The pilot of a Chipmunk light aeroplane was likely distracted by an unsecured engine cowling before an aerodynamic stall and collision with terrain shortly after take-off from Jandakot Airport, in Perth's south.
On 26 April 2024 a DHC-1 MK 22 Chipmunk single piston-engine aircraft took off from Jandakot Airport.
Shortly after take-off, the aircraft conducted a left turn, likely an attempt to return to land. The pilot declared a MAYDAY, and as the angle of bank increased, the aircraft descended and collided with terrain.
The pilot, who was the sole occupant of the aircraft, was transported to hospital, but later succumbed to their injuries.
An Australian Transport Safety Bureau investigation found the pilot did not detect the engine cowl latches on the left side were left unfastened prior to flight.
"Footage showed and witness reports indicate the cowling began to flap open and closed after take-off," ATSB Chief Commissioner Angus Mitchell said.
A review of past occurrences involving other Chipmunk aircraft did not indicate a flapping cowling would necessarily result in controllability issues.
"Rather, the flapping of the cowling likely distracted the pilot, resulting in a high cognitive workload," Mr Mitchell explained, "at which point the aircraft commenced a low level, high angle of bank turn, and aerodynamically stalled."
Mr Mitchell said the accident illustrated the importance of pre-flight preparation to reduce the likelihood of an abnormal occurrence.
"It should also remind pilots of the hazards that can lead to loss of control events, such as high angles of bank, particularly at low height," he added.
During its investigation, the ATSB also identified that all 12 rivets attaching the upper structure between the front and rear cockpits sheared during the accident sequence.
Metallurgical analysis showed all 12 of the rivets were of a non-conforming type, and half of them were about one-third of the specification strength.
While this compromised the crashworthiness of the aircraft, its impact on survivability in this accident could not be determined.
Nonetheless, the ATSB issued a Safety Advisory Notice on 11 September 2024, advising Chipmunk maintainers and owners of the importance of ensuring modifications are carried out to the required specification.
"The use of non-conforming rivets significantly compromised the accident aircraft's crashworthiness," Mr Mitchell summarised.
"Maintainers and owners of all aircraft are reminded that when modifications are made, they must conform to the required specifications, or be returned to these specifications during maintenance."
You can find here the final report: Collision with terrain involving Oficinas Gerais de Material Aeronautico DHC-1 MK 22 Chipmunk, VH-POR, at Jandakot Airport, Western Australia, on 26 April 2024
