Gear Safety bypass alarm

[Houman]

Hi,

I'm just wondering if anyone else finds the Gear safety bypass alarm a bit annoying on the takeoff ( but for sure usefull for safety for landing ).

I have tried and it seems that if I'm doing under 105 kias after takeoff when I retract the wheels, this alarm will ring, even if I press on the red bypass button beside gear and keep pressing it. It will only stop after I have gained speed over 105 kias.

Is this normal and works as designed ???

[kortopates]

It shouldn't be doing that. The service manual specifies the speed range it should be operating in - which you will find is much lower. Hopefully yours can be adjusted to be within spec by a qualified tech.

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[Seth]

This is not normal in my aircraft.

 

-Seth

[PaulB]

Granted I don't have a rocket or a missile but my warning only goes off if my manifold pressure is less than 13" and the gear is up.  Also I believe the gear safety bypass switch only disables the squat switch to allow you to retract the gear if the switch is malfunctioning.  I'm sure the guys on here with more experience will have more info.

[kortopates]

Two different alarms. One is to warn you to put the gear down controlled by a micro switch on the throttle. Another to prevent premature gear retraction controlled by a gear squat switch in the older vintage Mooneys or a air pressure switch/airspeed switch on the back of the ASI. Since it goes off at 105kias I was assuming the latter but the OP doesn't mention year and model. Missile or Rocket doesn't change anything other than indicate it is a J or K system suggesting a airspeed switch. Sent from my iPhone using Tapatalk

[OR75]

The only time that alarm is a nuisance is when I help my IA do the gear retraction test during the annual.

 

This is a picture of the LG safety bypass sensor

 

 

 

 

 

 

[Houman]

Well, it's a 1979 M20K Rocket, the previous owner who is now my partner says that you just have to hold the button until it stops, but I have tested it and it is really related to the speed, I can keep climing at 90 KIAS all the way to several thousand feets and the alarm continues. However, if I bring the nose down a bit after taking off, as soon as I pass the 100 kias it stops ( or near 105 kias ).

 

It is ok for me, but a bit annoying, since I have to cut my climb short, gain speed and then continue the climb if I want to have peace in my ears...

 

I guess at the next annual, I will have them look at it !

[kortopates]

Personally I would not wait. Have you looked up your max gear retract speed Vlr ? My K is 107, your will be real close if not the same. Not retracting the gear till over a 100 kias is imposing much heavier loads than you should be. Suggest retract before 80kias after clearing runway obstacles if any, followed by retracting flaps passing 80. You currently can't do that now without the distraction of the bypass switch. I sure wouldn't want that if I was taking off from a high DA field when it takes a lot more time to accelerate to 105kias. Sent from my iPhone using Tapatalk

[Houman]

Personally I would not wait. Have you looked up your max gear retract speed Vlr ? My K is 107, your will be real close if not the same. Not retracting the gear till over a 100 kias is imposing much heavier loads than you should be. Suggest retract before 80kias after clearing runway obstacles if any, followed by retracting flaps passing 80. You currently can't do that now without the distraction of the bypass switch. I sure wouldn't want that if I was taking off from a high DA field when it takes a lot more time to accelerate to 105kias.

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Well I always start by retracting the gear when I have a positive climb and have cleared the runway, so maybe at about 80 to 85 kias, and then I retract the flaps, then reduce power to 30 over 23, during all this time, the alarm is going, then I lower the nose to get over 105 kias and have the alarm stop. Once it stops, it dosn't start again even if I climb on a high rate and speed goes under 100 kias...

So wondering...

[kortopates]

Perhaps I am miss understanding you. While the gear horn is sounding on take off after raising the gear switch, the gear should NOT retract. With the horn on,  it should only retract when you either press the Gear Safety Bypass switch or wait till you get to the airspeed that silences it. If you press the Bypass switch, the gear will retract and silence the horn. This circuit is only operational while the gear is extended. Based on your comment that the horn continued to sound till you got to 105kias, the gear should not have retracted till then. This is why I was bringing Vfr to your attention as you are likely at it and likely exceeding it.

IF on the other hand the gear is retracting as soon as you raise the gear switch without pressing the Gear Bypass button while the gear horn continues to go off till you get up to speed, then that is another faulty issue as it should remain down. The point of the this circuit is to keep the gear down if you accidentally raise the gear switch while still on the ground.    I hope this clears up any confusion and you're able to get it corrected soon.

[Houman]

Perhaps I am miss understanding you. While the gear horn is sounding on take off after raising the gear switch, the gear should NOT retract. With the horn on,  it should only retract when you either press the Gear Safety Bypass switch or wait till you get to the airspeed that silences it. If you press the Bypass switch, the gear will retract and silence the horn. This circuit is only operational while the gear is extended. Based on your comment that the horn continued to sound till you got to 105kias, the gear should not have retracted till then. This is why I was bringing Vfr to your attention as you are likely at it and likely exceeding it.

