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Peter Dohm wrote:
.... 1) Was the canopy open/unlatched? (It very probably was) 2) Could this happen to an unimpaired pilot? (Obviously yes, since it has happened several times) 3) Could an open/unlatched canopy be prevented, or could the results be mitigated in a cost effective way? (I think so, and think it needs further discussion) As Stealth has pointed out, those canopies appear not to be a fail safe design. One would initially presume that they would only open slightly and maintain a slightly open position in trail, which was true in at lease one instance and might presumably have been true of the test aircraft. However, at least one other example appears to have behaved quite differently and I personally doubt that the difference in shape would need to be much greater than the thickness of a coat of paint to cause a dramatic difference in behavior. I suspect that a safety catch of a type common on the engine hoods of automobiles and placed close enough to the latched position to preclude oscillation, accompanied by the installation of a warning lamp when the canopy is not in its fully latched position, would both mitigate the result of an unlatched canopy and make the occurence less likely. I still would not personally choose a hinged canopy; but those improvements should be sufficient to render my other criticisms nearly moot. Peter Side and forward hinged canopies can lift in the airstream. This would not be a "gee-whiz how could that happen" type of problem. I have reported my own stone-cold sober experience with a side hinge top canopy unlatching at takeoff and I would be surprised to hear of side and front hinged canopies that DON'T lift in the air stream. Accordingly, I think a secondary catch sounds like a very, very sensible idea. You can't imagine how distracting it is 'til you experience it. an inch or two of bobble would be a whole lot less threatening, in my view. Brian W |
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On Sep 26, 9:38*pm, brian whatcott wrote:
Peter Dohm wrote: ... 1) * *Was the canopy open/unlatched? * * * * (It very probably was) 2) * *Could this happen to an unimpaired pilot? * * * * (Obviously yes, since it has happened several times) 3) * *Could an open/unlatched canopy be prevented, or * * * * could the results be mitigated in a cost effective way? * * * * (I think so, and think it needs further discussion) As Stealth has pointed out, those canopies appear not to be a fail safe design. *One would initially presume that they would only open slightly and maintain a slightly open position in trail, which was true in at lease one instance and might presumably have been true of the test aircraft. *However, at least one other example appears to have behaved quite differently and I personally doubt that the difference in shape would need to be much greater than the thickness of a coat of paint to cause a dramatic difference in behavior. I suspect that a safety catch of a type common on the engine hoods of automobiles and placed close enough to the latched position to preclude oscillation, accompanied by the installation of a warning lamp when the canopy is not in its fully latched position, would both mitigate the result of an unlatched canopy and make the occurence less likely. I still would not personally choose a hinged canopy; but those improvements should be sufficient to render my other criticisms nearly moot. Peter Side and forward hinged canopies can lift in the airstream. * *This would not be a "gee-whiz how could that happen" type of problem. I have reported my own stone-cold sober experience with a side hinge top canopy unlatching at takeoff and I would be surprised to hear of side and front hinged canopies that DON'T lift in the air stream. Accordingly, I think a secondary catch sounds like a very, very sensible idea. You can't imagine how distracting *it is 'til you experience it. an inch or two of bobble would be a whole lot less threatening, in my view. Brian W Sailplanes are adopting forward hinged canopies as a safety feature. Any canopy opening system can open inadvertently if not properly latched but the forward hinge system will open less violently than other systems. Regardless of the hinge system, an open canopy is not likely to render an aircraft unflyable. The first priority is to FLY THE AIRCRAFT and deal with the canopy on the ground after a safe landing. Long experience has shown that the biggest hazard of an open canopy in flight is the pilot trying to close the canopy and not flying the aircraft while he's doing it. There's a history of glider accidents with this scenario. Glider pilots are taught to assume an open canopy is trashed, put it out of their mind and fly the glider as an open cockpit aircraft. As a standard part of training, I will have students open the canopy in flight and enjoy a few minutes of open cockpit flying. The point is for them to see that the glider flies just fine with the canopy open so if it opens inadvertently, they aren't panicked. Finally, one has to consider the effect of a large jolt of adrenalin when added to Bill's drug cocktail. It's possible that he could have dealt with flying the airplane under non-emergency conditions but not with the stress and adrenalin of an open canopy. Bill Daniels |
