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Old 29th Dec 2012, 15:10   #1 (permalink)
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Join Date: Apr 2012
Location: Bangalore
Age: 25
Posts: 31
Red face thrust lever angle question

Cam someone explain what is the difference between thrust lever angle (TLA) and thrust lever resolver angle (TRA)
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Old 30th Dec 2012, 18:42   #2 (permalink)
Join Date: Apr 2008
Location: Central Europe
Posts: 55
Talking about the A320. TLA means the physical position of the thrust lever.
The lever is connected via rods to the throttle control artificial feel unit which basically is a friction brake and provides the notches for the different thrust lever detents.
Thereafter the motion is linked to the throttle control unit that contains the resolver and potentiometers and sends the signal = TRA to the ECU and flight control system.
The relationship between the throttle lever angle and throttle resolver
angle (TRA) is linear and : 1 deg. TLA = 1.9 TRA.
So TLA and TRA are linked values measured at different places.
Hope I could help you...

Oh , I just realized your Q might be related to the 737, but maybe you get the clue anyway.

Last edited by FLX/MCT; 30th Dec 2012 at 20:25.
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Old 30th Dec 2012, 21:39   #3 (permalink)
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Location: Australia
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The physical pivot points of the thrust levers are not necessarily where the position sensors (Thrust Resolvers) are located. Often there are rods/linkages attached to the thrust lever mechanisms which drive the position sensors. Due to the geometry of these linkages, the rotary motion of the thrust levers may not precisely correspond to the rotary motion of the position sensors. There may not necessarily be a linear relationship (aircraft dependent).

Of course, the engine control system is programmed to interpret TRA as required.

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Old 1st Jan 2013, 07:26   #4 (permalink)
Join Date: Feb 2009
Location: Singapore
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thrust lever angle question

TLA (thrust lever angle) indicates the position of the thrust lever in control stand from a reference point,usually this is 0degrees when thrust lever is at idle and increases up to 40 deg when thrust lever is advanced to take-off position.This thrust lever is connected by mechanical linkages to an electrical resolver synchro sensor called thrust lever angle resolver.The resolver has a stator and rotor,the angle of the rotor with respect to stator reference point changes as thrust lever is moved, this angle is called thrust lever resolver angle(TRA).This resolver is connected to electronic engine control(EEC) to control engine thrust for different positions of the thrust lever.Normally when thrust lever is at idle(TLA=0) then TRA may be 38deg. TRA may increase to 85deg when thrust lever is at take-off position.The exact values you can get in AMM. You have to rig the resolver to get correct angle when you install a new resolver,adjustment nuts will be provided on the linkages to do this.AMM gives the correct procedure.
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