As some would say...
...high skill levels and his extensive experience on type
But then, from the AAIB we have...
There was no record of the pilot having completed the currency training requirements as specified in the operator’s Organisational Control Manual
...mainly self-taught in his aerobatic skills. No record of any formal training course was available but he was described by associates as a competent basic aerobatic pilot... ...Some people who knew him well stated that he had never performed a Derry turn
Some contradictions here.