There was an incident around 1966/67 when a 56 Sqdn Lightning F3 out of Wattersham did a wheel up crash landing in a field. The aircraft had experienced problems and the Pilot attempted to eject, which failed, this was the first F3 ejection and the canopy release bolts failed to rise correctly and the canopy was not released so the poor chap was trapped.
He successfully carried out a landing in a field (I do not remember if he had any engine power ) but at the end of the landing slide the wing hit a tree/wall, the jolt, jarred the canopy which released, the seat then fired and the poor chap was killed as it was a 90knot minimum speed seat unlike todays zero/zero seats.
There were also other undercarriage problems with the T5, the T 5 had 2 brakeshoot release handles one on the left-hand side near the undercarriage up/down buttons. The other on the right-hand side. There were several incidents of T5s landing and the boots retracting, I witnessed one again at Wattersham in summer 68. 29 Sqdn borrowed a T5 from the OCU at Colt
for the Trappers visits. Touch down was normal, the brake shoot deployed and the left main gear retracted. Both walked away ok. Believe the problem was something along the lines as follows. The left hand brakeshoot handle had about 8 inches of movement, its made of soft iron. As its pulled its magnetic field caused an induced EMF in the U/C ccts located close to the handle. Believe the U/C airspeed switches were set at 145 knots and approaches flow at around 160 knots.
So a defective or miss set switch would not prevent an inadvertent retraction. The initial fix was to operate the brakeshoot handle from the right-hand seat only. So lots of ground crew manage a T5 flight.