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DH8D, vicinity Southampton UK, 2009

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Summary
On 3 March 2009, a DHC8-Q400 being operated by UK Regional airline Flybe on a scheduled passenger flight from Edinburgh to Southampton was making its approach at the planned destination in night IMC and moderate turbulence when the aircraft was allowed to loose airspeed to below its minimum manoeuvring speed and a momentary stick shaker activation occurred. The associated automatic disconnection of the autopilot was followed by extreme pitch up and excessive roll left before the flight crew regained full control of the aircraft.
Event Details
When March 2009
Actual or Potential
Event Type
Human Factors, Loss of Control
Day/Night Night
Flight Conditions IMC
Flight Details
Aircraft BOMBARDIER Dash 8 Q400
Operator Flybe
Domicile United Kingdom
Type of Flight Public Transport (Passenger)
Origin Edinburgh Airport
Intended Destination Southampton Airport
Take off Commenced Yes
Flight Airborne Yes
Flight Completed Yes
Flight Phase Descent
ENR / APR
Location - Airport
Airport vicinity Southampton Airport
General
Tag(s) Event reporting non compliant
HF
Tag(s) Ineffective Monitoring
LOC
Tag(s) Temporary Control Loss,
Extreme Bank,
Extreme Pitch,
Aircraft Flight Path Control Error
Safety Net Mitigations
Stall Protection Effective
Outcome
Damage or injury No
Causal Factor Group(s)
Group(s) Aircraft Operation
Safety Recommendation(s)
Group(s) None Made
Investigation Type
Type Independent

Description

On 3 March 2009, a DHC8-Q400 being operated by UK Regional airline Flybe on a scheduled passenger flight from Edinburgh to Southampton was making its approach at the planned destination in night Instrument Meteorological Conditions (IMC) and moderate turbulence when the aircraft was allowed to loose airspeed to below its minimum manoeuvring speed and a momentary stick shaker activation occurred. The associated automatic disconnection of the autopilot was followed by extreme pitch up and excessive roll left before the flight crew regained full control of the aircraft.

Investigation

The event was not reported by the flight crew to anybody and only became known to the Operator three days later as a result of their Flight Data Monitoring Programme. Operator response was limited to a request to the aircraft commander to raise a Mandatory Occurrence Report (MOR), which was not received by the National Aviation Authority (NAA) until over three weeks after the event. The UK AAIB noted the MOR and determined that a Field Investigation by their organisation was required.

The investigation found that the stall warning had occurred whilst turning left in a slow descent just above 4000 ft1,219.2 m
QNH and under radar control with the Autopilot engaged in HDG and VS modes. With the trailing edge flaps still set to 0°, airspeed had fallen below the minimum for that condition. The response of the co pilot, who was PF, to the stick shaker activation and the abnormal aircraft attitudes which followed was found to have been slow and her recovery action not in accordance with Operator SOPs.

The underlying issue relating to the occurrence of the stall warning was the process for adjusting aircraft reference IAS on this aircraft type to account for icing conditions, the same issue that had been associated with the activation of stall protection during the fatal accident to an aircraft of the same type in the USA a few weeks earlier. See DH8D, vicinity Buffalo NY USA, 2009

The AAIB Investigation concluded that the flight crew "did not operate effectively, either individually or as a crew, in that they first allowed the aircraft to reach an undesirable situation and then did not deal with the situation in an entirely appropriate manner."

As a result of the Investigation, a comprehensive response was initiated by the Operator and deemed satisfactory by the NAA.

The Report of the Investigation was published on 10 June 2010 and may be seen at SKYbrary bookshelf: AAIB Bulletin: 6/2010 EW/C2009/03/03

No Safety Recommendations were made.

Further Reading