Airworthiness Directive · Amendment 39-17507 · Wings
The Boeing Company Airplanes
This AD applies to all The Boeing Company Model 727, 727C, 727-100, 727-100C, 727-200, and 727-200F series airplanes, certificated in any category.
We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 727 airplanes. This AD was prompted by reports of spanwise cracks and corrosion in the wing center box upper skin and rear spar upper chord between left buttock line (LBL) 70.50 and right buttock line (RBL) 70.50 at body station (STA) 870. This AD requires repetitive inspections of the wing center box for cracking around certain fastener rows on the rear spar upper chord horizontal flange; for certain airplanes, repetitive inspections for cracking of the rear spar upper chord radius; for certain other airplanes, repetitive inspections for damage, cracking, and corrosion of the pressure seal; and repair if necessary. We are issuing this AD to detect and correct cracking and corrosion of the upper skin and rear spar upper chord of the wing center box, which could result in loss of the airplane wing and consequent loss of control of the airplane.
Except as specified in paragraph (h) of this AD, at the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 727-57-0187, dated March 8, 2012: Inspect the wing center box between LBL 70.50 and RBL 70.50, at STA 870, as specified in paragraphs (g)(1), (g)(2), (g)(3), (g)(4), and (g)(5) of this AD, as applicable, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 727-57-0187, dated March 8, 2012. Repeat the inspections thereafter at the applicable times specified in paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 727-57-0187, dated March 8, 2012. If any crack, corrosion, or damage is found during any inspection required by this AD, before further flight, repair using a method approved in accordance with the procedures specified in paragraph (i) of this AD.
(1) Do a high frequency eddy current (HFEC) or detailed inspection for cracking around the forward fastener row in the rear spar upper chord horizontal flange.
(2) Do a low frequency eddy current inspection for cracking around the aft fastener row in the rear spar upper chord horizontal flange.
(3) Do a detailed or HFEC inspection for cracking in the rear spar upper chord radius.
(4) Do a detailed or HFEC inspection for cracking in the upper skin around the forward fastener row common to the rear spar upper chord horizontal flange.
(5) Do a detailed inspection for damage, cracking, and corrosion in the pressure seal.
Boeing Special Attention Service Bulletin 727-57-0187, dated March 8, 2012, specifies compliance times “after the original issue date of this service bulletin.” However, this AD requires compliance within the specified compliance times “after the effective date of this AD.”
