B737 Thrust Lever TLA Question
 

Could someone please explain how the TLA at the B737 is measured (reference point for 0 degree, idle position, max thrust)

Thanks!

Ruediger

Not sure what you are trying to understand..Idle is fully closed, " full thrust" available at forward stop..not like airbus logic

I think the question might relate to these points:

1. takeoff config warning is triggered by TLA = XYZ
2. various QRH lists ask you to "reduce TL to mid position."

Most other issues are related to idle thrust.

Not specific to the 737, but 'standard' Boeing terminology is that the idle stop is 0 deg. TLA. Moving the thrust lever forward gives a positive TLA, pulling the reverse piggyback results in a 'negative' TLA (e.g. -75 deg.).
I don't recall the specifics of the 737, but full forward TLA is between ~50 and 60 deg. TLA, depending on the aircraft model.
Not to be confused with TRA - Throttle Resolver Angle - which is the signal read by the FADEC. TRA typically varies from ~5 deg. (max reverse) to ~85 deg. (max TO thrust), idle is ~35 deg. (again, specific numbers vary a bit with the aircraft model).

Here are some angles (in degrees) from the 737NG Maintenance Manual:


Idle (0~2.4 TLA) at or close to aft stop
Maximum Climb (44 TLA)
Maximum take-Off/go-around (52 TLA)
Maximum certified thrust (58 TLA) @ forward stop

TLA = Thrust lever angle.

Maximum reverse thrust (104 RLA)
Idle reverse (62 RLA)

RLA = Reverse lever angle

The microswitch which triggers the takeoff configuration warning (on the 737NG) is part of the thrust lever mechanism which is referenced to TRA (refer to tdracer's message). This is quoted as greater than 53 degrees, but there are a few degrees latitude (51~55). I couldn't find an equivalent TLA value.

--> Thanks for your replies. Now it is much more clear for me. I have to deal with TLA in a software project.

Ruediger