History of Flight
On December 22, 2011, at 1725 eastern standard time, a Cessna 441, registration N48BS, was substantially damaged when it impacted terrain near Nashville, Pennsylvania, while approaching York Airport (THV), Thomasville, Pennsylvania. The commercial pilot was fatally injured. Night visual meteorological conditions prevailed. The airplane had been operating on an instrument flight rules (IFR) flight plan from Long Beach Airport - Daugherty Field (LGB), Long Beach, California, to THV; however, the pilot had cancelled the flight plan and was proceeding visually via the airport traffic pattern at the time of the accident. The personal flight was operating under 14 Code of Federal Regulations Part 91.
According to the pilot's wife, he was joining the rest of the immediate family, who had previously arrived via a commercial flight for the Christmas holidays with relatives.
Air traffic control information indicated that the airplane departed LGB about 1105 and climbed to 33,000 feet. About 1522, it climbed to 35,000 feet, and about 1639, it began a descent. At 1707, the pilot cancelled the IFR flight plan with New York Center, and at 1716, he terminated flight following with Harrisburg Approach Control.
Radar data indicated that at 1719, the airplane was about 24 miles west of THV at 1,700 feet. The airplane continued eastbound and entered a 45-degree left downwind for runway 35. The airplane subsequently turned onto a left base, then slightly overshot runway centerline before commencing a right turn and disappearing from radar.
An airport employee stated that the pilot radioed for airport advisories, and about 4 or 5 minutes later, he saw the airplane on the left base leg for runway 35. When the airplane was about midway through the base leg, the pilot transmitted that he had an "engine out." The airplane did not then turn onto the final approach leg, but continued through it, heading east. The pilot then called "base to final," quickly followed by the airplane turning right, to the south, then to the west. The employee saw the angle of bank increase to where the airplane's wings were vertical, then inverted, and saw the airplane then make at least 1½ rolls and descend in a near-vertical descent.
Another witness saw the airplane flying "awfully slow," and subsequently saw it turn to the left. The airplane then nosed over and began to dive and spin, "snap rolling nose down, tail up." The witness also noted that although the sky was dark, it was not yet pitch black.
Measurements of plotted radar positions versus time indicated an approximate ground speed of 112 knots during the downwind leg, slowing to 102 knots at the beginning of the left base leg. During the subsequent right turn, the ground speed slowed to about 75 knots while the airplane maintained altitudes of 1,100 to 1,200 feet.
The airplane was equipped with an Enhanced Ground Proximity Warning System (EGPWS), which records data on non-volatile memory for the 20 seconds prior to a warning and 10 seconds afterwards. The report noted that the event which most likely triggered the EGPWS recording was an "Excessive Rate of Descent Warning." Consistent data prior to the airplane's rapid descent included an uncorrected altitude of about 1,100 feet as the airplane was turning to the right, and a ground speed of about 78 knots through the beginning of the airplane's final descent.
Personnel Information
The pilot, age 38, held a commercial pilot certificate with ratings for airplane single engine land and multiengine land airplane, and instrument airplane. According to the last entry in the pilot's logbook, appearing to have been written during the accident flight, the pilot had flown 1,409 total hours with 951 hours of that being in multi-engine airplanes and 463 turbine hours. Between the pilot's latest insurance application and his logbook, it was estimated that he had flown 502 hours in airplane make and model. The pilot had last completed a flight review on January 28, 2011 in a "Cessna Conquest II." His latest FAA third class medical certificate was dated November 7, 2011. The pilot had a communication device capable of voice calls, texting, email and alarms, among other functions. Emails were sent by the device until 0323 (EST), and an alarm sounded at 0920.
Aircraft Information
The airplane was powered by two Honeywell TPE331-10N-535S turboprop engines, flat-rated at 635 shaft horsepower each. Each engine powered a four-bladed, hydraulically operated constant speed Hartzell propeller with feathering and reverse pitch capability. According to the aircraft logbooks, the latest Phase 2 maintenance inspection was completed on July 1, 2011, at 5,890 airplane hours, and 514 hours since major overhaul of both engines. The hour meter indicated 2,874 hours at the time.
