We are revising an earlier proposed airworthiness directive (AD) for all The Boeing Company Model MD-90-30 airplanes. That NPRM proposed to require repetitive eddy current high frequency (ETHF) inspections for cracking on the aft side of the left and right wing rear spar lower caps at station Xrs = 164.000, further ETHF inspections if cracks are found, and repair if necessary. The NPRM also proposed repetitive post-repair inspections, and repair if necessary. That NPRM was prompted by reports of cracks of the wing rear spar lower cap at the outboard flap, inboard drive hinge at station Xrs=164.000. This action revises that NPRM by adding repetitive post-repair inspections, and corrective action if necessary. We are proposing this supplemental NPRM to detect and correct cracking of the left and right rear spar lower caps, which could result in fuel leaks and damage to the wing skin or other structure, and consequent loss of the structural integrity of the wing. Since these actions impose an additional burden over that proposed in the NPRM, we are reopening the comment period to allow the public the chance to comment on these proposed changes.
Agency Contact: Roger Durbin, Airframe Branch, ANM- 120L, FAA, Los Angeles Aircraft Certification Office (ACO), 3960 Paramount Boulevard, Lakewood, California 90712-4137; phone (562) 627- 5233; fax (562) 627-5210; email: email@example.com.
This is a proposed regulation. Comments were due on September 7, 2012.