INTERMEDIATE GEARBOX (Cont)

NAVAIR 17-15-50.3

TM 38-301-3

T.O. 33-1-37-3

CGTO 33-1-37-3

SH-60B, SH-60F, HH-60H, UH-60L (Cont)

EH-60A, MH-60L, MH-60K, MH-60S, MH-60R AND VH-60N

INTERMEDIATE GEARBOX

Iron may indicate wear or corrosion of input pinion gear, output bevel gear,

bearings, or liners. If iron level enters marginal or high range,

recommendation shall be to "Submit oil samples approximately each 10 flight

hours for the next 30 flight hours. Do not change oil at this time. If iron level

does not increase to abnormal upward trend occurs, change oil to remove

potentially abrasive iron particles and return to normal sampling". If abnormal

iron level or abnormal upward trend occurs, recommendation shall be to

"Change oil, submit sample after initial turn-up, and submit samples

approximately each 10 flight hours for next 30 flight hours. If iron level

remains below marginal range and non abnormal upward trend occurs within

this 30 hour period, return to normal sampling".

If iron level climbs to marginal range or above or if abnormal upward trend

occurs within this period, recommendation shall be to "Perform serviceability

check of intermediate gearbox in accordance with aircraft general information

manual."

Primary source of silver in the intermediate gearbox is plating on male

splines on the input opinion and output bevel gears. These splines mate with

the input and output flange splines. Though not in wetted area of gearbox,

wear particles can in some cases migrate through faying surfaces into oil

system. Secondary source of silver in intermediate gearbox is plating on

inner diameters of input and output flange sleeves. These surfaces are press

fit onto flanges and are not subject to normal wear. If silver level enters

marginal or high range, recommendation shall be to "Submit oil samples

approximately each 10 flight hours for the next 30 flight hours. Do not change

oil at this time. If silver level does not increase to abnormal range and no

abnormal upward trend occurs within this period, change oil at the end of the

30 hour period and return to normal sampling". If silver level enters abnormal

range, or if abnormal upward trend in silver occurs, recommendation shall be

to discontinue flight operations and check for proper torque on input and

output flange nuts per transmission system maintenance manual. If proper

torque is confirmed, recommendation shall be to "Change oil, submit oil

sample after initial turn-ups, and submit oil sample approximately each 10

flight hours for the next 30 flight hours. If silver level remains below marginal

range and no abnormal upward trend occurs within this 30 flight hour period,

return to normal sampling". If silver level returns to marginal range or above

or if abnormal upward trend in silver level occurs within this 30 flight hour

period, recommendation shall be to "Immediately discontinue further flight

operations, remove input and output flanges, and inspect flange splines and

gear splines for fretting/wear in accordance with system maintenance

manual".

There are two components in the intermediate gearbox that might produce

aluminum wear particles under specific wear conditions. Wear/fretting on the

input and output flanges can produce aluminum and titanium. A third and

fourth component, the input pinion and output bevel gear plugs, are 2024

aluminum, but are not normally subject to service wear. If aluminum level

enters marginal or high range, recommendation shall be to "Submit oil

samples approximately each 10 flight hours for the next 30 flight hours. Do

not change oil at this time. If contamination does not increase to abnormal

range and no abnormal upward trend occurs at any time within this period,

change oil and return to normal sampling". If aluminum level enters abnormal

A162