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Report No: 1/2009. Report on the serious incidents to Boeing 737-81Q, registration G-XLAC, on 29 December 2006; Avions de Transport Regional ATR-72-202, registration G-BWDA on 29 December 2006 and Embraer EMB-145EU, registration G-EMBO on 29 December 2006 and Boeing 737-81Q, registration G-XLAC on 3 January 2007 at Runway 27, at Bristol International Airport

Date of occurrence: 29 December 2006

Summary:

The serious incidents involving G-BWDA and G-EMBO were notified to the Air Accidents Investigation Branch (AAIB) on 29 December 2006. An investigation into the two serious incidents began on 2 January 2007. During this investigation, the events involving G-XLAC, and others, were identified. All events took place during landings at Bristol International Airport, hereafter referred to as BIA.

The AAIB investigation team comprised:
Mr K Conradi (Investigator-in-Charge)
Mr T J Atkinson (Operations)
Mr S J Hawkins (Engineering)
Mr C J Scott (Flight Recorders)
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 experienced poor stopping performance during landing. Later that day, the flight crew of G-BWDA 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 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.

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Report name:
AAR 1/2009 Boeing 737-81Q, G-XLAC; Avions de Transport Regional ATR-72-202,G-BWDA and Embraer EMB-145EU, G-EMBO
Registration:
G-XLAC; G-BWDA and G-EMBO
Type:
Boeing 737-81Q; Avions de Transport Regional ATR-72-202 and Embraer EMB-145EU
Location:
Runway 27, Bristol International Airport
Date of occurrence:
29 December 2006
Category:
Commercial Air Transport - Fixed Wing
Summary:

The serious incidents involving G-BWDA and G-EMBO were notified to the Air Accidents Investigation Branch (AAIB) on 29 December 2006. An investigation into the two serious incidents began on 2 January 2007. During this investigation, the events involving G-XLAC, and others, were identified. All events took place during landings at Bristol International Airport, hereafter referred to as BIA.

The AAIB investigation team comprised:
Mr K Conradi (Investigator-in-Charge)
Mr T J Atkinson (Operations)
Mr S J Hawkins (Engineering)
Mr C J Scott (Flight Recorders)
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 experienced poor stopping performance during landing. Later that day, the flight crew of G-BWDA 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 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.
Download report:
PDF icon 1-2009 G-XLAC G-BWDA G-EMBO.pdf (3,344.12 kb)