AD 73-11-01

73-11-01 HUGHES: Amendment 39-1641. Applies to Hughes Model 269C Helicopters, certificated in all categories, incorporating idler pulley bearings, P/N 269A5050-62.

Compliance required as indicated:

To prevent possible failure of idler pulley bearings, accomplish the following:

(A) For all helicopters, serial numbers 0004 through 0092 listed in Hughes Service Information Notice No. N-90.1, dated September 7, 1971, which, as of the effective date of this AD, have idler pulley bearings, P/N 269A5050-62 installed,

(1) but have not previously had the replacement and inspection of the bearings accomplished as described in said Notice; perform the replacement and inspection described in said Notice, or later FAA-approved revisions, within the next 50 hours time in service on helicopters having 150 or more hours time in service on the bearings on the effective date of this AD, or at the first 200 hour periodic inspection on helicopters having less than 150 hours time inservice on the bearings on the effective date of this AD. Repeat the installation and inspection, per (C), below.

(2) and have previously had the replacement and inspection of the bearings accomplished as described in said Notice as of the effective date of this AD, perform the replacement and inspection instructions in said Notice, or later FAA-approved revisions, before the accumulation of 600 hours total time in service on the bearings, or within 50 hours additional time in service after the effective date of this AD, whichever occurs later. Repeat the installation and inspection, per (C), below.

(B) For all helicopters, other than those listed in (A) above, which as of the effective date of this AD, have idler pulley bearings P/N 269A5050-62 installed, with less than 600 hours total time in service, replace the bearings with new P/N 269A5050-62 bearings within 50 hours additional time in service after the effective date of this AD, or before the accumulation of 600 hours total time in service, whichever occurs later, in accordance with the replacement and inspection instructions in Hughes Service Information Notice No. N-90.1, or later FAA-approved revisions. All helicopters with bearings with 600 hours or more total time in service as of the effective date of this AD, replace the bearings with new P/N 269A5050-62 bearings within 50 hours time in service after the effective date of this AD, in accordance with the replacement and inspection instructions in Notice No. N-90.1, or later FAA-approved revisions. Repeat the installation and inspection per (C), below.

(C) Thereafter, replace the idler pulley bearings, at or before the accumulation of 600 hours total time in service on the bearing, in accordance with the instructions provided in Hughes Service Information Notice No. N-90.1 dated September 7, 1971, or later FAA-approved revisions.

(D) Mutilate and discard old bearings per Part II, Hughes Service Information Notice No. N-90.1, dated September 7, 1971, or later FAA-approved revisions.

NOTE: Special caution should be exercised in performing the TIR runout and end play checks of Part III of the Notice.

(E) Equivalent replacement and inspection procedures of idler pulley bearing may be approved by the Chief, Aircraft Engineering Division, FAA, Western Region.

This amendment becomes effective May 21, 1973.