What happened
On 12 November 2015, a BAe Avro RJ85, registration EI-RJH, was operating a scheduled passenger flight from Paris Charles de Gaulle to Dublin. During pre-flight planning, the crew noted forecasts for high winds at Dublin, prompting them to load sufficient fuel for a Dublin approach, a diversion to Manchester, and an additional 25 minutes of flight time, alongside the mandatory 30-minute final reserve.
As the aircraft approached Dublin, wind gusts reached 47 knots, exceeding the maximum crosswind limits for the available runways. Although a brief window of calmer winds allowed for an attempted approach, the wind strengthened again, forcing the crew to divert to Belfast International Airport. While being vectored for an approach at Belfast, the crew encountered unexpected poor visibility and wind gusts at that location.
To manage the situation, the crew issued a 'PAN-PAN' call to notify air traffic control of their decreasing fuel state. As the weather cleared, the aircraft was cleared for landing on Runway 17. During the final stages of the flight, the crew realized the fuel level might drop below the 849 kg final reserve threshold and issued a 'MAYDAY' call. The aircraft landed at 1548 hrs with 650 kg of fuel remaining.
The investigation
The investigation examined the fuel planning, the decision-making process regarding the diversion, and the impact of rapidly changing weather conditions. The crew had considered the aircraft's landing weight in relation to potential windshear and had chosen Belfast as a diversion because it appeared to be a more viable immediate option than Manchester, despite Manchester having more favorable weather forecasts.
Findings
- The decision to attempt a landing at Dublin was influenced by a temporary period where wind speeds dropped below the crosswind limits.
- The crew selected Belfast as the diversion airport because it required less fuel than Manchester and offered two available runways.
- The aircraft landed with less than the required Final Reserve fuel due to the unexpected delay caused by localized poor weather at Belfast International.