N93CN

HISTORY OF FLIGHTOn December 15, 2012, about 1000 Pacific standard time (PST), a Piper PA31T1 Cheyenne, N93CN, was destroyed during an in-flight breakup near Ely, Nevada. The pilot was operating the airplane under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91. The private pilot and passenger sustained fatal injuries. The cross-country personal flight departed from Falcon Field Airport, Mesa, Arizona, at 0818, with a planned destination of the Portland-Troutdale Airport, Portland, Oregon. Visual meteorological conditions prevailed in the area surrounding the accident site and the flight was operating on a Federal Aviation Administration (FAA) instrument flight rules (IFR) flight plan.

Radar data gathered from both the Cedar City, Utah (CDC) and Battle Mountain, Nevada (BAM) radar sites revealed the airplane departed Mesa and continued on a northerly track for about 30 minutes. The airplane then turned to a northwesterly direction (around a bearing of 335-degrees magnetic) and remained at the cruise altitude of 24,000 feet mean sea level (msl), at about 230 knots ground speed. At 0937 the airplane's heading turned to about 320-degrees and continued on that bearing until the last several radar returns. Those last recorded targets showed the airplane during the last approximate 30 seconds, where it began a steep right spiral, descending from cruise altitude to 14,500 feet msl, which was the last recorded altitude. The final radar target was recorded at 1000 and was located 0.35 nautical miles northeast of the accident site.

The audio transcripts of the pilot's communications with Air Traffic Control were provided by the FAA. The pilot's last radio transmission was at 0959:40 at which time the pilot requested that he would "like to leave frequency for a couple of minutes." The air traffic controller responded that he was approved as requested and to report when he was back on frequency. PERSONNEL INFORMATIONA review of the airmen records maintained by the Federal Aviation Administration (FAA) disclosed that the pilot, age 84, held a private pilot certificate and ratings for single-engine and multi-engine land, as well as instrument flight. His most recent third-class medical certificate was issued on October 5, 2012 which contained the limitation that he must wear "corrective lenses and possess glasses for near/intermediate vision."

The pilot's personal flight records were not recovered. On his last application for a medical certificate he reported his total flight time to be 6,336 hours, 51 of which were obtained in the 6 months prior. According to the FAA records, the pilot had been involved in two airplane mishaps previously. AIRCRAFT INFORMATIONThe Piper Cheyenne PA-31T1, serial number (s/n) 31T-8004029, was manufactured in 1980. The airplane was equipped with two Pratt and Whitney PT6-11A engines. A review of the logbooks revealed that the most recent Piper Progressive Inspection, Program Number 1 and 2 Inspections were performed on March 23, 2012 at an airframe total time of 5,725 hours. According to an entry dated August 27, 2012, the left engine, s/n 10514, had amassed a total time of 4,600 hours, of which 505 hours were accumulated since the last overhaul; the right engine, s/n 10204, had amassed a total time of 5,800 hours of which 701 hours were accumulated since the last overhaul.

According to the logbook, the last maintenance performed occurred on October 15, 2012 at an airframe total time of 5,800 hours. At this date the left tip tank nosecone was repaired due to ground damage incurred.

The tachometer at the accident site showed a total time of 5,824.X hours (the last digit could not be determined). The pilot regularly completed a "flight log" that he kept in the airplane where he would record the following parameters (the notations in the parenthesis are the most recent entry): tachometer time when the trend was recorded (5,824.1); the altitude (24,000 feet); outside temperature (-36 degrees Celsius); indicated airspeed (160 kts); torque (900 and 890); interstage turbine temperature, ITT (650 and 675 Celsius); propeller rotation speed, Np (1,900 and 1,910 rpm); gas generator speed, Ng (96.8 and 95.3); fuel flow, FF (214 and 207); oil temperature (65 and 63 degrees Celsius); oil pressure (90 and 95); weight (7,595 pounds).

The airplane was equipped with a King/Bendix KFC250 autopilot which was the originally installed equipment at manufacture. The unit is designed where the pilot could engage the autopilot by depressing the "ON" switch and then selecting the desired mode on the autopilot control head. Once selected, the appropriate light will illuminate on the autopilot annunciator panel. To disengage the autopilot, the pilot could depress the appropriate mode switch a second time, or push the autopilot disengage switch on the control wheel, or turn off the autopilot switch on the control head.

