Japanese carriers All Nippon Airways (ANA) and Japan Airlines (JAL) have extended the grounding of its Boeing 787 fleet, following reports that official investigations into the 787 incidents could still be far from over.

ANA will be grounding its 787s until 31 January at least, and is using older Boeing 767s and 777s on some services originally scheduled to be operated by the problematic aircraft type.

The carrier is expecting to cancel a total of 459 flights - 398 domestic and 61 international - since the grounding of the 787s on 16 January until 31 January.

JAL is, meanwhile, suspending the operations of its 787 services till 3 February. The flag carrier is using other aircraft types on some routes previously served using the 787s, but will still be cancelling six flights on the Narita-Boston and Narita-San Diego routes on the second and third day of February.

The extensions indicate that both carriers expect the grounding to last at least for another week.

At a press conference on 25 January, the US National Transport Safety Board (NTSB) revealed that it has found "symptoms" related to the JAL 787 battery fire on 7 January, but is not yet able to nail down the root cause. It also could not pin down how long the investigations will likely take.

So far, the Japan Transport Safety Board and the NTSB have agreed that there is no evidence yet that batteries in the JAL and the ANA incidents were over-charged when they failed, but are continuing to examine the data.

The US Federal Aviation Administration issued a directive ordering the grounding of all US-registered 787s on 16 January, after an ANA 787 had to make an emergency landing because of a battery problem. Regulators worldwide have since issued similar directives to ground the aircraft type.

Source: Air Transport Intelligence news