What happened
On August 14, 2005, at 16:51 local time, an Embraer EMB-145 EP operating a scheduled flight from Birmingham to Hannover overran the end of runway 27L at Hannover Airport. The aircraft, carrying 45 passengers and four crew members, was landing during a period of heavy rain and thunderstorms. During the landing roll, the aircraft exited the runway on the right side, coming to a stop on unpaved ground approximately 160 meters beyond the runway end. One flight attendant sustained minor injuries, and the aircraft suffered light damage to the landing gear area, while some ground damage occurred.
Prior to landing, the crew had opted for the shorter runway (27L) to avoid construction on taxiway G and to reach the terminal more quickly. Although the crew had monitored weather updates earlier in the approach, they did not receive the final specialized weather updates broadcast via ATIS between 16:08 and 16:33, which indicated deteriorating conditions. At the time of touchdown, the aircraft was experiencing a 3-knot tailwind and heavy rain.
The investigation
The BFU investigation examined the flight data recorder, cockpit voice recorder, and braking system data. The investigation established that the aircraft touched down at 849 meters from the threshold, significantly later than the ideal touchdown point. The investigation also reviewed the runway conditions, noting that while the runway surface was concrete, it was covered with water and puddles. The investigation found that the aircraft's speed at the threshold was 140 knots, which was approximately 10 knots above the calculated VRef for the landing weight.
Furthermore, the investigation analyzed the pilot's actions during the braking phase. The captain attempted to use the parking brake (which also serves as the emergency brake) in an attempt to increase deceleration. This action deactivated the anti-skid system, causing the wheels to lock and inducing rubber reversion hydroplaning.
Findings
- The decision to use the shorter runway (27L) instead of the longer 27R was a disadvantageous choice given the weather conditions.
- The aircraft lacked thrust reversers, which limited the crew's ability to reduce speed during aquaplaning.
- The touchdown was late, exacerbated by a 3-knot tailwind and an approach speed 10 knots above VRef.
- The use of the emergency/parking brake deactivated the anti-skid system, leading to wheel lock-up and rubber reversion hydroplaning.
- The crew was not informed of the actual runway condition by air traffic control or the latest ATIS updates.
- The airport operator failed to provide necessary information regarding the runway state and did not perform continuous monitoring of the surface during the rapidly changing weather.