What happened
On 1 October 2004, an Avro 146-RJ100, registration G-CFAF, was performing a scheduled passenger flight from Birmingham Airport to Stuttgart. During the initial climb phase, the crew observed that the Honiley VOR appeared to be operational, despite previous information suggesting it was out of service.
In an attempt to verify the beacon's status, the co-pilot reached for the communications selector to activate the VOR identification button. During this movement, the co-pilot inadvertently manipulated the flap lever instead of the landing gear lever. This error caused the aircraft's flaps to retract while the aircraft was at approximately 750 ft agt.
As the flaps were retracted, the aircraft's airspeed dropped, triggering the stick shaker warning. The commander responded by reducing the pitch to accelerate the aircraft toward its zero flap speed. During this recovery, the aircraft lost approximately 110 ft of altitude, reaching a minimum terrain clearance of 624 ft. The crew subsequently engaged the autopilot and continued the flight to Stuttgart without further incident.
The investigation
Investigators examined flight data from the aircraft's solid-state flight data recorder, which revealed that the flap retraction began 5 to 6 seconds after takeoff and took roughly 20 seconds to complete. The data confirmed that the stick shaker activated at an altitude of approximately 750 ft AGL, shortly after the gear status changed from locked down to not locked down.
The investigation also looked into the crew's operational procedures regarding the use of the Flight Management System (FMS) for navigation. It was noted that while the aircraft was equipped with a system capable of RNAV departures, the operator's manual did not sufficiently clarify the specific restrictions regarding P-RNAV versus B-RNAV standards for the Birmingham Airport area.
Findings
- The primary cause of the incident was the co-pilot's accidental retraction of the flaps while attempting to identify the Honiley VOR.
- Fatigue was a significant contributing factor, as the co-pilot had been working a demanding roster and had not eaten since the first sector of the day.
- Distraction occurred as the co-pilot's focus on the navigation beacon led to the mis-selection of the control lever.
- The physical proximity of the flap lever to the communications selector box facilitated the error.
- The crew's decision to use the FMS for departure despite the reported VOR outage was influenced by a lack of clarity in the company's operational procedures regarding RNAV capabilities.