TM 55-1520-240-1
2-1.2.1 LOW FREQUENCY VIBRATION ISOLATION PROCEDURE (Continued)
2-1.2.1
1.
2.
3.
4.
5.
6.
7.
8.
9.
10
HAVE PILOT ESTABLISH 130 KNOT CRUISE PROFILE.
PLACE VIB PICKUP ON STA 95 BLOCK IN VERTICAL POSITION
TUNE BALANCER TO 225, 675, AND 1350 RPM AND RECORD
VIBRATION IN IPS.
PLACE VIB PICKUP ON STA 95 BLOCK IN LATERAL POSITION.
REPEAT STEP 3.
PLACE VIB PICKUP ON STA 482 BLOCK IN VERTICAL
POSITION.
REPEAT STEP 3.
PLACE VIB PICKUP ON STA 482 BLOCK IN LATERAL
POSITION.
REPEAT STEP 3.
LAND HELlCOPTER AND ANALYZE RECORDED VIBRATIONS.
1. DUPLICATE AIRCRAFT CONFIGURATION WHEN VIBRATION WAS
SENSED.
2. HAVE PILOT ESTABLISH FLIGHT PROFILE WHEN VIBRATION WAS
SENSED.
3. PLACE VIB PICKUP ON STA 95 BLOCK IN VERTICAL
POSITION.
4. TUNE BALANCER TO 225, 675, AND 1350 RPM AND RECORD
VIBRATION IN IPS.
5. PLACE VIB PICKUP ON STA 95 BLOCK IN LATERAL
POSITION.
6. REPEAT STEP 4.
7. PLACE VIB PICKUP ON STA 482 BLOCK IN VERTICAL
POSITION.
8. REPEAT STEP 4
9. PLACE VIB PICKUP ON STA 482 BLOCK IN LATERAL
POSITION.
10. REPEAT STEP 4.
11. LAND HELlCOPTER AND ANALYZE RECORDED VIBRATIONS
TABLE 2-1.2.
TABLE 2-1.2.
TASK 2-1.4.
TABLE 2-1.2.
TASK 2-1.3.
TASK 2-1.4.
TASK 2-1.5.
TASK 2-1.6.
TASK 2-1.5.
TABLE 2-1.2.1B. NORMAL VIBRATION
LEVELS AT 130 KNOTS
IDENTIFY BALANCER RPM SET-
TING AT WHICH HIGHEST LEV-
EL OF VIBRATION WAS
RECORDED. WAS HIGHEST
LEVEL AT 225 RPM (1/REV)?
REFER TO TROUBLE SYMPTOM
TASK 2-1.3.
2-4.4
Change 5
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