Gear Warning Horn on takeoff

[mooneyman]

My work schedule and the weather finally aligned so that I could go fly this afternoon. The plan was to go fly some practice approaches. After I rotated and had positive rate of climb I retracted the gear followed by the takeoff flaps. The gear warning horn then began sounding. This is the horn that usually sounds if the throttle is retarded below 12" manifold. I also noticed that the amber "gear up" light on the annunciator panel was not lit. The gear felt like they were up and the floor indicator did not show the gear still down. I notified departure that I wanted to return to the airport. As I turned to intercept the final approach course, the amber "gear up" light came on and the horn stopped. Even if the gear did not retract all the way, I would not think that would cause the warning horn to sound.

After I dropped the gear, the indicator on the floor indicated gear down, but the green panel light did not come on. I felt the gear come down and proceeded to land without incident. I searched "Sonalert" and gear horn in the forums and could not find a similar incident. There are three "horn alarms" that I am aware of: stall, gear up/ throttle back, altitude from Aspen. My mechanic is going to investigate. Anyone have any ideas?

Thanks-- Patrick

[John Pleisse]

Check the speed sensor for your gear switch. I needs info from a low voltage sensor/switch on your airspeed indicator. The gear won't come up without a/s info and the horn will remain on with your airspeed over 63 KIAS. Usually with the gear stuck in any position or full down.

 

Have you had a pitot static test lately? Heavy handed p/s tests can reek havoc or damage components. In this case, don't let the people who did the p/s test trouble shoot your problem.

 

I am not an A/P, but I had this problem that presented itself similarly. Not sure if this is helpful.

[Marauder]

My work schedule and the weather finally aligned so that I could go fly this afternoon. The plan was to go fly some practice approaches. After I rotated and had positive rate of climb I retracted the gear followed by the takeoff flaps. The gear warning horn then began sounding. This is the horn that usually sounds if the throttle is retarded below 12" manifold. I also noticed that the amber "gear up" light on the annunciator panel was not lit. The gear felt like they were up and the floor indicator did not show the gear still down. I notified departure that I wanted to return to the airport. As I turned to intercept the final approach course, the amber "gear up" light came on and the horn stopped. Even if the gear did not retract all the way, I would not think that would cause the warning horn to sound.

After I dropped the gear, the indicator on the floor indicated gear down, but the green panel light did not come on. I felt the gear come down and proceeded to land without incident. I searched "Sonalert" and gear horn in the forums and could not find a similar incident. There are three "horn alarms" that I am aware of: stall, gear up/ throttle back, altitude from Aspen. My mechanic is going to investigate. Anyone have any ideas?

Thanks-- Patrick

Your electric F model will have a squat switch that is activated when leaving the ground. The rubber donuts expand, trigger the switch and allow gear to come up. On really cold days or with old donuts, the switch may not be triggered and the gear won't retract.

Your symptom is different. What year is your F?

[mooneyman]

Your electric F model will have a squat switch that is activated when leaving the ground. The rubber donuts expand, trigger the switch and allow gear to come up. On really cold days or with old donuts, the switch may not be triggered and the gear won't retract.

Your symptom is different. What year is your F?

'74 F  

 

It was mid 20s today. Temp has been as low -15F in the past week. Plane kept in non heated hangar with preheater plugged in. Donuts are original. Gear felt like they came up. 

[MooneyPTG]

That is exactly what happened to us. Our mooney was in a cold hanger for 3 weeks before we could pick it up after a paint job in December . When we took off I raised the gear and the alarm went off. As Marauder said it was the rubber donuts that were cold and still kind of squished. Squat switch was doing what it was designed to do thinking it was still on the ground. Thankfully it was blowing like crazy and we had a bumpy ride out which help expand the donuts. Freaked me out and I was going to land. Had the squat switched checked and don maxwell confirmed how common this was.

[mooneyman]

That is exactly what happened to us. Our mooney was in a cold hanger for 3 weeks before we could pick it up after a paint job in December . When we took off I raised the gear and the alarm went off. As Marauder said it was the rubber donuts that were cold and still kind of squished. Squat switch was doing what it was designed to do thinking it was still on the ground. Thankfully it was blowing like crazy and we had a bumpy ride out which help expand the donuts. Freaked me out and I was going to land. Had the squat switched checked and don maxwell confirmed how common this was.

We've had arctic blast/ snow storm/ arctic blast every week since the holidays. Today was the first time I've been able to fly in about 5 weeks. Thanks for sharing your story! I'll still get it checked out, but I bet that explains it.

[Marauder]

There is a workaround. The 77 and newer Js have a bypass switch installed. There is a service bulletin out there that allows it to be installed on our vintage Mooneys. I had it installed in my years ago.

[Marauder]

There is a workaround. The 77 and newer Js have a bypass switch installed. There is a service bulletin out there that allows it to be installed on our vintage Mooneys. I had it installed in my years ago.