Systems and Controls
According to the airplane's Pilot's Operating Handbook (POH), minimum control speed (Vmca) was 91 KIAS. The POH also included an FAA-approved Flight Manual Supplement for a "441 Vortex Generator Kit"; Vmca remained at 91 KIAS. The supplement noted that 76 KIAS was the maximum-weight stalling airspeed in the landing configuration. The wing flap system allowed settings of UP (0 degrees), T.O. (10 degrees), APPR (20 degrees), and LAND (30 degrees). Outboard flaps extended at a slower rate, with full inboard extension of 30 degrees resulting in 20 degrees outboard. The power lever controlled engine operation in beta and propeller governing modes. Beta mode was for ground operation only. Prior to landing in normal mode, with condition levers in TAKEOFF, CLIMB AND LANDING and power lever at flight idle, engine fuel flow assumed a scheduled value for predictable drag. The Electronic Fuel Computers (EFCs) regulated fuel flow and engine speed; they had a self-monitoring feature that automatically transferred control from normal to manual in case of loss of power lever electrical input, low voltage, or disagreement. The Negative Torque Sensing (NTS) system operated automatically. The propeller governing system was interconnected with the NTS and fuel control system. Feathering was achieved by dumping oil pressure via engine shutdown or positioning the condition lever to EMERG SHUTOFF.
Emergency Procedures
The POH included memory items for engine failure in flight below Vmca: Power lever – retard as required to stop turn; aileron and rudder – as required toward operative engine; pitch attitude – lower nose to accelerate above 91 knots. For engine failure above Vmca: Engine power – adjust as required; inoperative engine – determine; condition lever – EMER SHUT-OFF; firewall shutoff – push to close; landing gear – up; wing flaps – up above 115 KIAS.
Meteorological Information
Weather recorded at 1753 included calm wind, clear skies, visibility 10 statute miles, temperature 7°C, dew point 4°C, and altimeter 30.02 inches Hg. According to U.S. Naval Observatory data, sunset occurred at 1645 and the end of civil twilight at 1716. There was no moon illumination at the time of the accident.
Wreckage and Impact Information
The wreckage was located about 1.56 statute miles from THV runway 35, on open, rolling terrain. There was no wreckage path; ground indentations matched the positions of extended landing gear and the nose and tail, consistent with an almost vertical descent and initial impact heading of about 060° magnetic. The airplane then bounced and came to rest heading about 090° magnetic. The tail section was broken off to the left; the left wing outboard of the left engine was broken forward; the aft portion of the right wing root was pushed into the fuselage; landing gear were fractured upward. The damage was consistent with a right-turning flat spin at initial ground impact. There was no evidence of in-flight or post-flight fire. Flight control continuity was confirmed; the flap handle was in approach and flaps extended approximately 30 degrees. The left engine throttle was near flight idle; the right engine throttle was full forward; effects of impact could not be determined. Both condition levers were in EMERG SHUT-OFF; a witness stated they were pulled to that position after initial responders smelled fuel. About 4 gallons of fuel were drained from the right fuel tank; the left tank quantity could not be determined. The right propeller exhibited no outward signs of significant power at impact; two blades had no damage, two had bending but no chordwise scratching. The right propeller did not appear to have been in feather at impact but had moved toward feather by the following day. The left propeller had significant damage: two blades broken off at the hub, one dangling, one bent opposite rotation. The hour meter indicated 2,955 hours.
Both engines and propellers were examined. The right engine had impact damage but no debris ingestion; no preexisting mechanical anomalies were noted. Fuel was found in the fuel pump filter housing. Witness marks on compressor components indicated rubs. The left engine had impact damage with debris ingestion; no preexisting mechanical anomalies were noted. First stage impeller vanes were bent opposite rotation. Fuel was found in the filter housing. Both propellers were at low pitch, not feathered; the right had little or no rotational energy; the left was rotating at low power. No preexisting anomalies were noted with propellers or governors (right governor could not be functionally tested due to impact damage; left governor functioned normally). The fuel flow indicator showed 475 gallons full and 370 gallons used. Engine manufacturer's estimate indicated sufficient fuel; the fixed base operator stated tanks were topped off. Fuel flow dividers from both engines functioned satisfactorily. The right engine EFC initially indicated an anomaly with the 80 percent speed output, but after reinsertion of a circuit card, all testing was satisfactory. It was unknown whether the anomaly existed prior to the accident. Honeywell personnel stated that had it been present, the engine would have remained at flight idle regardless of power lever position but would not have caused shutdown or speed reduction below the pilot's setting. The left engine EFC had no anomalies. Annunciator panels showed aging but no hot filament stretching. Fuel pumps tested within range.
Medical and Pathological Information
An autopsy determined the cause of death as blunt impact. Toxicological testing revealed no anomalies.
Additional Information
According to FAA Advisory Circular 61-21A, when an engine fails after becoming airborne, the pilot should hold heading with rudder and simultaneously roll into a bank of at least 5 degrees toward the operating engine. In this attitude, the airplane will tend to turn toward the operating engine, but the asymmetrical power from the engine failure will tend to turn the airplane toward the dead engine. The circular also stated that in most light twins, a single-engine approach can be accomplished with a flightpath almost identical to a normal approach.