| The 2nd latch idea is a good one. I had two straps on the inside of my Legacy bonded to the inside cabin. the straps kept the Canopy from flipping open with a tail wind and that can happen frequently while taxiing. In Texas, wind caught the canopy and ripped the two straps out of the cabin wall and the plane was not even moving. A secondary strap would probably be best near the rear of the canopy nearest the latching point, not where I had it closer to the hinge point.
On a least a few occasions while I've rushed to depart I've had the canopy start to open while pushing the throttle and realized my mistake immediately. Now, as part of the runup I push hard up on the canopy to confirm the lock as does another Legacy pilot I know. On my Legacy, its not possible to apply 20 inches MP and not have the canopy come up 4 inches with all the noise and motion that comes with it.
I also watch my annunciator and look for a clear board. So, the idea of the switch Dan Ballin wrote about really should be part of the standard circuitry. A door switch has been on every airplane I've every owned. I only wish Cessna had put a few on the nose baggage doors of its twins.
I have a mechanical pin that prevents the canopy bar from being raised. Many things can get caught on that bar. However, the pin could prevent egress unless everyone is familiar with the operation.
Last, the canopy rubber seal switch is a toggle and often gets hit while loading on the ground and sometimes in the air. Someday I would like to either move it to the panel or protect it or have it flush with the surface so things don't grab the toggle.
A secondary latch is not a bad idea, Gary. I also
considered something like a retractable seat belt attachment that would allow
the canopy to be raised at a normal speed but not at an explosive speed. But
in an airplane there are a lot of stupid pilot tricks that can have a bad
outcome. It would be difficult to engineer all of them out. A checklist
is a good tool…if you can remember to use it. Bill B
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Gary Casey
Sent: Friday, September 20, 2013
8:13 AM
To: lml@lancaironline.net
Subject: [LML] Re: Legacy down in Geraldton, Western
Australia
I guess it is none of my business, since I don't own a Legacy, but
I feel the need to put in my opinion, for what it's worth:
I have to respectfully disagree in principle with Gary Week's
post. Not because he is wrong, as he is absolutely correct. But, I
would treat this as a design flaw - (not)latching the canopy is something that
should not be a life-and-death event. The solution is simple - just add a
secondary latch, like the hood of most any car has. In that way the
canopy can be held open during taxi without relying on the pilot to latch it
fully before takeoff. And if the latch does come adrift there is another
one to catch it. I just don't like the idea of relying on a human to
actively do something that could be a problem. I, too, have heard of more
than one report of a problem with this. I just don't like the idea of
saying, "just be more careful." The stakes are too high.
Many thanks Bill for sharing that first hand account of an unlatched canopy.=
My comment was a reflection of what I had been told or had read somewhere pr=
eviously (not from actual experience) and I am happy to be corrected, especi=
ally from those who have been there and done that.
Yes we need to carefully check the canopy is latched before takeoff. Thanks a=
gain.
Gary
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