What happened
On August 24, 2023, a De Havilland DHC-6 400 operated by CAIRE was performing a commercial passenger flight at Saint-Barthélemy airport. During the approach, the captain experienced sudden ear pain, which required him to temporarily transfer controls to the co-pilot to perform the Valsalva maneuver. During this period, the crew also failed to inhibit terrain alerts, leading to several cockpit warnings.
Upon touchdown on runway 28, the aircraft began veering sharply to the left. The captain attempted several corrections, including rudder inputs and asymmetric reverse thrust, but the aircraft continued its lateral deviation. The aircraft exited the runway, struck a taxiway sign, and its left wing collided with an AS3 and parked AS350 helicopter. The impact caused substantial damage to the aircraft and the helicopter. Two persons sustained slight injuries during the event, and the aircraft was significantly damaged.
The investigation
The BEA investigation focused on the alignment of the nose wheel steering (NWS) system and the crew's adherence to landing procedures. Investigators examined the aircraft's maintenance history, which revealed that the NWS control cable tension had been insufficient during post-accident testing. Furthermore, the investigation reviewed the operator's documentation, finding that recent manufacturer amendments regarding NWS check procedures had not been integrated into the CAIRE operating manual.
Analysis of the cockpit voice recorder (CVR) also revealed that the crew was engaged in non-essential conversation during the sterile cockpit phase, which may have contributed to a lack of concentration. Additionally, the investigation noted that the captain was experiencing fatigue due to sleep deprivation in the days leading up to the accident.
Findings
- The nose wheel was not centred upon touchdown, causing the aircraft to veer left.
- The crew did not perform the required manual check of the NWS lever to ensure the gear was locked in the centered position, as the operator's manual lacked the updated 2017 manufacturer procedures.
- The NWS control cable tension was insufficient, which could allow the nose wheel to pivot during flight despite the cockpit lever appearing aligned.
- The captain's fatigue and the distraction caused by ear pain likely hindered the crew's ability to effectively monitor the aircraft's configuration.
- Non-compliance with the sterile cockpit rule and task saturation during the approach reduced the crew's situational awareness.