Raytheon Aircraft is working with aviation regulators and engine manufacturer Pratt & Whitney Canada in an attempt to rectify a problem with the fuel system of the Beechjet 400A light business jet, which has caused three double-engine flame-outs in the last two years.
The problem appears to centre on the fact that the aircraft does not have fuel heaters, and if ice crystals form in the fuel they can clog fuel line filters.
Raytheon is still investigating the cause of the flame-outs, together with the US Federal Aviation Administration, National Transportation Safety Board, P&WC and Transport Canada, but points out that because the aircraft is not fitted with fuel line heaters, anti-ice fuel additive has always been required for use in the type.
It is unclear whether the additive is always being used in the correct proportions, which may result from an operator not specifying it or a fixed-base operator not supplying it correctly mixed. The US military, which uses the 400A extensively as a trainer, says it has not experienced the same flame-out problem, and this may be because it pre-mixes the additive.
In a flame-out incident on 28 November 2005 the crew did not manage to relight the engines that had stopped operating during the cruise, but they glide-landed the aircraft safely. In the other two incidents the crew managed to relight one or both of the Pratt & Whitney Canada JT15D-5 engines before diverting to land.
Source: Flight International