The American FAA has allowed Boeing to carry out test flights of 787 Dreamliner planes. The entire fleet of 787s was grounded last month after a battery on one plane caught fire, while a malfunction forced another to make an emergency landing.
Regulators as well as Boeing have been conducting probes to find out what caused the incidents. Japanese transport ministers put forward that the fires were caused by the overcharging of batteries, while the NTSB concluded this was not the case. In a statement on 7 February, the Board The NTSB said a short circuit in one of eight cells in the APU battery of a Japan Airlines Boeing 787 led to the fire in the aircraft at Boston Logan Airport Jan. 7. At a news conference, NTSB Chairman Debra Hersman said evidence from the flight data recorder and damage to the battery itself indicated the battery and not the aircraft systems were at fault. “That cell showed multiple signs of short circuiting, leading to a thermal runaway condition, which then cascaded to other cells,” said an NTSB news release. “Charred battery components indicated that the temperature inside the battery case exceeded 500 degrees Fahrenheit.”
The FAA said the test flights will help collect data about battery performance ‘while the aircraft is airborne’, monitoring battery activity at every stage of flight. In addition to the FAA’s root cause analysis, the FAA is conducting a comprehensive review of the 787’s critical systems, including the aircraft’s design, manufacture and assembly.
Marc Birtel, a spokesman for Boeing, stated, “The findings discussed today demonstrated a narrowing of the focus of the investigation to short circuiting observed in the battery, while providing the public with a better understanding of the nature of the investigation.” He added, “We continue to provide support to the investigative groups as they work to further understand these events.”
The FAA stated the flights will be conducted in defined airspace over unpopulated areas.