Door keeps popping open

[DXB]

Question regarding a '68C- Does anyone have experience with their door popping open repeatedly despite it seeming to latch securely, and can relate how it got fixed?   Mine has been doing this for over a year now.  At annual last month, I had a reputable MSC work on it quite a bit, and they replaced some components of the mechanism, including the main pin that is supposed to lock when you push the handle down. The handle in the cabin does seem to latch with more authority and less play now, but it the door still pops open frequently, in climb only. It happens 50% of the time and particularly if I climb steep.  If someone keeps firm downward pressure on the handle during climb, it does not happen.  I've taken to using a big binder clip with a bungee cord on it to serve the same purpose- this works too but makes my plane look like a Rube Goldberg contraption.

SO I'm thinking that with age rear body panel with the hole for the two pins has started to flex just enough in climb to let the pins slip out.  Sometimes I'll notice that after leveling off I have a little more noise than expected, and the door is very slightly ajar- I suspect the shorter, spring loaded pin has slipped out at that point.  Any slight manipulation of the door after that makes it pop open fully. 

Obviously I'm taking back to the MSC, but any help in giving them guidance is appreciated. It's cold and noisy enough up there without the door making it worse. And it freaks out passengers even if I prepare them.

[N201MKTurbo]

Is the top hook or the side pin popping open?

[DXB]

Just now, N201MKTurbo said:

Is the top hook or the side pin popping open?

The side pins pop out.  Can't tell if the top hook is doing its job or not at that point.  Or if a lack of the top hook being snug causes the side pins to pop out.  I really don't understand the mechanism all that well. 

[N201MKTurbo]

Two things, back off the turnbuckle to the top hook. So you get more engagement of the pins before the handle goes over enter. Then add a few washers behind the striker plate to move it closer to the door.

[Steve65E-NC]

Take the door plastic off and think about over center toggle mechanisms.  I think there are two, one for  top and one for the side latch, but my door adjustment work was done in about 1996.  The linkage must be adjusted so that these over center assemblies pop thru or there is really nothing holding the latches in the closed position and they can just back off.  In a properly adjusted door you can feel the pressure back off the handle as you swing the handle forward past the top dead center.  The adjustments are just in rod length with common turnbuckle adjustment.  The mechanism that swings the top hook up and over the pin is simple but elegant.  A little trial and error thru the access openings in the inner door panel should bring you home.

[Guest]

Dev,

based on your description that if someone hold pressure on the handle it does not open, I would say that it is not adjusted correctly.  One the handle has passed over centre it should be firmly locked.

Clarence

[DXB]

12 hours ago, Steve65E-NC said:

Take the door plastic off and think about over center toggle mechanisms.  I think there are two, one for  top and one for the side latch, but my door adjustment work was done in about 1996.  The linkage must be adjusted so that these over center assemblies pop thru or there is really nothing holding the latches in the closed position and they can just back off.  In a properly adjusted door you can feel the pressure back off the handle as you swing the handle forward past the top dead center.  The adjustments are just in rod length with common turnbuckle adjustment.  The mechanism that swings the top hook up and over the pin is simple but elegant.  A little trial and error thru the access openings in the inner door panel should bring you home.

 

4 hours ago, M20Doc said:

Dev,

based on your description that if someone hold pressure on the handle it does not open, I would say that it is not adjusted correctly.  One the handle has passed over centre it should be firmly locked.

Clarence

Thanks Steve and Clarence- this makes sense to me, but when you push the handle down, you actually feel it pop past the over center point and stay there, and the door then feels very secure- this was so much improved by the shop that I was stunned when the door opened again - Dave Mathesien at AirMods seemed to know the door innards well and spent time working on it personally.  I'll of course have them check again, but I doubt the pin is actually retracting in flight from the mechanism not being over center .  Holding the handle down deliberately does push the side pin out a couple millimeters more, and I assume this is what makes the difference in it staying shut by putting pressure on the handle.  This is also what made me think the door or its frame was deforming on climb more than when it left the factory, where I doubt fit and finish were that great to begin with.  I was thinking of ways to jury rig this, for instance by increasing the thickness of the plate on the frame into which the two pins insert.  I'm curious if anyone else has had similar issues on these 50 year old beasts.  I want to get this one fixed so I can move on to obsessing over the next obnoxious quirk  .

[carusoam]

Removing the plastic cover on the interior of the door should reveal how well the system is working.

If the door is not closed all the way, before engaging the latch.  You may get the over center feel on the latch but the rods are not in the holes.

Not sure of the reasoning on how this can happen.  But holding the door closed while operating the latch really works better than thinking the door is closed and operating the latch...

There must be some springs that allow for the rods to not go into the holes...?

Best regards,

-a-

[Shadrach]

See attached pic of my door pins look in the latched position. The bottom pin extends fully as the handle crosses over center. If I had been thinking, I'd have put a ruler on it for the pic. 

