Summary
The FAA proposes to supersede an existing airworthiness directive (AD) for certain Boeing Model 727 series airplanes. That AD currently requires repetitive detailed inspections to detect cracking, corrosion, and existing stop-drilled repairs of cracking in the upper chord of the rear spar of the wing, and repair if necessary. This proposed AD would require new repetitive inspections to detect cracks, corrosion, minor surface defects, and existing stop-drilled repairs of cracks in the upper and lower chords of the front and rear spars of the wing; and repair if necessary. This proposed AD is prompted by our determination that further rulemaking action is necessary to require additional actions specified in the referenced service bulletin. We are proposing this AD to prevent structural failure of the wing and fuel leaks in the airplane due to stress corrosion cracking of the wing spar chords.