The Pilatus PC-21 single turboprop-powered military trainer has been cleared to resume flying following the removal of a grounding order imposed after a 13 January fatal crash at Buochs aerodrome, Switzerland while the company's two PC-21 prototypes were practising for an air display.
The grounding, ordered by FOCA, the Swiss federal office for civil aviation, was unconditionally rescinded on 21 January because the BFU air accident investigation bureau had established that "there was no sign of any technical malfunction" that had existed in the crashed aircraft (HB-HZB) before impact with the ground.
Flying as a pair, the aircraft were performing a practice display routine the pilots had previously flown, using Buochs' runway 07L as the display axis.
When the crash occurred, the formation leader - HB-HZA - was flying a loop above the runway, while HB-HZB broke away to fly a 360¡ low-level steep turn that was intended to end with the two rejoining over the runway, but with the leader role swapping to HB-HZB.
Witnesses reported to the BFU that, at the end of the 360¡ turn, HB-HZB descended slightly and its right wing hit the ground, causing the aircraft to tumble and break up. The captain, Pilatus's chief test pilot, was killed, and one person on the ground was severely injured by debris.
The PC-21 was certificated on 23 December 2004. Pilatus says its remaining aircraft, which was serving as the aerodynamic prototype, will be converted to take over from HB-HZB as the systems prototype, and is expected to fly again in about two months.
The company's first series production PC-21 is expected to undergo its flight debut in late August, with this to support autopilot certification trials.
DAVID LEARMOUNT / LONDON
Source: Flight International
