Rear Passenger Canopy latch opens in flight

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FlyingShrink
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Rear Passenger Canopy latch opens in flight

Post by FlyingShrink »

Has anyone else had this problem? Periodically, my rear passenger canopy "door open annunciation " goes off and I or my copilot have to lean over and latch it back again. The placard states that for safety reasons you cannot lock the rear canopy.
If this is an isolated incident, I will have to go to the shop, which I will do anyway but wondering if any of you have some solutions?

Please advise,

Regards,

Veeru
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Rick
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Re: Rear Passenger Canopy latch opens in flight

Post by Rick »

Most likely you have one of two problems. Either the gas strut that holds the rear latch closed is weak and needs to be replaced, or the switch actuator that shows the door as closed is bent a little. When you see this alarm and reach back, does the latch seem to be slightly out of position, and then pushing it back in turns off the alarm? If so, you probably need a new gas strut. There is another thread here somewhere that outlines the procedure for replacing the strut.

Edit: I just noticed you have a DA42 - I'm pretty sure the rear latch is the same, but I was referring to a DA40. I was going to add that earlier models (of the DA40) had a spring instead of a gas strut, but they weakened too over time. I'm not sure which the DA42 has, but I suspect it also changed over time from a spring to a strut. Someone else here will probably chime in and clarify.
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CFIDave
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Re: Rear Passenger Canopy latch opens in flight

Post by CFIDave »

The DA40 and 42 rear door designs are identical.

To the OP, I'm surprised that you were able to close the rear door in flight if it became partially open and was held only by the secondary red latch. If you release the secondary latch in an attempt to close the door in flight, there's a good chance the entire rear door will depart the aircraft. Consequently, it's strongly recommended to land first before trying to close the rear door.

This should be a very rare occurrence, so if this is happening periodically, it's good that you're having a shop investigate.
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Rich
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Re: Rear Passenger Canopy latch opens in flight

Post by Rich »

Perhaps move this to the DA42 forum?

In the early years I had a problem with the right-side canopy latch letting go, causing the canopy to twist open on that side. The latch handle never moved. No way to deal with that in flight. The problem was the locking pin didn't protrude far enough to reliably hold. I performed a temporary fix: vice-grips on the rod and yank repeatedly (on the ground, naturally). Diamond performed a permanent fix while I was at the first Diamond Fest, 2004.

If this is the problem with your rear door, I think there's a more straightforward way to adjust the amount of engagement of the locking pins. If the latch handle is moving, the over-center behavior of the handle is somehow compromised. Of course, the spring (metal or gas) participates in that.
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Re: Rear Passenger Canopy latch opens in flight

Post by Rick »

Rich wrote:
Mon Feb 03, 2020 5:07 pm
Perhaps move this to the DA42 forum?
Good idea. Done.
CFIDave wrote:
Mon Feb 03, 2020 4:21 pm
To the OP, I'm surprised that you were able to close the rear door in flight if it became partially open ...
Yikes!!! I was assuming the OP was just getting the G1000 warning, but the door was NOT actually open! If the door did pop open to where the latch grabbed it, I would be really concerned about flying the plane again without getting it fixed first! :shock:
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Re: Rear Passenger Canopy latch opens in flight

Post by Karl »

I agree with other posters that it is probably the gas strut but see also RSB42-125/RSB42NG-065 and RSBD4-105 for DA40.
If you are going to replace the gas strut best to order the parts for the SB and do it at the same time.
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Re: Rear Passenger Canopy latch opens in flight

Post by meowmeow »

The rear pax door of my Twin Star departed inflight last year, it was an instructional flight. The door had the secondary red latch, and the CFI said they had no open door warning on the ground, after a half hour of flight the door partially opened by itself (no rear pax), they were not attempting to close the door as they knew that it could likely make things worse, but it came off by itself anyway after a minute or so. Luckily it slid over and down the other side and didn't hit the fin. If you get that warning on the ground and the handle does appear to move by itself I recommend making it top priority to get that looked into.
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Re: Rear Passenger Canopy latch opens in flight

Post by FlyingShrink »

I have a diamond Twin star and I am having the same issue.Just two weeks ago I was solo and the Annunciation came on. When I reached back, the latch was half open.
We cannot lock the door due to safety reasons. So not sure if this is a design flaw. Wonder if there is an easy fix which will not compromise safety?
Maybe a latch to hold it in place ? WE can always fix the struts but I think that does not seem to be the main issue?

VG
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Re: Rear Passenger Canopy latch opens in flight

Post by Karl »

FlyingShrink wrote:
Sun Feb 23, 2020 6:32 pm
I have a diamond Twin star and I am having the same issue.Just two weeks ago I was solo and the Annunciation came on. When I reached back, the latch was half open.
We cannot lock the door due to safety reasons. So not sure if this is a design flaw. Wonder if there is an easy fix which will not compromise safety?
Maybe a latch to hold it in place ? WE can always fix the struts but I think that does not seem to be the main issue?

VG
As mentioned earlier, it is caused by a failed gas strut and /or the pin needs replacing IAW the RSB42-125. It is not easy to do so I would suggest you do both at the same time. It can be tested by operating the locking lever with the door open. The lever should snap to both the open and closed positions. I.E spring-loaded in both directions.
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