A320 takeoff thrust
Only half a speed-brake
(10 years on CFM-powered A320, thereafter mixed fleet)
It takes just under 2 sec from stabilized 50% (OEM procedure) to flex/TO/TOGA. J.L.S. most likely refers to the time needed from 18% ground idle to that 50% N1 stabilized, which once in a blue year varies just wildly.
The usual suspects: Dual or singular combustor (different engines), uneven use (asymmetrical thrust taxi), engine state (EGT margins), and a little crosswind seem to play a role. Waiting those 3 seconds for the slower engine to catch up (to 50%) feels like an eternity.
So 3+2 on one, 3+3+2 on the other.
Definitely saw that couple of times, and when the other person didn't, much screaming ensued.
It takes just under 2 sec from stabilized 50% (OEM procedure) to flex/TO/TOGA. J.L.S. most likely refers to the time needed from 18% ground idle to that 50% N1 stabilized, which once in a blue year varies just wildly.
The usual suspects: Dual or singular combustor (different engines), uneven use (asymmetrical thrust taxi), engine state (EGT margins), and a little crosswind seem to play a role. Waiting those 3 seconds for the slower engine to catch up (to 50%) feels like an eternity.
So 3+2 on one, 3+3+2 on the other.
Definitely saw that couple of times, and when the other person didn't, much screaming ensued.
Last edited by FlightDetent; 11th Feb 2023 at 18:55.
Only half a speed-brake
2 OP: I understand where that question comes from but after a little insight, it is just plain silly.
Please walk with me, from 50% (1,05) up:
a) If you shoved TLs to TOGA/FLEX in an instant, the actual engine acceleration will follow the FADEC schedule.
b) If you move the TLs in a controlled fashion up, but always staying ahead of the N1 as the engine accelerates, the FADEC schedule is the same as a) above.
c) If you advance too slowly and restrict the acceleration, that's plain wrong.
a) or b) is the same, c) is mishandling. Headwind makes no difference.
Please walk with me, from 50% (1,05) up:
a) If you shoved TLs to TOGA/FLEX in an instant, the actual engine acceleration will follow the FADEC schedule.
b) If you move the TLs in a controlled fashion up, but always staying ahead of the N1 as the engine accelerates, the FADEC schedule is the same as a) above.
c) If you advance too slowly and restrict the acceleration, that's plain wrong.
a) or b) is the same, c) is mishandling. Headwind makes no difference.
Get back in the sim, it goes 1 straight to 1.2, and that’s only a small part of the scale. Lot easier until you’ve got the muscle memory to set a visual picture than try and gauge 25% of the way of just a small scale graduation.
At least after a couple of hundred goes your hand just does it, surprisingly accurately as well.
At least after a couple of hundred goes your hand just does it, surprisingly accurately as well.
Only half a speed-brake
The jump from 1.1 to 1.2 probably refers to N1 exclusion zone on the IAE, where fadec refuses to command a setting within a specified vibration zone, resuliting in non-linear thrust control. No FCOM at hand, something like 62-75 N1.
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Get back in the sim, it goes 1 straight to 1.2, and that’s only a small part of the scale. Lot easier until you’ve got the muscle memory to set a visual picture than try and gauge 25% of the way of just a small scale graduation.
At least after a couple of hundred goes your hand just does it, surprisingly accurately as well.
At least after a couple of hundred goes your hand just does it, surprisingly accurately as well.
