June's Maintenance run

As part of the pre-season work up. XL231 had her monthly anti-det (anti deterioration) run on Sunday.  This was delayed by 2 weeks due to a snag with the APU Artouste engine that caused a bit of concern. Happily this turned out to be a partially sticking ADV (air delivery valve) that was soon cleared and the APU fuel control main solenoid valve was also removed and lubricated, as I was not happy with it.

APU slight wet start!

As a partial ant-det run the week previous and to thoroughly test the APU, I briefed Rich on how to 'dry run' the main engines and he carried out his first engine turns successfully, with myself on the the external intercom and John inside controlling the APU and other systems from the AEO position.

The main anti-det runs were carried out with Ollie on the external comms, John in the back and myself in the Left hand seat. Young Sam was sitting in the co-pilots seat and I wet-ran the engines. Basically, putting fuel through the burners and out of the back as vapour without actually igniting it. This ensures the fuel system is never allowed to dry out and that the engine has been turned to ensure oil pressure and lubrication. John also checked all 4 main engine alternators were generating AC power. I then let Sam dry turn the engines and he did this very nicely for his first time. A dry-turn is a full spin, but without fuel being introduced and it helps to dry the fuel vapour in the jet pipes.

We then carried out full hydraulic functionals, exercising the flaps to all 3 positions, air brakes to the full range of full out & full in and the Ram Air Turbine scoops (RATs) on top of the rear fuselage. The nosewheel steering was also tested and the Flight Refuelling Hose Drum unit (HDU) lowered and raised several times.  The flying controls which are fully powered and self contained were then all tested. No snags were noted, apart from the Starboard RAT sticking in the open position occasionally.

HDU lowered

Anti-det run

XL231 is now waiting eagerly for her next outing.