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Page 1 of 11 National Transportation Safety Board Aviation Accident Final Report Location: Yellow Pine, Idaho Accident Number: WPR14FA094 Date & Time: December 1, 2013, 13:03 Local Registration: N36ML Aircraft: Beech B36TC Aircraft Damage: Destroyed Defining Event: Fuel related Injuries: 5 Fatal Flight Conducted Under: Part 91: General aviation - Personal Analysis The instrument-rated pilot was on a 234-nm instrument flight rules (IFR) cross-country flight over mountainous terrain; instrument meteorological conditions prevailed at the time. During the flight, the pilot notified a controller at the Air Route Traffic Control Center (ARTCC) that the airplane was picking up too much ice and requested to divert to an airport located about 96 miles ahead of his position and to descend to 11,000 feet mean sea level (msl). The controller informed the pilot that he could descend to 12,000 feet msl for terrain clearance. Over the following few minutes, the ARTCC controller notified the pilot several times that he had to maintain an altitude of 12,000 feet or above due to terrain clearance, all of which the pilot acknowledged. Following a low-altitude alert issued by the controller, the pilot stated his altitude was 11,500 feet. Subsequently, the pilot advised the controller that he was having engine problems and needed to go to an airport immediately. When the controller asked the pilot to verify his altitude, the pilot responded that he was at 10,000 feet. The controller then asked the pilot if he was able to climb, and the pilot responded "negative." The controller advised the pilot of an airport that was 24 miles behind his position and asked if he wanted to divert. The pilot responded affirmatively and asked for guidance to the airport. About 1 minute later, the pilot advised the controller that the airplane had "just lost its engine." The controller advised the pilot that the airport was at the pilot's six o'clock position and suggested a heading of 253 degrees, adding that another airport was right below their position. There were no further communications with the accident airplane. Wreckage and impact signatures were found consistent with a wings-level, slightly nose-low descent into trees and terrain. Postaccident examination of the airframe and engine revealed no evidence of any preexisting mechanical malfunction that would have precluded normal operation. Airmen's Meteorological Information (AIRMETs) for IFR and mountain obscuration conditions, low- level wind shear and turbulence, and moderate icing were issued for the flight track area and timeframe. In additional to the AIRMETs, multiple pilot reports included reports of light rime-type icing between 8,000 feet and 13,000 feet throughout the region and National Weather Service data was consistent with the pilot reports and AIRMET that were current at the time. The investigation was unable to determine Page 2 of 11 WPR14FA094 whether the pilot obtained weather information regarding his planned flight. It is likely that the loss of engine power was due to a combination of structural and induction icing during the continued flight in icing conditions in an airplane that was not certified for flight in icing conditions. Probable Cause and Findings The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot's continued flight into known light-to-moderate icing conditions over mountainous terrain. Contributing to the accident was the loss of engine power due to induction icing. Findings Personnel issues Decision making/judgment - Pilot Personnel issues Use of equip/system - Pilot Environmental issues Conducive to structural icing - Effect on equipment Aircraft Air intake - Not specified Page 3 of 11 WPR14FA094 Factual Information History of Flight Enroute-cruise Structural icing Enroute-cruise Altitude deviation Enroute-cruise Fuel related (Defining event) Enroute-cruise Loss of engine power (partial) Enroute-cruise Controlled flight into terr/obj (CFIT) On December 1, 2013, about 1303 mountain standard time, a Beech B36TC, N36ML, was destroyed when it impacted terrain while maneuvering near Yellow Pine, Idaho. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. The instrument rated private pilot and his four passengers were fatally injured. Instrument meteorological conditions prevailed and an instrument flight rules (IFR) flight plan was filed for the personal flight. The 234 nautical mile cross-country flight originated from Baker City Municipal Airport (BKE) Baker City, Oregon, about 1222 with an intended destination of Butte, Montana. Information provided from the Federal Aviation Administration (FAA) revealed that the flight departed from BKE under visual flight rules. At 1226, when the aircraft was about 10 miles south of BKE at an altitude of about 6,200 feet, the pilot contacted the FAA Air Route Traffic Control Center (ARTCC) requesting to activate an IFR flight plan to Butte, Montana. At 1230, the controller issued the accident airplane the BKE altimeter and identified the airplane was located about 13 miles south of the BKE VOR. The controller then cleared the flight to Butte as filed and directed the pilot to climb and maintain 13,000 feet. The pilot acknowledged the clearance and altitude. The controller followed with a clearance for the flight to proceed direct to the Donnelly VOR. At 1240, the controller advised the pilot that the McCall Municipal Airport (MYL), McCall, Idaho, altimeter setting was 30.04. The pilot acknowledged about one minute and six