Airplane slide fall likely ‘human error’
Milton Times Mar 19, 2020
The Federal Aviation Administration (FAA) has found in a preliminary report that an improperly locked airplane compartment door likely led to an incident in which an evacuation slide fell from Delta Airlines flight 405 and landed in an Adams Street front yard on Dec. 1.
The preliminary report stated that the door of the compartment situated over the right wing of the Boeing 767-300 should have been secured with four “keeper pins” which are inserted and captured by the latches on the door, but indications are that two of the four pins “exhibited wear marks indicating improper contact with a closed latch.”
“Not being latched properly would enable the door to open in flight under the right flight characteristics/loads,” the report stated.
The report was released by U. S. Rep. Stephen Lynch and state Sen. Walter Timilty.
Timilty said that the preliminary report indicates that “unacceptable and inexcusable human error” was to blame for the incident.
“It’s all extremely unsettling,” Timilty said.
Timilty is dissatisfied with the scope of the investigation revealed in the preliminary report, which shows that this could potentially happen with any airline carrier that flies into Boston Logan International Airport.
“This investigation has to be more expansive than just Delta Airlines,” he said, adding that this is of “paramount concern.”
The flight was on the approach to Logan on runway 4R at the time it fell into resident Wenhan Huang’s front lawn on Adams Street.
Timilty said that when a final report is filed, he is hoping that sanctions will be imposed against the airline.
“There has to be accountability,” especially when it involves major industries where lives are at stake, he said.
Timilty said that since the NextGen navigation system was put in place in 2013, Milton has faced an unfair burden from Logan traffic.
“We’ve had a horribly inequitable flight path system foisted upon Milton and several communities in the Boston area,” he said. “Both Congressman Lynch and I find this to be unacceptable insofar as the system’s grave inequities and the FAA’s insensitiveness to the people we represent.”
Select Board Chair Mike Zullas said during the board’s March 11 meeting that the danger caused by this type of incident is exacerbated by the flight paths being concentrated “over the same houses and the same neighborhoods.”
Zullas said that this is a reason, in addition to noise and environmental burdens, for the FAA to recognize the need for dispersion of flight paths.
“When you disperse the flight paths, you disperse the risks,” he said.
The preliminary report stated that the compartment would have appeared flush and the pins were not visible from the outside.
“This condition could remain undetectable by maintenance and the crew since the door appears closed and warning indications would not be illuminated due to the mechanical linkage being in the locked position,” the report stated.
No one was injured by the uninflated slide and a large canister or bottle that is used to inflate the slide when it is deployed in an emergency, both of which would have been stored in the compartment.
The bottle contains carbon dioxide and was changed in Seattle three days prior to the incident. The aircraft flew from Seattle to Minneapolis, then on to Paris.
“On approach to Boston, the landing gear was extended, at an altitude of 1,950 feet, at which time the right over-wing escape slide inadvertently departed the aircraft and landed in a private residence yard,” the report stated.
“Based on this incident, in an effort to measure the breadth of this issue and to gather data, FAA Flight Standards tasked our Operations Research Analyst from the Safety Analysis and Promotion Division, to provide a list of inadvertent slide events that happened in flight for a 10-year period from 2009 to 2019. There were 13 in-flight events during that time, with eight events, on various fleet types in which the slides departed the aircraft.”