What happened
On October 23, 2017, a Sikorsky S-76B helicopter was performing a commercial passenger transport flight from the DOLWIN ALPHA offshore converter station to Emden. During the return leg of the flight, the crew encountered precipitation and cloud cover. As the aircraft approached the coastline near the JUIST waypoint, it began a descent. The aircraft's altitude dropped significantly, reaching approximately 20 feet above the water surface before the crew was able to recover and land safely at Empland.
The investigation
The BFU investigation focused on the flight sequence, the crew's performance, and the technical state of the aircraft. Investigators examined the flight data, cockpit voice recordings, and meteorological reports. The investigation also looked into the company's operational procedures, including task distribution and monitoring responsibilities, as well as the regulatory environment for offshore helicopter operations in the Bremen/Langen Flight Information Region (FIR).
Findings
The primary cause of the incident was poor airmanship and a loss of situational awareness by the crew. Several critical factors contributed to the near-collision with the sea:
- The helicopter entered precipitation where the cloud base was lower than the crew had anticipated or observed in previous weather reports.
- The crew failed to terminate the descent upon reaching 500 feet above ground level and did not consider an alternative instrument approach.
- At a dangerously low altitude, both pilots focused on looking outside the cockpit to find the coastline, thereby neglecting instrument monitoring.
- The more experienced pilot in command's decisions were not challenged by the less experienced co-pilot, due to a lack of confidence in intervening.
- The crew did not adhere to company procedures regarding task sharing and mutual monitoring.
Contributing factors included the crew's inability to identify why the Flight Director had decoupled, which forced them to manually control the aircraft's altitude and speed. Additionally, the investigation noted that the aircraft was not covered by the company's internal Flight Data Monitoring system at the time of the event.