A jammed canopy and aircraft on fire.
In the early 1950 era, the United States Air Force installed canopy breaker tools in some of their aircraft following a series of fatal accidents involving F-80 Shooting Star fighters. These aircraft had carried out high speed rejected takeoffs which resulted in over-runs.
In some cases damage caused by over-runs into rough ground caused the canopy to warp and locking devices to jam, which in turn prevented pilots from exiting the aircraft. Fire caused the death of some pilots trapped in the cockpit. In those days ejection seats were not capable of safe ejection on the ground.
Following the USAF decision to install specifically designed canopy breaker tools, the RAAF conducted their own trials at the Aircraft Research and Development Unit at RAAF Base Laverton, on Sabre and Vampire fighters. These proved successful and canopy breaker tools were later installed on CT-4, Macchi and PC-9 training aircraft.
The first life was saved when a Sabre had an engine failure due to a bird strike on take off causing the pilot to forced land straight ahead into a rice paddy. The aircraft caught fire and initially the pilot was unable open his canopy more than an inch due to a warped canopy rail. He quickly extracted his canopy breaker tool from its position in the cockpit and was able to break through the canopy and escape without injury.
Some Light Sports Aircraft (LSA) have one piece canopies that slide on rails and are locked with one or two over-centre levers. These canopies can be quite heavy to operate. The over-centre levers are operated by the pilot and his passenger.
If the pilot is flying solo, he must lean well over to the passenger side to actuate that canopy locking lever as well as his own. The close tolerances of these locking devices mean they are often stiff to lock and unlock. The relative fragility of LSA design means it doesn't take much of an impact to jam the locking devices or warp the rails making the canopy impossible to open. The term "Death Trap" comes to mind.
It takes little imagination to wonder how the occupants could escape if the canopy jammed after a forced landing where the machine became upside down on touch down on rough terrain.
Barring the current availability of a dedicated aircraft canopy breaker tool that has been thoroughly tested before being put on the market, pilots of LSA, whether home or ready built, would be wise to equip themselves with a suitable device robust enough to break through the glass canopy in an emergency.
Last edited by Judd; 21st Feb 2016 at 04:32.