A while ago, before the mid 80's when I gave up on flying, I considered myself somewhat of a hotshot private pilot.
In June of 1977 I was living in Colorado Springs, Co. and regularly rented aircraft from an FBO at the Colorado Springs Airport.
Among there inventory was a set of Grumman American planes, the four seat Cheetah, or AA5A, and Tiger, AA5B, and a two seat version called the AA1C.
Although fully certified these particular planes were placarded (prominent written instructions on the instrument panel) against intentional spins as there was no assurance you could recover the aircraft to normal flight before you ran out of space between you and the ground. This particular plane, AA1C tail number N9517U, was tricked out in camoufage paint with D-Day stripes on the wings - it was a fun airplane.
On this day, June 26, 1977, a buddy of mine had the plane out when I arrived at the airport for my rental period. When he landed and parked I went out to the aircraft to meet him and chat as he tied down. He informed me that he had been able to perform a forbidden acrobatic maneuver (such maneuvers are forbidden in any aircraft not specifically designed for acrobatics), a barrel roll. He explained how he had done it telling me the control positions and aircraft attitudes to use to enter the maneuver.
When moving small planes around on the ground you use something called a tow bar which attaches to the nosewheel and makes it easier to horse the plane around on the ground for parking, pushing into hangers etc. The tow bar for this plane was stored on the floor behind the pilot and copilot/passenger seats. Small straps were provided to fasten the tow bar in place. A good 90% of the time the tow bar just lays back there. After my buddy parked the plane he did just that, laid the tow bar behind the seats. I didn't check to be sure it was secure.
In aircraft maneuvers, a roll causes the airplane to rotate around it's horizontal axis. The craft goes in a straight line and simply rotates 360 degrees. In a barrel roll, the airplane not only rotates 360 degrees but also travels in a 360 degree circle in a corkscrew like motion. There is a considerable amount of time that the aircraft flies upside down.
After leaving the airport and flying east toward the flatlands (Colorado Springs is at the foot of Pikes Peak and the Rockies). I climbed to what I considered a safe atltitude above the ground (about 9,000 feet because the ground is over 6,000 ft at the colorado Springs Airport, a long way from sea level which is the starting point for measuring Aircraft altitude), I began to set up to attempt a barrel roll. Everything was fine until I was inverted and starting the next 180 degrees of roll to level flight. The unsecured tow bar struck me in the back of the head.
I was stunned, and out of it for a few seconds, in an inverted aircraft approaching a stall and a quite possible inverted spin. I didn't know how to recover from a "normal" spin.
When I came to my senses, the plane was just completing a split "S" at about 200 ft above the ground. A split "S" is half of a loop started from inverted flight. Now in level flight, I reached behind me and fastened the tow bar down, climbed back to 9000ft and successfully completed a barrel roll, my first and last one ever.
Why is this important? It wasn't the only "brain dead" thing I've tried in an airplane. But it is the only one that needed another hand on the controls. There is an old expression, "God is my co-pilot". On that day, I became a passenger and he was the Pilot.