A320-Thrust Lever Movement.

[Flyman35]

I’ve been advised during simulator sessions in Toulouse that I should take the thrust lever from CL to Idle (at touch down) progressively and not gradually as it is not going to make any difference as FADEC is managing the process,the instructor stated that he saw many people doing it gradually but there is no reason for it as he said. now my question what about setting FLEX or TOGA in Take off should it be gradually from the stabilized point (50% N1) or should be progressively and why?

[Founder]

I do it gradually, takes about 3-5 secconds for me to go from 50% to Flex...

Any engine is subject to thermal shock and its not "healthy" in the long run to stress the engines more than necessary so why not go slow =)

sure if you are on a very short runway it might be advisable to advance the thrust-levers faster...

[BOAC]

sure if you are on a very short runway it might be advisable to advance the thrust-levers faster...- runway performance should be predicated on throttle handling EXACTLY iaw the manufacturer's (doorman's) drivers' handbook.:) There should be no need to change the way you do it for 'short' runways (other than 'for mum').

[Meikleour]

On the A320/A330/A340 with the autothrust engaged on finals you will see that the achieved N1 is considerably less than the TLA position (the blue circle is the thrust limit at the time due to the levers being in the CL detent.) When the thrust levers are retarded for landing you will see that the first large part of the lever movement simply brings the blue donought down towards the actual N1 being used. Until it passes below the actual N1 there is NO CHANGE in the thrust. So a slow, progressive closure of the thrust levers actually makes no difference to the thrust until the last part of the movement. The final part also disengages the autothrust.

I think this should explain to you what your instructor was trying to put across plus unlike more conventional aircraft, it is possible for the thrust to slowly rise in the flare if the lever closure is too slow.

[Flyman35]

thanks for the explanation,now what about take off,is there any problem if I apply the Thrust lever sharply and progressive or should it be slow and smooth.

[Joetom]

I thought with autothrust engaged, autothrust info is based on detent above lever position if out of a detent, so only when lever is in the idle detent will autothrust change from CL to IDLE.

So may be on short runways, people may like to move levers quick to idle.

I think the report on the TAM 320 in 2007 may be a good info read.

Cheers....

[guiones]

Thrust lever movement should be positive, on take off after 50% N1(CFM) or 1.05 EPR(IAE), just take it to the next position desired without any hesitation. The FADEC will take care of the engine, slow movement of the T/L is not necessary.

On landing with A/TH on, the ONLY reason to take the T/L to idle is to disconect the A/TH, it should be retarded immediately to idle, no reason to delay or do it slow.

Your Airbus Instructor is right on!!

G

[autoflight]

After touchdown, reverse idle then reverse thrust are normally your targets to save on brake wear. If thrust lever is already at zero on touchdown, there is no additional delay. Work back from there to find a comfortable retardation rate depending on the circumstances.

[PENKO]

I thought with autothrust engaged, autothrust info is based on detent above lever position if out of a detent, so only when lever is in the idle detent will autothrust change from CL to IDLE.


Joetom, the thrust limit is based on whatever the position of the TL is at that moment. In the climb detent it happens to be climb thrust but if you position the TL halfway, say at 55% N1, autothrust will command up to 55% N1 (and you get an 'A/THR limited' caution on ECAM reminding you of this fact). So in the flare when you slowly move the tl towards idle, all you are doing is slowly restricting the autothrust and whatever N1 it is commanding, until you disengage it in the idle detent.

So yes, if you want to chop all the power quickly, you move the levers quickly, as you would in any other aircraft. If you move them slowly, well, be my guest if you know what you are doing...but you could then ask yourself why you are using autothrust in the first place?:ok:

[Flyman35]

The FADEC will take care of the engine, slow movement of the T/L is not necessary.


Thanks for the information, but is there any reference?