In a final report released on October 23, UK AAIB investigators were puzzled by the pilot's reaction—or rather the lack of it—after he acknowledged low fuel warnings in his Airbus Helicopters EC135 T2+, which eventually crashed and killed 10 in Glasgow, Scotland, in November 2013. Without flight recorders, investigators cannot understand why the police observers and the Bond pilot undertook a task in the latter part of the flight, with such warnings active for eight minutes.
Moreover, the two pumps that transfer fuel from the main tank to the supply tanks (one for each engine) were deactivated during the flight for an undetermined reason. These transfer pumps can be switched off in flight to avoid a prolonged run-dry situation that could happen in certain conditions.
However, AAIB investigators could not find any circumstance during the flight that would have prompted the “run dry” caution message. More than 160 pounds of usable fuel in the main tank was rendered unusable as a result of the fuel transfer pumps being switched off.
Next year, Airbus will introduce changes to the transfer pump management logic—they will be switched on for takeoff and only switched off after landing. The dry-run indication will be omitted, due to improvement in the later generation of pumps.
The AAIB's safety recommendations center on the need for voice, data and image recorders aboard helicopters.