this so I'd appreciate an actual reference to backup your answer. Thanks.
Do they differentiate between a cruise descent, descent into the terminal area or a descent on vectors to final?
I've heard plenty of opinions on this so I'd appreciate an actual reference to backup your answer. Thanks.
01-18-2009, 08:58 PM
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Originally Posted by Adlerdriver
What rate of descent does ACT normally expect from aircraft?
Do they differentiate between a cruise descent, descent into the terminal area or a descent on vectors to final?
I've heard plenty of opinions on this so I'd appreciate an actual reference to backup your answer. Thanks.
Do they differentiate between a cruise descent, descent into the terminal area or a descent on vectors to final?
I've heard plenty of opinions on this so I'd appreciate an actual reference to backup your answer. Thanks.
There are minimum rates (500 fpm I think), but they are so fuel inefficient that no one would normally want to descend at that rate. I have several friends who are controllers and they say that everything is normally based on traditional descent points. They know, based on experience, where to issue descents because if they wait too long there is a spot where pilots will always request lower.
01-18-2009, 09:05 PM
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Originally Posted by rickair7777
I've heard 1.5, but 1.0 would be reasonable in the terminal area. I think it's in the aim.
Don't descend at 0.5 without warning ATC...they will be very unhappy.
Don't descend at 0.5 without warning ATC...they will be very unhappy.
What I'm asking for is the minimum they expect.
01-18-2009, 09:13 PM
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Originally Posted by 2themoon
There are minimum rates (500 fpm I think), but they are so fuel inefficient that no one would normally want to descend at that rate. I have several friends who are controllers and they say that everything is normally based on traditional descent points. They know, based on experience, where to issue descents because if they wait too long there is a spot where pilots will always request lower.
I want to know what they would expect in that situation. Another common situation would be while on vectors in the terminal area. If I'm at 10,000 and get a descent to 3,000 but I'm no where near getting turned to final, what would be the minimum descent rate that I could use. I'm talking about situations where we are given an early descent and I don't want to descend at a normal rate and get down early.
01-18-2009, 09:17 PM
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All depends on the situation. 500fpm is what the ask for as a minimum. The rest is usually dependent upon passenger comfort, descent planning or ATC request.
If I'm in the terminal area and it's a situation like you mentioned, 1000fpm seems to be a good number.
If I'm in the terminal area and it's a situation like you mentioned, 1000fpm seems to be a good number.
01-18-2009, 09:53 PM
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I've had this discussion in person and I've seen it on forums. I'm not looking for a number someone thinks is okay or asking for everyone's opinion.
I'm asking if there is an ATC controller or pilot out there who knows of an actual regulation, ATC rule, or some other reference, etc. Something that's actually published in writing that will support a specific minimum descent rate that can be used in the event of an early descent.
I'm asking if there is an ATC controller or pilot out there who knows of an actual regulation, ATC rule, or some other reference, etc. Something that's actually published in writing that will support a specific minimum descent rate that can be used in the event of an early descent.
01-18-2009, 10:28 PM
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Most STARS have crossing altitudes that allow the pilot to make the most economical decent (or what ever profile works that day) when "cleared to descend via.....". If not on a STAR, most controllers will assign an crossing restriction on the cleared route - then it's up to the pilot to make that or declare the ever popular "unable". In both cases it's up to the pilot to adjust the rate to make the crossing.
01-19-2009, 08:11 AM
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AIM 4-4-10 (d)
Climb or Descend at a rate consistent with the operating characteristics of the aircraft to 1000' above/below the assigned ALT. Then maintain 500-1500 fpm to the assigned ALT.
Advise ATC if you cannot maintain at least 500 fpm.
That should be the answer, unless the AIM contradicts itself somewhere else.
However...if you descend at 500 fpm out of the flight levels, expect ATC to get upset (unless you doing a crossing restriction). They plan descents based on what most airplanes usually do (2000-3000 fpm), not 500 fpm.
Climb or Descend at a rate consistent with the operating characteristics of the aircraft to 1000' above/below the assigned ALT. Then maintain 500-1500 fpm to the assigned ALT.
Advise ATC if you cannot maintain at least 500 fpm.
That should be the answer, unless the AIM contradicts itself somewhere else.
However...if you descend at 500 fpm out of the flight levels, expect ATC to get upset (unless you doing a crossing restriction). They plan descents based on what most airplanes usually do (2000-3000 fpm), not 500 fpm.
01-19-2009, 10:06 AM
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Originally Posted by HSLD
Most STARS have crossing altitudes that allow the pilot to make the most economical decent (or what ever profile works that day) when "cleared to descend via.....". If not on a STAR, most controllers will assign an crossing restriction on the cleared route - then it's up to the pilot to make that or declare the ever popular "unable". In both cases it's up to the pilot to adjust the rate to make the crossing.
I really don't think some of you guys are reading my question. I'm not talking about descending via a STAR to meet a restriction or some other restriction if not on a STAR. I understand what is required of pilots in order to make crossing restrictions.
What I am talking about are the times we are given a descent MANY MILES BEFORE the "normal" descent points on a STAR, or a cruise descent to a new flight level HOURS before we will begin the true descent on a STAR into the terminal area.
Originally Posted by rickair7777
However...if you descend at 500 fpm out of the flight levels, expect ATC to get upset (unless you doing a crossing restriction). They plan descents based on what most airplanes usually do (2000-3000 fpm), not 500 fpm.
I disagree with this because I do it all the time. There’s no way I’m going to descend at 2000-3000 fpm in order to change flight levels or if I’m given an early descent. If what you say is true, however, give me a reference. Not just your opinion that I should expect “ATC to get upset”, because in my experience they don’t. I’m just trying to find out what they do expect for my own knowledge.
What is the lowest vertical speed I am allowed to use in order to ease my aircraft down to the new flight level or slowly descend until I meet the normal STAR descent profile? If that's not clear enough, I'm going to give up. If you have an answer, PLEASE include a reference to back up your answer.
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