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![]() "bildan" wrote Finally, one has to consider the effect of a large jolt of adrenalin when added to Bill's drug cocktail. It's possible that he could have dealt with flying the airplane under non-emergency conditions but not with the stress and adrenalin of an open canopy. The adrenalin theory may be true, but I favor the John Denver type scenario. If you turn around to the left (to turn a fuel valve or close a canopy, you turn to the left, 99.9% of the time. Low to the ground, with clothes and probably some dirt from the floorboards blowing around in your eyes, you have an ideal accident chain continuing onward. -- Jim in NC |
#4
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"bildan" wrote in message
... On Sep 26, 9:38 pm, brian whatcott wrote: Peter Dohm wrote: ... 1) Was the canopy open/unlatched? (It very probably was) 2) Could this happen to an unimpaired pilot? (Obviously yes, since it has happened several times) 3) Could an open/unlatched canopy be prevented, or could the results be mitigated in a cost effective way? (I think so, and think it needs further discussion) As Stealth has pointed out, those canopies appear not to be a fail safe design. One would initially presume that they would only open slightly and maintain a slightly open position in trail, which was true in at lease one instance and might presumably have been true of the test aircraft. However, at least one other example appears to have behaved quite differently and I personally doubt that the difference in shape would need to be much greater than the thickness of a coat of paint to cause a dramatic difference in behavior. I suspect that a safety catch of a type common on the engine hoods of automobiles and placed close enough to the latched position to preclude oscillation, accompanied by the installation of a warning lamp when the canopy is not in its fully latched position, would both mitigate the result of an unlatched canopy and make the occurence less likely. I still would not personally choose a hinged canopy; but those improvements should be sufficient to render my other criticisms nearly moot. Peter Side and forward hinged canopies can lift in the airstream. This would not be a "gee-whiz how could that happen" type of problem. I have reported my own stone-cold sober experience with a side hinge top canopy unlatching at takeoff and I would be surprised to hear of side and front hinged canopies that DON'T lift in the air stream. Accordingly, I think a secondary catch sounds like a very, very sensible idea. You can't imagine how distracting it is 'til you experience it. an inch or two of bobble would be a whole lot less threatening, in my view. Brian W Sailplanes are adopting forward hinged canopies as a safety feature. Any canopy opening system can open inadvertently if not properly latched but the forward hinge system will open less violently than other systems. Regardless of the hinge system, an open canopy is not likely to render an aircraft unflyable. The first priority is to FLY THE AIRCRAFT and deal with the canopy on the ground after a safe landing. Long experience has shown that the biggest hazard of an open canopy in flight is the pilot trying to close the canopy and not flying the aircraft while he's doing it. There's a history of glider accidents with this scenario. Glider pilots are taught to assume an open canopy is trashed, put it out of their mind and fly the glider as an open cockpit aircraft. As a standard part of training, I will have students open the canopy in flight and enjoy a few minutes of open cockpit flying. The point is for them to see that the glider flies just fine with the canopy open so if it opens inadvertently, they aren't panicked. Finally, one has to consider the effect of a large jolt of adrenalin when added to Bill's drug cocktail. It's possible that he could have dealt with flying the airplane under non-emergency conditions but not with the stress and adrenalin of an open canopy. Bill Daniels -------------new post begins--------------- You have fewer choices with the sailplane, because few if any could accept a rearward sliding canopy. Therefore, the front hinged canopy should be a big safety improvement over the side hinged designs--especially with the lower speeds and narrower cabin. Personally, I would still include a safety catch; but the benefit should be far less dramatic. Peter |
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On Sep 27, 3:18*pm, "Peter Dohm" wrote:
