On 14 August 2005, an Embraer 145 being operated by British Airways Regional on a scheduled passenger flight from Birmingham to Hannover overran the wet landing runway by 160 m in normal visibility after flying a daylight ILS approach with the approach lights visible from about 4 nm. There was no fire and only one of the 49 occupants received minor injuries. The aircraft suffered only minor damage.
An Investigation was carried out by the German Federal Bureau of Aircraft Accidents Investigation, the Bundesstelle für Flugunfalluntersuchung (Germany) (BFU). This found that the aircraft commander had been PF and that when offered either Runway 27L or the longer 27R for landing, he had been influenced in his choice by the more convenient taxi route to the usual parking gate after landing from 27L. The aircraft was operating at close to MLW and it was noted that thrust reversers were not fitted.
The Investigation found that the ILS approach had been stable at 500 feet aal and that the autopilot had been disconnected at 180 ft aal, after which the aircraft had remained above the ILS GS. The landing runway threshold was over-flown at a height 62 ft at a speed of 140 KIAS compared to the target height of 50 feet and an applicable Reference Speed (Vref) of 138 KIAS. The subsequent touchdown occurred at 122 KIAS and was estimated to have taken place about 850 metres after the runway threshold. Automatic ground spoiler deployment occurred but there was no significant deceleration as a result of brake application.
Towards the end of the runway when the aircraft was still at a speed of 68 knots and it was clear than at overrun was likely, the aircraft commander selected the emergency / parking brake which is designed for use only in the event of brake failure. No beneficial effect on deceleration resulted, as the wheels locked and the ground spoilers auto retracted. Evidence of reverted rubber aquaplaning was found from this point until the aircraft left the end of the paved surface at a speed of 58 knots. After a further 11 seconds and an overrun totalling approximately 160 metres across flat ground with relatively minor obstructions, the aircraft came to a stop.
Hannover Airport Diagram
Findings of the Investigation included:
- That, in theory, Runway 27L would have been long enough had all parameters used for the calculation been adhered to. However, the aircraft touched down 849 m after the threshold which resulted in the fact the LDA was theoretically and practically insufficient given the prevailing conditions.
- Based on the slow deceleration, the BFU is of the opinion that dynamic aquaplaning occurred shortly after touchdown in the middle part of the runway. A soft landing on a runway contaminated with water aided aquaplaning.
- The aerodrome operator did not provide the Tower Controller with required information on runway conditions necessary for a safe conduct of flight operations.
- A continuous observation and assessment of the runway conditions through the aerodrome operator which the quickly changing weather situation would have made necessary did not occur.
Causal Factors of the Accident were detailed by the Investigation as:
- The decision to land on the shorter runway which was aided by insufficient information regarding the real runway condition.
- The late touchdown which was caused by insufficient situational awareness, light tailwind and increased landing speed.
- The missing braking action which was caused by aquaplaning. The use of the emergency brake which aided aquaplaning.
The Investigation noted that three Safety Recommendations had been made as a result of the Operator’s own internal Accident Investigation:
- A review of the way in which pilots on the EMB-145 might be reacquainted with the importance of using the correct landing technique on wet runways should be made.
- A review of guidance provided to flight crew for circumstances where braking effectiveness during landing is not sufficient should be undertaken.
- A review should be made of the circumstances under which aquaplaning can occur on wet runways so as to better inform the management of this risk.
The BFU decided that “based on the described actions (of the Operator) the BFU will abstain from Safety Recommendations.”
The Final Report of the Investigation was published in January 2007 and may be seen in full at SKYbrary bookshelf: BFU - Investigation Report EX006-0/05