Accident Summary
On April 3, 2008, at 2014 eastern daylight time, a Cessna 750, N750WM, registered to WM Aviation LLC, departed the right side of runway 13L during landing rollout at John F. Kennedy International Airport (JFK), New York. The positioning flight was conducted under 14 Code of Federal Regulations Part 91 on an instrument flight rules flight plan. Night visual meteorological conditions prevailed. The airplane received substantial damage. The airline transport rated pilot-in-command (PIC) and co-pilot (CP) reported no injuries. The flight departed Orlando International Airport at 1816.
Flight Crew Actions
Runway 13L was 10,000 feet long and 150 feet wide. The PIC stated they were in cruise flight with the CP flying. Air Traffic Control (ATC) was providing a vector for the VOR approach to runway 13L when an amber abnormal indicator light illuminated on the engine indicating and crew alert system (EICAS), indicating low hydraulic fluid on system A. The PIC and CP completed the checklist up to the blow down procedure for the landing gear. The flight crew did not inform ATC of the hydraulic problem. The landing gear was subsequently lowered and the CP landed the airplane. The airplane touched down within the first 1,000 feet of runway 13L. The CP informed the PIC that the brakes were not working. The PIC activated the emergency brakes once, and they appeared to work. The CP applied reverse thrust and the arm extend light illuminated on the right thrust reverser. The airplane started veering to the right and the CP could not maintain directional control. The PIC continued pulling the emergency brake handle as the airplane went off the right side of the runway, sheared off the left main landing gear, and came to a complete stop.
The CP stated that after touchdown, he applied thrust reversers, the airplane yawed slightly right, and the right reverser arm, unlocks, and deploy light illuminated. He took the reversers out of reverse, aligned with the centerline, and applied normal brakes. The brakes were spongy, and he informed the PIC he had no brakes. The PIC deployed emergency brakes; the airplane slowed straight ahead then yawed right. The CP was unable to maintain directional control. The flight crew informed the FAA that after touchdown at about 80 knots, the CP had no nose wheel steering, brakes, or thrust reverse feel. The crew applied emergency air brakes, and the airplane veered off the runway right, collided with a dirt divider, sheared off the left main landing gear, buckled the nose gear, and dug the left wing into sand.
Post-Incident Examination
A Cessna representative examined the airplane and runway under FAA supervision. Examination of the 10,000-foot runway revealed 300 feet of tire marks as the airplane veered right just beyond the high-speed turnoff at taxiway ZA. The left main landing gear (MLG) assembly and actuator separated. The right MLG outboard tire had a flat spot to the cord; the inboard tire had a wear spot. Damage occurred to the nose section and wheel well area, left wing, and center fuselage. The left belly fairings were crushed upward. Fluid streaking was observed from the center belly to the tail and from the left pylon aft along the tail cone. The emergency brake bottle gauge read 1,500 PSI. The nose wheel gear was displaced aft and right; the nose wheel steering (NWS) cable separated. The NWS accumulator gauge read 2,400 PSI. Power on, NWS linkage actuated 15–20 degrees left/right for 4-5 cycles before accumulator bled to 1,300 PSI pre-charge. Right hydraulic reservoir B level was full; left reservoir A level was about 5 percent.
The reservoir was serviced to full; breached lines at the parking brake valve were capped. The auxiliary hydraulic pump (pressurizes only A system) operated twice, about 8 minutes each, with no obvious leaks. The NWS accumulator recharged; linkage actuated again for seven cycles before bleeding to pre-charge. Maximum NWS travel was not attempted due to surrounding damage. A subsequent test on June 4, 2008, found no anomalies in hydraulic quantity, pressure, and warning indication systems.
Review of Orlando Citation Service Center Work Order 6026183 indicated the left hydraulic reservoir was a repaired unit previously removed for low volume indication issues. The vendor reported a low-volume switch out of adjustment. OCSC personnel stated the airplane was placed on jacks; the system was purged of air, serviced to full, and an engine run was normal. No leaks were found. Three possible sources of hydraulic fluid fitting leakages were found post-accident, but it could not be determined if they were loose before or during the incident. None were believed to be the root cause of the in-flight loss. No leaks were found in the area of the recently replaced reservoir. No conclusive evidence pointed to the cause of the in-flight hydraulic leak. The general consensus was the leak could have been related to flight conditions such as cold soaking and in-flight flexing of plumbing.
EICAS and CVR Data
The EICAS download, conducted by the aircraft manufacturer with an FAA inspector, recorded these messages: at 1943, "HYD VOL LOW A"; 1946, "HYD PUMP UNLOAD A"; 1955, "HYD PTU FAIL"; 1959, "HYD VOL LOW A"; 2000, "HYD PTU FAIL"; 2008, "SLATS FAIL"; 2009, "HYD VOL LOW A"; 2009, "HYD PUMP UNLOAD A"; 2010, "HYD PTU FAIL"; at 2014, no takeoff annunciation and speed brakes annunciation indicating on ground; at 2014, "TR auto stow R". According to Cessna, the initial low volume message at 16% reservoir fluid level likely indicated fluid and pressure remained. The pump unload message was from crew action. PTU fail occurred when System B pressure >2200 PSI and System A <1000 PSI, likely from pulling the HYDR B/PTU circuit breaker. The slats fail message was likely from a calculated miscompare, but no slat asymmetry message posted. The crew did not evaluate the auxiliary hydraulic pump to restore pressure, and continued trouble-shooting without following the checklist. The A-side pump was turned on and PTU circuit breaker engaged enabling normal gear extension. The crew did not complete the landing checklist.
The cockpit voice recorder (CVR) was removed and sent to the Safety Board Vehicles Recorders Laboratory. A partial transcript was prepared. The recording began at 18:11:18 during taxi. Review showed no abnormal amber messages until 19:43:00 when HYD Volume Low A illuminated. The crew initiated the HYD VOL LOW-A procedure but did not complete all steps as per the checklist.