Pterodactyl Ascender II + 2 ZK-FKF, mid-air breakup, Manukau Harbour, 8 March 1992
Status
Closed
Occurrence Date
Report Publication Date
Jurisdiction
NZ
Legacy Inquiry Number
92-007
ZK-FKF was the second in a loose formation of three microlight aircraft which had taken off from Pikes Point Aerodrome, to fly to Raglan. While the formation was flying over the Manukau Harbour, parallel to the north shore, the aircraft was seen to dutch roll, then pitch nose-down. The right wing folded at about one-third span, and the aircraft fell into the sea, killing the pilot.
Similarities between the structural damage of ZK-FKF and other Pterodactyl Ascender microlights involved in mid-air breakups suggested design deficiencies. Video recordings of two such accidents demonstrated that the wings fluttered following an uncontrollable pitch down, the flutter forces resulting in the subsequent breakup.
Analysis indicated an insufficient reserve of pitch stability when the aircraft was flown at the upper end of its speed range, together with other control and structural design shortcomings.
It was recommended that the type's Permit to Fly be withdrawn.
Similarities between the structural damage of ZK-FKF and other Pterodactyl Ascender microlights involved in mid-air breakups suggested design deficiencies. Video recordings of two such accidents demonstrated that the wings fluttered following an uncontrollable pitch down, the flutter forces resulting in the subsequent breakup.
Analysis indicated an insufficient reserve of pitch stability when the aircraft was flown at the upper end of its speed range, together with other control and structural design shortcomings.
It was recommended that the type's Permit to Fly be withdrawn.
Location
Manukau Harbour (-36.954230,174.660623) [may be approximate]