CHECK ENGINE COASTDOWN TIME
Army Rotary Wing Aviator
TM 55-2840-254-23 Without 74
TM 1-2840-265-23 With 74
Battery Connected (Task 1-39)
Engine Work Platform Open (Task 2-2)
Engine Access Cover Open (Task 4-49)
Procedure is same to check
coastdown time on No. 1 or No. 2
Have pilot operate engine until PTIT and oil
temperature has stabilized (TM 55-1520-240-10).
Set ENGINE CONDITION lever to GROUND.
After engine rpm has stabilized, set ENGINE
CONDITION lever to STOP.
Watch N1 indicator and check time required to
reach 0 rpm. If coastdown time is more than
25 seconds, go to Follow-On Maintenance. If
coastdown time is less than 25 seconds, go to
Inspect chip detectors (TM 55-2840-254-23
without 74 , TM 1-2840-265-23 with 74 ).