Introduction
On 9 February 2004, a Dassault Falcon 900EX (registration VP-BMS) suffered a runway excursion at London Stansted Airport after the right main landing gear partially retracted during the landing roll. The aircraft, manufactured in 1999 and equipped with three Garrett TFE 731-60-1C turbofan engines, was on a private flight from Kilimanjaro, Tanzania, to London Luton Airport. There were two crew and two passengers on board; no injuries were reported. The aircraft sustained extensive damage to the right wing and landing gear doors.
History of the Flight
The flight departed Kilimanjaro at 1515 UTC with a known hydraulic problem. The crew believed the issue was permitted under the Minimum Equipment List (MEL), but this was incorrect. Shortly after departure, the HYDR#1 PUMP 3 caution light illuminated intermittently and then remained steady. The No. 1 hydraulic system quantity began to decrease and eventually indicated empty, though pressure remained normal. The crew referred to checklists and selected the No. 2 braking system, reviewed emergency slat and gear extension procedures, and added 5 kt to approach speed with an additional 60% to landing distance.
During the approach to Luton Runway 26, the flap selection resulted in abnormal slat indications. The crew attempted to lower the landing gear using the normal lever, but only red lights appeared. Emergency gear extension was initiated by pulling the Emergency Hydraulic Extension Gear Pull Handle and the main and nose gear manual release handles, but the gear remained unsafe. After a 30-minute hold, the crew requested a diversion to Stansted.
Approach and Landing at Stansted
ATC vectored the aircraft for an approach to Runway 05. The crew did not declare an emergency but requested full emergency services. The aircraft was configured for a full flap (Flap 40) landing. Prior to touchdown, the co-pilot dumped cabin pressure and switched off generators and batteries. The commander flared with a slightly higher nose attitude. The aircraft initially settled onto its gear, but as speed reduced, the right wing dropped and the aircraft veered right, leaving the paved surface near the runway midpoint. It crossed the grass and came to rest 1,900 metres from the threshold and 139 metres right of the centreline. The co-pilot opened the passenger door and everyone evacuated. Emergency services applied foam.
Aircraft Examination
On-site examination revealed the nose and left main landing gears were extended and locked, but the right main landing gear was partially retracted. The aircraft rested on the right wing tip, causing damage to the right flap, outboard slat, and wing tip. The right main gear outer door and both inboard main gear doors were damaged. Flight deck switches were found in positions consistent with emergency actions. When jacked, the right main gear extended and locked normally. The flight data and cockpit voice recorders were recovered and provided data on the flight.
Probable Cause
No probable cause was stated in the source.