What happened
During a departure from Linköping/SAAB Airport toward Stockholm/Västerås Airport, the crew of a DC-3C, registration SE-CFP, operated by Flygadamente Veteraner, received a fire warning for the left engine. In response, the crew feathered the engine and deployed the fire extinguishing system, though the fire persisted. After notifying air traffic control, the crew attempted a visual approach but was forced to perform a go-around before eventually landing on the opposite runway.
Upon landing, the aircraft experienced a total failure of the braking system. The crew shut down the remaining operational engine, and the aircraft eventually came to a stop on the runway strip. While the airport rescue services successfully extinguished the fire and the aircraft was evacuated without no injuries, the left engine nacelle and the accessory compartment sustained substantial damage.
The investigation
SHK investigators examined the wreckage and discovered that three screws were missing from the exhaust collector. This deficiency caused components of the exhaust system to detach, allowing exhaust gases to ignite accumulated oil residue and melt portions of the engine cowling. This process subsequently melted several hydraulic lines, causing oil leaks that provided additional fuel for the fire.
Furthermore, the investigation traced the origin of the mechanical failure to a recent engine change performed in Groningen. This maintenance task was conducted without a formal work order and deviated from the operator's established service manual. The investigation also noted that the crew failed to close the cowl flap control valve as required by the emergency checklist.
Findings
- The primary cause of the incident was the engine change being performed without following established maintenance procedures.
- The severity of the fire was increased by the design of the hydraulic system, which lacks the ability to isolate hydraulic oil from engine zone 2.
- The fire was exacerbated by the failure to follow the emergency checklist regarding the cowl flap control valve.
- The lack of a formal work order during the maintenance in Groningen led to the missing hardware on the exhaust collector.