B733, Birmingham UK, 2009
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|On 6 February 2009, the crew of a Boeing 737-300 departing Birmingham successfully rejected take off from well above V1 when it became clear to the First Officer as handling pilot, that it was impossible to rotate. The Investigation found that cause of the rotation difficulty was that the crew had failed to set the stabiliser trim to the appropriate position for take off after delaying this action beyond the normal point in pre flight preparations because ground de icing was in progress and not subsequently noticing.|
|Actual or Potential
|Ground Operations, Human Factors, Runway Excursion|
|Flight Conditions||On Ground - Normal Visibility|
|Type of Flight||Public Transport (Passenger)|
|Origin||Birmingham International Airport|
|Intended Destination||Edinburgh Airport|
|Actual Destination||Birmingham International Airport|
|Take off Commenced||Yes|
|Flight Phase||Take Off|
|Location - Airport|
|Airport||Birmingham International Airport|
|Tag(s)||Inadequate Aircraft Operator Procedures|
Procedural non compliance,
Ineffective Monitoring - SIC as PF
|Tag(s)||RTO decision after V1,|
Unable to rotate at VR
|Damage or injury||No|
|Causal Factor Group(s)|
On the morning of 6 February 2009, the crew of a Boeing 737-300 (G-OGBE) being operated by bmibaby on a scheduled domestic passenger flight from Birmingham to Edinburgh had rejected take off from significantly above V1 when it was impossible to rotate the aircraft. The aircraft was brought to taxi speed on the runway and taxied back to the terminal without further event.
An Investigation into the occurrence was carried out by UK AAIB. FDR data were available. It was noted that the 39 year-old Captain had 5398 hours total flying experience which included 4300 hours on type.
It was established that the aircraft was operating its first flight of the day and had been de-iced on the gate prior to departure. Because of this, the stabiliser trim had not been set to the correct position for take off and had remained in the fully down position set for overnight parking. This omission was not noticed after start when the crew became preoccupied with the flap setting. The aircraft subsequently started its take-off run with the incorrect stabiliser trim setting and the First Officer, the designated PF, was subsequently unable to raise the aircraft nose when he attempted to do so at the calculated VR of 132 knots. The Captain then decided to take over and reject the take-off and FDR data showed that the thrust levers were closed at 155 kts287.06 km/h
, 29 knots in excess of V1. The aircraft was stopped on the runway without further consequences.
The Investigation concluded that a number of distractions, combined with the issues raised by the poor weather, had led to a break down of normal procedures and had also allowed a missed action to go unchecked. It was noted that concerns about the weather conditions were reported by the Captain to have featured strongly in his decision to reject the take-off above V1 having earlier decided that in view of “moderate to heavy” falling snow post de icing, the Holdover Time (HOT) given by the Type 2 de/anti icing fluid which had initially been determined should be reduced to between 35 and 40 minutes. It was noted that since the stabiliser had been selected to the fully nose-down position using the electric trim switch as per company procedures and this position was within the 'green band' range, there had been 'out of trim' aural warning to alert the crew to this.
It was noted that a safe stop on the runway had been possible because of the margin of take off distance available on the particular runway used, whereas attempting to stop from above V1 would normally be considered hazardous due to the possibility of overrunning the end of the runway. However, if takeoff mass is not limited by runway length, V1 may be increased, subject to certain restrictions, so that the aircraft would still be able to stop from the higher speed if necessary. It was further noted that in normal circumstances, crews do not consider the range of possible values for V1 but use a single value obtained from the Regulated Takeoff Mass (RTOM) tables provided by their Operator.
The Captain advised believing that both he and the First Officer had become pressurised by the desire to meet their revised holdover time. This situation had then been compounded by an ATC taxi clearance that required them to taxi to the runway holding point via the longest route and led to the aircraft being at the back of the queue on arrival there. The takeoff then commenced just inside the revised holdover time and the Captain stated that he was “very aware of this situation at the point at which the decision was made to reject”. He also reported being acutely aware of snow and potential ice accretion in relation to his assessment of available hold over time. Consequently, when the First Officer said he could not rotate the aircraft, the Captain quickly made the decision to reject the takeoff having judged there was sufficient runway remaining to do so and believing the aircraft was not capable of flying.
The Final Report of the Investigation was published on 9 July 2009. No Safety Recommendations were made.
- Recommendations for De-icing/Anti-icing Aeroplanes on the Ground, 30th Edition, July 2015
- Training Recommendations and Background Information for De-Icing /Anti-Icing of Aeroplane on the Ground, 12th Edition, August 2015
Note: Although the AEA ceased to exist in 2016, the most recent of their publications still contain some pertinent information. Readers are cautioned to validate the recommendations of these guidebook using more current information sources.