Japanese investigators have conducted their first tests on a problematic All Nippon Airways Boeing 787.
The Japan Transport Safety Board (JTSB) tells Flightglobal Pro it is collecting data on the voltage and current flows, while using the aircraft "under normal conditions".
This is so as to allow them "a better understanding of the battery system", says the JTSB official. He adds that the agency has no plans to conduct test flights using the aircraft.
JTSB began the tests on 8 April on the ANA 787, registration JA804A, which was forced to make an emergency landing at Takamatsu airport in January after pilots observed an error message related to battery malfunction. The aircraft has been grounded at the airport since the incident.
Boeing has since dispatched maintenance teams to Japan, where they are standing by to retrofit a new battery containment system to the 787s once it is certified by the US Federal Aviation Administration and the Japan Civil Aviation Bureau (JCAB).
"Boeing has done test flights with the new battery and we understand that it's a big progress," says an ANA spokesman.
He adds that although the new battery containment system could be certified as early as this month, the carrier will stick to its plans of offering domestic tickets for 787 services from 1 June.
Japan Airlines meanwhile says that neither the JTSB nor Boeing has conducted any tests on its 787s.
"JAL will start preparations for the 787s concerned after approval from the JCAB is announced. Today we have no comment on when our 787s could return to service," adds a spokesman.
ANA and JAL together operate half of the global 787 fleet. Flightglobal Pro data shows that ANA has a fleet of 17 787-8s, and an additional 19 -8s and 30 787-9s on order.
JAL has received seven -8s, with another 18 of the variant to be delivered. It also has 20 -9s on order.