TM 55-2840-254-23
1-107
1-107 TEST ENGINE (AVIM) (Continued)
d. Check calibration of vibration meter and check for indications from all transducers; indications
shall not exceed limits given below.
Velocity (Inches/Second)
Position
0.94
Water Brake*
0.63
Front Vertical
Rear Vertical
0.84
0.94
Axial
*For indication of water brake condition only. Do not reject engine
if this position exceeds limit.
e. Visually check engine for external leaks.
f. Check all pressure and temperature indicators.
g. If gearbox pressure is greater than 5 psig or if No. 2 bearing oil temperature indication is high, shut
down engine (Ref. Paragraph 21) and check No. 2 bearing package for seal leakage (Ref. Task 1-87).
h. Maintain speed for 2 minutes and take a short reading.
i. Mark oil level on engine oil level indicator.
j. Ensure N2 master hydronic control is advanced to maximum position before proceeding with test.
6. BLEED BAND CLOSURE CHECK
NOTE
When bleed band closes, a distinctive change in engine pitch will
be noted. Bleed band closure shall be gradual within 3 to 6 percent.
To properly check bleed band operation, station helper at engine
during following test to physically check for air movement past
bleed band.
GO TO NEXT PAGE
1-470
