Question: take-off procedures

earthman · Post by **earthman** » 03 Nov 2005, 00:07

Hello all,

I seem to recall that once upon a time, before take-off, the plane would stand at the beginning of the runway, turn the throttle all the way up, with the brakes on, throttle down again, release the brakes, and then throttle up and go.

I haven't experienced anything of the sort in a long time. Why was this done, and why isn't it anymore? Or was this specific to certain regions and/or aircraft?

- Chris

Post by **luchtzak** » 03 Nov 2005, 00:12

On short runways this procedure is still used: e.g. London City, Florence (Italy).

As far as I know all the rest are rolling take-offs.

earthman · Post by **earthman** » 03 Nov 2005, 13:11

But why the engine run-up and back to idle before the actual take-off? Engine test? Warming up the engine?

Post by **luchtzak** » 03 Nov 2005, 13:17

I am sorry but I misread your original message, this part I overlooked: throttle down again

AFAIK this is not done anymore. As to my earlier post the procedure in London City and Florence are 'static take-offs': full throttle on the breaks, then releasing the breaks and take-off

V-Bird · Post by **V-Bird** » 03 Nov 2005, 15:03

I read several times that some russian build aircrafts ( Il-86 / Il-96 and An-124 ) need to warm up there engines before take off. I noticed my self that an Antonov 124 departing from Maastricht stands at the beginning of the runway, turn the throttle all the way up for at least 5 minutes, then released the brakes and took off....

earthman · Post by **earthman** » 03 Nov 2005, 15:34

Well, it most probably was on a Tu-154, in the 80s.

thomascookie · Post by **thomascookie** » 03 Nov 2005, 22:26

With a cessna 152 and other small planes we do this to see if the engine is working at a high RPM (+-1700RPM) so that we know that we have a working engine in TO.

Avro · Post by **Avro** » 03 Nov 2005, 22:49

V-Bird wrote:I read several times that some russian build aircrafts ( Il-86 / Il-96 and An-124 ) need to warm up there engines before take off. I noticed my self that an Antonov 124 departing from Maastricht stands at the beginning of the runway, turn the throttle all the way up for at least 5 minutes, then released the brakes and took off....

This is done on the AN124 because the engines are not reliable and the systems need to stabilize and warm up. This takes a while.

On current civil planes you will mostly hear the engine spool up to about 60-70% during initial take off and when the RPM needles are synchronized they spool up at full T/O thrust. This is apperently done to avoid asymetric thrust during take off and to stabilize the system. However I'd like a pro to back up this cause I'm not 100% sure of the reaosn.

Chris

bigjulie · Post by **bigjulie** » 05 Nov 2005, 22:40

It was a good feeling spooling up the engines against the break then letting the brakes off & whooshing down the runway for t/o

Zorba · Post by **Zorba** » 05 Nov 2005, 23:01

Avro wrote:
V-Bird wrote:I read several times that some russian build aircrafts ( Il-86 / Il-96 and An-124 ) need to warm up there engines before take off. I noticed my self that an Antonov 124 departing from Maastricht stands at the beginning of the runway, turn the throttle all the way up for at least 5 minutes, then released the brakes and took off....
This is done on the AN124 because the engines are not reliable and the systems need to stabilize and warm up. This takes a while.

On current civil planes you will mostly hear the engine spool up to about 60-70% during initial take off and when the RPM needles are synchronized they spool up at full T/O thrust. This is apperently done to avoid asymetric thrust during take off and to stabilize the system..

I think this is correct, the pilot non flying is normaly checking if both engines run at the same percentage during take off, and they indeed spoil the engines first up to see if both engines run fine.

The times I flew on GA aicraft we also did an engine test before line up (about 1700 rpm like thomascookie said). Always nice to feel the whole aircraft shaking like that