Fatigue Material

Fatigue Material

Aloha Airlines Flight 243’s Tragic Case

Aloha Airlines Flight 243 was a scheduled Aloha Airlines flight from Hilo and Honolulu in Hawaii. On the 28^th of April 1988, a Boeing 737-297 that served the flight experienced severe damage after it underwent explosive decompression during the flight;however, it was able to land safely at the Kahului Airport in Maui. Unfortunately, there was one casualty, Clarabelle “C.B.” Lansing, a flight attendant who got expelled from the aircraft. About 65 crew and passenger were injured.

The aircraft’s safe landing in spite of the extensive damage due to the decompression recognized Aloha Airlines Flight 243 as an important event in the aviation history, with comprehensive effects on the safety policies and procedures in aviation.

Aircraft

The air frame, the 152nd Boeing 737 built, named Queen Liliuokalani after Lili’uokalani, with registration N73711,was built in 1969 and delivered to Aloha Airlines as a brand-new aircraft. While the air frame had only got 35,496 flight hours before the accident, those hours were over 89,680 flight cycles (a flight cycle is defined as a takeoff and a landing), owing to its use on short flights.

Aftermath

As a consequence of the incident, the aircraft was identified to be damaged beyond repairs. It was taken apart on-site. The horizontal stabilizers of the aircraft were also damaged and dented because they were smashed by flying debris. The tail fin of the aircraft was also struck with some metal debris adding further damage. The engine cowlings and leading edges of both wings were also dented and damaged.

In spite of a great search effort at the ocean at the probable location of the accident, neither the body of Lansing nor the part of the fuselage that separated from the aircraft was found. The NTSB or United States National Transportation Safety Board conducted an investigation, and they have concluded that the incident was triggered by metal fatigue made worse by crevice corrosion. The aircraft was 19 years old and had operated in a coastal setting, with salt and humidity exposure.

Based on the report of the NTSB, Gayle Yamamoto, who was one of the passengers, saw a crack in the fuselage as she was about to board the aircraft before the unfortunate flight but didn’t inform any of the crew.

Conclusion

The investigation has showed that the weather had no part in the incident. It was, however, determined that the quality of inspection and maintenance were poor. Furthermore, the fuselage failure started in the lap join along S10L; the failure mechanism was the outcome of multiple site fatigue cracking of the aircraft’s skin next to the rivet holes in the lap join upper rivet row and tear drop disbanded, as a result, negated the fail-safe characteristics of the fuselage. And lastly, the fatigue cracking that started from the knife edge related with the countersunk lap joint rivet holes; the knife edge concentrated stresses that were transferred through the rivets because of lap joint disbonding.

Under the present FAA regulation for the Boeing 737 established during the 2010s, this air frame type would have to withdraw permanently from service ad 34,000 hours of 34,000 flight cycles, whichever comes first. Under the new FAA rules, the nearly 90,000 flight cycles far exceed the “lifetime of validity” of the Boeing 737-100/200.

In all probability,an essential lesson to come from this tragic case is the importance of proper aircraft maintenance. It’s terrible that this accident had to occur. You’ll be pleased to know private aircraft for chartered flight are fulfilled to the same rigorous safety and maintenance regulations as commercial aircraft. And in several cases, chartered flight pilots and their crews are permanently assigned to a particular jet – so they know their aircraft too well – which can mean an even safer chartered flight for you and your family. With that being said, we highly suggest you take a chartered flight!