84-15-02 DOUGLAS AIRCRAFT COMPANY: Amendment 39-5031. Applies to Douglas Aircraft Model A-26/B26 series airplanes certificated in all categories.
Compliance schedule as prescribed in the body of the AD, unless previously accomplished.
To prevent loss of wing structural integrity due to failure of a lower spar cap, accomplish the following:
A. Within ten (10) hours time in service after the effective date of this AD, perform a visual dye penetrant inspection of the lower forward and aft spar cap, outboard and inboard of each nacelle in the area where the nacelle fairing upper edge runs across the lower spar cap surface. Trim the fairing edge if necessary, to ensure that the fairing edge is smooth and that there is a minimum of one-sixteenth inch (1/16") clearance between the fairing and spar cap surface.
B. If no cracking or fretting of the spar cap is detected, repeat the inspection for cracks, surface clearance, and condition in accordance with Paragraph A. of this AD at intervals not to exceed 500 hours time in service.
C. If any evidence of cracking or fretting is found in the spar caps, polish out to a machine finish not to exceed approximately 125 microinches on both sides of the damaged area to a maximum depth of 0.030 inches and repeat the inspection of Paragraph A., above. Continue to inspect in accordance with Paragraph A. at intervals not to exceed 30 hours time in service.
D. If cracking or fretting in excess of 0.030 inches in a spar cap is detected, repair in a manner approved by the Manager, Western Aircraft Certification Office, FAA, Northwest Mountain Region, Hawthorne, California.
E. For those aircraft which have been modified to incorporate a steel or titanium lower front spar cap strap (in the area where the nacelle fairing upper edge is in contact with the lower wing surface) in accordance with AD 64-12-03, the requirements of Paragraph A. of this AD are applicable only to the lower aft spar cap, outboardand inboard of each nacelle.
F. Within 72 hours after performing the inspections required by Paragraph A., above, report the results of the inspections to the Manager, Western Aircraft Certification Office, ANM-170W, FAA, Northwest Mountain Region, 15000 Aviation Blvd., Hawthorne, California. Mailing address: P.O. Box 92007, Worldway Postal Center, Los Angeles, California 90009. The reports should cite the airplane registration and serial number, crack location and extent of damage, total airplane operating hours, and time since last inspection.
G. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of inspections required by this AD.
H. Alternate inspections, modifications, or other actions which provide an acceptable level of safety may be used when approved by the Manager, Western Aircraft Certification Office, FAA, Northwest Mountain Region, Hawthorne, California.
This amendment becomes effective April 16, 1985, and it was effective earlier to all recipients of priority mail AD 84-15-02, issued August 1, 1984.