MH370 investigation reveals anomalies in emergency locator transmitters

Investigation files regarding the disappearance of Malaysia Airlines flight MH370 have highlighted anomalies concerning the aircraft's Emergency Locator Transmitters (ELT). Despite the Boeing 777 being equipped with four such devices, no emergency signals were recorded by search and rescue agencies following its disappearance on March 8, 2014.

According to a 2018 safety investigation report from the Malaysian Ministry of Transport, all four ELT units had batteries that were still within their valid service life at the time of the incident. The devices included one fixed unit in the rear passenger ceiling, one portable unit in the forward cabin, and two integrated into the emergency evacuation slides and life rafts at doors 1L and 4R.

The fixed and portable units had battery expiration dates in November 2014, while the raft-integrated units were valid until 2016 and 2017, respectively. The failure of these devices to transmit signals despite being functional has prompted investigators to review data from hundreds of other aviation accidents.