Speed brakes mechanical issue

[Tavo]

M20R.

Today I deployed them during approach and noticed that they were not deploying, at first I thought there both of them since I was only looking at the left wing, after checking the circuit breakers tried again and looked at the right wing. The right break comes out for 2 seconds, then comes back down in a very fast movement, the left one is not even trying

After landing I tried again in the hangar and got the same results

Any ideas or recommendation?

Thank you

[LANCECASPER]

57 minutes ago, philip_g said:

Check the connections to see that they're getting power if electric and send them to precise flight? You sure they're electric and not vacuum? That behavior sounds like what if expect from a failing accumulator 

Ovations never had vacuum speed brakes. 

A search on Mooneyspace shows that there are things you can do besides send them off to Precise Flight. The most likely issue is that the worm gear hasn't been lubricated with the proper Aeroshell 22 grease during each annual. 

[Mooney217RN]

You'll likely need to send them out to Precise Flight.  What you're describing is a safety feature where if one doesn't deploy, neither deploys.  There are the speed brake assemblies and the logic box that controls simultaneous operations.  

Look at your logbook(s).  If the speed brakes have never been sent out to Precise Flight, it's now time.

[Will.iam]

34 minutes ago, LANCECASPER said:

Ovations never had vacuum speed brakes. 

A search on Mooneyspace shows that there are things you can do besides send them off to Precise Flight. The most likely issue is that the worm gear hasn't been lubricated with the proper Aeroshell 22 grease during each annual. 

+1 on this advice. My left speed brake would start to come up and then fail down the right would synthetic fail with the left. I took them both out and cleaned all the old gunk and grim off the gears and worm drive. Then lubed the worm gears with aeroshell grease. Put them back into the wing and they have been working great ever since. You owe it to your self to try this before just sending them off and paying $1900 unless spending $1900 is no big deal. 

[carusoam]

We have two threads that are similar today…

I’ll go advise that thread to look hear as well…

Best regards,

-a-

[rgpilot]

I had the same problem a few years ago. Precise Flight said to send both speedbrakes and the controller back for service. It turned out that the problem was the controller.

[Tavo]

Thanks all for the great feedback. My last annual was done a month ago and the brakes were only tested, not serviced. 

I'll have my mechanic open them, inspect, grease them etc. I'll report any findings. 

Thank you

[HXG]

Agree, you’ll likely need to send the speed brakes into  precise flight. I just sent my Bravo speed brakes into Precise flight for failure of my right speed brake to deploy at about 500 hours after my last 1000 hour service. Well over $2,000 bill coming. 

Edited June 24, 2021 by HXG

[Will.iam]

Here is my original post when I was asking questions about cleaning the worm gear and it has pics of where to grease. 

[irishpilot]

There's two camps of advice here. The price is more like $4500 if you send both brakes and the control box in, which is what Precise recommends if you call them.

If they are still under warranty, then send them in. If not, then see if you can fix them on field. These speed brakes are really simple and I agree with others, you and your A&P should at least open them up and inspect. Worm gears and springs are easy to lube or replace.

Lastly, I disagree that only one deploying is a safety issue.  Bottom line, speed brakes are not required, otherwise Mooney would have had them as part of the airframe certification process. If only one comes up, drag increases, but there is no loss of stability or aileron control. Do I recommend flying around with one speed brake - no, but if it happens and you can't get it to go back down with the switch, pull the SB circuit breaker and it should retract. 

Lastly, my advice should not be construed as advocating for deferred Mx. It isn't. If the speed brakes don't work, you should get them fixed one way or another. They are a useful tool.

[PT20J]

Recently I noticed during preflight test that my right brake did not deploy. The series 100 circa mid-1990 brakes don’t have the interlock to prevent asymmetric deployment. It has since been repaired by Precise Flight (the motors aren’t sealed and it apparently got water in the motor during a rainstorm when it was parked outside). I tried deploying the working left brake in flight at approach speed and, although there was a noticeable yaw, it wasn’t excessive and the airplane was easily controllable. 

Skip

[A64Pilot]

During Certification, even approach and landing with a single flap has to be demonstrated, I believe with speed brakes a go-around at max gross is also demonstrated, one speed brake out ought to be little more than an annoyance having to hold a little rudder.

Of course get them fixed, I like them, but don’t have them

[CAV Ice]

I sent our speedbrakes and controller out for the exact same issue a few months ago (Columbia 400).  Initially I wanted to just send the problem speedbrake out, but precise flight strongly recommended sending both with the controller.  They updated our controller to the latest and greatest and went through both brakes.  Total cost was $2069.50

[ArtVandelay]

I sent our speedbrakes and controller out for the exact same issue a few months ago (Columbia 400).  Initially I wanted to just send the problem speedbrake out, but precise flight strongly recommended sending both with the controller.  They updated our controller to the latest and greatest and went through both brakes.  Total cost was $2069.50

Where is the controller located, my installation appears to be just the switch?

