PUTRAJAYA: Malaysia Airlines (MAS) flight MH370’s battery for its underwater locator beacon (ULB) had expired more than a year before the aircraft vanished on March 8, 2014, the Malaysian team investigating the flight’s disappearance revealed in its interim report.

The report, which was released yesterday, said that the battery’s expiry date was December 2012, and no evidence suggested it had been replaced before then.

“However, once beyond the expiry date, the ULB effectiveness decreases so it may operate for a reduced time period until it finally discharges,” read the report prepared by the Malaysian International Civil Aviation Organization Annex 13 Safety Investigation team.

“While there is a definite possibility that a ULB will operate past the expiry date on the device, it is not guaranteed that it will work or that it would meet the 30-day minimum requirement. There is also limited assurance that the nature of the signal [characteristics such as frequency and power] will remain within specification when battery voltage drops below the nominal 30-day level.”

The report also said the technical logs showed that the aircraft’s solid state flight data recorder (SSFDR) and the ULB were last replaced on Feb 29, 2008. According to the report, the MAS engineering technical records staff told the investigation team it had failed to replace the battery before its expiry date because the engineering maintenance system had not been updated correctly when the SSFDR was replaced in 2008. — The Malaysian Insider

This article first appeared in The Edge Financial Daily, on March 9, 2015.