The AAIB released the final report on their investigation of several incidents at Bristol International Airport.
Resurfacing and re-profiling work was taking place on parts of the runway at BIA as part of a major project to resurface the manoeuvring area pavements, and sections of the runway surface were ungrooved ‘base course’ asphalt. From 14 November 2006, there were reports from flight crew of a variety of problems related to the friction characteristics of the temporary runway surface, though no serious incidents occurred until 29 December 2006. On that day, the flight crew of G-XLAC (a Boeing 737-81Q) experienced poor stopping performance during landing. Later that day, the flight crew of G-BWDA (an ATR-72-202) experienced stopping and lateral control difficulties during landing, and the aircraft departed the runway surface and came to rest on the grass area at the side of the runway. Later still, the flight crew of G-EMBO (an EMB-145EU) experienced lateral control difficulties during landing, and the aircraft partially left and then regained the runway. On 3 January 2007, another flight crew, also operating G-XLAC, experienced poor stopping performance. The airport was subsequently closed whilst grooves were cut in the base course. After it re-opened there were no further incidents.
The investigation identified the following causal factors:
1. Reduced friction on the wet ungrooved base course sections of the runway caused flight crews to experience reduced braking action and reduced lateral controllability on landing in strong crosswinds;
2. The Flight Operations Department Communication (FODCOM) advice published by the CAA regarding operations on runways notified ‘slippery when wet’, in wet conditions, was not communicated by operators to flight crews;
3. The passing, by ATC, of braking action reports based on Mu-meter friction assessments, gave flight crews a false confidence in the braking action available on the wet runway.
The investigation identified the following contributory factor:
1. G-BWDA landed in a crosswind outside the operator’s published limits and the subsequent use of reverse thrust was contrary to the advice contained in the company’s Operations Manual.
The AAIB has made five Safety Recommendations. (AAIB)