TAIL ROTOR GEARBOX (NAVY ONLY) (Cont)

NAVAIR 17-15-50.3

TM 38-301-3

T.O. 33-1-37-3

CGTO 33-1-37-3

H-53 (Cont)

TAIL ROTOR GEARBOX (NAVY ONLY)

A reading in excess of 150 ppm will require monitoring. Do not allow an oil change at this

time. Remove the pitch change shaft when Ti reaches high range of 250 ppm. These

high readings indicate wear to the inner shaft splines and to the output shaft.

Increasing high readings of Fe, Ti, and Cu indicate excessive wear to the gearbox and

pitch change shaft. When the Fe readings reach the abnormal level, remove gearbox and

pitch change shaft. Do not allow an oil change during the period of increasing wear metal.

A-144