What happened
On August 24, 2015, an Embraer 190 was performing a descent from 4,000 feet to 3,000 feet at Frankfurt Airport (EDDF). During the approach, the pilot monitoring (PM) accidentally moved the flap lever from the 0 position to the 1 position. This movement occurred without a prior command from the pilot flying (PF).
As a result of the unintended flap deployment, the aircraft's overspeed warning system was activated. In response to the alert, the pilot monitoring immediately returned the flap lever to the 0 position. Simultaneously, the pilot flying adjusted the aircraft's descent rate to stabilize the flight. During this period, the aircraft's speed decreased from 240 knots to 210 knots.
The investigation
The investigation focused on the actions of the flight crew and the mechanical response of the aircraft. Analysis of the flight parameter recorder revealed that the flaps remained in the 1 position for a duration of 7 seconds. Following the landing, the crew notified the Maintenance Control Center (MCC) of the incident. A special inspection was conducted in accordance with the Aircraft Maintenance Manual (AMM 05-50-07 REV. 22), after which the aircraft was cleared for return to service.