An Emergency Airworthiness Directive (AD) was issued by the FAA yesterday for the owners and operators of Boeing Model 737-300, -400, and -500 series aircraft. Emergency AD 2011-08-51 was prompted by a report indicating that a Model 737-300 series airplane experienced a rapid decompression when the lap joint at stringer S-4L between body station (BS) 664 and BS 727 cracked and opened up. Investigation showed that the cracking was located in the lower skin at the lower row of fasteners. The airplane had accumulated 39,781 total flight cycles and 48,740 total flight hours. This condition, if not corrected, could result in an uncontrolled decompression of the airplane. Because the lap joint and tear strap spacing configuration is the same on Model 737-400 and -500 series airplanes, these airplanes may be subject to the identified unsafe condition. “We are issuing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of these same type designs,” said the FAA. The full AD can be accessed here:
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/Frameset?OpenPage