What happened
On November 19, 2006, at approximately 19:15 local time, a Fokker F27 MK500 experienced a serious malfunction during takeoff at Mönchengladbach aerodrome. The aircraft, which had been flown from Cologne/Bonn the previous day for nose gear maintenance, was attempting a return flight to Cologne.
During the takeoff roll on runway 31, the crew—consisting of two pilots and one additional passenger—reached the rotation speed ($V_R$) of 96 knots. However, the aircraft failed to lift off. The crew subsequently initiated an aborted takeoff. Due to the inability to stop within the 1,200-meter runway, the aircraft overran the threshold, coming to rest on unpaved ground approximately 55 meters beyond the runway end. The nose gear sank halfway into the soft ground, and the aircraft struck a concrete base of the approach lighting system, causing damage to the tire, rim, and three lighting units. There were no fatalities and no injuries to the occupants.
The investigation
The BFU investigation focused on the aircraft's weight and balance, as well as the takeoff performance. Investigators examined the flight data recorder (FDR) and cockpit voice recorder (CVR), both of which were fully functional. The investigation also reviewed the loading procedures and the accuracy of the load and trim sheets prepared prior to departure.
Findings
Several critical discrepancies were identified regarding the aircraft's loading and center of gravity. While the aircraft had been loaded with ballast in the rear compartment to maintain a proper center of gravity for an empty flight, the actual amount of ballast loaded in Cologne/Bonn was only 282 kg, rather than the required 580 kg specified in the operating manual for a three-person cockpit.
Furthermore, the load and trim sheet prepared by the co-pilot used incorrect aircraft data. The sheet utilized a Dry Operating Weight (DOW) of 11,511 kg and a Dry Operating Weight Index (DOI) of 27, whereas the actual DOW was 11,956 kg and the DOI was 22. A recalculation using the correct values revealed that the aircraft's center of gravity was outside the forward limit. This improper weight and balance, combined with the failure to rotate at the calculated speed, contributed to the runway excursion.