What happened
On 23 April 2003, a Cessna Citation 560 Ultra, registration VP-CSN, was operating a passenger flight from Copenhagen to Edinburgh. During the landing phase on Runway 24, the crew experienced an intense deceleration when applying the toe brakes that felt disproportionate to the pressure applied to the pedals. Upon inspecting the flight deck controls, the commander identified that the parking brake selector had not been moved to the fully 'OFF' position.
Although the crew managed to bring the aircraft to a stop on the runway, both main landing gear tyres had already deflated. The first officer evacuated the five passengers, and while the Airport Fire Service attended, no fire was reported. The damage was confined to the two main tyres, which had been abrading against the runway due to the locked wheels.
The investigation
The investigation established that the parking brake selector, a plunger-type control, requires a travel of approximately five inches to move from 'ON' to 'OFF'. Crucially, there is no cockpit indication to show the status of the parking brake other than the physical position of the selector itself.
Prior to the incident, the crew had faced several distractions during their departure from Copenhagen. These included a last-minute change to the departure runway, a revised taxi route, and the need to re-brief for takeoff. Additionally, the crew had been managing pitot heater settings to prevent overheating during an extended hold and had experienced difficulties communicating with Air Traffic Control regarding wake vortex categories. The commander noted that these distractions likely contributed to the oversight of the brake selector position.
Findings
- The primary cause of the tyre deflation was that the parking brake selector was not fully released before the aircraft departed Copenhagen.
- The crew did not realize that the partially engaged brake was degrading the aircraft's takeoff performance, partly because the exceptionally long runway at Edinburgh provided an unusual perspective.
- The existing pre-takeoff and pre-landing checklists did not include a specific item to verify the parking brake selector position.
- The lack of a flight deck warning or indicator for the parking brake status meant the crew had no visual confirmation of the selector's position.