N54PV

HISTORY OF FLIGHT

On April 19, 2008, about 1010 Pacific daylight time, a Cessna 510 Citation Mustang, N54PV, sustained substantial damage following the pilot's intentional ground loop maneuver during the landing roll on runway 24 at McClellan-Palomar Airport, Carlsbad, California. California Natural Products was operating the airplane under the provisions of 14 Code of Federal Regulations Part 91. The commercial pilot and three passengers were not injured. The personal flight departed from Lincoln Regional Airport, Lincoln, California, about 0854, with a planned destination of Carlsbad. At the time of the accident, the pilot had canceled his instrument flight rules (IFR) flight plan, and was executing a visual flight rules (VFR) approach to runway 24 in visual meteorological conditions.

The pilot was interviewed by a National Transportation Safety Board investigator both immediately after the accident and the following day with regards to his recollections of events that transpired. He affirmed that he is the president of the company operating the airplane. The pilot reported that on the morning of the accident, he flew the accident airplane from Stockton, California, to Lincoln, which consisted of a 16-minute flight. After landing in Lincoln he picked up passengers. He subsequently departed at 0854, and was cleared to 35,000 feet mean sea level (msl) as requested on his IFR flight plan. The en route cruise was normal as the airplane approached Carlsbad and the pilot began a standard terminal arrival route (STAR). During the initial segment of the STAR the pilot configured the autopilot in vertical speed mode.

The pilot further stated that as the airplane crossed over the Avenal transition [waypoint on the SADDE6 STAR] about 30,000 feet msl, the right [copilot's] Primary Flight Display (PFD) began to flicker. About 5 minutes later, as the airplane continued to descend through 28,000 feet msl, the left PFD flashed an alert indicating that the autopilot had disconnected. The pilot immediately felt the disengagement of the autopilot from the heavy control forces on the control yoke that he had to exert to fly the airplane. He additionally noted that the autopilot activation light was not illuminated, further confirming that the system had disengaged. Shortly thereafter, the pilot discovered that the electric pitch trim [located on the control yoke] was not operational. After establishing that the pitch trim was not functional, he ultimately began using the trim wheel located on the center consol, which operated normally. The pilot noted that following the autopilot failure, the flight director bars overlaid about a 10-degree pitch up attitude despite the descending flight path.

Flying the airplane by physical manipulation (i.e., "by hand"), the pilot continued the STAR and reported to air traffic control (ATC) that he had an autopilot malfunction. As the pilot descended to 5,000 feet msl, the airplane encountered instrument meteorological conditions (IMC). Controllers vectored the pilot to the instrument landing system (ILS) to runway 24. The airplane broke out of the overcast conditions at 2,600 feet msl and the pilot relayed to controllers that he would make a visual approach to the runway. The pilot noted that he was overwhelmed with the electrical failures and fatigued from maneuvering the airplane by hand for such a long duration (which he approximated was around 45 minutes).

The airplane crossed the runway threshold configured with the wing flaps fully extended [30 degrees] and flying about 15 knots faster than the predetermined landing speed, which the pilot had previously calculated as a Vref speed of 87 knots. From looking at the airspeed indicator, he noted that the airplane was fast for landing but thought the runway would be long enough to accommodate the likely delayed touchdown. As the airplane progressed down the runway he approached a small uphill slope that was located around the middle. The airplane approached the apex of the sloping runway and the pilot began to clearly distinguish where the runway surface ended, which was sooner than he had anticipated.

The airplane touched down beyond the midpoint of the 4,897-foot-long runway. The pilot realized that despite his braking attempts and extension of speed brakes, the airplane was going to continue off the runway surface over a small downsloping cliff at the end. He determined that he would not be able to abort the landing due to the airplane's diminished groundspeed and elected to perform a 180-degree course reversal by rapidly turning the control yoke and depressing the left rudder pedal. The airplane ground looped, coming to rest in a dirt area south of the runway; the main landing gear collapsed and the flaps folded under the wings.

The pilot noted that during the event he never attempted to reset the autopilot system. He did not recall hearing an audible autopilot disconnect warning and did not think the airplane had such a function. He could not remember the exact error message when the autopilot disconnected, but thought it may have been "PFD" or "PTF."

