What happened
On 2/25/2018, a Falcon 7X (registration VQ-BLP) was at Changi Airport, Singapore, preparing for a flight to the Seychelles. While the crew was performing the AT RAMP checklist, they were interrupted by cabin and ground personnel. Due to these distractions, the crew failed to switch off the backup hydraulic pump.
Following the aircraft's arrival from Seletar, the engine-driven pump had stopped, but the backup pump continued to run in AUTO mode for nearly two hours. This led to a "BACKUP PUMP HI TEMP" alert and a subsequent smoke warning in the baggage compartment. During troubleshooting, the crew attempted to restart the pump multiple times. During the final attempt, hydraulic pressure dropped sharply, and a fire broke out in the mechanic service compartment. The crew used onboard extinguishers to suppress the fire, which involved leaking hydraulic fluid contacting the overheated pump motor.
The investigation
Investigators examined the mechanical state of the backup hydraulic pump and the crew's adherence to operational procedures. The investigation focused on why the pump remained active and why the crew continued to attempt restarts despite receiving a high-temperature warning. The team also reviewed the cockpit environment and the effectiveness of the electronic checklist during the period when the crew was distracted by ground service requests.
Findings
- The primary cause of the fire was hydraulic fluid leaking from a pressure line and coming into contact with the overheated pump motor.
- The pump motor had overheated because it had been running continuously for approximately 1 hour and 50 minutes, far exceeding its certified 40-minute continuous operation limit.
- The crew failed to complete the checklist item to deactivate the pump because they were distracted by cabin and ground crew members.
- The crew did not follow the manufacturer's dispatch guidance, which indicated the pump was a "NO GO" item and required replacement rather than further troubleshooting.
- There was a failure to observe sterile cockpit policies, as the crew engaged with ground personnel while the checklist was still in progress.
Safety action
While the investigation suggested recommendations regarding the diligent use of dispatch guides, better use of electronic checklists, and stricter adherence to sterile cockpit policies, the operator has since ceased operations.