Unsecured door involving a Beech Aircraft Corp B300, VH-OXF, Brisbane, Queensland, on 9 August 1996

During climb, passing 5,300 ft, a loud bang was heard. The pilot initially thought the noise to be a birdstrike, however it was noticed that the inner cowl on the left engine had fallen from the aircraft. The pilot elected to return to Brisbane. Post flight inspection revealed that the cowl had torn off along the hinge line and had struck the fuselage forward of the entry door causing denting and scoring of the fuselage skin.

The aircraft had undergone maintenance on the previous day, but no work had been done on the left engine, and there was no known reason for the left engine cowl to be unfastened. The copilot, who performed the daily inspection in the early hours of the morning (it was still dark) had not noticed the cowl was not properly fastened. The cause of the cowl being unfastened could not be determined.