Synopsis
On 12 March 2015, a Raytheon 390 Premier I, registration G-OOMC, was conducting a commercial passenger flight from Avignon Airport, France, to Blackpool Airport, Lancashire, United Kingdom. The aircraft sustained a hydraulic system problem shortly before commencing its approach, leading to a total hydraulic system failure that was not recognized by the flight crew. The loss of hydraulic pressure rendered the speedbrake/lift dump system and power brakes unavailable, though the emergency braking system remained operational. During landing, the emergency brakes were not applied, and the aircraft overran the runway at approximately 80 kt, suffering extensive damage. The two crew members and two passengers evacuated without assistance and were uninjured.
History of the Flight
The aircraft departed from Avignon with two pilots and two passengers. The co-pilot performed external checks, including the hydraulic reservoir fluid level. The flight to Blackpool was uneventful until the descent, when the crew noted ATIS information for Runway 10. While descending through FL120, the left and then right hydraulic low pressure cautions illuminated. The hydraulic pressure gauge showed fluctuating pressure, mostly around 2,800 psi within the green arc. The co-pilot actioned the hydraulic pump failure checklist, which allowed continued flight if hydraulic pressure was at least 2,800 psi. Shortly before reaching the Blackpool NDB, roll fail and speed brake fail caution messages appeared. The co-pilot actioned the relevant checklists, which called for a flaps-up landing and an increase in landing distance required (LDR) by 65% (from the roll fail) and 21% (from speed brake fail). The crew used the larger 65% increase, calculating an LDR of 5,950 ft, which was less than the available landing distance of 6,131 ft on Runway 10. They decided to continue the approach.
During final approach, the co-pilot lowered the landing gear on the commander's request. About eight seconds later, the commander stated "just lost it all," referring to the aircraft's general state. A landing gear unsafe warning sounded as the main gear did not indicate down and locked. The commander initiated a go-around by selecting altitude hold and increasing thrust, but before the co-pilot could complete the alternate gear extension checklist, the main gear indicated down and locked. The commander disconnected the autopilot and continued the approach. The crew did not review the hydraulic pump failure checklist, as they had not recognized the symptoms of total hydraulic pressure loss.
ATC cleared the aircraft to land with wind from 140° at 17 kt, giving a headwind component of about 10 kt and a crosswind of about 12 kt. At 500 ft and 1.5 nm from the threshold, the commander instructed the co-pilot to advise ATC of a hydraulic problem and request RFFS standby. The aircraft touched down approximately 1,500 ft from the start of the paved surface at 132 kt airspeed (124 kt groundspeed). The commander applied the toe brakes but felt no significant retardation. The crew did not attempt to use the emergency brakes. The co-pilot tried to operate the lift dump, but it failed due to lack of hydraulic pressure. A MAYDAY call was transmitted. As an overrun became imminent, the commander shut down the engines. The aircraft exited the runway end at about 80 kt groundspeed. The commander later said he was in a "state of panic" and was unsure whether he had applied the emergency brake.
After leaving the paved surface, the commander steered slightly right to avoid a shallow downslope. The aircraft crossed rough, uneven ground; the nose gear collapsed and wing-to-fuselage attachments were severely damaged. Once stopped, the commander shut down remaining systems, and all four occupants evacuated via the entry door and moved upwind to a safe distance. The RFFS arrived shortly thereafter.
Recorded Data
The aircraft was equipped with a 30-minute cockpit voice recorder (CVR), which was successfully replayed. The recording began as the aircraft descended from FL250 at 1118 hrs and ended as it overran the runway at 1148 hrs. Radar data from St Annes, less than 1 nm southeast of Blackpool Airport, provided a complete record of the approach and landing, including Mode S groundspeed and airspeed data.
Aircraft Damage
Runway marks showed the main landing gear inboard doors remained extended throughout the landing, suffering edge abrasion. The aircraft traveled approximately 123 m beyond the runway surface, during which the nose landing gear collapsed and the nosewheel detached. The left wingtip struck the ground, deflecting the aircraft from its path. All four wing-to-fuselage mounting forgings were damaged, three fractured. The wing was displaced to the right, causing extensive root fairing and inboard flap track damage. Examination found evidence of a hydraulic fluid leak within the left engine nacelle, near the hydraulic pump. Hydraulic fluid had congealed on the engine bleed air pipe, surrounding pipes, and at the bottom of the lower panel. The hydraulic reservoir was empty, with only residual fluid in filter housings. The filter blockage indicators had not popped, and the fluid and filters were clean and uncontaminated.
Operational Procedures
The Premier I/IA Airplane Flight Manual (AFM) and Pilot Checklist provided procedures for hydraulic pump failure. The checklist noted that certain component failures could compromise multiple systems, and that different procedures resulting in conflicting configurations should use the most restrictive. Landing distance factors from different failures were additive. The crew applied a 65% increase from the roll fail checklist but did not add the 21% from the speed brake fail, as the source indicates the factors were additive. The failure to recognize total hydraulic loss prevented the crew from applying the emergency brakes, which remained functional.
Conclusion
The investigation determined that a fatigue crack in the port cap of the left hydraulic pump caused a hydraulic leak, leading to total loss of the hydraulic system. The runway's landing distance available was insufficient for the aircraft to stop with a complete hydraulic failure, regardless of the omission to apply the emergency brakes.