What happened
On January 19, 2004, a McDonnell Douglas DC10-40F cargo flight arriving from Novosibirsk landed at Frankfurt-Hahn airport during snowfall. The aircraft, carrying approximately 60 tonnes of freight, touched down on runway 21 within the touchdown zone.
During the landing roll, the crew activated the thrust reversers; however, the reverse thrust system on the left engine failed, becoming stuck in a partially deployed transition position. To maintain directional control, the pilot had to reduce power on the right engine, leaving only the center engine's reverse thrust fully available. As the aircraft continued to decelerate, engines 1 and 3 experienced compressor stalls accompanied by visible flames, prompting an immediate fire service response.
Due to poor braking conditions, the aircraft failed to stop within the runway limits. It rolled through the 300-meter stopway and onto an adjacent, unpaved asphalt area that had not been cleared of snow. While attempting to maneuver the aircraft to avoid a localizer antenna and a row of runway lights, the nose gear and both main gears entered unpaved terrain, resulting in minor damage to the aircraft and the nose gear tire.
The investigation
The BFU investigation examined the runway condition, the accuracy of the ATIS (Automatic Terminal Information Service) broadcasts, and the crew's landing performance calculations. The investigation reviewed the recent runway maintenance, noting that deicing fluid application had been inconsistent across the runway surface. Investigators also analyzed flight data recorder information and interviewed the crew, the air traffic controllers, and the airport winter service personnel.
Findings
- Inaccurate runway information: The ATIS broadcast provided braking action coefficients in the reverse order of the landing direction, contrary to ICAO standards. Furthermore, the ATIS did not disclose that the runway was contaminated with snow or slush.
- Inadequate landing calculations: The crew had calculated their landing distance based on dry and wet runway conditions but had not performed a calculation for a contaminated runway.
- Mechanical failure: The left engine's thrust reverser failed to deploy fully, significantly reducing the available braking assistance.
- Environmental factors: The presence of snow and slush on the latter portion of the runway, combined with a crosswind, contributed to the loss of braking effectiveness and difficulty maintaining directional control.
- Inconsistent runway maintenance: The application of deicing fluid was uneven, leading to significantly different friction coefficients on different parts of the runway surface.
Safety action
Following the investigation, the BFU issued safety recommendations to ensure that airport personnel are trained to report braking action in the correct landing direction and that all staff are instructed on the standardized assessment and publication of runway surface conditions in accordance with ICAO Annex 14.