MIL-L-23699E C/I (Corrosion Inhibiting)

NAVAIR 17-15-50.3

TM 38-301-3

T.O. 33-1-37-3

CGTO 33-1-37-3

MH-60A/UH-60L/MH-60L/MH-60K (U.S. ARMY ONLY) (Cont.)

TAIL ROTOR GEARBOX

c. Si - If silicon concentrations exceed 100 ppm, have the unit replace the lubricant. If silicon continues to

increase, have the unit drain and flush the component at the next PMS-2 phase inspection. More frequent

lubricant change is not required.

d. Cr - Do not track chromium. Chromium is used as a plating on seal wear sleeves and the pitch change

shaft. Other inspections are in place to maintain these items.

e. Al, Ni, Sn, Pb, Ag, Na, B, Mo, Zn - Do not track these elements. Do not recommend maintenance based

on concentrations of these elements.

4. MIL-L-23699E C/I (Corrosion Inhibiting) oil exhibits a detergent action when added to or used in place of

MIL-L-23699D oil in tail rotor gearboxes. This could cause false high Fe concentration levels in spectrometric

analysis results. Request AOAP laboratories use the following procedure to determine if Fe concentration levels

flagged during spectrometric analysis results were the result of detergency action:

Perform a spectrometric analysis of the oil sample.

Record the Fe concentration (ppm level).

Filter the sample through a millipore (0.45 micron) filter.

Rerun the spectrometric analysis using the filtered sample.

e. If there is no debris present in the filter and the level of Fe in the second spectrometric analysis remains

at approximately the same level as the first sample, then the Fe in the sample is in the form of soluble iron. If

there is a difference, then the difference should be used when evaluating the engine IAW TM 38-301-3 guidelines.

However, if nonmagnetic wear particles are present, perform the test in paragraph f.

Ferrographic analysis will be performed using the Direct Reading (DR) ferrograph to record the small to

large particle wear particle readings. If they are within prescribed ratio limits, then a ferrogram will not be required.

If they exceed the prescribed DR limits, then a ferrogram will be performed to validate the abnormal internal wear.

Maintenance recommendation will then be made in accordance with component guidelines.

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