C1/2010L AVRO RJ85 Jetliner Fuel Feed Low Level Failure During the Cruise Phase on 17 December 2009

On 17 December 2009, at approximately 17:05 an incident occurred to a Blue1 airliner which was on the scheduled flight BLF284 from Vaasa airport to Helsinki-Vantaa airport. The incident was caused by a fuel feed problem. The aircraft, registration OH-SAK, was a four-engine Avro 146-RJ85 manufactured by BAE Systems Limited. There were 64 passengers and four crew members onboard.

Approximately 11 minutes after takeoff, during the climb, the master warning panel annunciated the following right wing inner feed tank warning: R FEED TANK LO LEVEL. The flight crew began completing the related emergency checklist. The checklist instructs the flight crew to LAND ASAP, unless the warning disappears. The flight crew continued the flight to their destination even though the warning light remained on. As they were passing the city of Tampere the flight crew noticed that the fuel quantity in the right wing's outboard feed tank had begun to decrease. Approximately two minutes later the warning system also generated a fuel level warning from the left wing's inner feed tank. At that point in time the flight crew had simultaneous problems with three separate feed tanks. When the aircraft landed at Helsinki-Vantaa airport the flight crew used the normal trailing edge flap setting of 33 degrees. The checklist that relates to this particular malfunction calls for 24 degrees flaps.
The rescue units alerted by the air traffic control were ready at their stations, poised to provide assistance as the flight landed at its destination. The incident did not result in any injuries to persons nor damage.

A technical inspection following the landing showed that frozen water in the fuel probably obstructed the transfer of fuel from the main tank to the engines' feed tanks. This caused the fuel level in the feed tanks to drop. In a normal situation each engine's feed tank is always full of fuel. According to the information received from the aircraft's manufacturer, other operators, too, have had similar fuel feed problems, particularly during cold winters. The number of such occurrences decreased when operators increased the fuel tank water drain frequency. The manufacturer-recommended minimum fuel temperatures must also be observed during water draining so as to make the procedure adequately efficient. Blue1 also began to add anti-icing additive to its fuel.

The flight crew's decision to disregard the emergency checklist's LAND ASAP instruction also contributed to the incident. Due to its location, good weather and runway conditions Tampere-Pirkkala airport would have been a suitable en-route alternate. Contributing factors included the flight crew's poor airmanship and decision-making. The layout of the checklist for this emergency is both complex and verbose.

The investigation commission recommends that the European Aviation Safety Agency (EASA) oblige BAE Systems Limited, the aircraft manufacturer, to make the Feed Tank Low Level checklist easier to use.

C1/2010L Report (pdf, 0.38 Mt)