Ok -- found it: http://www.mooney.com/images/pdfs/sb-pdf/sbm20-196a.pdf

[air cooled dad]

I'm resurrecting an old post.  

'75 F  ITT gear actuator with old gears about 30 hours away from AD inspection .

Cold day for Georgia, 40f.  Brrrrr.  After takeoff I selected gear up.  Heard the motor and felt the gear moving.  The red gear light illuminated and the warning horn sounded.  The floor indicator did move off of green.  

Put the gear back down just fine.  Tried to raise the gear again.  No joy.  Gear motor makes its normal noises, green floor indicator moves, red warning light illuminates and warning horn sounds. This time I walk the rudder to wiggle the plane.  Red warning light goes out but the warning horn remains.   

Cycle the gear once more and it works perfectly.  Cruise around for 10 minutes and enter downwind. Cycle gear a couple more times and it works great.  

Good news is my new-to-me JPI 830 looks and works great!  Thanks Oscar!  The fine wire plugs I installed yesterday make her purr like a kitten.  Garmin G5 finally off of back order.  Install within a couple weeks. Pics to follow.

[carusoam]

ACD,

Is there a question to go with that?  Or this is a status update?

Best regards,

-a-

[air cooled dad]

1 hour ago, carusoam said:

ACD,

Is there a question to go with that?  Or this is a status update?

Best regards,

-a-

Lol.  Sorry. Guess it's a cry for help.  I tried searching old posts to find a solution to my problem.  Now I seek out answers from all of you. My problem is similar to Guitarmasters but my gear actually moves and goes down just fine. Just not all the way up.  Didn't want to hijack his thread.  So yes, my question is, what's wrong?   

Thanks in advance. 

Jason

Edited January 28, 2017 by air cooled dad

[carusoam]

Cold weather and old donuts often don't go together very well.  There is a squat switch that doesn't make proper contact during cold weather and this somehow becomes an issue with retraction.

Some planes have a button to allow for the over-ride of the system.

See if this is what you are seeing?

Best regards,

-a-

[Cyril Gibb]

15 minutes ago, carusoam said:

There is a squat switch that doesn't make proper contact during cold weather and this somehow becomes an issue with retraction.

My 75F 22-1188 has an airspeed switch, not a squat switch.  Was there a change during the model year, or do I have a retrofit?  Gladys also has the dual relay gear (SI M20-34B) done before my time.  Maybe they were done together?

 

 

[carusoam]

The airspeed switch is the current design with a panel mounted button if the switch doesn't work as expected.

Somewhere along the way the design changed.  Canadian winters probably makes a good driving force to update the system if it wasn't done already.

PP speculation only.  Not a mechanic.

Best regards,

-a-

[Bob - S50]

19 minutes ago, Cyril Gibb said:

My 75F 22-1188 has an airspeed switch, not a squat switch.  Was there a change during the model year, or do I have a retrofit?  Gladys also has the dual relay gear (SI M20-34B) done before my time.  Maybe they were done together?

 

 

I don't know 1/10th of the maintenance stuff that others at MS know, but I believe the airspeed switch is only supposed to keep you from raising the gear while on the ground.  Gear up/down and light/sound warnings would come from other micro switches that tell the system whether or not the gear is all the way up or down.  An intermittent switch or gear that doesn't quite make the contact would result in unsafe gear indications.

[Marauder]

My 75F 22-1188 has an airspeed switch, not a squat switch.  Was there a change during the model year, or do I have a retrofit?  Gladys also has the dual relay gear (SI M20-34B) done before my time.  Maybe they were done together?
 
 

There were electrical changes made in the 1975 F series. SN 1179 through 1272 were different than 1273 through 1305. Also SN 1246 and the series after 1306 were different. Mine falls in the 1273 through 1305 group. I have a mechanical squat switch.




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[Marauder]

12 hours ago, air cooled dad said:

I'm resurrecting an old post.  

'75 F  ITT gear actuator with old gears about 30 hours away from AD inspection .

Cold day for Georgia, 40f.  Brrrrr.  After takeoff I selected gear up.  Heard the motor and felt the gear moving.  The red gear light illuminated and the warning horn sounded.  The floor indicator did move off of green.  

Put the gear back down just fine.  Tried to raise the gear again.  No joy.  Gear motor makes its normal noises, green floor indicator moves, red warning light illuminates and warning horn sounds. This time I walk the rudder to wiggle the plane.  Red warning light goes out but the warning horn remains.   

Cycle the gear once more and it works perfectly.  Cruise around for 10 minutes and enter downwind. Cycle gear a couple more times and it works great.  

Good news is my new-to-me JPI 830 looks and works great!  Thanks Oscar!  The fine wire plugs I installed yesterday make her purr like a kitten.  Garmin G5 finally off of back order.  Install within a couple weeks. Pics to follow.

What you are describing is the retraction problem when the squat switch is not depressed when the donuts expand after takeoff. You probably don't have the override switch. I had one installed when I lived in Buffalo. Even with "fresher" donuts, when the temps got into the single digits, my gear would not retract.

