What happened
On 20 January 2017, an Agusta AW139, registration G-VINB, was engaged in a seven-sector passenger shuttle operation in the North Sea. Following weather-related delays earlier in the day, the flight crew received a revised mission profile that allowed them to complete the entire rotation without an offshore refuelling stop.
While the commander was occupied reviewing the aircraft's technical log and assisting the engineering department, the co-pilot performed the necessary flight re-planning. During this process, the destination for the fourth sector was incorrectly selected as Ravenspurn North instead of Ravenspurn Alpha.
After completing the first three sectors and a turnaround at West Sole Alpha, the crew approached the Ravenspurn field. During radio communications with the Helideck Landing Officer (HLO), the crew used an abbreviated name for the platform. Although the HLO explicitly mentioned "Ravenspurn Alpha," the crew did not identify the discrepancy and proceeded to land at Ravenspurn North. Upon landing, they discovered the helideck was unmanned, contrary to operational requirements. The crew remained rotors running and followed established procedures to wait for a crew to be present before proceeding to the correct destination.
The investigation
The AAIB investigation examined the flight planning software and the communication protocols used during the approach. The investigation found that the operator's planning software and the customer's payload system (Vantage) utilized different coding nomenclatures for platforms. For example, Ravenspurn Alpha was identified as "RA" in the aircraft systems but "RAVA" in the payload system, while Ravenspurn North was "RVN" versus "RAVN". This difference in coding made cross-checking the flight plan and payload information more difficult.
Furthermore, the investigation looked into the radio transmissions between the crew and the HLO. It was noted that the crew's use of the abbreviated term "Ravenspurn" contributed to the lack of clarity regarding which specific platform was being discussed.
Findings
- The primary cause of the incident was a destination error during the flight planning stage.
- Time pressure resulting from morning weather disruptions and the need to rapidly re-plan the mission contributed to the error.
- The crew failed to identify the incorrect destination during several critical stages, including the pre-flight briefing, the cross-checking of payload information, and the programming of the Flight Management Computer (FMC).
- Discrepancies in platform naming conventions between different software systems complicated the verification of the flight plan.
- The crew's use of abbreviated radio terminology and potential confirmation bias prevented them from noticing the HLO's specific mention of Ravenspurn Alpha.