There have been a few curious Gazelle accidents over the years. One of the first was an Army Gazelle that crashed killing three at Wallop in the early seventies. The pilot who survived said the cyclic froze and he was unable to recover from a manoevre. I believe it was put down to jack stall and later on the Army installed a hydraulic accumulator to help counteract the problem.. .. .About 1977 while a Gaz was under maintenance we discovered that a mis-manufacture of the discs at the base of the cyclic allowed the stick to jam solid and no amount of force would allow aft stick movement. A problem similar to that in the crash. The aircraft serial number was XW851 which was within 2 of the lost aircraft. Sadly the accident aircraft had long gone to the tip and it was not possible to say that this was the cause of the original accident. . .. .As no AD was ever issued it is possible that some of the very early civil Gaz's still have this as a dormant problem. About 5 years ago I wrote this up for the CAA, the silence is deafening!!!!!!!