I have been flying in Mooneys my whole life and I've never had a door pop in flight. I asked my dad about it today (he's owned 3 Mooneys) and he cant recall a single instance in 2500hrs of Mooney time. Something on your bird needs to be adjusted.

If there's anything else I can do in terms of comparisons let me know; I'll be back out at the hangar over the weekend.

 

Edited January 29, 2016 by Shadrach

[DXB]

1 hour ago, Shadrach said:

See attached pic of my door pins look in the latched position. The bottom pin extends fully as the handle crosses over center. If I had been thinking, I'd have put a ruler on it for the pic. 

I have been flying in Mooneys my whole life and I've never had a door pop in flight. I asked my dad about it today (he's owned 3 Mooneys) and he cant recall a single instance in 2500hrs of Mooney time. Something on your bird needs to be adjusted.

If there's anything else I can do in terms of comparisons let me know; I'll be back out at the hangar over the weekend.

 

thanks a bunch Ross- to my eye, yours looks identical to mine.  I'll reference your pic when I'm back at the hangar this weekend.

[Cyril Gibb]

11 hours ago, Shadrach said:

The bottom pin extends fully as the handle crosses over center.

 

The important point is over centre... mine would pop open even after it seemed tight.  The adjustment I needed was to get the over centre nailed.  It took me a full day of adjusting to finally get it right.  Total pain in the rump with the various threaded rods and diabolically small access holes, but it hasn't popped since.

[Shadrach]

2 hours ago, Cyril Gibb said:

The important point is over centre... mine would pop open even after it seemed tight.  The adjustment I needed was to get the over centre nailed.  It took me a full day of adjusting to finally get it right.  Total pain in the rump with the various threaded rods and diabolically small access holes, but it hasn't popped since.

Agreed, in looking at the assembly, I think a lot of door troubles (wind noise, gaps, air leeks, etc.) are caused by poorly adjusted latch mechanisms. You can see that the holes are offset so that the top pin holds the door closed enough for the second pin to engage which then draws the door in further forming it to the fuselage. My plane has never suffered from air leaks. Whe our old door seal got ratty, an A&P recommended the inflatable door seal which he installed. Our door fits so tight it cannot be inflated with the door closed. For that reason, I removed the bulb pump years ago.

[DXB]

On January 29, 2016 at 9:24 AM, Cyril Gibb said:

The important point is over centre... mine would pop open even after it seemed tight.  The adjustment I needed was to get the over centre nailed.  It took me a full day of adjusting to finally get it right.  Total pain in the rump with the various threaded rods and diabolically small access holes, but it hasn't popped since.

Yeah I looked at my plane today in comparison to Takair's E model. His outside handle snaps all the way against the door when it's closed from the inside. Mine in comparison sticks out, not even making it parallel to the door sheet metal, unless you hold the inside handle down. I'm  beginning to think it's been the over center issue  folks mentioned here all along- A little frustrating after paying for major work on the door.  Not sure I have the skills to fix on my own - need to find someone who does.  

Sometimes the collective wisdom of Mooneyspace does seem to exceed the abilities of any one expert.  

[M20F-1968]

I do not think making alterations to the mechanism is the answer.  I am unfamiliar with the two pin system in your pictures. 

I have a 1968 F, but it now has 1998 Ovation hardware for the locking mechanisms in the doors.  I did need to adjust it.  Mine has only one tapered pin on the side of the door and a clothes-pin type grabber for the top of the door. 

Adjusting the mechanism took the better part of an afternoon, and I started with getting the outside handle to positively close with the door open first.  This put me in the ballpark, then made further adjustments with the door closed.  There are really only 2 turnbuckle type (actually a threaded rod with stop nuts) to adjust.  It just takes time and fiddling.  Adjusting it with the door open helps a lot as it will show you how the lock react to the various adjustments.

Why do the older planes have 2 side pins in the passenger door?  What is different from the newer design?

John Breda

[Shadrach]

5 minutes ago, M20F-1968 said:

I do not think making alterations to the mechanism is the answer.  I am unfamiliar with the two pin system in your pictures. 

I have a 1968 F, but it now has 1998 Ovation hardware for the locking mechanisms in the doors.  I did need to adjust it.  Mine has only one tapered pin on the side of the door and a clothes-pin type grabber for the top of the door. 

Adjusting the mechanism took the better part of an afternoon, and I started with getting the outside handle to positively close with the door open first.  This put me in the ballpark, then made further adjustments with the door closed.  There are really only 2 turnbuckle type (actually a threaded rod with stop nuts) to adjust.  It just takes time and fiddling.  Adjusting it with the door open helps a lot as it will show you how the lock react to the various adjustments.

Why do the older planes have 2 side pins in the passenger door?  What is different from the newer design?

