Stall Warning Does Not Sound in Flight - M20K

[SkyBound]

I was not able to get the stall warning to sound in flight on my recently purchased 1979 M20K.  The switch moves freely and operates as designed when tested on the ground.

 

The mechanic was not sure what adjustments and additional troubleshooting could be done.  Any thoughts or suggestions on what I could try?

 

Thanks.

 

--Alex

[jdrake]

Could simply be the Sonalert.  Seems as though I replace 1 every few years (stall, gear or A/P).  The good news is that they're relatively inexpensive.

[Alan Fox]

Make sure the switch isnt installed upside down....

[SkyBound]

Would the Sonalert sound on the ground, but not in the air?  The strange part of the issue is that I can make the warning go off when I wiggle the tab on the ground, but not while in flight.

[SkyBound]

The switch is installed correctly... 

 

Please keep the ideas and suggestions coming!

 

--Alex

[duke]

make shure it isn't slightly binding in its travel.

adjustment procedure is in the sm

[Bob_Belville]

How close to nominal stall speed did you get when trying to make it sound? The only time I hear mine is once in a while on short final doing "max performance" short field landing.

[SkyBound]

Got it to stall speed and did a couple of power-off stalls and recoveries.  All without a sound at all.

[Hank]

The one in my C sounds on every landing, just before the tires chirp. I thought it was wired into the headset, but checked yesterday [pulled the Halo insert out of my right ear] and I hear it from the ceiling buzzer. Interesting.

 

Does your "not while flying" stall horn sound on landing? Are you wearing an ANR headset? The only other thing I can think of is that the tab is incorrectly positioned or bent.

[Jeff_S]

Mine is like that more or less. I have only heard it during VERY extreme nose up attitude in power-on stalls. That vane has to be angled at just the right point so that it catches the appropriate angle of attack of the air, so if it's not set correctly it won't trigger (or not easily). You could try bending it a bit (probably upward) and go test it. Worst case scenario is it just goes off constantly until you land and bend it again.

 

(NOTE: This is probably not an approved owner/operator maintenance item, so make your A/P bend it instead!)

[Hank]

On the other hand, during an IPC last fall I flew for several minutes at MCA with the horn blaring. She wouldn't stall, though, and we eventually got tired of trying and moved on to other things. So at least mine works, in the air and in the flare, but I've never tried to set it off intentionally in the hangar.

[Jamie]

Uh, guys, n00b here, but I've been studying the POH.

 

Do NOT try to bend the tab. It even warns in the POH that it is tempered metal and will most likely break. I forget the exact wording, but remember this because it was an explicit warning about this very situation.

[carusoam]

It is very adjustable. My MSC fixed mine at annual. It had been quiet for a while. Who new???

-a-

[SkyBound]

Carusoam - which MSC do you use?  Could I contact them for guidance on the adjustment?

 

Thank you!

 

--Alex

[sreid]

On the other hand, during an IPC last fall I flew for several minutes at MCA with the horn blaring. She wouldn't stall, though, and we eventually got tired of trying and moved on to other things. So at least mine works, in the air and in the flare, but I've never tried to set it off intentionally in the hangar.

Interesting that you have a rare, one-off, unstallable Mooney. Maybe you should patent this feature. Are your fuel tanks also more full after a flight than before? ;-)

[Hank]

Interesting that you have a rare, one-off, unstallable Mooney. Maybe you should patent this feature. Are your fuel tanks also more full after a flight than before? ;-)

 

Oh don't I wish!! Actually, having resealed them a year ago, my block fuel burn has gone down.   The CFII was surprised flying around with the horn on, additional power reduction, turns in both directions and no stall. [Trim is definitely my friend!] I was quite content. My only point was that the horn works in flight.

 

Do you mid-body folks not make full-stall landings?? If so, does your stall horn not routinely sound? That's what puzzles me--how could someone not realize their stall horn didn't work until they go do some stall practice? It's very unusual for me to not get a beep on landing my C.

[Alan Fox]

I always stall on landing , Once I get it pitched in ground effect , the horn sounds about 1 second before the mains touch.....

[carusoam]

Hank,

Mine was down for about six months. It would always give a warning as I slowed during landing.

When it stopped, my brain didn't notice it gone. Don't be surprised when it doesn't happen!

When it got turned back on it was very noticeable, and the memory of it stood out. It's amazing that you can forget that you should have heard it. Just thought I was too fast each time or something.

Now really being too fast in an Ovation, the end of the runway will get very large in the window, that would have stood out in the memory.

Insidious memory...

Best regards,

-a-

[duke]

[DonMuncy]

As I understand it, you should NEVER attempt to bend the stall warning tab. It is adjustable by loosening the screws holding the switch in place and moving it slightly. Personally I would be very reluctant to mess with it.

[SkyBound]

Duke - thank you for posting the information on how to adjust the stall warning tab.  I have forwarded it to my mechanic.

 

--Alex

[yvesg]

Would anyone be able to send me the sheets that Dule posted? I can't download them for some reasons... and I need them to adjust my stall warning. Tried on a few computers.

yvesg@semo.ca

Yves

[SkyBound]

Yves,

 

Just sent to your e-mail.

 

--Alex

[yvesg]

Thanks Alex. Got it now.

Yves

[bumper]

I adjusted mine over 20 years ago. The warning horn would not come on until almost stall break, and my instructor wanted to hear it blaring steadily through a MCA turn. I was somewhat uncoordinated and was rewarded with a flip over the top spin entry.

 

Make a small mark on the paint at the top edge of the stall warning mounting plate with a fine line marker. Loosen screws, mounting holes in plate are slotted to allow movement of the plate. Shift it up, try 1/8" or so (you can always return it to the starting spot by aligning the mark). Go fly and test operation. Mine is set at about 3 knots above stall - I think. 

 

bumper