On 30 November 2010, a Bombardier DHC8-400 being operated by Flybe on a scheduled passenger flight from an unrecorded origin to Southampton was unable to select any trailing edge flaps when preparing for the intended landing at destination. The night non precision approach in Visual Meteorological Conditions (VMC) was discontinued and a diversion was made to Bournemouth where a longer runway with an Instrument Landing System (ILS) procedure was available for the necessary flapless landing and during the subsequent touchdown, a tail strike occurred. None of the 73 occupants were injured and damage to the aircraft was minor.
An Investigation was carried out by the UK AAIB. Flight Data Recorder (FDR) data was available to the Investigation, which was assisted by the Operator and the aircraft manufacturer.
It was established that as the aircraft approached touchdown on runway 08 at Bournemouth after a flapless ILS approach, the aircraft commander, as PF had perceived a high rate of descent and had increased the pitch attitude to reduce it. The First Officer, who had been calling pitch attitudes during the approach, had called “Pitch 8°, don’t pitch any more” but as the aircraft touched down, a Master Warning activated and the ‘touched runway’ annunciation illuminated.
It was noted that the applicable drill in the Quick Reference Handbook (QRH) requires that pitch attitudes in excess of 6° at touchdown are avoided. Aircraft manufacturer Bombardier’s advice to Operators current at the time advised them to include in their procedures an alert call at 5° pitch attitude and also stated that descent control below 200 ft agl must be through power lever management rather than pitch adjustment.
In respect of landings with abnormal flap configurations, it was noted that the Flybe Operations Manual stated that “Power should be reduced to Flight Idle at touchdown and the nose-wheel promptly lowered to the ground.” The Aircraft Flight Manual (AFM) for the aircraft type stated that “Power should be reduced gradually to achieve Flight Idle at or just prior to touchdown.” In both cases, there was a caution to avoid pitch attitudes in excess of 6° at touchdown.
FDR data showed that the power levers were retarded slightly as the aircraft passed 100 ft agl and retarded to idle below 30 ft agl. A reduction in rate of descent as touchdown neared corresponded to an increase in aircraft pitch attitude from 6° nose-up at 30 ft agl to 9° nose-up immediately before touchdown occurred.
The Investigation was informed by Bombardier that it believed that the AFM contained adequate information to enable pilots to control the rate of descent at maximum pitch attitude and concluded that, in this incident, the appropriate pilot action required the ‘application of power coincidental with lowering of the pitch attitude to the allowed 6°.’
It was considered that by the Investigation that “The rate of descent required for a flap 0° approach is significantly higher than for a normal approach but the operator’s pilots practise flap 0° approaches in the simulator only once every three years. Consequently, the incident aircraft pilot’s perception of a high rate of descent might be expected of most of the operator’s pilots when flying a flap 0° approach. The aircraft’s rate of descent was already higher than required when the pilot began to reduce power towards flight idle in accordance with the ECL instructions. The reduction in power would probably have increased the rate of descent further in the absence of any other action. However, the pilot increased the aircraft pitch attitude at the same time, and the aft lower fuselage struck the runway.
It was further considered that “as a source of guidance for pilots who rarely fly or train for abnormal flap approaches, the (Emergency Check List) should contain the most complete information that it is practical to provide” and that a marginal improvement could be made in this respect.
One Safety Recommendation was therefore made as a result of the Investigation:
- That Bombardier Aerospace amends the DHC-8-402 Dash 8 emergency checklist section concerning abnormal flap landings to reflect their advice that power will be maintained until main wheel contact. (2011-081)
The Final Report AAIB Bulletin: 9/2011 EW/C2010/11/04 was published on 8 September 2011