A loose screw caused an iPhone 4 to spontaneously ignite just after a Regional Express flight landed in Sydney late last year, the ATSB has concluded.
An examination of the iPhone, conducted at a “specialist facility” in the US, concluded that a small screw had been misplaced inside the phone’s battery bay, apparently during maintenance on the phone. The screw punctured the battery casing, causing an internal short circuit that led to “thermal runaway.”
The investigation found that the screw had likely been misplaced during an earlier repair of the phone’s screen, which had been carried out at a non-authorised service provider.
“This investigation highlights the risks associated with the use of non-authorised agents for the repair of lithium battery-powered devices,” the ATSB said in its unusual foray into consumer electronics. The safety agency said the case underscored the importance of CASA recommendations that mobile phones not be carried in checked baggage.
The phone combusted as a Rex Saab 340B taxied to its gate after arriving in Sydney from Lismore on November 25, 2011. A cabin crew member noticed smoke coming from near a passenger’s seat and instructed the passenger in that seat to throw the source of the smoke into the aisle.
“The cabin crew member then discharged the fire extinguisher onto what was later identified as a mobile telephone,” the report said. “After several minutes, the smoke cleared.”
The examination of the phone, which was overseen by the FAA and included a CT scan, indicated “a lack of appropriate quality control on behalf of the unauthorised repair facility.” The passenger told the ATSB that he could not remember where he’d gotten the phone fixed, the report said.