Table A-3. Element Sources

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

f. Silver (Ag) - Silver is used as plating on the input pinion and output gear splines. Presence of silver wear

particles usually indicates spline wear is occurring. Performance of torque checks on the nuts/bolts connecting the

input flange/inboard retention plate to the gearbox is used to determine if wear of these splines is present. See

also paragraphs 6c and 6d below.

g. Chromium (Cr) - Chromium is present in some steels, and as a plating on the input/output seal wear

sleeves. The presence of chromium wear particles may indicate wear of the seal sleeves, which would be

detected through excessive seal leakage.

h. Silicon (Si) - Silicon should be monitored due to its potential for causing abrasive wear inside the gearbox.

Usual sources are contamination from dirt and sand, or from silicon-based grease through the pitch control shaft

seal. Drain and flushes are recommended for silicon levels over 100 ppm.

Table A-3. Element Sources

Element

Component

Source

Fe (Iron)

Input Pinion

Wear with gear.

Output Gear

Wear with pinion.

Bearing Rollers,

Rolling Wear

Races, Cages

Pitch Change Shaft

Wear with gear ID.

Al (Aluminum)

Input Pinion Plug

Corrosion.

Input Flange1

Seal Wear.

Inboard Retention

Spline Wear.

Plate 1

Split Cones1

Wear with gear

and

Pitch Control Shaft

retention plate.

Bushing1

Wear with gear ID.

Ti (Titanium)

Input Flange

Seal wear.

Inboard Retention

Spline wear.

Plate

Mg (Magnesium)

Housings.

Corrosion.

Oil Spiral.

Corrosion.

Cu (Copper)

Split Cones.

Wear with gear

and

Pitch Control Shaft

retention plate.

Bushing

Wear with gear ID.

Input Pinion1

Ag (Silver)

Spline wear.

Output Pinion1

Spline wear.

A155