stall warning sensor after heavy rain

[akosmaroy]

Hi,

I have an issue with the stall warning sensor on the DA-40. after some heavy rains a lot of water got into the hole, which eventually dried out. Now if I test the stall warning on the ground (e.g. cause vacuum in the whole by sucking the air out of it), the horn sounds. but, in the air it doesn't make a sound before or in case of a stall (I tried, performed a few stalls just to test this).

What can be wrong here?


Akos

[Rich]

I would guess there's still water in there at some low spot and you're providing more suction in your testing on the ground (bubbling the water out of the way) than is generated in the approach to a stall.

[akosmaroy]

I would guess there's still water in there at some low spot and you're providing more suction in your testing on the ground (bubbling the water out of the way) than is generated in the approach to a stall.

any ideas on how to get the water out of there?

[Chris B]

any ideas on how to get the water out of there?

Well, I know one thing *NOT* to do: use compressed air, on either end of the warning horn tubing.
Then you get to remove the wing (and the tank?) and re-attach the hose...

But a vacuum should be safe (worst-case, the "kazoo" part of the horn gets damaged and you replace the horn).

Chris

[Lou]

Just checking on the latest for this problem. I think I have some water in the tube to the stall horn. I tried to vacuum it out but without success. The AMM (27-39-00) says to unplug the tube from wing root connector to drain the line underneath the LH pilot's seat. While removal of the pilot's seat is permitted owner maintenance, I am wondering if this is necessary. Bonus question: what do folks do to ensure correct torque of the bolts in replacing the seats? The values are very low, below the range of conventional torque wrenches. (i.e 4.7 ft-lbs)

[Spinner]

if the stall warning is similar to the DA20 which it sounds like, we have disconnected the horn and blown compressed air through without any issues. I would check the horn and make sure that the 'Kazoo' is still in its proper place and has not broken loose.

The seat bolt torque is it a trick question? 4.7 ft-lbs is 56.4 inch-lbs use an inch lbs torque wrench?

Paul

[Lou]

Turns out there is an access panel so I don't have to take out the seat. But I don't see water in the line.

[Chris B]

we have disconnected the horn and blown compressed air through without any issues.

Be *very* careful with this. If the hose disconnects behind the wing leading edge, re-attachment requires removing the fuel tank for access. The DA20 may be different, but on the DA40 removing/reinstalling a fuel tank is a major project.

Chris

[Chris B]

But I don't see water in the line.

You might try using a turkey baster to apply gentle suction at the hose under the seat. If there is water in the line, there may (?) be a low point somewhere in the wing.

Chris

[Lou]

Thanks for the comments. I was able to disconnect the hose at the access panel and determine that there was no blockage at all from the wing hole to the connection. I then took it to my AME who disassembled the kazoo (not permitted owner maintenance in Canada ) and cleared the stuck reed.

One final note: a kazoo for New Year's Eve costs $.25, and you get to drink when you use them. An aviation kazoo, which lasts just about as long, costs $80. Oh brother.