The override switch overrides the squat switch and allows for retraction. It's the item in the green circle.

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[Hank]

Sounds like what my pucks were doing for two winters, gradually getting worse. Eleven new pucks at $105 each plus some labor made it all stop. It was aggravating, I could raise, lower and raise the gear, the durn buzzer going off for twenty or thirty minutes before finally they would thump up into the belly and the plane would immediately jump 10-15 mph indicated. The floor indicator would be red and white stripes, a very narrow barber pole.

The manufacture date is molded into the pucks. Mine were all upside down, and passed the test in the Maintenance Manual where you measure the gap above them. Imthiughtnthendate was "9-96." When we removed them turned out they said "6-69," the factory original pucks; I replaced them in Dec 2012, and my first landings were so smooth! 

[air cooled dad]

I hope it's just that.  Today I flew over my mechanic while putting up the gear.  Here's the indications in the cockpit after selecting gear up....

gear selected up, motor makes normal noise, gear starts traveling up, motor stops after the normal 2-3 seconds, gear unsafe light stays illuminated and the gear warning horn sounds.  

Mechanic said it looked like the gear was in the normal up position. I'm still new to Mooney ownership. From what I can understand, when the nose gear comes up, it moves a pushrod.  That pushrod makes contact with a switch turning off the warnings.  Is this correct? 

Were putting my Mooney mistress on jacks soon.  Looks like I'll be taking a closer look at my pucks too. Maybe I can use hockey pucks. I have lots of those!!!!  

Jason

 

Edited January 29, 2017 by air cooled dad

[Marauder]

Just now, air cooled dad said:

I hope it's just that.  Today I flew over my mechanic while putting up the gear.  Here's the indications in the cockpit after selecting gear up....

gear selected up, motor makes normal noise, gear starts traveling up, motor stops after the normal 2-3 seconds, gear unsafe light stays illuminated and the gear warning horn sounds.  

Mechanic said it looked like the gear was in the normal up position. I'm still new to Mooney ownership. From what I can understand, when the nose gear comes up, it moves a pushrod.  That pushrod makes contact with a switch turning off the warnings.  Is this correct? 

Were putting my Mooney mistress on jacks soon.  

Jason

 

I posted these pictures on Guitarman's thread. He was having a problem as well. His 75 F is only a few serial numbers from mine so the drawings I provided were pertinent. Your serial number should be 1244. So your schematic will be different, but it should be close. Ask your mechanic if you have a squat switch. It is on the left gear.

[Marauder]

3 minutes ago, air cooled dad said:

I hope it's just that.  Today I flew over my mechanic while putting up the gear.  Here's the indications in the cockpit after selecting gear up....

gear selected up, motor makes normal noise, gear starts traveling up, motor stops after the normal 2-3 seconds, gear unsafe light stays illuminated and the gear warning horn sounds.  

Mechanic said it looked like the gear was in the normal up position. I'm still new to Mooney ownership. From what I can understand, when the nose gear comes up, it moves a pushrod.  That pushrod makes contact with a switch turning off the warnings.  Is this correct? 

Were putting my Mooney mistress on jacks soon.  

Jason

 

I posted these pictures on Guitarman's thread. He was having a problem as well. His 75 F is only a few serial numbers from mine so the drawings I provided were pertinent. Your serial number should be 1244. So your schematic will be different, but it should be close. Ask your mechanic if you have a squat switch. It is on the left gear. If you do, it is likely this schematic will apply.

[Hank]

Take the belly off. The micro switches are on one of the pushrods that goes from near the nose gear back to the spanwise rod that goes to each main gear. They are just a couple of inches apart.

You can check the date on your pucks with a flashlight while the plane is on the ground. You may need to look at several, as orientation is random and the dates on the edge of the pucks will face in all directions.

[Guitarmaster]

On 1/28/2017 at 9:03 AM, air cooled dad said:

Lol.  Sorry. Guess it's a cry for help.  I tried searching old posts to find a solution to my problem.  Now I seek out answers from all of you. My problem is similar to Guitarmasters but my gear actually moves and goes down just fine. Just not all the way up.  Didn't want to hijack his thread.  So yes, my question is, what's wrong?   

Thanks in advance. 

Jason

IF you have the squat switch (vs airspeed switch), jack the plane up on the left side when it is cold.  See how much the wheel will move.  You will probably notice the squat switch is being activated and de-activated while you are doing this.  

It seems Mooney didn't set the switch very close to the contact plate (my term) so when it gets cold, the gear is pushed backward by the slipstream and allowing the switch to open.  Switch depressed=weight off wheels.  I had the same problem of not retracting all the way as well.  

With weight on wheels, I moved my switch to within 1/8" of the contact plate.  No problems since.  

[Marauder]

And here is the picture of what my squat looks like on the ground.




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[air cooled dad]

Thanks for all the responses. This will give me some ideas when I head back out to the hangar.

Jason