AS350 Overtorque Question
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Join Date: Jan 2004
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AS350 Overtorque Question
I found out recently that there is a difference on inspections to be done after an overtorque in an AStar (AS350) Helicopter. The Maintenance Manual states that if at hover or in flight the torque is over a certain % (I believe it is 117%), certain components have to be scrapped where as if the overtorque happens just before hover or after hover it is only a visual inspection.
Can anybody explain to me as to why such a big difference in inspection criteria?
Cheers,
Bitmonx
Can anybody explain to me as to why such a big difference in inspection criteria?
Cheers,
Bitmonx
Join Date: Feb 2004
Location: Just west of here
Posts: 62
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Tq is measured within the engine reduction box which is driving the power output shaft. Power is taken from the front of the output shaft for MGB drive and from the rear of the shaft for T/R drive. Thus the measured Tq needs to provide drive for both rotors but the aircraft is Tq limited by the MGB only.
During hover some 10% - 12% of the total measured Tq is being absorbed by the TGB. Once forward airspeed increases less and less Tq is absorbed by the TGB and the MGB is receiving an increasing share, hence the arbitrary 40 kts Tq values.
It follows that 117% in flight means that most of it went to the MGB but below 40 kts and down to a hover, the TGB has absorbed an increasing portion of the measured 117%. OK?
WRL
During hover some 10% - 12% of the total measured Tq is being absorbed by the TGB. Once forward airspeed increases less and less Tq is absorbed by the TGB and the MGB is receiving an increasing share, hence the arbitrary 40 kts Tq values.
It follows that 117% in flight means that most of it went to the MGB but below 40 kts and down to a hover, the TGB has absorbed an increasing portion of the measured 117%. OK?
WRL
