Thread: ASI

Yesterday i went out flying on take of my brauniger ASI was only reading 20kts and flashing red light at me after climb out it was only reading 50kts my gps was showing 160knts ground speed (windy day) thought it was probably ice in pitto tube on landing at desternation removed pipe from indicator and tried to blow down tube air was going through but felt restricted after sitting plane in the sun for a few hours ruled out ice refitted pipework and flew home with same result if not worse has anyone had any experience of this ? or possible cure ... going to try sticking some mig welding wire down pitto tube at weekend to if anything is jammed in pipe

Thanks Mike

Mike,
You should be able to pull the Pitot out & point it downwards to shake anything hostile out. Remove the dash plate & connection Pipe & you can blow up the pipe towards the pitot forcing anything out. Try not to blow into the Brauniger... not good!
Mal

i have had similar experiences. after more than an hour of flying, not until descending for a landing approach did my asi begin to grossly under report my speed.

this happened a few times, on the first event i landed at high speed trying to get a normal approach speed, after that i learned to rely on pitch attitude.

we never found the cause but the symptom hasn't returned for the last 2 years. my primary and backup asi were reading very slow but not the same speed so i figured it was the tubing, we played with the tubing and all has been fine since.

Hi Mal/Charlie tango

Mal i tried blowing pipe out with a compressor from ASI( i have 2 ASI's both reading wrong) back to pitto but only had a few drips of water come out, it was still hard to blow through with mouth after and still didn't work, so will pull it apart at weekend and have a look at everything and will let you know what i find ...

Charlie tango i find flying with pitch attitude is the best way to do it anyway with a quick glance at Asi at last count im on 1600 hrs experience now so landing wasn't a problem


Thanks Mike

I've had to blow out the pitot before and didn't get much out. However, the ASI started working again, so all good.

Be sure to disconnect everything on the pitot line before applying compressed air. Several of the trutrak autopilots will have a pitot and static connection.

Doug

Well i ran a wire up the pitto tube from Asi's to the pitto tube found nothing in the pipe or anywhere else best i can tell there is no kinks in the hard plastic tube BUT the Asi's still do not work so am now a bit stuck as to what to do all i can think of is replace the whole tube system and see what that does .. although im not holding out much hope with that ... i don't see how it worked one day then plane was parked up for 8 weeks while i flew another and now it doesn't ...

Mike

If I'm not mistaken, the ASI is also connected to the static port. Have you checked out that part yet?

Hi John

Yes that was one of the first things i looked at in case any mud had got in there as its pretty wet over here at the mo and i fly from grass strips ...

Thanks Mike

What about water in the pipe that froze & cracked it?
If you blow down one end with an airline does it come out the other, same with the static?
Have you spoken to Oliver about it?
Mal

Hi Mal

Thats an idea possible crack in plastic pipe air does come out of the end when blown through , im going to replace it at weekend, going to ring Oliver today to see if he has any ideas

Thanks Mike