"bildan" wrote in message ... On Sep 26, 9:38 pm, brian whatcott wrote: Peter Dohm wrote: ... 1) Was the canopy open/unlatched? (It very probably was) 2) Could this happen to an unimpaired pilot? (Obviously yes, since it has happened several times) 3) Could an open/unlatched canopy be prevented, or could the results be mitigated in a cost effective way? (I think so, and think it needs further discussion) As Stealth has pointed out, those canopies appear not to be a fail safe design. One would initially presume that they would only open slightly and maintain a slightly open position in trail, which was true in at lease one instance and might presumably have been true of the test aircraft. However, at least one other example appears to have behaved quite differently and I personally doubt that the difference in shape would need to be much greater than the thickness of a coat of paint to cause a dramatic difference in behavior. I suspect that a safety catch of a type common on the engine hoods of automobiles and placed close enough to the latched position to preclude oscillation, accompanied by the installation of a warning lamp when the canopy is not in its fully latched position, would both mitigate the result of an unlatched canopy and make the occurence less likely. I still would not personally choose a hinged canopy; but those improvements should be sufficient to render my other criticisms nearly moot. Peter Side and forward hinged canopies can lift in the airstream. This would not be a "gee-whiz how could that happen" type of problem. I have reported my own stone-cold sober experience with a side hinge top canopy unlatching at takeoff and I would be surprised to hear of side and front hinged canopies that DON'T lift in the air stream. Accordingly, I think a secondary catch sounds like a very, very sensible idea. You can't imagine how distracting it is 'til you experience it. an inch or two of bobble would be a whole lot less threatening, in my view. Brian W Sailplanes are adopting forward hinged canopies as a safety feature. Any canopy opening system can open inadvertently if not properly latched but the forward hinge system will open less violently than other systems. Regardless of the hinge system, an open canopy is not likely to render an aircraft unflyable. *The first priority is to FLY THE AIRCRAFT and deal with the canopy on the ground after a safe landing. Long experience has shown that the biggest hazard of an open canopy in flight is the pilot trying to close the canopy and not flying the aircraft while he's doing it. *There's a history of glider accidents with this scenario. *Glider pilots are taught to assume an open canopy is trashed, put it out of their mind and fly the glider as an open cockpit aircraft. As a standard part of training, I will have students open the canopy in flight and enjoy a few minutes of open cockpit flying. *The point is for them to see that the glider flies just fine with the canopy open so if it opens inadvertently, they aren't panicked. Finally, one has to consider the effect of a large jolt of adrenalin when added to Bill's drug cocktail. *It's possible that he could have dealt with flying the airplane under non-emergency conditions but not with the stress and adrenalin of an open canopy. Bill Daniels -------------new post begins--------------- You have fewer choices with the sailplane, because few if any could accept a rearward sliding canopy. *Therefore, the front hinged canopy should be a big safety improvement over the side hinged designs--especially with the lower speeds and narrower cabin. Personally, I would still include a safety catch; but the benefit should be far less dramatic. Peter True, few modern gliders could accommodate the classic sliding canopy but an old one did - the USAAF TG-4. War surplus TG-4's were used by many US soaring clubs from WWII to around 1965. The rear seat had a sliding canopy which made summer instructing much more fun. OTOH, the canopy didn't seal very well when closed so winter instruction was cold and drafty. |
#6
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![]() Sailplanes are adopting forward hinged canopies as a safety feature. Any canopy opening system can open inadvertently if not properly latched but the forward hinge system will open less violently than other systems. Regardless of the hinge system, an open canopy is not likely to render an aircraft unflyable. The first priority is to FLY THE AIRCRAFT and deal with the canopy on the ground after a safe landing. Long experience has shown that the biggest hazard of an open canopy in flight is the pilot trying to close the canopy and not flying the aircraft while he's doing it. There's a history of glider accidents with this scenario. Glider pilots are taught to assume an open canopy is trashed, put it out of their mind and fly the glider as an open cockpit aircraft. Bill is correct. The biggest hazard of an unlatch/open canopy is trying to close it. I can make this statement as a "voice of experience." http://www.soaridaho.com/Schreder/HP-16/nocan.htm I only had about 30 hours in glider when this incident occurred. If I my glider had a forward hinged canopy the result of an unlatched canopy would have been a bit of noise caused by the canopy not being properly sealed. One of these days I am going to have to replace the canopy on my current homebuilt sailplane. When the time arrives a I will install forward hinged canopy. Wayne http://tinyurl.com/N990-6F |
