The FAA is releasing an Airworthiness Directive aimed at operators of Boeing 737-300, -400, and -500 operators after a Southwest Airlines incident in
July. The flight was going from Nashville to Baltimore, and made an emergency landing in Charleston, West Virginia with a 17 inch hole (43cm x 20cm)
in the upper rear fuselage between two stringers.
This is an eerily similar (yet safer) incident to Aloha 243
in Hawaii on April 28,
1988 (a 737-200). A passenger boarding the aircraft noticed a crack in the fuselage, which during flight opened and tore the top of the aircraft off,
at 24,000 feet while they were South-Southwest of the island of Maui. It's now believed that the flight attendant that was killed (C.B. Lansing) was
pulled into the hole, and blocked it, causing a pressure increase that tore the top of the plane off. This added to corrosion and other structural
weaknesses allowed the stringers to fail, creating a zipper effect.
The AD being released in relation to the Southwest incident would require external fuselage NDI inspections after every 500 cycles. The aircraft
involved had 42,569 cycles at the time of the incident. Operators that have installed an external doubler, as long as it meets previous AD
specifications wouldn't have to do the extra inspections, after the first one.
I remember the AQ243 incident when it happened. It's a miracle that the pilots were able to land the aircaft. At one point the pilots looked over
their shoulder to check on the passengers, and they were looking down into the cabin, because the nose of the aircraft had flexed up so high. They
had very limited communications with the tower, due to noise in the cockpit, they landed at a very high rate of speed, because they had no flaps, and
they didn't dare use some of the flight control systems, due to the stress on the airframe they could cause. They wound up barging the aircraft to
Honolulu, where it sat for months, before being sold for scrap.
This particular incident, being near the tail of the aircraft could have had disastrous consequences for the crew and passengers if it had failed the
way AQ243 did. AQ243 did a lot to increase awareness of metal fatigue, because aircraft in Hawaii have MUCH shorter cycles than others, so they put a
LOT more strain on the airframes (the longest flights are 45 minutes, the average ones are only 20). Hopefully this AD will be passed, and they will
be more aware of metal fatigue as airframes age on newer airframes.