[CAV Ice]

@ArtVandelay our controller was under the baggage area.  We have a Columbia 400 though not a Mooney. 

[RJBrown]

10 hours ago, A64Pilot said:

During Certification, even approach and landing with a single flap has to be demonstrated, I believe with speed brakes a go-around at max gross is also demonstrated, one speed brake out ought to be little more than an annoyance having to hold a little rudder.

Of course get them fixed, I like them, but don’t have them

Yes, what A64 said.

The slower you get the less effective the speed brakes become. The location on the wing contributes to the relative ineffectiveness at slow/high angle of attack.

It is not just that at lower speeds they have less effect. They do but when the angle of attack gets higher the air flows over the brakes. I have left them out on purpose to feel the difference. Landing all they do is help reduce the “Mooney float” a bit. On take off it is hard to feel much difference. Asymmetrical deployment is very noticeable at speed but almost insignificant landing or taking off.

I had one fail to deploy on the Rocket while still under warranty. (1995) and played with them just to see what would happen.
 

 

[carusoam]

Great logic RJ, thanks for writing all that out…

They work incredibly well at Vlg….

Much less affective at slowing down in ground affect…. Unfortunately.

Best regards,

-a-

[rgpilot]

16 hours ago, ArtVandelay said:

Where is the controller located, my installation appears to be just the switch?

J's don't have a controller.

[Costa Leite]

In our 1998 M20J Allegro (1500Hrs TTAF), equiped with PF SpeedBrakes since new [P/N 540S108A – 100 Series – Cartridge Assy 28 V (P/N 01577) RH/LH], we have been dealing with some problems on the brakes along the years. Sometimes they do not retract on full down position. Sometimes they just go up halfway. And this happens sometimes on Right side and sometimes on the Left side. Maintenance from our mechanic solved the problems, including new Gears replacement on both sides in 2015 @ $262,86 TOTAL for the 2x gears.

A couple of years ago, after reading several topics here on MS, we realized that the SpeedBrakes needed Aeroshell22 lubrification on every Annual Inspection, and so our mechanic started doing the SpeedBrakes ICA preventive maintenance, which helped keeping them in working conditions for a longer period of time than before. I also noticed that these problems usually happens after a wash, which make sense according to some posts here referring that water will remove the lubrification. ( I started to protect the SpeedBrakes with tape every time I wash the aircraft now. And also, I am ordering dry wash products form Aerocosmetics to avoid these washing issues on SB).

 

Right now the RightSide SpeedBrake is not going up. Today I took it out and confirmed that the motor is working, but the gear is not connecting. I did a quick lubrification but did not solved anything.

Maybe the gears are worn out again?? Seems not possible because they were replaced only 7 years ago we do not use the brakes very often. Any thoughts what could be the problem? Did someone already had this issue that can share the solution?

I know PF will do an OVHL for about 2000Usd, but I would prefer to try to solve this issue by myself before spending so much money!!

I send in attach some pictures and videos.

Thanks in advance for your help.

Fredi

[Costa Leite]

VIDEO OF THE CURRENT PROBLEM:

 

https://share.icloud.com/photos/016_JX7QGu8JQc8RFj64sS5xA

 

[carusoam]

Typically the clutches wear out and get replaced…

If you haven’t replaced the clutches at least once in your ownership… now might be the time…

Sent to PF, returned in a week or so… expensive as usual…

Best regards,

-a-

[PT20J]

Agree with Anthony, looks like it might be a bad clutch.

[Guest]

12 hours ago, Costa Leite said:

VIDEO OF THE CURRENT PROBLEM:

 

https://share.icloud.com/photos/016_JX7QGu8JQc8RFj64sS5xA

 

It’s hard to tell in the video, but it looks to me like the motor gear is not engaged in the larger gear.  Look for loose screws on the motor mounts.

Clarence

[MatthiasArnold]

On 7/20/2022 at 12:41 PM, M20Doc said:

It’s hard to tell in the video, but it looks to me like the motor gear is not engaged in the larger gear.  Look for loose screws on the motor mounts.

This - visible at 8seconds
Great observation Clarence!
Best, Matthias

[MatthiasArnold]

On 7/20/2022 at 12:41 PM, M20Doc said:

It’s hard to tell in the video, but it looks to me like the motor gear is not engaged in the larger gear.  Look for loose screws on the motor mounts.

This!
Great observation Clarence - visible in the video at 8seconds.
You might also refer to the thread 

Best, Matthias