What happened
On 16 July 2018, a DHC-8-402, registration G-JEDU, was performing a commercial passenger flight departing from Düsseldorf Airport, Germany. During the initial climb phase following takeoff from Runway 05R, the pilot monitoring mistakenly retracted the flaps instead of raising the landing gear.
The commander did not immediately identify the error. The sunlight shining into the cockpit made the primary flight display difficult to read, and because the aircraft was operating at normal takeoff power rather than a reduced setting, the performance characteristics of the aircraft masked the effects of the premature flap retraction. While the commander noted he might have heard the co-pilot mention "flaps," he initially dismissed the comment as a mishearing of a different standard operational call. The flight continued without further incident, and there were no injuries to the 4 crew members or 77 passengers on board.
The investigation
The AAIB examined the cockpit procedures and the circumstances surrounding the error. The investigation focused on the standard operating procedures (SOPs) for both landing gear and flap retraction. At the time of the incident, the procedures involved a single-stage selection and movement of the lever by the pilot monitoring in response to a command from the pilot flying.
The investigation also reviewed the operator's history with similar events. The operator noted that while such mis-selections had occurred previously, they considered the frequency to be at a tolerable level and identified distraction as a common contributing factor. The operator expressed reluctance to implement new training measures, fearing that specifically highlighting the error might inadvertently prime crews to make similar mistakes.
Findings
- The pilot monitoring inadvertently retracted the flaps instead of the landing gear.
- The commander's ability to monitor the flight displays was hindered by sunlight glare in the cockpit.
- The use of normal takeoff power, rather than a reduced power setting, prevented the crew from immediately noticing the change in aircraft performance caused by the flap retraction.
- The error was a skill-based human error involving the mis-selection of flight controls during a phase of flight where both actions are expected.