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  #1  
Old 02-19-2015, 06:08 AM
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LettersFromFlyoverCountry LettersFromFlyoverCountry is offline
 
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Default NTSB on open canopies

The NTSB seems to be at it again, guessing on a cause without much reliable information.

It has released a factual (not probable cause, but a well detailed report) into the crash of an RV-6 near St. Cloud MN a couple of years ago.

It points out the canopy and the latching mechanism were consumed by the fire, but it still considered an open canopy as a possible cause:

TESTS AND RESEARCH
The effects of wake turbulence, if any, could not be determined without relative position and time information from radar/recorded data for both airplanes.

The Lancair Legacy Canopy Safety Issue (Thorn 2014) discusses accidents resulting from flight with the upward opening canopies that become unlatched/open in flight for Lancair and not RV airplanes, which also have upward opening canopies. The paper states in part:

"There are several potential root causes of the Legacy's open canopy flight hazard. One is the canopy is large and, if not latched down in flight, it will open to varying degrees and alter the air flow over the tail/stabilizers and under some situations create significant pitch attitude stability and control issues.

Another potential root cause may be the pilot's loss of reliable airplane pitch attitude reference where the canopy's structural frame serves as a key attitude reference line and as the open canopy moves it corrupts the pilot's normal visual pitch attitude reference cues.
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  #2  
Old 02-19-2015, 07:05 AM
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The LancAir canopy is a different design than our tip-up's. I could see it causing problems, if it came open in flight on a LancAir.

During my Phase 1 test period, I took off with the canopy unlached to verify the plane was controllable. It was and I found out that if you slow down and deploy all the flaps you can close it in flight.
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Last edited by N941WR : 02-20-2015 at 07:13 AM.
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  #3  
Old 02-19-2015, 08:47 AM
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LettersFromFlyoverCountry LettersFromFlyoverCountry is offline
 
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If the canopy came off, I'd like to see some investigation of the path it took during ejection. As I recall Van's says they're not aware of any data of an RV canopy being ejected in flight via the quick-release mechanism, which I didn't bother to install.
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  #4  
Old 02-19-2015, 09:02 AM
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rvbuilder2002 rvbuilder2002 is offline
 
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Location: Hubbard Oregon
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Quote:
Originally Posted by LettersFromFlyoverCountry View Post
The NTSB seems to be at it again, guessing on a cause without much reliable information.

It has released a factual (not probable cause, but a well detailed report) into the crash of an RV-6 near St. Cloud MN a couple of years ago.

It points out the canopy and the latching mechanism were consumed by the fire, but it still considered an open canopy as a possible cause:

TESTS AND RESEARCH
The effects of wake turbulence, if any, could not be determined without relative position and time information from radar/recorded data for both airplanes.

The Lancair Legacy Canopy Safety Issue (Thorn 2014) discusses accidents resulting from flight with the upward opening canopies that become unlatched/open in flight for Lancair and not RV airplanes, which also have upward opening canopies. The paper states in part:

"There are several potential root causes of the Legacy's open canopy flight hazard. One is the canopy is large and, if not latched down in flight, it will open to varying degrees and alter the air flow over the tail/stabilizers and under some situations create significant pitch attitude stability and control issues.

Another potential root cause may be the pilot's loss of reliable airplane pitch attitude reference where the canopy's structural frame serves as a key attitude reference line and as the open canopy moves it corrupts the pilot's normal visual pitch attitude reference cues.
I somewhat share your skepticism Bob.

There are instances of side by side RV's being flown to a fully controlled and safe landing, with unlatched canopies, all the way back to the early 90's when customer RV-6 and 6A's first started being flown.

That doesn't totally rule it out since open canopies have caused a lot of accidents because of pilots allowing themselves to become distracted by it (this usually occurs at low altitude immediately after take-off).

It does seem that in this case there is little to no evidence to support the theory though.
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  #5  
Old 02-19-2015, 09:06 AM
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For what it is worth, there are a couple of RV12 accidents suspected to be caused by canopy coming open in flight, not caused by pilot error in controlling the plane.