#7
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![]() "Wayne Paul" wrote in message news ![]() Bill is correct. The biggest hazard of an unlatch/open canopy is trying to close it. I can make this statement as a "voice of experience." http://www.soaridaho.com/Schreder/HP-16/nocan.htm To add to Wayne's excellent post, the following canopy-caused accident always sticks in my mind. It caused fatal injuries to a paying passenger, severe injuries to the Commercial pilot, & less severe injusies to the tow pilot. There happened to be an FAA inspector watching the accident happen, so the witness description is probably better than most. "A Federal Aviation Administration (FAA) Aviation Safety Inspector witnessed the accident. In a written statement the Inspector said: "My attention was drawn to the glider by its erratic pitch changes. As I concentrated on the glider I saw that the rear canopy had opened and the person in the rear seat extended an arm toward the open canopy. At the same time, the glider pitched up rather steeply and the arm returned inside the glider. With the canopy still open, the glider reduced its pitch but remained on high tow. This effort to close the canopy occurred at least three times with the glider going higher and higher. Toward the end of the runway, the tow plane began to descend then pitch up once or twice then descend and impact the ground. As the tow plane impacted the ground, the glider, which was much higher and still on the tow rope, continued forward and climbing and the tow rope became almost vertical...[which] separated from the glider and fell in a pile by the tow plane. The glider continued...beyond the tow plane...rolled left to the inverted position...and impacted the ground..." http://www.ntsb.gov/ntsb/GenPDF.asp?...9FA004B&rpt=fa Like I said, this one sticks in my mind, but if you search the NTSB database you will find too many more. Vaughn |
#8
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On Sep 28, 8:56*am, "vaughn"
wrote: "Wayne Paul" wrote in message news ![]() Bill is correct. *The biggest hazard of an unlatch/open canopy is trying to close it. *I can make this statement as a "voice of experience." http://www.soaridaho.com/Schreder/HP-16/nocan.htm To add to Wayne's excellent post, the following canopy-caused accident always sticks in my mind. *It caused fatal injuries to a paying passenger, severe injuries to the Commercial pilot, & less severe injusies to the tow pilot. *There happened to be an FAA inspector watching the accident happen, so the witness description is probably better than most. "A Federal Aviation Administration (FAA) Aviation Safety Inspector witnessed the accident. In a written statement the Inspector said: "My attention was drawn to the glider by its erratic pitch changes. As I concentrated on the glider I saw that the rear canopy had opened and the person in the rear seat extended an arm toward the open canopy. At the same time, the glider pitched up rather steeply and the arm returned inside the glider. With the canopy still open, the glider reduced its pitch but remained on high tow. This effort to close the canopy occurred at least three times with the glider going higher and higher. Toward the end of the runway, the tow plane began to descend then pitch up once or twice then descend and impact the ground. As the tow plane impacted the ground, the glider, which was much higher and still on the tow rope, continued forward and climbing and the tow rope became almost vertical...[which] separated from the glider and fell in a pile by the tow plane. The glider continued...beyond the tow plane...rolled left to the inverted position...and impacted the ground..." http://www.ntsb.gov/ntsb/GenPDF.asp?...9FA004B&rpt=fa Like I said, this one sticks in my mind, but if you search the NTSB database you will find too many more. Vaughn I should have added that when letting a student open a canopy in flight, it is done at low airspeed and in a glider whose canopy is known to be easily opened and closed in flight. There are many expensive two-east gliders with canopies costing thousands of dollars that I would never let a student risk. On at least one occasion a student of mine who had experienced a deliberate canopy opening with me later suffered an inadvertent opening and handled it well. He told me the story years after his training. Bill Daniels |
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