What happened
On February 23, 2019, a Boeing-737-800, registration SP-RSF, was operating a flight from EPGD to EGSS. While operating within the London TMA, the crew was assigned an Expected Approach Time (EAT) and entered a holding pattern over the ABBOT waypoint. The crew initially considered diverting to the alternate airport, EGBB, but determined that weather conditions at the alternate were worse than those forecasted in the TAF.
As the crew monitored the weather at the destination, they noted improving visibility along the runway, with RVR increasing from 600m toward 800m. Observing that other aircraft were landing at EGSS without difficulty, the crew decided to proceed with the landing at the destination. During this period, the crew declared "MINIMUM FUEL" to Air Traffic Control (ATC). This declaration was intended to signal that their fuel levels were reaching a point where further delays could jeopardize their final reserves, though the declaration did not grant them landing priority as the situation was not an emergency.
Shortly after, ATC informed the crew that they could begin their descent in approximately 10 minutes. The approach and landing were completed without further incident.
The investigation
The investigation focused on the necessity of the fuel declaration and the communication between the crew and ATC. Investigators examined the fuel levels on board at the time of the declaration and the operational requirements for declaring minimum fuel. The investigation also looked into the communication environment within the London TMA during the period in question.
Findings
- The crew decided to land at EGSS based on improving meteorological conditions and the successful landings of preceding aircraft.
- The unjustified declaration of minimum fuel occurred because the aircraft still possessed over 1,000 kg of fuel above the final reserve level at the time of the report.
- A declaration of minimum fuel is only required when a subsequent EAT would result in fuel levels dropping near the final reserve.
- High levels of radio traffic within the London TMA hindered the crew's ability to contact ATC to request updated information regarding their expected approach time.