US National Transportation Safety Board officials inspecting a Northwest Airlines McDonnell Douglas DC-9 that collided on the ground with a Northwest Air­bus A319 at Minneapolis/St Paul in May have found that the DC-9's right hydraulic reservoir fluid quantity was below "empty".

The incident, which happened on 10 May, came after the DC-9-51 crew experienced a loss of right hydraulic system fluid shortly after taking off from Columbus, Ohio.

The crew landed without incident at their destination, Minneapolis/St Paul, and taxied to the gate, where they stopped the DC-9 and awaited a tow. At the same time, the A319 was being pushed back and the DC-9 "then moved forward and impacted the right wing" of the A319, says the NTSB. The DC-9 came to rest lodged underneath the A319, resulting in substantial damage to both aircraft. The DC-9 captain received serious injuries, while its first officer and a flight attendant received minor injuries.

In its preliminary report, the safety regulator says the DC-9's right-side hydraulic system "was pressurised with hydraulic fluid and a leak from the rudder shut-off valve housing was noted". It adds that the rudder shut-off valve, which had a recorded service life of 62,436h, has been sent to the agency's materials laboratory for further examination. Inspection of the DC-9's left hydraulic reservoir fluid quantity, meanwhile, showed that it was above "full", notes the NTSB.


Source: Flight International