AD 75-16-03

75-16-03 MCDONNELL DOUGLAS: Amendment 39-2276. Applies to all Model DC-9 Series airplanes, certificated in all categories, including Military C-9A, C-9B, and VC-9C.

Compliance required as indicated.

To prevent possible restriction of operation of the nose landing gear manual release system as the result of the accumulation of liquids and formation of ice in the nose landing gear emergency uplock release mechanism pressure can, P/N 9910073-87, accomplish the following:

(a) Within 12 flight hours time in service after the effective date of this AD, unless already accomplished:

(1) Permanently remove the pressure can drain plug, P/N 1103-1 (refer to paragraph (c)(2) for disposition of plug); and,

(2) Inspect for and drain any liquid.

(b) Thereafter, for those airplanes with the nutplate retained and the cover not installed:

(1) Check once daily while in service, until (c) below is accomplished, to ascertain that the drain hole is clear; or,(2) Drill a .190/.194 diameter hole in bottom of the can, 5/8 inch outboard of centerline of and in line with the existing .190/.194 diameter nutplate clearance hole, and inspect at intervals not to exceed 100 hours time in service, until (c) below, is accomplished, to ascertain that the drain hole is clear.

(c) Within the next 1600 hours time in service after the effective date of this AD, unless already accomplished:

(1) Modify the nose landing gear emergency uplock release mechanism pressure can, P/N 9910073-87, in accordance with the instructions in Douglas Service Bulletin 53-91, or later FAA-approved revisions, or an equivalent means approved by the Chief, Aircraft Engineering Division, FAA Western Region.

NOTE: 1. The drain plug nutplate, listed in S/B 53-91 as an optional removal item, must be permanently removed per the requirements of this paragraph; or,

2. Incorporate a .190/.194 diameter hole as outlined in (b) (2), above, in lieu of removing the nutplate.

(2) For those airplanes that do not have the nutplate removed after compliance with (c)(1), above, the drain plug may be reinstalled at the operator's discretion, provided that the drain hole is incorporated.

NOTE: The checks required per this AD may be performed by a flight crew member or other person designated by the operator.

(d) The requirements of this AD may be terminated when (c), above, has been accomplished.

This supersedes Amendment 39-2215, 40 F.R. 22538, AD 75-11-08.

This amendment is effective August 1, 1975 for all persons except those to whom it was made effective by airmail letters dated May 28, 1975, which contained this amendment.