WHILE CRUISING AT 200 FT AGL, 130 KTS, PILOTS FELT LATERAL VIBRATIONS THAT CONTINUED TO INCREASE IN INTENSITY. ACFT WAS LANDED AND SHUT DOWN FOR INSPECTION. FORWARD ROTOR HEAD WAS TOO HOT TO TOUCH, TO TOUCH, HORIZONTAL HINGE PIN BEARING ON YELLOW BLADE HAD FAILED. HORIZONTAL HINGE PIN AND BEARING ON FORWARD ROTOR HEAD OVERHEATED.¿¿
16. COMPONENT AND PART FAILURE/MALFUNCTION DATA
Major Component Information
a. Nomenclature
b. Type/Design/Series
c. Part Number
d. NSN
e. MFG Code
f. Part Serial No
ROTOR & XMSN
Part Information
a. Nomenclature
c. Part Number
d. NSN
e. MFG Code
f. Part Serial No
PIN
114R21971
1615001858295
77272
g. Cause Failure
Functional Group
Material
Maintenance
Design
Manufacture
04 - ROTOR AND TRANSMISSION 08 - MAIN ROTORS, NOT BLADES
DEFINITE ROLE
NONE
50 - GRIP 08 - EIGHT
Type Failure
Cause Failure
509 - SPALLED
-
859 - METAL FATIGUE
-
17. ENVIRONMENTAL
a. General
(1) IMC
(2) VMC
(3) Unknown
b. Environmental Conditions
1. Weather Conditions
2. Other Conditions
(a) Hail
(a) Animals
(b) Sleet
(b) Fowl
(c) Fog
(c) Surface
(d) Drizzle
(d) Noise
(e) Rain
(e) Chemicals
(f) Snow
(f) Radiation
(g) Lightning
(g) Glare
(h) Thunderstorm
(h) FOD
(i) Gusty Winds
(i) Temperature
(j) Freezing Rain
(j) Vibration
(k) Other
(k) Dust
c. Aircraft Icing
No Yes
d. Turbulence
No Yes
19. MOON ILLUMINATION DATA
a. Above Horizon
b. Visible
c. Degrees Above Horizon
d. Percent Illumination
e. Clock Position
No Yes
No Yes
20. WIRE STRIKE DATA
a. Wire Strike
b. WSPS Installed
c. WSPS Engaged
No Yes
No Yes
No Yes
d. WSPS Cut Wire
e. WSPS Functioned
f. Wires Struck
No Yes
No Yes
Number wires
0
Dia.(inches)
21. PERSONNEL DATA
Person # 1
c. Grade
d. Sex
e. Duty
W4
PI - PILOT
f. SVC
g. UIC
h. Role
i. On Controls
O - OTHER
WC5LAA
U - UNKNOWN
No Yes
j. Lab Test
k. Hrs Slept 24
l. Hrs Worked 24
m. Hrs Flown 24
Yes No
n. RL
o. FAC
p. Injury
q. MTDS Total Flt Hrs
1 2 3
1 2 3
-
0
Person # 2
c. Grade
d. Sex
e. Duty
W2
PC - PILOT IN COMMAND
f. SVC
g. UIC
h. Role
i. On Controls
O - OTHER
WC5LAA
U - UNKNOWN
No Yes
j. Lab Test
k. Hrs Slept 24
l. Hrs Worked 24
m. Hrs Flown 24
Yes No
n. RL
o. FAC
p. Injury
q. MTDS Total Flt Hrs
1 2 3
1 2 3
-
0
22. IMPACT/PROTECTIVE/ESCAPE/SURVIVAL/RESCUE DATA
a. Aircraft Space Compromised
b. Escape/Survival Difficulties
c. Protective/Restraint Equip Functioned
No Yes
No Yes
No Yes
24. FINDINGS AND RECOMMENDATIONS
Findings
DISASSEMBLY INSPECTION REPORT--CH-47C, 68-15993 CONCLUSIONS A. ANALYTICAL INVESTIGATION OF THE MAIN ROTOR HEAD ASSY REVEALED THE PRIMARY FAILURE WAS THROUGH SPALLING FATIGUE MECHANISMS OF THE PIN AND BEARING RACEWAYS. B. THE ROLLER BEARINGS FAILED THROUGH IMPACT LOADING. REF: LABORATORY REPORT NUMBER 78MX25 (INCL 11-18).