A Federal Aviation Administration (FAA) inspector spoke with a controller that was in contact with the pilot during the accident sequence. She observed the airplane approaching runway 24 and noted that it appeared to be quite high in altitude. In a radio transmission she queried, "do you think you can make it," to which the pilot replied "yes." The airplane then touched down on the runway past taxiway A4 and subsequently ground looped.

PERSONNEL INFORMATION

The 57-year-old pilot was certified to operate the accident airplane (Cessna Mustang CE510) in accordance with existing Federal Aviation Regulations (FARs). A review of the FAA Airman and Medical Records database disclosed that the pilot held a commercial pilot certificate, with an airplane single and multiengine land rating; the certificate listed the type rating of CE510 (s). The pilot additionally held an instrument rating. His second-class medical certificate was issued on August 01, 2007, with the limitation that he must have glasses available for near vision.

The pilot's self-reported flight time indicated he had amassed 1,398 hours total flight experience, with 140 hours accumulated in Cessna 510 airplanes. The pilot reported a total of 279 hours of instrument experience and 35 hours of night flight. During the preceding 90 days, 30 days, and 24 hours, the pilot reported that he had flown in the capacity of pilot-in-command approximately 78, 38, and 2 hours, respectively.

A review of flight training records revealed that the pilot completed training for his initial CE510 type rating at Flight Safety Training Centers on September 17, 2007, which held the limitation that he may not act as pilot-in-command until reaching 25 hours of supervised operating experience in the CE510; he accomplished those flight hours following the training with the operator's chief pilot.

AIRCRAFT INFORMATION

The accident airplane was a Cessna Mustang CE510, serial number 510-0028, manufactured in 2007. Its standard airworthiness certificate (normal category) was issued on September 19, 2007. The airplane was certified in accordance with FAR Part 23 airworthiness standards, and could be operated by either single or two pilot crews. A type rating is required to operate the airplane, and a waiver is required to operate the airplane with one pilot.

The aircraft underwent its last periodic inspection on April 14, 2008. At the time of the accident, the airframe and both engines had accumulated 120 hours total time.

As originally provided by Cessna, the airplane was equipped with a Garmin G1000 Integrated Flight Deck with a GFC700 autopilot.

Autopilot and Yaw Damper

The Cessna Citation Mustang's autopilot and yaw damper operate the flight control surface servos to provide automatic flight control. The autopilot controls the aircraft pitch and roll attitudes following commands received from the flight director. Pitch auto-trim provides trim commands to the pitch trim servo to relieve any sustained effort required by the pitch servo. The servo gearboxes are equipped with slip-clutches set to certain values, enabling the servos to be overridden in case of an emergency.

The autopilot pitch axis uses pitch rate to stabilize the aircraft pitch attitude during upsets and flight director maneuvers. Flight director pitch commands are rate and attitude limited, combined with pitch damper control, and sent to the pitch servo motor. The pitch servo measures the output effort (torque) and provides this signal to the pitch trim servo. The pitch trim servo commands the motor to reduce the average pitch servo effort. The autopilot roll axis uses roll rate to stabilize aircraft roll attitude during upsets and flight director maneuvers. The flight director roll commands are rate and attitude limited, combined with roll damper control, and sent to the roll servo motor. The yaw damper uses yaw rate and roll attitude to dampen the aircraft's natural dutch roll response. It also uses lateral acceleration to coordinate turns. Yaw damper operation is independent of autopilot engagement.

The autopilot can be disengaged by the pilot via activation of the Autopilot Disengage (AP DISC) Switch. Additional methods to disengage the autopilot are threefold: depressing the Autopilot (AP) Key on the Automatic Flight Control System (AFCS) Control Unit, activating the Go-Around (GA) switch, or activating the Manual Electric Pitch Trim (MEPT ARM) switch. Positive confirmation of manual autopilot disengagement is indicated by both a five-second visual warning (yellow "AP" flashes) and three-sound audible warning.

Automatic disengagement of the autopilot can occur from the following events transpiring: system failure, invalid sensor data, yaw damper failure, stall warning, inability of system to compute default flight director modes. Following an automatic discon...