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oy tower personnel. A local weather observation made at 1236 reported high scattered clouds, VlSlblllty‘ 8 miles. The wind was south-southwest at 12 knots.
New York Airways voluntarily suspended all passenger flights when notifi— cation of the accident was received.
Exanunation of company records revealed that the crew was qualified for this flight, and the helicopter had been maintained in accordance with applicable. regulations of the Federal Anation Agency (FAA). Computations indicated it was loaded With a center of gravity at 291.6 inches, and a gross weight of 13,985 pounds, both well within the allowable limits.
Over [1.5 eyeWitnesses to the accident were interViewed. A consensus of their accounts indicates that the flight climbed to an altitude of approximately 150 feet where structural failure occurred. Seventeen of the 25 who described this as rotor failure indicated that it was the aft rotor which separated. There was less agreement on the final maneuver; however, impact was described as tail first.
Examination of the wreckage indicated that the helicopter crashed tail first. in a left bank of 16 degrees, approxmately 800 feet from the lift-off pomt. The magor portion of the fuselage was consumed by fire. Separation of the aft rotor assembly, aft rotor drive shaft assembly, and aft pylon had occurred in flight. The forward greeré/ rotor blade, and aft yellow and green rotor blades had col— lided and dieintegrated in flight. The outboard section of the forward green blade was located 3,020 feet on an azmuth of 321 degrees from the crash Sites
There was no evidence of fatigue on any failed section of any of the Six rotor blades.
The two General Electric 01' SB-llO-«l Jet engines which prov1de the power for the Vertol lOT—II were subgeoted to detailed examination and no eVidence of pre— impact operational distress was found.
Follomng the acc1dent, the entire drive systemé/ of N 6673B was taken to the Vertol DiVision of the Boeing Company at Morton, Pennsylvania. Teardown and de- tailed examinatfifin, superViseg, by Board personnel, revealed that quill shaft P/N 10?D2067—l,_, S/N TA—lO2,_/ which transmits the drive force from the mix box to the aft transmission, had failed in fatigue. Three of the Six stepped studs P/N AN150832 which hold the mix box collector gear bearing retainer in plgfe had also failed in fatigue. In addition, it was diacovered that the two Jets_ de- Signed to lubricate the quill shaft were plugged With metal shavmgs. These
2/ The forward and aft rotors each contain color—coded red, yellow, and green—blades.
_3_/ The drive system consists. of: (l) a mix box which is a gearing assembly to mix the power from the twm turbine engines into a Single drive System, (2) a forward transmiSSion to transmit power to the forward rotor head, (3) an aft trans- mission to which the mix box is bolted, and which transmits power to the aft rotor head, and (h) a synchronizing shaft which promdes synchronization between the rotor heads, and transmits power from the mix box to the forward transmiSSion.
14/ The identifying part number for this part.
The identifying serial nmaber for this part.
/ P/N 107D2268—l is a finger jet which provides lubrication through an .OhO inch orifice directly onto the unsplined area of the quill shaft, and P/N 107D221h—1 is a plug Jet which prOVides lubrication through an .OhO inch orifice into the inn diameter of the quill shaft.
