81-23-06: Flap Track Structure

81-23-06 PIPER: Amendment 39-4254. Applies to Model PA-31P, Serial Nos. 31P-1 thru 31P-7730012, Model PA-31T, Serial Nos. 31T-7400002 thru 31T-8020086 and Model PA-31T1 Serial Nos. 31T-7804001 thru 31T-8104001 certificated in all categories except aircraft incorporating Piper Kit No. 763 986. To prevent possible hazards in flight associated with cracks in the outboard flap track, attachment angles, wing rib flange and the rear spar web accomplish the following: a. Within the next 50 hours in service from the effective date of this AD or upon the attainment of 1000 hours in service, whichever is later, inspect, repair and alter the flap track structure in accordance with Piper Kit No. 763 986 or equivalent. b. Alternate inspections, repairs or alterations which provide an equivalent level of safety may be used when approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region. c. Upon submission of substantiating data by an owner or operatorthrough an FAA Maintenance Inspector, the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region may adjust the inspection intervals specified in this AD. (Piper Service Bulletin No. 647A dated November 24, 1980, refers to this subject.) This amendment is effective November 16, 1981.