All autopilot servos were also equipped with a clutch mechanism which allows the pilot to physically override the servo at any time. METEOROLOGICAL INFORMATIONA staff meteorologist with the National Transportation Safety Board (NTSB) conducted a study of the observed and forecast meteorological conditions for the time and location of the accident site area. The complete study is contained in the public docket for this accident.

The National Weather Service (NWS) Surface Analysis Chart for the time of the accident depicted station models in the region of the accident site which indicated light or calm winds with variable directions. Temperatures were generally in the low 30 degrees Fahrenheit (F). A regional Next-Generation Radar (NEXRAD) mosaic did not identify any pertinent areas of reflectivity close to the accident location.

Ely Airport, Ely, Nevada, was located approximately 18 miles northwest of the accident site at an elevation of 6,659 feet. It was the closest official observation station with a ceilometer. Automated reports were issued from the station during the period surrounding the accident time. At 0953, it recorded the wind was from 160 degrees at 5 kts; temperature of 23 degrees F and a dew point of 19 degrees F; clear sky below 12,000 feet agl; and altimeter 29.85 inHg.

A North American Mesoscale (NAM) model for the accident location was retrieved from the National Oceanic and Atmospheric Administration's ( NOAA) Air Resources Laboratory. The wind profile indicated the wind remained below 10 kts from varying directions below about 26,000 feet. Calculations made by the Rawindsonde Observation Program (RAOB) did not identify any significant icing or turbulence potential above about 12,000 feet agl. A publically disseminated pilot report was made within 100 miles of the accident site at 1153 a pilot at 40,000 feet reported wind from 240 degrees at 40 kts and no turbulence.

A review of the Satellite Imagery Geostationary Operational Environmental Satellite (GOES) and infrared data disclosed that there were clouds in the region; however, these clouds were difficult to discriminate from snow covered-terrain below. A loop of the visible imagery indicated that there were partly cloudy skies throughout the region with clouds moving through the immediate vicinity of the accident site. GOES-13 infrared data indicated coldest cloud-top brightness temperatures near the accident site were approximately -28 degrees F, which, when considering the NAM model sounding, corresponded to cloud-top heights of about 16,000 feet.

An Area Forecast that included Utah was issued at 0345 PST. The portion of the Area Forecast directed toward northeastern and east-central Nevada forecasted a cloud ceiling broken between 7,000 and 9,000 feet msl, overcast cloud bases at 12,000 feet msl, clouds tops to 18,000 feet msl, widely scattered light snow showers. AIRPORT INFORMATIONThe Piper Cheyenne PA-31T1, serial number (s/n) 31T-8004029, was manufactured in 1980. The airplane was equipped with two Pratt and Whitney PT6-11A engines. A review of the logbooks revealed that the most recent Piper Progressive Inspection, Program Number 1 and 2 Inspections were performed on March 23, 2012 at an airframe total time of 5,725 hours. According to an entry dated August 27, 2012, the left engine, s/n 10514, had amassed a total time of 4,600 hours, of which 505 hours were accumulated since the last overhaul; the right engine, s/n 10204, had amassed a total time of 5,800 hours of which 701 hours were accumulated since the last overhaul.

According to the logbook, the last maintenance performed occurred on October 15, 2012 at an airframe total time of 5,800 hours. At this date the left tip tank nosecone was repaired due to ground damage incurred.

The tachometer at the accident site showed a total time of 5,824.X hours (the last digit could not be determined). The pilot regularly completed a "flight log" that he kept in the airplane where he would record the following parameters (the notations in the parenthesis are the most recent entry): tachometer time when the trend was recorded (5,824.1); the altitude (24,000 feet); outside temperature (-36 degrees Celsius); indicated airspeed (160 kts); torque (900 and 890); interstage turbine temperature, ITT (650 and 675 Celsius); propeller rotation speed, Np (1,900 and 1,910 rpm); gas generator speed, Ng (96.8 and 95.3); fuel flow, FF (214 and 207); oil temperature (65 and 63 degrees Celsius); oil pressure (90 and 95); weight (7,595 pounds).

The airplane was equipped with a King/Bendix KFC250 autopilot which was the originally installed equipment at manufacture. The unit is designed where the pilot could engage the autopilot by depressing the "ON" switch and then selecting the desired mode on the autopilot control head. Once selected, the appropriate light will illuminate on the autopilot annunciator panel. To disengage the autopilot, the pilot could depress the appropriate mode switch a second time, or push the autopilot disengage switch on the control wheel, or turn ...