What happened
On June 17, 2010, a City Jet British Aerospace Avro RJ85, registration EI-RJW, was operating a passenger flight from Paris Charles de Gaulle to Zurich. Due to deteriorating weather conditions and a missed approach in Zurich, the crew decided to divert to Basel-Mulhouse Airport. Upon arrival at Basel-Mulhouse, the crew requested a shortened approach trajectory without specifying the reason.
During the final approach, the crew observed an Airbus A319 positioned on the runway. While the EI-RJW was approximately 4.7 NM from the threshold, the crew queried the tower controller regarding landing authorization. The controller informed them that an A319 was currently departing. At 1.8 NM from the threshold, the tower controller ordered the A319 to stop immediately due to the approaching BAe 146 performing a go-around. The crew of the EI-RJW initially resisted the instruction to go around, citing low fuel levels, but eventually complied after a second instruction. Following the go-around, the crew declared a Mayday fuel emergency and requested priority landing. The aircraft landed safely at 17:34 UTC with 1,220 kg of fuel remaining.
The investigation
The investigation focused on the communication between the flight crew and air traffic control, as well as the fuel management procedures. Investigators examined the fuel quantities, noting that the aircraft was operating with low fuel levels, which triggered a "FEED LO LEVEL" warning. The investigation also reviewed the radio communications, specifically the use of French between the tower and the departing A319, which was not understood by the English-speaking crew of the EI-RJW.
Findings
- The primary cause of the incident was the delayed communication by the crew regarding their low fuel status and emergency situation, which prevented the controller from being fully aware of the urgency.
- The use of non-standard phraseology by the controller and the departing aircraft crew regarding the "departure in a minute" created ambiguity.
- The crew of the EI-RJW did not understand the French-language exchange between the tower and the A319, which prevented them from realizing the runway was occupied until very late in the approach.
- There was an absence of a specific, standardized "Minimum Fuel" procedure within the regulatory framework at the time.
- The aircraft's fuel reserves did not explicitly account for the possibility of a go-around during a diversion.