Fatigue failure of flap control screw leads to fatal crash of APM30

Casualties unknown • Arras-Roclincourt, FR

A single-engine APM30 crashed near Arras-Roclincourt after a mechanical failure caused asymmetric flap extension, resulting in the pilot's death.

What happened

On August 2, 2020, an Issoire Aviation APM30, registered F-HHOP, crashed during a local flight near the Arras-Roclincourt aerodrome in France. The pilot was performing a routine local flight when, during the approach for landing on runway 22, the aircraft lost control and struck the ground in a field of tall corn. The impact destroyed the aircraft and resulted in one fatality.

The investigation

The BEA investigation focused on the mechanical state of the flight controls and the effectiveness of the search and rescue response. Investigators examined the wreckage and found that the left wing had struck the ground first, causing the wing to tear off. The flap control selector was found set to the 25° landing position, matching the position of the right flap; however, the left flap had failed to maintain this position.

Laboratory analysis of the left flap control mechanism revealed that the screw fastening the actuating rod to the flap had failed. Furthermore, investigators looked into why the Emergency Locator Transmitter (ELT) failed to alert rescue services. They discovered that while the ELT had activated upon impact, the connector linking the unit to the antenna had ruptured, preventing the distress signal from being received by search and rescue authorities.

Findings

Technical analysis determined that the left flap control screw failed due to a fatigue cracking process caused by alternating bending loads. Evidence suggested that a tightness fault in the assembly may have contributed to the development of these cracks. The resulting asymmetric flap extension created significant aerodynamic imbalances, which likely led to the loss of control at a low altitude, leaving the pilot with insufficient time to react.

Additionally, the investigation found that the rupture of the ELT-antenna connector—potentially caused by passenger movement or luggage in the rear seat—prevented the activation of standard aeronautical alert phases. The high corn crop also obscured the wreckage from ground-based searchers, delaying the arrival of medical teams until approximately 75 minutes after the accident.

Probable cause

The primary cause of the accident was the fatigue failure of a left flap control screw, which induced aerodynamic asymmetry and subsequent loss of control. Contributing factors included the low altitude of the failure and the failure of the ELT signal to transmit due to a broken antenna connector.

Frequently asked questions

What happened in the 2020-08-02 ISSOIRE AVIATION - APM30 accident near Arras-Roclincourt, FR?

A single-engine APM30 crashed near Arras-Roclincourt after a mechanical failure caused asymmetric flap extension, resulting in the pilot's death.

What aircraft was involved and where did it happen?

The accident on 2020-08-02 involved a ISSOIRE AVIATION - APM30, registration F-HHOP, at Arras-Roclincourt, FR.

What was the probable cause of the accident?

The primary cause of the accident was the fatigue failure of a left flap control screw, which induced aerodynamic asymmetry and subsequent loss of control. Contributing factors included the low altitude of the failure and the failure of the ELT signal to transmit due to a broken antenna connector.

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