April 23, 2018, © Leeham News: Last week’s engine malfunction on a Southwest Airlines Boeing 737-700 was another in a rare, but not unknown, uncontained engine anomaly in recent years.
All recent similar failures didn’t cause a loss of life or serious injuries if the passengers were evacuated. Unfortunately, this accident caused one fatality and seven injuries.
Let’s put the context to this issue.
Southwest’s pilots made a textbook emergency landing, despite holes in the fuselage, damage to the wing and a large portion of the engine cowling missing.
The pilots landed 30 knots faster than normal, with only five degrees of flaps instead of 30-40 degrees, cabin depressurization and an initial report to the cockpit that one passenger had been sucked out of the airplane when a window blew out.
The passenger was only partially ejected from the airplane. Passengers pulled her back in but were unable to save her life. She died from blunt force trauma to the head, neck and torso.
Despite all this, the accident wasn’t a “crash.” Three broadcast media called me wanting my take on this “crash.” One, perhaps not surprisingly, was Fox News network, which has a history of not getting its facts straight. (I declined to help Fox, given its history.)
Two others were Seattle broadcast media—one radio and one TV news operation, both of which should know better being in Boeing’s back yard. I helped these media understand the situation and provided context and history.
The National Transportation Safety Board said that worldwide, there are about 3-4 uncontained engine failure per year.
Some of the higher profile failures include:
United Airlines, February 2018, over the Pacific
A United Airlines Boeing 777 was en route to Hawaii when an uncontained failure occurred. The airplane continued to Hawaii for a safe emergency landing. The engine was a PW4000
Air France A380, September 2017, near Greenland
The Airbus A380, equipped with Engine Alliance GP7200 engines, suffered an uncontained failure in No. 4 engine. The airplane diverted to Goose Bay, Canada. The cause is still under investigation.
American Airlines, October 2016, Chicago O’Hare
This Boeing 767-300ER was speeding for takeoff when a disk on the No. 2 engine broke apart. The engine caught fire. The pilots, just seconds away from rotation, aborted the take-off. Passengers exited the aircraft in an emergency evacuation. Fire melted the right wing. A defective part was blamed. The engine was a GE CF6.
Southwest, August 2016, US Gulf Coast
This was eerily similar to last week’s incident. Like last week, the No. 1 engine blew apart, with the front of the cowling disintegrating very much like the flight last week. Metal fatigue of a blade was identified as a cause. Metal fatigue appears to be the cause of last week’s accident.
Qantas Airways, November 2010, Singapore
Shortly after take-off from Singapore, a Qantas Airways A380 Rolls-Royce engine had an uncontained failure. Parts below through the wing, damaging hydraulic lines and causing a fuel leak. The crew responded to more than 1,000 “faults” identified by the computer system before returning to Singapore. Then, the No. 1 engine would not shut down until drowned by the airport fire department. The incident became the subject of an hour-long TV program. Oil starvation was blamed for the failure.
American Airlines, 2006, Los Angeles
An American 767 had undergone maintenance when its engine blew up. The subsequent fire destroyed the aircraft. This was a CF-6 engine.
United Airlines, over Iowa, July 1989
Perhaps the most famous, and most spectacular uncontained failure was the No. 2 engine on a DC-10, United flight 232 from Denver to Chicago. The engine exploded at cruising altitude, destroying all hydraulic lines. Capt. Al Haynes and his crew, learning to fly an airplane with no controls by using engines only, landed at Sioux City (IA). There had been enough time for news crews to reach the airport before the airplane and there is famous television footage of the DC-10 cartwheeling down the runway after a wing dipped and caught the ground just before touchdown. There were nearly 300 people on board; 111 died in what otherwise would have been a total disaster had it not been for the piloting skills of the flight deck crew. This crash became a TV movie and the subject of air disaster TV shows.
The initial news report reversed the number of dead and survivors.
There are more, including a Delta Air Lines McDonnell Douglas MD-88 in which two people were killed when an uncontained failure occurred.
Lest one get the impression this happens “all the time,” it doesn’t, as noted above.
The engines involved—the GE/CFM CFM 56 on the Southwest flights is perhaps the most reliable jet engine in aviation history. The model is the exclusive powerplant on the 737 and it powers perhaps 60% of the Airbus A320s. Its first use was on the Douglas DC-8 re-engining program in the 1970s and it’s been retrofitted on some Boeing KC-135 tankers.
The CF6, also by GE, powered virtually every wide-body airplane from the DC-10 through the 767 and early Airbus models. It, too, is highly reliable.
The Rolls-Royce and Engine Alliance engines on the A380 have proved reliable since entry into service in 2008.
Uncontained failures are scary and dangerous and can lead to destruction of the aircraft and deaths. But flying is still the safest mode of travel.
Getting on a CFM-powered 737 or A320 for your next airline flight isn’t something anyone should worry about.