78-22-10 AIRESEARCH MANUFACTURING COMPANY of ARIZONA: Amendment 39-3335. Applies to AiResearch Model TFE 731 - 2, - 3 and - 3R engines of the serial numbers listed certificated in all categories, equipped with low pressure rotor thrust ball bearings (number three bearings), Part No. 358736-2, manufactured by SNFA Bearing Corporation.
This AD applies to the following listed engine serial numbers:
ENGINE SERIAL NUMBERS
74606
77239
73431
73430
73433
74609
77240
80193
84121
74614
74604
74590
74615
74618
78227
77238
77241
73432
75294
77245
74591
74602
84123
84122
77243
84111
74587
76113
84120
78229
74605
75282
74616
75286
78226
74603
75279
74617
76112
77247
74589
75281
75285
77244
74620
75191
74419
77246
74101C
73299
74619
78151
73215
74624
73221
75175
74623
78129
75178
73111
74224
74508
75280
73209
Compliance required as indicated.
To prevent failure of the lowpressure rotor thrust ball bearing which could result in an immediate inflight shutdown of the engine, accomplish the following unless already accomplished.
(a) Before further flight after receipt of this AD, remove from the engine and visually inspect the inner face of both halves of the split inner race of the low pressure rotor thrust ball bearing (number three bearing), Part No. 358736-2, to determine the presence of the six radial oil lubrication grooves.
(1) If the inner face halves of the bearing inner race do not have a total of six radial oil lubrication grooves, the bearing should be removed and replaced with a conforming part which does have the six oil lubrication grooves in the inner face halves of the split inner race.
NOTE: There is an optional method of manufacturing raceway oil slots in low pressure rotor thrust ball bearing, Part Number 358736-2. Three raceway oil slots may be machined into each inner face of both halves of the split inner race or six raceway oil slots may be machined into the inner face of the forward inner race. Both options are acceptable.
NOTE: Bearings found to be improperly manufactured should be returned to the AiResearch Manufacturing Company of Arizona.
(2) If the bearing inner race halves do have the six radial oil lubrication grooves, the bearing may be reassembled, reinstalled and returned to service provided it is found to be otherwise serviceable.
(b) Special flight permits may be issued per FAR 21.197 and 21.199 to authorize operation of aircraft to a base where this inspection required by this AD may be performed provided that there is not more than one affected serial numbered engine listed in this AD installed on the aircraft.
(c) Equivalent inspection procedures and repairs may be used when approved by the Chief, Aircraft Engineering Division, FAA Western Region.
This amendment is effective November 13, 1978 and was effective upon receipt for all recipients of the priority mail letter dated September 22, 1978, which contained this amendment.