AD 75-15-06

75-15-06 GATES LEARJET: Amendment 39-2267. Applies to 23 (Serial Numbers 23- 003 thru 23-099); 24 (Serial Numbers 24-100 thru 24-297); and 25 (Serial Numbers 25-003 thru 25-182) series airplanes.

Compliance: Required as indicated, unless already accomplished in accordance with Gates Learjet Service Bulletin No. SB 23/24/25-259A or later approved revisions.

To check for flaws in the upper main landing gear struts, accomplish the following:

A) Within the next 600 hours' time in service after the effective date of this AD, but not later than September 30, 1976, using eddy current or ultrasonic inspection equipment and procedures, inspect the left and right upper main landing gear struts for flaws in accordance with the instructions and sketches outlined in Gates Learjet Service Bulletin No. SB 23/24/25-259A or later approved revisions, or alternatively, remove the left and right upper landing gear struts from the airplane, disassemble, clean, and inspect the struts forflaws in accordance with the aforementioned Service Bulletin.

B) If, as a result of the inspections referred to in Paragraph A, flaws are detected, within the next 50 hours' time in service, accomplish the following:

1. Remove any flaw in an upper main landing gear strut with a depth less than .025 inches in accordance with the procedures outlined in the aforementioned Service Bulletin.

a. After flaw removal, reinspect using eddy current or ultrasonic methods to assure complete removal of the flaw and then treat and paint the affected area in accordance with the aforementioned Service Bulletin.

2. For flaws that exceed a depth of .025 inches, modify the upper main landing gear strut in accordance with instructions provided by the manufacturer or alternatively, replace with an airworthy part.

C) Any equivalent method of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region.

NOTE: Aircraft inspected and in compliance with Gates Learjet Service Bulletin SB 23/24/25-259 (i.e., the original Service Bulletin on this subject) are considered to have complied with the requirements of this AD.

This amendment becomes effective July 25, 1975.