JOAP ATOMIC EMISSION ROTRODE

NAVAIR 17-15-50.3

TM 38-301-3

T.O. 33-1-37-3

CGTO 33-1-37-3

ENGINE:

J85-GE-4A

AIRCRAFT:

(T-2C)

JOAP ATOMIC EMISSION ROTRODE

Abnormal Trend

(PPM Increase

in 10 hrs)

Normal Range

0-35

0-5

0-12

0-4

0-16

Marginal Range

36-44

6-7

13-15

*5-6

17-19

High Range

*45-53

8-10

16-17

13-14

20-23

Abnormal

54+

11+

18+

15+

24+

Average Concentration Other Elements:

Recommend remove if Fe and Cu are both in ranges indicated (High Fe and Marginal Cu)

NOTE

If iron (Fe) is in the high range with copper (Cu) less than 5 ppm and nickel (Ni) is

approximately 15% of the iron value, recommend that the unit be placed on 5 hour

sampling intervals until next aircraft phase inspection or operated for 125 hours,

whichever occurs first. Inspect compressor shaft for spline wear.

When Fe trend is increasing and with increasing Cu, suspect main bearing or accessory bearing defect. Suspect

first No. 1 main bearing; next, No. 2 main bearing or Axis "E" accessory bearing. High Fe is frequently due to Axis

"C" aft carbon seal mating ring wearing into Axis "C" aft bearing inner race. High Fe is also due to combination of

Axis "B" forward and Axis "F" forward bearing outer races spinning in their housings. J85 Power Plant Change 5

provides for chromium plating of Axis "B" forward, Axis "C" aft and Axis "D" forward bearing housings. This

change should reduce high Fe. Outer races turning will show increasing and high chromium. Fuel contamination

can be detected by the sampling catching fire. Small concentrations of fuel will be detected by odor. Recommend

inspection of fuel heat exchanger or fuel pump.

No. 1 bearing races

No. 1 bearing rollers and front frame casing

Nos. 2 and 3 bearing support

Accessory drive gearbox and PTO bearing balls/rollers and races

Accessory drive gearbox seal and bearing housings

Gearbox bearing spinning in liners, PTO scavenge tube

Main bearing carbon seal runners

No. 1 bearing compressor rotor front shaft

No. 2 bearing locknut and compressor driveshaft

No. 3 bearing locknut and turbine wheel shaft

PTO radial driveshaft, bevel gears, bearing housing, axial bearing support and

retainer

Accessory lube and scavenge pump spur gear, lube filter and oil cooler valve

Accessory drive gearbox shaft and bevel gears

A21