Quote:
Originally Posted by rvbuilder2002 View Post
I somewhat share your skepticism Bob.

There are instances of side by side RV's being flown to a fully controlled and safe landing, with unlatched canopies, all the way back to the early 90's when customer RV-6 and 6A's first started being flown.

That doesn't totally rule it out since open canopies have caused a lot of accidents because of pilots allowing themselves to become distracted by it (this usually occurs at low altitude immediately after take-off).

It does seem that in this case there is little to no evidence to support the theory though.
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  #6  
Old 02-19-2015, 09:20 AM
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One of the reasons I miss RVator is because Van would write long pieces that might address things like this.
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  #7  
Old 02-19-2015, 09:42 AM
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Quote:
Originally Posted by DonFromTX View Post
For what it is worth, there are a couple of RV12 accidents suspected to be caused by canopy coming open in flight, not caused by pilot error in controlling the plane.
This is not a correct statement

As far as I am aware, there is only one case where the pilot claimed the canopy opened and caused the airplane to be difficult to control.
There are a number of other instances where the pilot has specifically said the airplane flew normally (one of those was part of a safety article published in Kitplanes).

All evidence at this point seems to imply all accidents with RV-12's where an unlatched canopy was involved, were the result of some level of pilot distraction.
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Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

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Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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  #8  
Old 02-19-2015, 10:56 AM
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Fred.Stucklen Fred.Stucklen is offline
 
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Default Flying an RV with an open canopy

I have intentionally flown two RV-6A's and my current RV-7A with the canopy open with no ill effects (other than a high noise level). All have been tip-up variety canopies, not sliders. This was done on all three aircraft during the phase one flight testing. I have since forgotten to lock the canopy once or twice on the RV-7A, again with no ill effects. But you MUST still fly the airplane first!

In fact, I can say from testing experience that one can successfully land the pane by using the tip up canopy in place of a non-usable elevator. Once the aircraft is slowed and trimmed for level flight with the canopy open (and floating) pushing the canopy up causes the nose to be lowered, pulling it shut causes the nose to rise (assuming a constant power setting). Flaps MUST be in the up position for this to work.

Is this recommended: Definitely not. But it's nice to know that you could do it in an emergency situation.

Quote:
Originally Posted by rvbuilder2002 View Post
I somewhat share your skepticism Bob.

There are instances of side by side RV's being flown to a fully controlled and safe landing, with unlatched canopies, all the way back to the early 90's when customer RV-6 and 6A's first started being flown.

That doesn't totally rule it out since open canopies have caused a lot of accidents because of pilots allowing themselves to become distracted by it (this usually occurs at low altitude immediately after take-off).

It does seem that in this case there is little to no evidence to support the theory though.
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  #9  
Old 02-19-2015, 11:23 AM
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Quote:
Originally Posted by Fred.Stucklen View Post
I have intentionally flown two RV-6A's and my current RV-7A with the canopy open with no ill effects (other than a high noise level). All have been tip-up variety canopies, not sliders. This was done on all three aircraft during the phase one flight testing. I have since forgotten to lock the canopy once or twice on the RV-7A, again with no ill effects. But you MUST still fly the airplane first!

In fact, I can say from testing experience that one can successfully land the pane by using the tip up canopy in place of a non-usable elevator. Once the aircraft is slowed and trimmed for level flight with the canopy open (and floating) pushing the canopy up causes the nose to be lowered, pulling it shut causes the nose to rise (assuming a constant power setting). Flaps MUST be in the up position for this to work.

Is this recommended: Definitely not. But it's nice to know that you could do it in an emergency situation.
Thanks for the additional additional information Fred to additionally confirm what 25+ years of time in service has shown.

Don's comment was specific to the RV-12. It has a stabilator (sometimes referred to as a full flying) horizontal control surface, which is different from the rest of the RV's so could conceivably act differently to an opened tip-up canopy, but at this point all solid evidence appears to imply that it does not.
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Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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  #10  
Old 02-19-2015, 12:37 PM
tal454 tal454 is offline
 
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Has anyone tried an unlocked canopy or had one come open with the slider type?

-Tim
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