TD 17 Flashcards
Spike Knock
A. Spike knock occurs when the round pin in the drag-pin fitting contacts the side of the square hole of the pylon stop, which is mounted to the roof. It creates a loud noise and will occur during the rocking of the pylon. The following factors can cause spike knock: low rotor RPM, extreme asymmetric loading, poor execution of autorotational landing and low G maneuvers below +.5 Gs.
B. Spike knock will be more prevalent during zero ground run autorotational landings than for sliding autorotational landings and running landings.
C. Spike knock in itself is not hazardous but it is an indicator of a condition that could be hazardous. If spike knock is encountered, an entry must be made on DA Form 2408-13-1 to include the flight conditions under which the spike knock occurred. An inspection will be performed by maintenance personnel before continuing.
D. During landing, starting, and rotor coastdown, spike knock could also occur, especially if there are high winds and/or the elastomeric damper is deteriorated. This type of spike knock is not considered damaging to the aircraft and does not require any entry in DA Form 2408-13-1.
Engine Surges
If surges in engine RPM are experienced:
A. GOV INCR switch- INCR for maximum RPM.
B. Throttle- Adjust to 97% N2.
C. Land as soon as POSSIBLE.
If engine surges are not controlled in steps A and B above, proceed as follows:
A. Autorotate- when over a safe landing area.
B. Emergency shutdown- accomplish during descent if time permits.
Fuel Boost Pump Failure
WARNING
Operation with both fuel boost pumps inoperative is not authorized. Due to possible fuel sloshing in unusual attitudes and out of trim conditions and one or both fuel boost pumps inoperative, the unusable fuel is ten gallons.
With one or both fuel pumps inoperative:
NOTE
The engine will operate without boost pump pressure under 6,000 feet pressure altitude and one boost pump will supply sufficient fuel for normal engine operations under all conditions of power and altitude. Both fuel boost pumps shall be operating for all normal operations.
A. Descend to below 6,000 feet pressure altitude if possible.
B. Land as soon as PRACTICABLE.
Fuel Boost Pump Limits
Fuel boost pumps shall be ON during normal operations.
