History of Flight
On 7 April 2005, a McDonnell-Douglas MD-11 aircraft, registration N413LT, conducted a series of test flights at Singapore Changi Airport following a passenger-to-freighter (PTF) conversion at a maintenance facility in Paya Lebar Airport. The test flights included three landings and one go-around. The first two landings were normal. During the third landing at about 1110 hours local time on Runway 02L, the centre landing gear (CLG) lower drag brace link forward attachment point and the gear retract actuator end broke loose from the aircraft structure.
Prior to departure, two braking tests were performed at Paya Lebar: a low-speed autobrake rejected take-off (RTO) and a high-speed autobrake RTO. After the high-speed RTO, the brake temperature monitoring system recorded an overheat alert for brake #5 and brake #10, and a simultaneous failure of the two CLG tyres was logged (though the tyres appeared intact later).
The aircraft then flew to Changi and performed two landings without issue. On the third landing, the PIC was pilot flying, using autopilot 1, 35° flap, and autobrake set to MED. After a normal touchdown, heavy vibrations were felt, and the CLG "Gear Unsafe" red indication appeared. The aircraft vacated the runway and stopped for inspection.
Damage to Aircraft
Inspection revealed the CLG was angled at about 45° aft of vertical (normally 15° forward). The forward lugs of the lower drag brace link and the lugs on the CLG gear retraction actuator were broken. Additional damage included deformation of the aft bulkhead of the CLG wheel well, one dislodged CLG door, a shattered electrical terminal strip in the right main landing gear (MLG) wheel well, a broken accumulator bracket in the left MLG wheel well, dents and tyre marks on the aft fuselage, dents from debris, and flat spots on both CLG tyres.
Personnel
The pilot-in-command, aged 49, held an Airline Transport Pilot Licence issued by Germany, with 9,500 total flying hours (3,600 on type). The first officer, aged 58, also held a German ATPL, with 12,000 total hours (2,700 on type). Both had recent checks and medicals.
Aircraft Information
The MD-11 was manufactured in 1992 and had accumulated 50,632 hours and 9,227 cycles. The CLG had 52,029 hours and 10,126 cycles since new, last overhauled in April 2000. The aircraft underwent PTF conversion and C check from September 2004 to March 2005. The aircraft was declared serviceable for test flights.
Injuries
No injuries were reported.