History of Flight
On January 6, 2016, at approximately 0835 eastern standard time, a Pilatus PC-12/47E, registration N978AF, collided with a ditch during a precautionary landing after takeoff from Savannah/Hilton Head International Airport (SAV), Savannah, Georgia. The pilot and copilot sustained minor injuries, and the airplane was substantially damaged. The airplane was registered to Upper Deck Holdings, Inc. and operated by PlaneSense, Inc. as a Title 14 Code of Federal Regulations Part 91 positioning flight. Visual meteorological conditions prevailed, and an instrument flight rules flight plan was filed for the flight to Blue Grass Airport (LEX), Lexington, Kentucky.
The pilot in the left seat was the pilot monitoring, and the copilot in the right seat was the pilot flying. The crew had the full length of runway 1 (7,002 ft) available for takeoff. According to the pilots, acceleration and takeoff were normal. After establishing a positive rate of climb, the crew received an auditory annunciation and a red crew alerting system (CAS) torque warning. The engine torque indicated 5.3 pounds per square inch (psi); the nominal torque value for the conditions was reported by the crew to be 43.3 psi. With about 2,700 ft of runway remaining at an altitude of 200 ft msl, the copilot elected to land immediately. The copilot pushed the nose down and executed a 90° left descending turn, subsequently landing in the grass. Although he applied "hard" braking in an attempt to stop, the airplane impacted a drainage ditch, resulting in substantial impact damage and a postimpact fire.
The pilot reported that after takeoff, he observed a low torque CAS message and the copilot told him to "declare an emergency and run the checklist." The pilot confirmed the landing gear were extended, and the copilot turned the airplane left toward open ground between the runways and the terminal. About 60 seconds elapsed from the start of the takeoff roll until the accident.
Airport security cameras captured the event. One camera, pointed west-southwest, recorded the airplane's left descending turn and landing in the grass, followed by impact and smoke. A second camera, mounted on the control tower and pointed southeast, showed the initial climb, level off, descending left turn, and landing before colliding with the ditch.
Personnel Information
Federal Aviation Administration (FAA) records showed the pilot held an airline transport pilot certificate with airplane single- and multi-engine land ratings. His most recent FAA first-class medical certificate was issued November 19, 2015. He reported 23,141 total flight hours, with 534 hours in the accident airplane make and model. In the 90 and 30 days before the accident, he reported 154 and 35 flight hours, respectively. His most recent flight review was completed on September 14, 2015, in the PC-12.
The copilot held an airline transport pilot certificate with airplane single- and multi-engine land ratings, plus instructor ratings for airplane single engine, multi-engine, and instrument. His most recent FAA second-class medical certificate was issued January 16, 2015. He reported 7,900 total flight hours, with 5,100 hours in the accident airplane make and model. In the 90 and 30 days before the accident, he reported 168 and 37 flight hours, respectively. His most recent flight review was completed on September 14, 2015, in the PC-12.
Aircraft Information
According to FAA records, the airplane was a low-wing, T-tail, retractable-gear aircraft powered by a Pratt & Whitney Canada PT6A-67P, 1,200 shaft horsepower turboprop engine equipped with a Hartzell four-bladed, hydraulically actuated, constant-speed propeller. It was issued a normal category airworthiness certificate on December 19, 2008.
Maintenance records indicated the most recent Approved Aircraft Inspection Program (AAIP) inspection was on December 31, 2015, at airframe and engine total time of 4,189 hours, with 3,976 cycles since new.
According to the operator, the estimated takeoff weight was 9,100 lbs, 1,350 lbs below the maximum gross weight of 10,450 lbs. Takeoff distance performance calculations from the pilots operating handbook (POH) indicated a required runway of 2,000 ft to clear a 50-ft obstacle using 15° flaps; the runway was 7,002 ft long. Aircraft condition monitoring system (ACMS) data showed the airplane rotated about 2,100 ft down the runway.
According to the POH, red CAS warning messages required immediate corrective action; amber caution messages required attention but not immediate action. Red messages triggered a continuous chime; amber messages triggered a single chime. The torque and engine temperature gauges were pointer-type with digital values. Normal digital values were white; abnormal conditions turned the digital indicator and pointer red. There were no CAS messages for low torque values; only high torque exceedances activated a CAS caution or warning.
The POH emergency procedures for an engine torque CAS warning or caution directed: (1) Check torque indication. (2) If torque above 44.3 psi, reduce power. If the CAS warning or caution remains: (3) Land as soon as possible, using minimum power, retaining glide capability if possible. "Land as soon as possible" was defined as landing without delay at the nearest airport where a safe approach and landing could be reasonably assured.
Meteorological Information
At 0853, weather at SAV included wind from 020° at 9 knots, visibility 10 statute miles, broken clouds at 4,300 ft, temperature 1°C, dew point -7°C, and an altimeter setting of 30.46 inches of mercury.
Wreckage and Impact Information
The airplane came to rest in a drainage ditch about 2,300 ft west of runway 1 and 1,800 ft south of the main terminal, oriented on a 270° heading. Three distinct landing gear ground tracks about 700 ft long led to the airplane. The airplane sustained substantial airframe damage from impact and fire. The engine compartment was damaged by impact and fire, the cockpit was charred, and the airframe buckled in multiple locations. The cockpit area was nearly separated from the fuselage, and both wings sustained significant structural damage.
Examination of the engine at Pratt & Whitney Canada revealed the compressor section showed no pre-impact anomalies. Apart from thermal and impact damage, no pre-impact anomalies were found in the gearboxes, governor, torque limiter, or fuel control unit (FCU) bellows. Testing of the FCU bellows at Woodward, Inc. showed no anomalies. The modular avionics unit (MAU) data was downloaded; a small amount of debris on a couple of pins inside the custom I/O module could not be sourced, but tests of engine torque signals met specifications with no faults. The torque transducer showed no excessive mechanical damage or bent connections; continuity was confirmed, and testing revealed no anomalies.
Additional Information
The ACMS captured engine trend, cockpit, and flight-specific non-volatile memory files, along with the fault history database (FHDB). Takeoff power applied at about 0834:46 showed torque 10.6 psi, fuel flow 353 lbs/hour, gas generator speed (Ng) 80.2%, and inter turbine temperature (ITT) 603°. About 1,500 ft down the runway at 90 knots, torque was 40.9 psi, fuel flow 713 lbs/hour, Ng 94.5%, ITT 711°. At rotation (0835:03, 93 knots), torque was 44.9 psi, fuel flow 691 lbs/hour, Ng 94.2%, ITT 709°. Six seconds later, during initial climb at 107 knots and 127 ft msl, torque climbed to 71 psi while other parameters remained normal; fault history confirmed engine torque caution and warning were displayed. Four seconds later, torque, fuel flow, Ng, and ITT decreased to 47.3 psi, 683 lbs/hour, 93.6%, and 705°. As the copilot initiated the left descending turn, torque and fuel flow dropped to 6.6 psi and 335 lbs/hour, Ng 80.4%, ITT 607° and decreasing. During final approach for landing on a heading about 260°, torque increased to 18.9 psi, and fuel flow, Ng, and ITT increased simultaneously until touchdown. The recorded parameters did not include flight control positions or power control lever position.