Main Gearbox/Overtorque

Question 1

1) Loss of XMSN lubrication OR illumination of a GB CHIP warning light with an MGB CHIP annunciation on the VEMD Caution/Fuel page in conjunction with any one of the following:
- Yaw kicks
- Abnormal transmission noises
- Unusually high power requirements

2) Loss of XMSN lubrication AND illumination of a GB CHIP warning light with an MGB CHIP annunciation on the VEMD Caution/Fuel page

Answer 1

Main Gearbox Failure Imminent (pg 5-6)

(Warning: the potential loss of the airframe after aircrew egress is not sufficient cause to continue flight)

1) Landing/Hover checklist - complete (200 foot checks minimum based on urgency)
2) Land/Ditch immediately (power on)

Question 2

Any ONE of the following conditions:

1) Loss of MGB oil pressure and/or a complete loss of MGB lubrication
2) GB CHIP warning light illuminated with a MGB CHIP annunciation on the VEMD Caution/Fuel page
3) Abnormal transmission noises

Answer 2

Main Gearbox Malfunction (pg 6-7)

1) Monitor for secondary indications
2) Fly at a minimum safe altitude
3) Avoid high power maneuvers
4) Land as soon as practicable

(Note: in order to determine whether or not power requirements have increased for a MGB problem, the pilot should note flight regime, airspeed, and current power setting at the onset of the malfunction to establish a baseline for later comparison)

Question 3

1) Illumination of MGB PMP MAIN caution light
2) Decrease in XMSN oil pressure
3) Increase in XMSN oil temperature

Answer 3

Main Gearbox Pump Main Element Failure (pg 8)

1) Monitor xmsn oil pressure and temperature
2) Land as soon as practicable

Question 4

1) Illumination of MGB PMP AUX caution light

Answer 4

Main Gearbox Auxiliary Element Failure (pg 9)

1) Monitor xmsn oil pressure and temperature
2) Abort mission

Question 5

Any ONE of the following conditions:

1) MGB PRESS warning light illuminated
2) XMSN oil pressure in red or zero (may be accompanied by MGB exceedance in CDU due to shared transducer)
3) OIL TEMP warning light illuminated
4) XMSN oil temperature in red or zero

Answer 5

Main Gearbox Indicating System Failure (pg 9-10)

1) Monitor for secondary indications
2) Abort mission

Question 6

1) OIL TEMP warning light illuminated

2) Abnormal rise in MGB oil temperature

Answer 6

Main Gearbox Overtemp (pg 10)

“This failure may not be evident at airspeeds above 120 kias”

1) Cruise airspeed - 120 kias minimum
2) Land as soon as practicable

Question 7

1) Transmission oil pressure greater than 80 psi

Answer 7

Main Gearbox High Pressure (pg 10)

1) Land as soon as practicable

Question 8

1) MGB Q > 100% (10.0) but less than 104% (10.4) for 5 seconds or less
2) MGB Q > 104% (10.4) but less than or equal to 107% (10.7) or MGB Q >100% (10.0) but less than or equal to 104% (10.4) for more than 5 seconds
3) MGB Q > 107% (10.7)

Answer 8

Overtorques for Hover Flight and Transition Flight Between 0 and 80 kias (pg 12)

1) Reduce torque to within limits, when able
2) Abort mission
3) Land as soon as practicable

Question 9

1) MGB Q > 88% (8.8) but less than 94% (9.4) for less than 5 seconds
2) MGB Q > 88% (8.8) but less than or equal to 94% (9.4) for more than 5 seconds, or MGB Q > 94% (9.4) but less than or equal to 103% (10.3)
3) MGB Q > 103% (10.3)

Answer 9

Overtorques for Cruise Flight Above 80 kias (pg 13)

1) Reduce torque to within limits, when able
2) Abort mission
3) Land as soon as practicable