John Breda

The second pin draws the door in so tight that it should "mold" to the fuselage. Looking at the receiver you can see that it's a 2 stage process with the lower hole being off set inward. Mine has never leaked nor made so much of a peep of wind noise. There are many things on my old bird that are worth upgrading. I'm not sure the newer single pin set up is worth it. I'm not even sure it's an upgrade.

[N601RX]

Be sure when putting everything back together that the pin that holds the interior door handle in place is fully inserted.  There have been cases of it backing out in flight leaving the occupants no way out other than calling someone to come let them out from the outside.  

Mooney also sells a kit that has a secondary door latch.

[DXB]

So does anyone happen to have a diagram of the door innards for the two pin system that might indicate how to adjust the over center position for the latch?   I tried the service manual, but it contains nothing on it.  

[Hank]

My C only has one pin in the door. I have a Service Manual from the late 70s in the hangar; I'll check the PDF I received several years before buying the bound version.

[takair]

Dev

Mooney Service Instruction M20-39 has some info and a few diagrams.  I think your aircraft likely has this kit installed and this describes how it should be rigged.  Not extensive, but a small piece of the puzzle.  

[DXB]

Interim update- hopefully final update but I'm a pessimist.   Per MSC, the door on the older planes including my '68 does not have the over center adjustment (which essentially changes length of the top of two rods inside the door locking mechanism - i.e. the one that connects to the outside handle).  They changed the door seal - which it needed anyway - and now it requires more force to close, as expected.  The door did not pop on the way home, likely because the closing pressure held the pin in place.  It was a bit quieter too.  But I think when the seal softens up it will open again.  Apparently it is possible to change the top rod to the newer kind with over center adjustment- per my MSC this would be the next step.  Does this sound right to the mechanical gurus here?

[Bob_Belville]

On 1/30/2016 at 4:16 PM, N601RX said:

Be sure when putting everything back together that the pin that holds the interior door handle in place is fully inserted.  There have been cases of it backing out in flight leaving the occupants no way out other than calling someone to come let them out from the outside.  

Mooney also sells a kit that has a secondary door latch.

A needle nose vice grip in your bag of necessities is advised. An extra roll pin might not be a bad idea.

[takair]

5 hours ago, DXB said:

Interim update- hopefully final update but I'm a pessimist.   Per MSC, the door on the older planes including my '68 does not have the over center adjustment (which essentially changes length of the top of two rods inside the door locking mechanism - i.e. the one that connects to the outside handle).  They changed the door seal - which it needed anyway - and now it requires more force to close, as expected.  The door did not pop on the way home, likely because the closing pressure held the pin in place.  It was a bit quieter too.  But I think when the seal softens up it will open again.  Apparently it is possible to change the top rod to the newer kind with over center adjustment- per my MSC this would be the next step.  Does this sound right to the mechanical gurus here?

Does your external handle go flush when the internal handle is closed?  One way to confirm if you are getting full travel might be: close the door from the inside, have a second person check the handle (as we tried at 44N, but with new twist) have the same second person try to lock the door without touching the outside handle.  If it can not be locked, you are likely not getting full travel and risk the mechanism vibrating open.  You may have a small panel with three screws located around the internal handle.  If those screws are loose, you may not get full travel.  The seal may help hold things shut due to more tension and friction on the pin, but you still want to be sure you are getting full travel.

[Hank]

The OP's door latch is probably like mine--the external handle is a bent piece of ~1/4" bar stock that always sticks out some. Later models have a wide, flat piece that actually closes and gets flush with the door surface. I think my lock is several inches below the handle, and I don't recall ever needing to mess with the handle to get the key way down below it to turn.

I'm supposing this because his plane is the same model as mine, and only two years older.

Edited March 18, 2016 by Hank

[takair]

Hank,

You are correct about he handle.  I really meant that it should be fully streamlined.  When we looked at Dev's the first time, the outer handle was not streamlining when closed from inside.  Regarding the key, there is a plate welded to the rod attaching to the outer handle.  I'm pretty sure it is a good indicator if the door mechanism is complete.  As I recall, you can't lock the door unless the outer handle is streamlined.  If it is not, the locking mechanism doesn't line up with the plate correctly and you can't turn the key all the way...but I could be wrong...

[DXB]

22 hours ago, takair said:

Hank,

You are correct about he handle.  I really meant that it should be fully streamlined.  When we looked at Dev's the first time, the outer handle was not streamlining when closed from inside.  Regarding the key, there is a plate welded to the rod attaching to the outer handle.  I'm pretty sure it is a good indicator if the door mechanism is complete.  As I recall, you can't lock the door unless the outer handle is streamlined.  If it is not, the locking mechanism doesn't line up with the plate correctly and you can't turn the key all the way...but I could be wrong...

You are correct my handle does not quite streamline like yours, whether you latch it from the inside or the outside.  However mine locks without difficulty- i.e. no need to hold the handle further in, so I am unsure of the significance of the handle position.