Rear Door Integrity

[Scotsman58]

A pilot friend recently sent me the following message:

"My friend was giving instrument instruction over the [Long Island] Sound in a student’s DA40 a couple of weeks ago. A warning came on indicating that the rear door was ajar. The student/owner turned around to grab the handle, and the whole rear door came off (“departed the plane,” as you might read in an official report), and now presumably rests at the bottom of the sea off the Connecticut coast. They had no problem returning to HTO. My friend did some research. This has apparently happened before, and the DA40 manual warns not to touch the handle if the warning indicates that the door is ajar. Apparently that disengages the last little bit that’s hanging on, and off comes the door. Some owners open and then close and lock the rear door before every flight, just to be sure."

Is this a known issue in DA40s? And do any of you follow the suggested practice of locking the rear door before every flight?

[Don]

Sounds like they overlooked the "Door Open" warning message which is also on the check list during run up. That said, never key lock the back door before flight. In the event that you do an off field landing and the plane flips over, then you can not exit via the canopy and the back door would be your only exit from the aircraft. My pilot wife and I also have a rule to make sure the back door is properly latched during our preflight walk around. Also, if we have a back seat passenger(s), during the before taxi safety briefing, we explain how to use the emergency door hinge breakaway lever for rapid exit from the aircraft.

[Rich]

To answer your question, the loss of that rear door isn't exactly common. But in both D440s and 42s, it has happened quite a few times. That secondary catch is there for a reason. It needs to be unlocked for flight. Other than coming back without the door, no accident has ever been caused by this event.

[Scotsman58]

I took from my friend's message that the door ajar light came on during flight -- maybe it was also on during run up, but that's not clear. I can ask my friend if he knows. Anyway, I think it's wise advice not to lock the door and possibly prevent emergency egress -- I'm assuming that if the door is locked with the key from the outside, then it cannot be opened from the inside (but I have never tried this).

[Rich]

I took from my friend's message that the door ajar light came on during flight -- maybe it was also on during run up, but that's not clear. I can ask my friend if he knows. Anyway, I think it's wise advice not to lock the door and possibly prevent emergency egress -- I'm assuming that if the door is locked with the key from the outside, then it cannot be opened from the inside (but I have never tried this).

With the door locked you can't operate the latch. But there is an emergency release overhead, which disengages the hinges. It's unclear whether one could then kick the door free if the latch is still engaged. Not willing to try it myself.

With respect to using it for emergency egress from the front seat, I confess I have serious doubts I could manage to crawl back there and squirm my way out, especially if injured in some way.

[Don]

I took from my friend's message that the door ajar light came on during flight -- maybe it was also on during run up, but that's not clear. I can ask my friend if he knows. Anyway, I think it's wise advice not to lock the door and possibly prevent emergency egress -- I'm assuming that if the door is locked with the key from the outside, then it cannot be opened from the inside (but I have never tried this).

With the door locked you can't operate the latch. But there is an emergency release overhead, which disengages the hinges. It's unclear whether one could then kick the door free if the latch is still engaged. Not willing to try it myself.

With respect to using it for emergency egress from the front seat, I confess I have serious doubts I could manage to crawl back there and squirm my way out, especially if injured in some way.

I am just under 200lbs and wanted to see if I could enter the backseat from the front seat. Of course the plane was in the upright position when I tried this. Actually, I had no problem getting through the seats. If you add some post crash adrenaline to this and the airframe was upside down, I think it would be even faster and easier to do this.

[Steve]

This is the reason Diamond put out an MSB: MSB40-070/1: Replacement of Passenger Door Retaining Bracket incl. WI Rev. 1:

http://support.diamond-air.at/fileadmin ... -rev-1.pdf

This "improved" the secondary latch mechanism. The primary latch is still the door handle activating the two locking pins which go into the fuselage frame. The door lock simply prevents opening the primary mechanism. I wouldn't intentionally do anything in-flight to risk relying on the secondary latch, as it is marginal, at best. Likewise, I would never lock the rear hatch in flight, since it might limit one's ability to break the hinges and open the door.

[Boatguy]

The short answer is:

- yes, known problem which occurs more frequently at flight schools.
- securely latch the passenger door before entering the cockpit - put it on checklist if necessary
- don't lock the passenger door with the key as it will deny first responders access, except those with axes and the jaws of life!

[Soareyes]

lt also happened on the ground while taxiing. I'm paranoid about opening the door while parked with a strong wind from the left.

[MarkA]

I took from my friend's message that the door ajar light came on during flight -- maybe it was also on during run up, but that's not clear. I can ask my friend if he knows. Anyway, I think it's wise advice not to lock the door and possibly prevent emergency egress -- I'm assuming that if the door is locked with the key from the outside, then it cannot be opened from the inside (but I have never tried this).

Actually, you can open the rear door from the inside (at least on a 2010 model DA40) when the rear door is locked. There is a small lever in the door lock handle that overrides the locking mechanism. This is in addition to the "emergency release" mentioned else ware. However, if the door if the door is locked no-one outside the plane (e.g. emergency personnel) would be able to open the door to help after an accident hence the requirement for the rear door to be unlocked during flight.