Ian Posted December 8, 2012 Report Share Posted December 8, 2012 A little advice on where to look would be very welcome please.... A little background - my CTLS is based at a grass field which is now very muddy (this is England in winter!) and only just flyable. I flew just over a week ago and on landing the aircraft picked up a fair amount of mud spattered over the fuselage and onto the elevator - I couldn't wash it off as the water supply at the airfield automatically cuts of if there is a danger of freezing (and there was and still is!!) - however on the flight everything seemed perfectly normal and all instruments worked fine. Today - it had stopped raining and I decided to go flying (still too cold to get a hose and wash it), so pulled the aircraft out and started it up - Outside temp was 0, QNH 1025mb which I set on the Dynon D-100 giving an indicated field elevation of 174' which is about as expected. After a couple of minutes I noticed that the manifold pressure indicated on the Dynon D-120 EMS was off the scale with the numbers in red! Other indications (oil pressure, oil temp, volts, amps etc seemed OK) So I switched off, took a look around, took the cowling off and checked all the wires that I could, nothing obvious - so started up again. Immediatey the MAP indication went to the top of the scale, the D-100 changed its display colours and gave a message "Attitude Recovering" - eventually apparently resetting itself - BUT - the indicated altitude was now 190' with no change having been made to the Baro setting. In addition on the D-100 as I increased the power (still stationary) the Indicated Air Speed started saying 19 knots and the OAT section on the screen said: OAT 6C -1260 FT 000KTS and the angle of attack indicator suddenly displayed - as I reduced power the airspeed dropped back to zero and the AOA indicator disappeared (all with the brakes on standing still!!!!) I'm somewhat puzzled at what is going on here - unlikely that both instruments, D-100 and D-120 have failed but both are giving spurious readings - however airspeed, altitude and Manifold pressure all rely on the static pressure - I'm wondering if that's the clue - could operating in very muddy conditions cause such a problem? I'm ashamed to say I don't understand where the static source is taken from - no static vent on the fuselage that I can see, and no way to switch to alternate air. Any thoughts anyone? Many thanks Ian Link to comment Share on other sites More sharing options...
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