IF on the other hand the gear is retracting as soon as you raise the gear switch without pressing the Gear Bypass button while the gear horn continues to go off till you get up to speed, then that is another faulty issue as it should remain down. The point of the this circuit is to keep the gear down if you accidentally raise the gear switch while still on the ground.    I hope this clears up any confusion and you're able to get it corrected soon.

Thanks Paul,

The first few lights, I was bringing the gear up without pressing the button and doing so well below the 107 kias gear retraction max speed, but the horn would continue and gear unsafe light would be on and it would seem that only a gear cycle(lever dow and up again) would do the trick.

obviously that is a bit unusual and unnerving, so I asked the previous owner who is my partner on the plane now, he told me that he usually presses and holds the bypass red button while bringing up the gear, that seems to work, the gear goes up and gear unsafe light is the turned off as is gear down off as well indicating gear is fully and safely up, the alarm rings all the way trough this process, and stops as speed is gained.

I guess I didn't make a fuss out of it, but it is really annoying and requires more attention and handling than just a simple gear up action should require at a critical time that I much rather have my attention on the takeoff and climb than holding the bypass button for 15 seconds while flying the plane in a steep angle as to not surpass 1077 kias...

Anyway... Any thoughts would be great !!!

[kortopates]

So without pressing the Gear Bypass safety switch - the gear partially raises and the gear unsafe light stays on while the horn blares till you get above ~105kias. Then gear unsafe light remains on till you recycle the gear suggesting its only partially retracted. 

You don't say if the gear cycle works normally the second time or if you need to press the Gear Bypass switch the second time to get a complete gear retraction (extinguish the gear unsafe light).

Alternatively on takeoff,  if you press the Gear bypass switch after you hear the horn, the gear now fully retracts yet the horn continues to blare till you hit ~105kias.

 

That is more than annoying! You have an un-airworthy gear. Some pilots would say often your plane talks to you when something is not right and needs help and that you really need to pay attention and listen to it. But your airplane is literally screaming at you for attention to the gear! Don't continue to ignore it, get somebody to look at it asap. Don't wait till the gear will no longer continue to fully retract on a second or third time. You may then find the manual gear extension will not work either.

 

I wish I could help you to diagnose it over the internet. But it really looks like you may have more than one thing wrong with it. For one, it needs  an adjustment to your airspeed switch (or replacement switch) which per the service manual is suppose to keep the horn on only till 65 +7/-4 kias. Another issue may be a wiring issue or ground that is allowing the gear to go up partially or even all the way while the airspeed switch is below its threshold speed (issue 2). Your third issue is the gear only partially retracts and needs a second attempt.   

 

Apparently your partner find this acceptable too so you also need to come to an agreement with him as well. I suggest calling favorite Mooney knowledgeable mechanic or MSC and heed their advice to get it in for servicing asap.  I personally would only fly it keeping the gear down and locked if I wasn't able to perform  a gear retraction and manual extension test in the hangar on jacks before further flight.

Good luck.

[Pooldoc]

Maybe I should start a new thread, but since there are people tuned in here who have been through this, I'll ask here...

I have a 1975 F model and believe I have a squat switch and a gear safety bypass switch which I think was added after original manufacture. I don't believe I have an airspeed activated switch.

Here is the problem:

2 days ago, at a visiting airport, after being tied down in a heavy cross wind all day, I started up and after idling a while, the gear unsafe light and audible alarm went off. It continued until I pressed the bypass switch. I then taxied and it went off again and I did the same thing and it went off again. After figuring it was just a problem with the warning system and not the gear, I took off. Looking back at it, it was probably a bad decision, not knowing what was really wrong. At the time, I thought the turbulence on the ground might have temporarily disturbed something as well as some moderate turbulence on the way there. The gear retracted normally, I flew for 2 hours, no warning lights, sounds and landed at my home airport with no malfunctions. I then taxied back to my hangar and no warnings occurred.

After reading above, I plan on having it looked at ASAP.

I was wondering if anyone knew what could of caused it. Thanks in advance.

Larry

[Top Heavy]

If you want a quick fix just pull the Gear Warning circuit breaker as part of your pre takeoff check list and then push it back in when you do your cruise check list.

The problem is likely due to a faulty switch which is located beyond the firewall down low on the right side of the aircraft. It is very near the throttle cable and immediately adjacent to two similar switches, one of which automatically activates the boost pump at full throttle on the Bravo model. Surprisingly this switch is inexpensive and fairly easily accessible.

Good luck