Two new seat-belt air-bag accidents on Boeing jets being prepared for delivery in Everett, the latest on Saturday, Dec. 13, have raised safety concerns among workers.
Last month, a passenger-seat air-bag inflator accidentally discharged during installation inside a 777 jet on the Everett flight line, injuring two people, one of whom later died of head injuries.
No one was seriously hurt in the Dec. 13 incident, in which an air bag deployed while workers from seat supplier Zodiac Aerospace were troubleshooting the system on a business-class seat inside a 787 Dreamliner for Etihad Airways of Abu Dhabi.
Boeing spokesman Wilson Chow confirmed that there have been three air-bag incidents, but had information about only two of them.
He said the latest accident had a different cause than the fatal accident in November. He said the company is implementing safety inspections and adding additional procedural safeguards.
Though the workers directly involved in these incidents worked for suppliers, not Boeing, the International Association of Machinists union says it is concerned about potential risks to its members at Boeing because they load the seats with these air bags onto the jets and work around them inside the airplanes.
On certain seat configurations, Boeing employees also connect wires to the air-bag system’s electronic control sensor after the seat belt is installed by suppliers.
A shortage of high-end seats from suppliers including Zodiac has recently caused bottlenecks in the assembly process and held up delivery of jets to airlines.
One worker wrote in an email that he and his work group “feel that management and engineers are not taking these incidents seriously enough.”
IAM District 751 spokeswoman Connie Kelliher said the union wants a thorough investigation and training for all those who work with or near the air bags.
“There is widespread concern,” said Kelliher. “We are actively involved and working to ensure our members’ concerns are addressed.”
The air bags are built into the seat belt only on business-class seats that are angled to face an aisle, or in seats that face a bulkhead wall or some other hard surface. Such air bags make the lap belt look puffy.
In case of an accident, an electronic sensor in the air-bag system triggers a blast of compressed gas through a rigid tube, the inflator, inside the seat-belt cover.
When the air bag inflates, it deploys upward and away from the lap belt, filling the space in front of the passenger to cushion the head and neck.
Boeing emphasizes that the accident last month did not involve deployment of a fully installed air bag.
In an internal safety communiqué issued to workers this month, the company said the fatal accident occurred when the air-bag system was still under assembly, “before the inflator was fully secured to the seat structure and attached to the air bag.”
“The inflator unexpectedly discharged and the escaping gas propelled the inflator towards the employee, striking him,” the safety communiqué states.
That employee, who worked for Boeing seat supplier Jamco, was violently struck in the face and died Dec. 8.
The communiqué adds new detail about that accident, tracing the cause to wires that connect a battery inside the electronic sensor module to the inflator.
“The unexpected discharge was caused by a pin-to-pin short circuit within the wire bundle,” the communiqué states. “Wire bundles of this type are used only on the NexGen airbag system.”
That’s a brand made by air-bag supplier AmSafe of Phoenix, Ariz.
Chow, of Boeing, said the Dec. 13 incident had a different cause: A bent connector pin caused the air bag to deploy accidentally.
He had no information about the cause of the third incident.
Chow said Boeing has inspected the wire bundles of all NexGen seat-belt air-bag systems on “every plane in our factory and on the flight line, as well as all the seats at our supplier facilities.”
“We also have held six meetings with team members to explain what occurred and address their concerns about safety,” he said.
The NexGen-model air bag is installed on some planes already in passenger service – for example, the 787s recently delivered to Air Canada and Virgin Atlantic, according to AmSafe instruction manuals for those airplanes.
Chow said he did not know if air bags on in-service planes have been inspected.
However, he insisted that any danger is confined to the assembly process and that “the seat-belt air bag poses no risk to the flying public.”
“The probability of a short circuit is very low, because passengers aren’t working inside the seats or on the seat components,” Chow said. “To date it has not happened.”