Airworthiness Directive · Amendment 39-17013 · Fuselage
The Boeing Company Airplanes
This AD applies to all The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and 747SP series airplanes; certificated in any category.
We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 747 airplanes. This AD was prompted by reports of fractured latch pins found in service; investigation revealed that the cracking and subsequent fracture were initiated by fatigue and propagated by a combination of fatigue and stress corrosion. This AD requires repetitive general visual inspections for broken or missing latch pins of the lower sills of the forward and aft lower lobe cargo doors; repetitive detailed inspections for cracking of the latch pins; and corrective actions if necessary. We are issuing this AD to detect and correct fractured or broken latch pins, which could result in a forward or aft lower lobe cargo door opening and detaching during flight, and consequent rapid decompression of the airplane.
Before the accumulation of 6,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later: Do a general visual inspection for broken or missing latch pins of the lower sills of the forward and aft lower lobe cargo doors, and a detailed inspection for cracking of the latch pins, in accordance with paragraph 3.B., “Work Instructions,” of Boeing Alert Service Bulletin 747-53A2835, dated October 28, 2010; or Boeing Alert Service Bulletin 747-53A2835, Revision 1, dated December 8, 2011. Repeat the inspections thereafter at the applicable intervals specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2835, dated October 28, 2010; or Boeing Alert Service Bulletin 747-53A2835, Revision 1, dated December 8, 2011. Before further flight, do all applicable corrective actions, in accordance with paragraph 3.B., “Work Instructions,” of Boeing Alert Service Bulletin 747-53A2835, dated October 28, 2010; or Boeing Alert Service Bulletin 747-53A2835, Revision 1, dated December 8, 2011.
