What happened
On 12 March 2015, a Raytheon Premier I, registration G-OOMC, was conducting a commercial passenger flight from Avignon, France, to Blackpool Airport. During the descent, the crew observed fluctuating hydraulic pressure and intermittent low-pressure warnings. Following the loss of hydraulic pressure, the aircraft experienced failures in the roll spoiler and speedbrake systems.
As the aircraft approached the runway, the hydraulic pressure dropped completely, which also caused a delay in the landing gear reaching the locked position. Upon touchdown, the pilot found the power brakes to be ineffective. Due to the lack of hydraulic pressure, the lift dump system also failed to operate. The crew did not apply the emergency braking system during the landing roll. Consequently, the aircraft overran the paved surface at approximately 80 kt, resulting in the collapse of the nose gear and significant damage to the wing attachments. There were no fatalities and no injuries to the two crew members or two passengers on board.
The investigation
The AAIB investigation focused on the cause of the hydraulic pressure loss and the crew's decision-making process. Investigators examined the aircraft's hydraulic system and discovered a leak within the left engine nacelle. Laboratory testing of the left hydraulic pump revealed a fatigue crack in the port cap, which had originated from a pitted thread root and propagated to the outer surface of the component.
The investigation also reviewed the crew's use of checklists. While the crew had initially followed the hydraulic pump failure checklist, they did not return to it once the system pressure dropped below the required threshold. This omission meant they were unaware of the necessity to use emergency brakes and the significant increase in required landing distance. Furthermore, the investigation noted that the landing distance available at Blackpool was insufficient for the aircraft's condition, regardless of the braking error.
Findings
- A fatigue crack in the left hydraulic pump's port cap caused a fluid leak that led to the total loss of hydraulic system pressure.
- The crew did not recognize the full extent of the hydraulic failure and failed to complete the necessary checklist items.
- The crew's calculation of the required landing distance was incorrect, and they were unaware that the landing distance would increase by approximately 133%.
- The emergency brakes were not applied during the landing roll.
- The landing distance available at Blackpool was insufficient for the aircraft to land safely with the hydraulic failure.