JOAP ATOMIC EMISSION ROTRODE (Cont)

NAVAIR 17-15-50.3

TM 38-301-3

T.O. 33-1-37-3

CGTO 33-1-37-3

ENGINE:

J79-GE-15/-17 (Cont)

AIRCRAFT:

(F-4)

Caution must be exercised when evaluating this system due to the common oil supply of engine and CSD. When

Fe increases by itself or in combination with Cu, recommend transfer gearbox starter drive area be checked for

loose nut on drive or for broken carbon seal. Also recommend inspection of the front of transfer gearbox for same

problem and inspection of filters including CSD filter. When Cu increases in combination with Fe, but Cu is higher,

the problem will usually be in the CSD. Also, increase in Mg and/or in combination with Fe and/or Cu may be

caused by CSD's. The CSD should be removed and bench checked to determine if CSD replacement will

eliminate the wear metal problems. High Mg is usually indicative of discrepancy in the gearbox. Any increase in

Ag is usually indicative of incipient No. 2 bearing failure and will be accompanied with high Fe with or without

increases in Cu. When Fe increases 5 PPM, between consecutive oil samples from J79-15 and J79-17 engines

without accompanying increases to other wear metals, it may be indicative of an afterburner fuel pump bearing

failure. Check samples should be requested to confirm Fe increases. All unmodified afterburner fuel pumps (Part

Number P/N 512D809P8, P9, P11, and P12) will be removed and sent to repairable supply. Fuel pumps with

other part numbers may be retained but visually examined for discrepancies.

Main bearing housings

Afterburner fuel pump gears and bearings

No. 2 bearings, balls and races

No. 1 bearing rollers, races and carbon seal runners

Gearbox gears, shafts and splines

No. 3 bearing rollers and races

A-18