Do not unlatch door in flight!

[JG3]

The following is an account of an incident that happened to me near Ceduna several years ago, that I had published before. Then yesterday I found the same situation, that the rear latch of the door hadn't engaged properly. I was already 15 minutes out from the strip, and well remembered the incident below, but didn't want to turn back, big mistake! I figured that if I slowed to 50 and was prepared for the forces involved, I could close the door properly. Once again, I was firmly pulling on the door, but as soon as the main latch disengaged, the door snatched outward and then reversed and slammed in with the front edge inside the door post. Could easily have ripped the door off completely.... Then a hell of a struggle to get it closed properly..... I should have learned from that first experience, but hopefully others will pay attention and not make the same mistake.......

 

Recently I had a violent experience while opening a door in flight. I had installed a three-way latch system that was very secure, but when I closed the door one time I must have been leaning on the door a little bit, such that the rear latch didn't engage properly and ended up on the outside of the door post, leaving a 20mm gap at the rear of the door. I didn't notice this until well into a x-country flight and thought it would be easy to close. I knew there would be an outward pull on the door, so held the operating handle in my left hand while pulling inward firmly on the fillet at the rear of the window. Then carefully eased open the main latch, planning to pull the rear closed and re-latch. As soon as the front latch released, the door snatched open violently, swinging up about 45 degrees, then reversed and slammed shut so violently that the flange at the front edge of the door ended up inside the door post rather than outside. The inner frame of the door was broken in several places, but didn't break away. I continued on to the next airstrip, now with the rear of the door sticking out 80mm, and a bleeding arm from some skin that had been lost in the incident.

 

It all happened in an instant, but I did a horror vision of the door ripped off a 701 that Hans was flying. The door flew back and impacted the horiz stab, breaking a mounting bracket and leaving the stab askew...... A very close call.....

 

 

 

This incident has demonstrated that opening a door can instantly change from benign to violent...... Totally unpredictable!

 

Flying with a door removed is no problem, but DON"T UNLATCH A DOOR WHILE IN FLIGHT!!

 

 

[IBob]

Many C185 jump aircraft are fitted on the passenger side with a standard door, but hinged along the top edge, so opening upwards like the Zenith Savannah.

 

And they are routinely opened at altitude to despatch the jumpers, then closed by the pilot.

 

I think there are 2 crucial differences between those and the Zenith/Savannah:

 

1. The C185 door is quite rigid in construction: it does not readily twist. The Zenith/Savannah doors are of much lighter construction and can easily twist.

 

2. And most important: the Savannah has a gas strut on the trailing edge of the door (and I'm guessing the Zenith has also). This is a recipe for disaster for inflight opening, as the strut acts like a motion damper on the rear of the door: once the air gets one side or the other of the leading edge of the door, the door will begin to twist, which increase the air pressure on that side of the door, which increases the twisting, and so on, causing the door to slam open and/or closed.

 

I have wondered about opening the Savannah door with the gas strut disconnected. But I won't be undertaking the experiment!

 

Thank you for the warning...

 

 

[Deskpilot]

Hmm, years ago I flew with the shark patrol, always over water. Being in the rear seat of a 172, I was instructed, if it came to it, to open the nearest door before we ditched into the ocean. This was to provide a quick exit for me, the pilot or co-pilot would then push his seat back and follow me out. I don't think we really cared where the door went as long as it was outwards.

 

 

[rotax618]

The Savannah door is airfoil shaped, the back edge of the door is sucked outward when only fitted with the standard single latch. A 3 poin latch is an absolute necessity.

 

 

[IBob]

Hmm, years ago I flew with the shark patrol, always over water. Being in the rear seat of a 172, I was instructed, if it came to it, to open the nearest door before we ditched into the ocean. This was to provide a quick exit for me, the pilot or co-pilot would then push his seat back and follow me out. I don't think we really cared where the door went as long as it was outwards.

Deskpilot, your 172 door would have have been hinged at the leading edge, so not prone to the violent slamming described above.

 

In the event of sinking, you'd want a door open or the water pressure would hold the doors shut. There used to be a theory about opening car windows under water to allow the doors to then be opened.

 

Certainly if it came to ditching, I would want a door open before hitting the water. And I have wondered about disconnecting the gas struts before flying over water....

 

 

[red750]

I was trained in GA aircraft with hinges on the leading edge. As part of training for emergency landings I was instructed, and it was part of the checklist, to unlatch the door, in case distortion of the frame could prevent the door from opening once on the ground.

 

 

[IBob]

I was trained in GA aircraft with hinges on the leading edge. As part of training for emergency landings I was instructed, and it was part of the checklist, to unlatch the door, in case distortion of the frame could prevent the door from opening once on the ground.

Makes sense, though evidently we can't be doing that with the abovementioned gullwing doors.

On the plus side, these doors are very light in construction and close against the outside of the aircraft. And while the stiffening framework of the door does sit within the door frame, it does so with considerable clearance . Which is to say that they would (hopefully) be a lot easier to force open than a typical GA door.

 

 

[JG3]

2. And most important: the Savannah has a gas strut on the trailing edge of the door (and I'm guessing the Zenith has also). This is a recipe for disaster for inflight opening, as the strut acts like a motion damper on the rear of the door: once the air gets one side or the other of the leading edge of the door, the door will begin to twist, which increase the air pressure on that side of the door, which increases the twisting, and so on, causing the door to slam open and/or closed.

/QUOTE]

 

That's exactly correct. I couldn't explain it better. I have thought of moving the strut to the front of the door, in which case the open door would probably just stream with the airflow, but then would be inconvenient for enter/exit, and of course don't need to open the door in flight. I have opening windows for photography.

 

I'm usually extra careful to ensure that the rear latch has engaged correctly but missed it that time...... Won't miss it again.....

[Kiwi]

I think it is caused by the shape of the fuselage in front of the doors on the Savannah. My Rans S6 also has a top hinged door with the gas strut on the rear of the door, you can open the door in flight if you slow down to 50 knots, then you can speed back up to cruise speed. Been a Drifter pilot I quite like the doors been open.

 

 

[IBob]

I think it is caused by the shape of the fuselage in front of the doors on the Savannah. My Rans S6 also has a top hinged door with the gas strut on the rear of the door, you can open the door in flight if you slow down to 50 knots, then you can speed back up to cruise speed. Been a Drifter pilot I quite like the doors been open.

That's interesting. The S6 has a flat door with a steel frame?

 

The Savannah has an aluminium framed door of very light construction, and as Rotax618 said (above), the door on the more recent XL and S models is dished outwards, so highly unlikely to behave in a 'neutral' fashion out in the slipstream.

 

 

[Kiwi]

Mine has a alloy tube frame with centre brace and the two peice1.5 mm lexen bubbles out. The door frame is about 25mm from the opening.

 

I know the Savannah quite well, I helped a friend build one, it now has hinged windows on the upper half that can be opened in flight. I will try and get some photos.

 

Here is a clip of a door opening (unintentional) in flight ( not mine)

 

 

 

[Bernie]

I had my door on my gazelle open while under instruction above Kilcoy Qld .

 

I just changed hands from the joy stick and closed it....no dramar .

 

Bernie .

 

 

[eightyknots]

JG3: do you have any pictures of the opening window that you use for photography?