TM 1-1520-238-T-4
5–64
Change 9
5–24.
ISOLATING/MONITORING OTHER VIBRATIONS USING AVA EQUIPMENT (cont)
5–24
Source
RPM*
Hz*
Main rotor 1 per rev
289
4.82
Main rotor 2 per rev
578
9.6
Main rotor 3 per rev
867
14.4
Main rotor 4 per rev
1156
19.3
Main rotor 8 per rev
2312
38.4
Main rotor 12 per rev
3488
57.6
Main rotor 16 per rev
4624
76.8
Tail rotor 1 per rev
1403
23.4
Tail rotor 2 per rev
2806
46.8
Tail rotor 3 per rev
4210
70.2
Tail rotor 4 per rev
5616
93.6
Tail rotor drive shaft 1P
4815
80.3
Tail rotor drive shaft 2P
9630
160.6
Tail rotor vert drive shaft 1P
3636
60.6
Tail rotor vert drive shaft 2P
7272
121.2
Generator and SDC drive
12,251
204.2
Eng out drive shaft
20,952
349.2
Input drive shaft
9841
164.0
Hydraulic pump
12,635
210.6
APU drive shaft
8251
137.5
SDC Impeller
86,442
1440.7
M/R gearbox G3
1121
18.7
M/R gearbox G1
4391
73.2
M/R gearbox G2
4789
79.8
AGB Idler
4813
80.2
AGB Idler
4925
82.2
2 x SDC drive
24,503
408.4
Multiply by 1.01 for aircraft equipped with 701C engines.
2. EQUIPMENT INSTALLATION FOR PROBES OR FFT MEASUREMENT
a. Install Aviation Vibration Analysis (AVA) kit (TM 1-1520-238-23). Install DAU, CADU and associated
cables per para 1.108A only.
