Sequence of Events
On September 11, 2024, an Embraer-550 Praetor 600 departed from Runway 12 at Stockholm/Bromma Airport. Shortly after takeoff, the pilots received a warning message indicating a failure of the Flight Control System. The aircraft then experienced an increased pitch angle that rose rapidly beyond what the crew expected. The pilot flying attempted to counteract the pitch movement using the control stick but found that the stick had limited authority. The pilot then operated the manual pitch trim to decrease the angle of the horizontal stabilizer, which stopped the continued climb. The crew declared a Mayday over the radio, and the air traffic controller directed the aircraft for an approach and landing back at the departure airport after the full functionality of the Flight Control System had been restored.
Aircraft and Flight Control System
The aircraft involved was an Embraer-550 Praetor 600. The Flight Control System is designed to manage control surfaces and provide stability. In this incident, the system degraded after a failure in both flight control computers following rotation. The pilots were confronted with a warning message "FLTCTRL N-MODE FAIL" and had to rely on manual pitch trim to maintain control.
Cause of the Incident
According to the Swedish Accident Investigation Authority, the unexpected upward pitch movement was caused by a failure in both flight control computers after rotation. As a result, the Flight Control System degraded to a simpler configuration. The investigation also noted that the control stick had limited authority in the degraded mode, prompting the pilot to use the manual pitch trim.