AD 79-03-04

79-03-04 LOCKHEED: Amendment 39-3404. Applies to all Model 382 series aircraft with Calco manufactured ballscrew assembly, P/N 8353, installed in the main landing gear (MLG). Compliance required as indicated.

To prevent the collapse of the MLG due to a failure of the ballscrew P/N 8353-25 lower mounting flange and consequently possible loss of the aircraft, accomplish the following:

Within 10 hours time in service after the effective date of this AD and at each preflight thereafter on all airplanes with suspect P/N 8353 ballscrew assemblies, lower mounting flange P/N 8353-25 (castings only, not forgings), perform the repetitive visual check of the MLG Calco P/N 8353 Ballscrew Assembly in accordance with Lockheed Alert Service Bulletin A328-32-28 (NOTE: Four (4) ballscrew assemblies per airplane). The checks required by this AD may be performed by the flight crew. If cracks are detected or suspected in the lower mounting flange of the P/N 8353 ballscrew assembly as a result of the above service bulletin inspection requirements, replace the P/N 8353-25 casting with a serviceable forging prior to further flight. In addition to the above repetitive visual checks the following inspection of the P/N 8353-25 casting is required:

1. Prior to 50 hours time in service from the effective date of this AD, perform a Rockwell hardness test to determine that the P/N 8353-25 casting is within acceptable hardness limits of RC-35 to RC-45. If these limits are exceeded the P/N 8353-25 casting must be replaced prior to further flight except that if only one casting per aircraft is determined to be outside these limits, a ferry flight to a place of repair is permissible.

2. If the Rockwell hardness test confirms that the P/N 8353-25 casting is within the prescribed above limits, the casting must be replaced with a serviceable forging within 25 landings or 150 flight hours, whichever occurs first.

NOTE: The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to Lockheed-Georgia Company, Marietta, Georgia 30063. These documents may also be examined at FAA, Southern Regional Office, 3400 Whipple Street, East Point, Georgia, and at FAA Headquarters, 800 Independence Avenue, S.W., Washington, D.C. A historical file on this AD which includes the incorporated material in full is maintained by the FAA at its Headquarters in Washington, D.C. and at the Southern Regional Office.

This amendment is effective February 5, 1979.