80-08-13 DeHAVILLAND: Amendment 39-3747. Applies to DHC-7 model airplanes, Serial Numbers 1 thru 18, certificated in all categories.
To prevent possible failure of the main landing gear due to cracking in the upper drag strut, accomplish the following:
1. Prior to next flight, and daily thereafter, visually inspect the lower lug end of the upper drag strut sub=assembly on the main landing gear for cracks, in accordance with ACCOMPLISHMENT INSTRUCTIONS in DeHavilland Alert Service Bulletin A7-32-18, paragraphs 1. and 2., dated February 6, 1980, or equivalent.
2. At intervals of 40 hours in service or 50 landings, whichever occurs first, after the effective date of this AD, with gear partially retracted, inspect lugs for cracks in accordance with paragraph 3. of the above DeHavilland service bulletin ACCOMPLISHMENT INSTRUCTIONS or equivalent.
3. If cracks are found, the upper drag strut assembly must be replaced before further flight by parts with the same part numbers or equivalent, inspected and found serviceable in accordance with the above DeHavilland service bulletin or equivalent.
4. Within 200 hours in service or 250 landings, whichever occurs first, after the effective date of this AD, inspect the upper drag strut lower lug ends by Eddy Current methods in accordance with paragraph 4. of the ACCOMPLISHMENT INSTRUCTIONS in the above DeHavilland service bulletin or equivalent.
5. When inspection in paragraph 4. is accomplished the inspections in paragraphs 1. and 2. are no longer required.
6. Report positive findings, including crack length, from any inspection, to the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region, within 10 days of inspection. (Reporting approved by Office of Management and Budget under OMB No. 04-R0174.)
7. Equivalent parts and inspections must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region.
8. Compliance times may be increased by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region, upon receipt of substantiating data submitted through an FAA Maintenance Inspector.
This amendment is effective April 16, 1980.