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:

TF34-GE-100A (AIR FORCE ONLY) (Cont)

AIRCRAFT:

(A-10)

Fretting between No. 3 bearing housing and front frame

Main lube and scavenge pump bearings

A-Sump scavenge pump bearings and drive coupling

Accessory gearbox bearing cages

No. 3 bearing anti-rotation key or fan labyrinth seal teeth

No. 7 main bearing rotating oil seal

Nos. 3, 4, 5 and 7 main bearing housings

No. 6 main bearing housing

No. 1 main bearing cage

Front fan shaft

Power take-off assembly bearing housing

No. 7 main bearing stationary oil seal

Fan forward shaft spline wear or No. 1 or No. 2 bearing loose on fan forward shaft

NOTES

1. A rapid increase of Fe could indicate No. 1 bearing spalling. This failure occurs

quickly, often with OAP readings within normal range.

If a 4 ppm increase of Fe, or if abnormal trend of any metal is noted, or if Fe increases

in combination with a 2 ppm increase in two or more of Ag, Cr, or Ni between

consecutive samples:

Perform chip detector inspection per T.O.'s 1A-10A-2-71JG-5 and 2JA18-2-2-1,

Section IV and 1A-10A-10-2 paragraph 4-22. If engine is not rejected for chip detector

contamination, perform three ground runs: idle-80% (for 5 minutes) idle (for 5 minutes)

per run and take OAP sample after each run.

a. If ground runs confirm the 4 ppm increase in Fe or abnormal trend, remove

engine for teardown inspection.

b. If the 4 ppm increase in Fe or abnormal trend is not confirmed, place engine

on special sampling after every flight until normal trend is firmly reestablished.

2. High Si indicates oil contamination, possibly from engine wash chemicals. Oil tank

should be drained and reserviced.

3. Fuel contamination in oil indicates oil cooler leak.

A59