seconds later. At 1256, the controller asked the pilot to confirm he was level at 13,000 and established on victor airway 121. The pilot responded with "negative, three six mike lima's picking up too much ice uh we'd like to divert to uh Salmon." Shortly after, the pilot requested to descend to 11,000 feet. The controller advised the pilot to maintain 12,000 feet for terrain clearance. The pilot acknowledged 12,000 feet. At 1257, the controller then asked the pilot if he would like to divert and the pilot subsequently verified that he would like to divert to Salmon. The controller cleared the pilot to Salmon via direct to the Salmon VOR and again instructed the pilot to maintain 12,000 for terrain clearance. The pilot acknowledged with "maintain one two thousand six mike lima." At 1300, the controller asked the pilot to confirm he was still on victor airway 121 and the pilot responded with "establishing victor 121." The controller directed the pilot to turn right 15 degrees to be established on the airway. The pilot acknowledged. The controller then issued the pilot a low altitude alert, instructing him to check his altitude immediately. The controller stated that the minimum IFR altitude was 11,900 and instructed the pilot to climb and maintain 12,000 feet immediately. When asked Page 4 of 11 WPR14FA094 to say altitude, the pilot advised that he was at 11,500 and climbing. The controller reiterated to the pilot that they had to maintain 12,000 feet for terrain. At 1301:04, the pilot advised the controller that he was having engine problems and 15 seconds later advised that he needed to "go to three uniform two immediately." The controller asked the pilot to verify his altitude, which the pilot responded he was at 10,000 feet. The controller then asked the pilot if he was able to climb, and the pilot responded "negative." The controller advised the pilot that MYL was 24 miles behind him and asked if he wanted to divert. The pilot responded affirmatively and asked for guidance. The controller suggested a heading of 253 degrees and reminded the pilot that the minimum IFR altitude was 11,900. At 1302, the pilot reported that "36ML just lost its engine" and asked the controller to "say again heading for six mike lima." The controller advised that MYL was at the pilot's six o'clock position and suggested a heading of 253 degrees, adding that 3U2 was right below their position. The controller stated that he had information for the airport and asked the pilot if he'd like that information. There was an unintelligible response that could not be associated with any specific aircraft. The controller attempted to relay communications via other aircraft in the area and broadcast 3U2 airport information to N36ML in the blind. There were no further communications with N36ML. The FAA subsequently issued an Alert Notification (ALNOT) at 1328. The United States Air Force Rescue Coordination Center (ARCC), Civil Air Patrol, local law enforcement, Idaho Air National Guard, Idaho Department of Aeronautics, and volunteers commenced search and rescue operations throughout the area where radar contact was lost. There were no reported ELT signals within the area of the last radar target. The wreckage was located in snow covered wooded mountainous terrain on January 10, 2014 by a ground search team about 1.5 miles east of the last recorded radar target. Pilot Information Certificate: Private Age: 51 Airplane Rating(s): Single-engine land Seat Occupied: Unknown Other Aircraft Rating(s): None Restraint Used: Unknown Instrument Rating(s): Airplane Second Pilot Present: No Instructor Rating(s): None Toxicology Performed: Yes Medical Certification: Class 2 With waivers/limitations Last FAA Medical Exam: March 27, 2013 Occupational Pilot: No Last Flight Review or Equivalent: Flight Time: (Estimated) 1050 hours (Total, all aircraft) The pilot, age 51, held a private pilot certificate with an airplane single-engine land and instrument airplane ratings. A second-class airman medical certificate was issued to the pilot on March 27, 2013, with the limitation stated "must wear corrective lenses." The pilot reported that he had accumulated a total of 1,050 total flight hours at the time of his most recent medical application. The pilot's logbook was not located. Page 5 of 11 WPR14FA094 Aircraft and Owner/Operator Information Aircraft Make: Beech Registration: N36ML Model/Series: B36TC TC Aircraft Category: Airplane Year of Manufacture: 1983 Amateur Built: No Airworthiness Certificate: Normal Serial Number: EA-375 Landing Gear Type: Retractable - Tricycle Seats: 6 Date/Type of Last Inspection: June 3, 2013 Annual Certified Max Gross Wt.: Time Since Last Inspection: Engines: 1 Reciprocating Airframe Total Time: 1612 Hrs as of last inspection Engine Manufacturer: Continental Motors ELT: Installed, not activated Engine Model/Series: TSIO-520-UB3F Registered Owner: Rated Power: 300 Horsepower Operator: On file Operating Certificate(s) Held: None The six-seat, low-wing, retractable-gear airplane, serial number (S/N) EA-375, was manufactured in 1983. It was powered by a Continental Motors TSIO-520-UB3F, serial number 527486, rated at 300 horsepower. The airplane was also equipped with a McCauley 3A32C406-C adjustable pitch propeller. Review of partial copies of the aircraft logbooks revealed that the most recent annual inspection was completed on June 3, 2013, at a tach time of 1,611.85 hours. The engine was overhauled on March 19, 2010, and subsequently installed on the airframe on April 1, 2010, at a tach time of