Just wanted to depart from LFEY to LFEA, but had completely erroneous airspeed indication after t/o. Relanded on GS and known wind. The problem is that there is no mechanic on the island, and chances are I will not be able to get professional help before Monday.
Any (technical) ideas from the forum?
Yes, I had the pitot probe covered …
Follow the plastic tube that is the pitot, see where it is open. Another reason might be dirt in the tube. Open it inside the aircraft and blow in the tube going to the pitot.
Depending on the aircraft, I would fly home or to the next repair station. With my aircraft it would be safe because I know it well, the stall warning comes on very early (test it before departing) and I can approach a bit faster than I usually do and then just flare for a long time (large runway required).
Another reason might be dirt in the tube.
Actually I think that is the most likely reason. So yes, release the plastic line from the pitot to the ASI at the ASI side and blow through it. You would not be the first to blow out a nest of some kind of insect or spider. Perhaps release it at the other side too, and bind some cloth/paper towel over that end – you can then see what was blown out – if anything.
Come to think of it, a secondary cause could be a line leaking – either pitot or static. Were the altimeter and vario still reading reasonable values? If so, the static line must be ok.
BTW “completely erroneous” is enough to get a pilot off her/his usual assurance, but is not very helpful to the helpdesk. Were the speeds indicated consistently low or consistently high? Lift off at 17 knots or at 177? Or was the needle dancing up and down indicating anything at any time?
Correct at start of t/o run, but thereafter erroneous reading. 100 knots at parking.
blueline wrote:
Correct at start of t/o run, but thereafter erroneous reading. 100 knots at parking.
Could be static blocked – have you tried opening alternate static ?
Come to think of it, for the speed indicator to become blocked at say 100k, that would suggest that both the static AND the pitot are clogged.
Sounds more like a faulty speed indicator
BTW: The ONLY time in over 20 years of aviating that I had a blocked pitot was at … LFEY !
Attempts at fixing the ASI myself failed, will fly in the aeroclub mechanic from the mainland tomorrow morning. Thanks to all who contributed.
How did it get to 100K ??? No doubt that Socata rotates at something like 60K so how the hell did the ASI get to 100 ? Did someone blow in it after the TO attempt ?
No idea. Vr is 65, yes.
Problem solved – one startic port had partly and the other completely been blocked by insects that were not visible from the outside. We had to use a compressor to get them out.
@ Michael: There seems to be something with the fauna in LFEY .