Kevin,
It would be ideal to have wind tunnel, CFD, and flight test data to confirm the theories outlined in the Canopy Safety Issue Paper. Of course they require some expense and risks with no benefactors volunteering until you just did.
It is my judgment that we have enough information to draw conclusions with reasonable confidence in their accuracy. With the information and opinions in the paper, the experimental airplane builders and pilots can review it and respond however they see fit. We’re working from the information provided by witnesses and investigators of fatal unlatched canopy accidents and pilots skilled and/or lucky enough to have survived the experience and shared their invaluable observations with us. As more information is available we can update the paper as needed.
When you get into the details of the paper, you’ll read that my opinion is that it doesn’t really matter what all the causes are for most pilots having significant challenges controlling their airplane’s flight attitude when flying with the canopy unlatched -- since everyone will likely agree that as long as the canopy gets latched and stays latched for flight then there’s no problem.
It surprises me that some are interpreting the issue paper as a kind of condemnation of the Legacy’s overall design. What I see we’re discussing is that area of the man-machine interface that has been debated since the Wright Brother’s first flying machine. For example, if an airplane designer puts the flap switch right next to the landing gear switch with both switches looking and feeling identical, when the pilot accidentally retracts the landing gear on the ground when he intended to retract the flaps, whose fault is it? Likewise, if it is known a pilot (being human and imperfect) will eventually miss a critical check list item, when he misses it and it results in his death, is it all his fault…?
In my work we do these mental experiments every day as we scrutinize aerospace system designs, how they fail, their fault tolerance, and the crew interaction with those systems. In the Legacy canopy context, we would never control the hazard of flight with the canopy unlatched (no matter what is causing the control problems with the canopy unlatched for most pilots) with pilot use of the check list alone.
A simple warning system and very minor modification of the Legacy latching mechanism can be incorporated for less than $50 that will essentially eliminate the possibility of pilots taking their Legacy airplanes airborne without the canopy latched. There’s really no down side to incorporating these measures that would justify waiting for more “hard data” before adopting them. It is, of course, up to each pilot and builder to decide for themselves. The issue paper just collects much of the known information on the subject as well as various opinions to help people with these decisions.
The Legacy is a great airplane. I believe we should continue to review the safety record to find ways to further improve the airplane and ourselves as pilots. That’s what all of us who’ve contributed to the Legacy Canopy Safety Issue Paper are working to do…
Valin Thorn
-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Kevin Stallard
Sent: Tuesday, April 29, 2014 6:12 AM
To: lml@lancaironline.net
Subject: [LML] Re: Legacy White Paper
I have to add my support to this post. I appreciate the time put into the report. But there are a number of conclusions that are drawn without corresponding test data. This concerns me. There are even some diagrams of airflow over the airplane in some configurations, do we have wind tunnel data that supports this?
I feel strongly enough that the airplane is fully controllable during flight that I have on my own agenda to put together some tests to either show or disprove this idea that the airplane is or is not controllable (with the help of knowledgeable people I might add).
To put blame on the airplane and its design for the fatal accidents that have occurred seems too easy of an out. I understand that people have killed themselves, but we need to fully identify the reason and this report (however well meaning) isn't backed by real data or testing.
I don't mind calling it a collection or repository of information and experiences, but to call it a report wherein specific action is outlined, I'm just not comfortable with it.
The legacy is a fantastic airplane, I really need hard data if I am going to take any action to change its design. Having extra locks and things on the canopy could result in unintended consequences....
Thanks
Kevin
________________________________________
From: Lancair Mailing List [lml@lancaironline.net] On Behalf Of Jon Socolof [jsocolof@ershire.com]
Sent: Monday, April 28, 2014 1:37 PM
To: lml@lancaironline.net
Subject: [LML] Legacy White Paper
The Legacy canopy design is not unsafe or inadequate and does the job exactly as Lancair intended. In all my training in the Legacy, attention to the canopy has always been stressed. It’s a check list item and as in my military jet, a verification item by pushing on the canopy prior to takeoff. After the tragic Lakeland accident Lancair incorporated an additional canopy safety warning into the design. If a builder wants to change the design, that’s a judgment call.
I don’t believe there is a case of a “secured” canopy opening in flight and it has been demonstrated here, the plane can be flown with the canopy open. These are high performance airplanes, deserve respect and require skill to operate. Yes, some pilots failed to secure their canopies before fight. Some recovered their airplanes and some had lesser results.
Human factors are the issue here and unfortunately, failures will occur. Failure to use checklists or missing items, rushing, complacency and non-standard procedures, continuing takeoffs with the canopy unsecured, operating on runways with insufficient Accelerate Stop Distances, etc.
I am concerned how a paper like this may be perceived. Will it scare off potential builders and buyers or be interpreted to indicate a design flaw? I don’t believe this paper presents anything new or unknown. As far as I know, there is no record of an in-flight breakup or failure of a Legacy, yet the airframe has developed a certain reputation by biting a few unwary pilots, but just how does this paper help?
FWIW
Jon
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