Boeing has declined to specify the nature of a fault that caused the first significant operational issue for All Nippon Airways' newly introduced 787 as a malfunction prevented the main gear from extending on the crew's first attempt.

Photographs taken of the incident, on 6 November, show the first 787 delivered, JA801A, on approach to Okayama Airport, with its main landing gear doors in the retracted position and the nose gear extended normally.

The Wall Street Journal indicated that a failed hydraulic valve was at fault, which was later replaced on site. Boeing said the aircraft has since been repaired and has re-entered service. The airframer did not discuss the nature of the failure.

Photos taken of the aircraft following landing at Okayama show the nose and main landing gear body doors hanging free from the aircraft. This indicates the crew selected an alternate gear swing to achieve full extension.

"Boeing has a support staff in Japan based at Haneda as part of our ongoing support for our customer and it is an expanded crew during initial entry into service activities," the airframer stated, adding that it can position staff on an "as needed basis" depending on the requirement.

ANA began its first scheduled routes on 1 November between Tokyo-Haneda airport and Okayama and Hiroshima.

The 787's landing gear is hydraulically actuated by the centre 5,000psi hydraulic system. The centre system and its twin electric-motor-driven hydraulic pumps actuate the flaps, nose gear and steering, main gear and flight controls. One of the two centre system pumps is constantly running, while the second is available during high demand phases of flight.

Each main landing gear has four different hydraulic valve modules, each responsible for a different part of the sequence of raising and lowering the 787's main landing gear and associated body doors.

Source: Air Transport Intelligence news