Cleared for desent

[thatwasclose]

Hi guys,

When ATC gives a desent clearance, for a jet aircraft, what is the min ft per min that they presume the aircraft will do. I was under the impression that it was a 1,000 ft, but would like to make sure. If someone has the answer could they please give a referance source if they could.

Cheers

Thatwasclose

[MancBoy]

500fpm unless informed by the driver

[!turnleftrightnow!]

I think there is no rule!
Experience shows that every airline is doing it differently:
-SWR would give you 1000ft/min
-AUA 300ft/min
-UAE 2500ft/min
...after a while you know how your "babies" behave...:cool:

[Dream Land]

I was taught that ATC expects you to advise them if you are unable to climb at least 500 FPM or better...:confused:

[2 sheds]

There is a "rule" - as MancBoy sums up, from the UK AIP...

Minimum Rates of Climb and Descent
2.2.1 In order to ensure that controllers can accurately predict flight profiles to maintain standard vertical separation between aircraft, pilots of aircraft commencing a climb or descent in accordance with an ATC Clearance should inform the controller if they anticipate that their rate of climb or descent during the level change will be less than 500 ft per minute, or if at any time during such a climb or descent their vertical speed is, in fact, less than 500 ft per minute.
2.2.2 This requirement applies to both the en-route phase of flight and to terminal holding above Transition Altitude.
Note: This is not a prohibition on the use of rates of climb or descent of less than 500 ft per minute where necessary to comply with other operating requirements.

[thatwasclose]

Thanks for the reply guys. Is there an IACO standard. Thanks again for the info.

[Farrell]

ICAO Air Traffic Management Doc 4444

4.7.1.3
The flight crew shall inform the ATC unit concerned if unable, at any time, to comply with a specified rate of climb or descent. In such cases, the controller shall apply an alternative method to achieve an appropriate separation minimum between aircraft, without delay.

[2 sheds]

But the latter refers to a specified rate of descent, i.e. specified by ATC tactically to maintain vertical separation in a particular instance.

[DirtyPierre]

In Oz no rate of descent is assumed.

Every company, and indeed every pilot will descend at varying rates even in the same type. There are general parameters for types, but these a large range in which pilots can work.

As a radar controller doing sequencing into a major airfield, I'm more concerned with ensuring an aircraft meets its feeder fix time to be placed in the sequence correctly and that I ensure separation with crossing, merging or other conflicting traffic.

Also, ATCs, through experience, know roughly where each aircraft type will commence descent and how quickly they will descend. E.G. A320 has a shallower profile compared to the B738/7.

[aviator007]

Generally the standard is 500fpm for non pressurised aircraft. Turbine can vary but will be limited by descent angle and speed

[eyeinthesky]

500fpm is indeed the minimum, but does not apply (in the UK at least) when on a CDA approach after leaving the terminal holding fix.

[ElNino]

500fpm is indeed the minimum, but does not apply (in the UK at least) when on a CDA approach after leaving the terminal holding fix.

Would you have a reference for this?

Or is it covered by
Note: This is not a prohibition on the use of rates of climb or descent of less than 500 ft per minute where necessary to comply with other operating requirements.

I have used the latter quote as my argument for maintaning sub-500fpm ROD when on CDA's, as some argue that you must maintain 500fpm, even if this results in being unable to maintain a CDA. A reference (if it exists) would be nice for the next debate on the matter!