Incident Overview
On 20 July 2016, a Saab-Scania SF340B (registration G-LGNC) experienced a serious incident during departure from Glasgow Airport. The aircraft, operating a commercial passenger flight with 3 crew and 13 passengers, took off with an unsecured left engine cowling. The commander noticed the cowling flapping in the airflow while passing FL090 and decided to return to Glasgow. The aircraft stopped climbing at FL100, performed two orbits to allow cabin preparation, and then landed safely. No injuries were reported.
Damage
Post-landing inspection revealed damage to the left-hand upper nacelle fairing (part 451AT) at its leading edge. Additionally, the trailing edges of all four propeller blades on the left engine showed signs of contact with the loose cowling. The forward face of the cowling exhibited wear, and small sections of the propeller blade cuffs had been abraded.
Operator Investigation
The operator concluded that a member of engineering staff had been distracted during a maintenance task performed the day prior to the incident, resulting in the cowling latches not being secured. The unsecured latches were not detected during subsequent before-flight checks by engineering personnel or during the flight crew's pre-flight external inspection. Further investigation revealed that some of the cowling fasteners were of an incorrect length; when fully secured, these fasteners protruded, making it harder to identify insecure fasteners by visual comparison. The operator issued a safety notice emphasizing adherence to correct procedures and the importance of routine inspections.
Flight Details
The aircraft, a twin-engine turboprop (General Electric CT7-9B engines), was manufactured in 1992. The commander, aged 37, held an Airline Transport Pilot's Licence and had 5,020 total flying hours, with 4,700 hours on type. The flight occurred at 0545 UTC, and the aircraft returned to Glasgow without further incident.