A passenger’s oxygen mask hangs from the roof next to a chipped window and part of the sidewall of Alaska Airlines Flight 1282, which suffered decompression shortly after takeoff while bound for Ontario, California, in Portland, Oregon, January 5. It is beingInstagram/@strawberrvy/Reuters
Investigators on Sunday were searching for debris from the plane that blew up a Boeing jetliner over Oregon on Friday, hoping to obtain physical evidence of what happened.
A large hole in the side of an Alaska Airlines jet was where aircraft manufacturer Boeing installed a “plug” to cover an emergency exit the airline doesn’t use.
Plugs are included on most Boeing 737 Max 9 jets. The Federal Aviation Administration temporarily grounded the planes until the area around the door plugs was inspected.
Why is there a plug?
Some large Boeing 737s are equipped with emergency exits in the fuselage behind the wings to meet federal requirements that passengers be evacuated within 90 seconds even if half of the exits are blocked. It has been.
The more passenger seats a plane has, the more exits it needs.
Some airlines, such as Indonesia’s Lion Air and Corendon Royal Dutch Airlines, pack more than 200 seats into their Max 9s, which means they must be equipped with additional emergency exits. However, Alaska Airlines and United Airlines have set the seating capacity of their 737 Max 9s to less than 180, so his two exits in the middle of the cabin are not required to comply with US evacuation rules.
Alaska Airlines and United Airlines are the only two U.S. airlines using the Max 9, but the side exit near the back of the plane has been replaced with a permanent plug the same size as the exit door.
Is it only available on Max 9?
No, Boeing also makes a larger version of the Max’s predecessor, the 737-900, and the Max 8, which has additional egress space in the rear. Purchasers of these airplanes may also choose to install an exit door or plug.
Who installs the plug?
A spokesperson for Spirit Aero Systems, which is not affiliated with Spirit Airlines, told The New York Times that the company had installed door plugs on its Max 9s, including the plug on the Alaska Airlines plane involved in Friday’s incident. Admitted. The Seattle Times reported that the door plugs are assembled on 737 planes at Spirit’s Wichita, Kansas, factory.
Spirit AeroSystems declined to answer questions from The Associated Press. Boeing declined to comment on the issue.
boeing suppliers
Spirit is Boeing’s largest supplier of commercial aircraft, producing fuselages and other parts for the Boeing Max jet. The company has been at the center of several recent problems with the manufacturing quality of both its Max planes and its larger jetliner, the Boeing 787 Dreamliner. Last year, Boeing and Spirit AeroSystems discovered holes in the improperly drilled fasteners in the bulkheads that keep 737 Max jets pressurized at cruise altitude.
investigation
Officials from the National Transportation Safety Board, led by Commissioner Jennifer Homendy, arrived in Portland, Oregon, on Saturday to begin an investigation that is expected to last more than a year. When Homendy briefed reporters Saturday night, he declined to discuss a possible cause.
The NTSB team also includes a metallurgist, and Homendy said investigators will examine the exit door plug, its hinges and other parts if they can find them.
An independent expert said examining the damage to the door will be key to the investigation.
“The great thing about metal is that metal paints pictures, metal tells stories,” said Anthony Brickhouse, who teaches accident investigation at Embry-Riddle Aeronautical University in Daytona Beach, Florida. “I’m pretty confident they’ll find the peel and be able to scientifically explain what caused this failure.”
Brickhouse said the exit door, closed or not, is not necessarily a weak point on the aircraft. He had never heard of an emergency exit door plug falling off a plane before Alaska Airlines Flight 1282.
Was there a warning?
Aerospace analysts at investment bank Jefferies wrote that the plane involved in Friday’s accident had experienced pressurization problems on two previous flights. The NTSB would not comment on the plane’s history, but Homendy said investigators will examine maintenance records even on new planes like this one.
Blown away other aircraft
There have been rare instances where a hole has been created in the fuselage of an airliner. In most cases, they are the result of metal fatigue in the airplane’s aluminum skin.
In one of the most frightening cases, an Aloha Airlines flight attendant was blown out of the cabin of a Boeing 737 over the Pacific Ocean in 1988 when an 18-foot chunk of its roof came off. Her body was never found. The tragedy led to stricter rules for airlines to inspect and repair microscopic cracks in planes before they split during flight.
In 2009, a hole ripped through the roof of a Southwest Boeing 737 while flying at 35,000 feet over West Virginia. And in 2011, another Southwest Boeing 737 sustained a 5-foot-long gash, forcing the pilot to make an emergency landing at a military base in Arizona. No one was injured in either incident, and metal fatigue is believed to be the cause.