Locked in – The Almost Undocumented Cheetah Feature
One of the neat things about the Grumman series of single-engine aircraft are the fighter-like canopies. It’s great to be able to open them on the ground, especially in the summer when it’s so hot, to get a natural fan blowing through the cockpit. They can even be opened in flight; I met one Tiger pilot who told me his wife would almost refuse to fly during the summer without it open.
There are some downsides to that arrangement, however. One is that, in the event of a crash, there is some significant chance the canopy will be sealed closed, usually by some deformation of the fuselage. The second is that it’s possible to be locked in the airplane, especially when the locks get old and can rotate, even a little, on their own.
When we bought the airplane, the previous owner mentioned to me the lock could be problematic. I think he had gotten locked in once. In the year and a half we have owned the airplane, I have suffered through it twice. Why didn’t I get it fixed? Believe me, after the first time it happened, I did talk to my mechanic about doing just that. The problem was one of parts and FAA approval. In short, I wasn’t able to find a good solution. That has caused my wife and I some significant concern, even though we knew from past experience we could climb out through the baggage door if necessary. The scenario that really concerned us was getting locked in the airplane in the event of a fire.
The second time it happened to me was when I took the airplane down to Galveston to get an oil change a couple of weeks ago. Once I got home, I started searching the Internet to see if someone had come up with a solution. Not finding one, I went to the American Yankee Association (AYA) website and started looking through the Service Bulletins and Letters for anything having to do with canopy locks. Much to my surprise, I did find something. It didn’t do a thing to help me fix the canopy lock; but I learned that the Grumman (or American or Bede) engineers had provided me an “out”. I didn’t know it was there because it was not documented in my 76 owner’s manual, a later model 77 pilot’s handbook, and the placard pointing to it, put there by the Service Letter, wasn’t there. I hadn’t seen it because the only time it became evident was when the canopy was locked, and most of the time I wasn’t in the airplane it was.
When you lock the canopy, a small lever sitting above the normal canopy lever pops out. This lever is designed to unlock the canopy regardless of the external lock position as long as it is pushed in. It is a safeguard against the occupants of the airplane getting locked into the aircraft. The Service Letter (77-3) was addressing the fact that many pilots back then, just like now, were not aware the feature had been designed into the canopy linkage.
Needless to say, I was and am extremely relieved to learn about it. My wife was and is, too. My mechanic and I are now working to comply with the Service Letter. That means making and placing the proper placard in the airplane and getting the little Savior Latch painted red.
What is hard to understand is how such a major safety feature could escape mention in any of the airplane’s pilot’s handbooks. You can bet I’ll be digging through the rest of the airplane’s maintenance documentation to make sure there’s nothing else I need to know about and don’t.
There is one consistent thing about being an airplane owner, and it is that I’m always learning something I didn’t know.
There are some downsides to that arrangement, however. One is that, in the event of a crash, there is some significant chance the canopy will be sealed closed, usually by some deformation of the fuselage. The second is that it’s possible to be locked in the airplane, especially when the locks get old and can rotate, even a little, on their own.
When we bought the airplane, the previous owner mentioned to me the lock could be problematic. I think he had gotten locked in once. In the year and a half we have owned the airplane, I have suffered through it twice. Why didn’t I get it fixed? Believe me, after the first time it happened, I did talk to my mechanic about doing just that. The problem was one of parts and FAA approval. In short, I wasn’t able to find a good solution. That has caused my wife and I some significant concern, even though we knew from past experience we could climb out through the baggage door if necessary. The scenario that really concerned us was getting locked in the airplane in the event of a fire.
The second time it happened to me was when I took the airplane down to Galveston to get an oil change a couple of weeks ago. Once I got home, I started searching the Internet to see if someone had come up with a solution. Not finding one, I went to the American Yankee Association (AYA) website and started looking through the Service Bulletins and Letters for anything having to do with canopy locks. Much to my surprise, I did find something. It didn’t do a thing to help me fix the canopy lock; but I learned that the Grumman (or American or Bede) engineers had provided me an “out”. I didn’t know it was there because it was not documented in my 76 owner’s manual, a later model 77 pilot’s handbook, and the placard pointing to it, put there by the Service Letter, wasn’t there. I hadn’t seen it because the only time it became evident was when the canopy was locked, and most of the time I wasn’t in the airplane it was.
When you lock the canopy, a small lever sitting above the normal canopy lever pops out. This lever is designed to unlock the canopy regardless of the external lock position as long as it is pushed in. It is a safeguard against the occupants of the airplane getting locked into the aircraft. The Service Letter (77-3) was addressing the fact that many pilots back then, just like now, were not aware the feature had been designed into the canopy linkage.
Needless to say, I was and am extremely relieved to learn about it. My wife was and is, too. My mechanic and I are now working to comply with the Service Letter. That means making and placing the proper placard in the airplane and getting the little Savior Latch painted red.
What is hard to understand is how such a major safety feature could escape mention in any of the airplane’s pilot’s handbooks. You can bet I’ll be digging through the rest of the airplane’s maintenance documentation to make sure there’s nothing else I need to know about and don’t.
There is one consistent thing about being an airplane owner, and it is that I’m always learning something I didn’t know.
posted by Andy Foster at 9:31 PM
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