COMBINING GEARBOX (NAVY ONLY)

NAVAIR 17-15-50.3

TM 38-301-3

T.O. 33-1-37-3

CGTO 33-1-37-3

SH-2G

COMBINING GEARBOX (NAVY ONLY)

JOAP ATOMIC EMISSION ROTRODE

Abnormal Trend

(PPM Increase

in 10 hrs)

Normal Range

0-60

0-12

0-20

0-18

Marginal Range

61-70

13-15

21-25

19-22

High Range

71-86

16-17

26-30

23-26

Abnormal

87+

18+

31+

27+

Average Concentration Other Elements:

WATER LIMIT: 1,000 ppm on 0.100% (if equipment is available at lab)

The combining gearbox shares a common oil system with the main gearbox with oil

filters both in the oil pump and in the scavenge oil return line. Normal wear particles will

continue to increase until the gearbox is drained, flushed and reserviced in accordance

with NAVAIR 01-260HCD-2-4.1. Water in the oil will cause high iron and magnesium

because of corrosion. When high or abnormal wear metal readings are obtained, check

the oil for water content. If high or abnormal wear metals are detected and/or the water

content of the oil exceeds 1,000 (0.100%)*, the laboratory recommendation should be

"flush gearbox, reservice and perform serviceability check in accordance with NAVAIR

01-260HCD-2-4.1. Submit oil sample after serviceability check and special oil sample

after 10 flight hours of operation for both wear metals and water content."

*Water content check dependent on special equipment availability.

High metal readings without exceeding 1000 ppm water content may result in a

laboratory recommendation for flushing or removal of the gearbox. A minimum of two

consecutive high readings is required prior to recommending flushing or gearbox

removal unless secondary indications (chips, unusual noise, etc.) are present. Inform

CFA when recommending flushing. CFA concurrence is required prior to

recommending gearbox removal. Furnish CFA with five previous NOAP readings when

recommending gearbox removal.

A126