N36ML

HISTORY OF FLIGHTOn 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 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. PERSONNEL INFORMATIONThe 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. AIRCRAFT INFORMATIONThe 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 1,275.67 hours.

Review of the Raytheon Aircraft Company model B36TC pilot operating handbook, section 2, heading KINDS OF OPERATIONS states in part "…flight in icing conditions prohibited."

Section 3, Emergency Procedures, revealed that under the heading "BLOCKED INDUCTION SYSTEM", a checklist included the following:

"1. Alternate Air T-Handle….PULL AND RELEASE

2. See INDUCTION SYSTEM BLOCKAGE later in this section. "

The heading titled "INDUCTION SYSTEM BLOCKAGE", stated in part "…if the alternate induction air door becomes stuck in the closed position, it can be opened by: ALT AIR PULL & RELEASE T-Handle (lower left sub panel)…….PULL AND RELEASE." The section further states "with the induction air filter completely blocked, the alternate air opening will provide sufficient air to allow the engine to develop maximum continuous power up to approximately 13,000 feet. Above that altitude, the manifold pressure will drop at a rate of approximately 1 inch per 1,000 feet."

Section 7, Systems Description, heading INDUCTION SYSTEM ICING states in part "…the possibility of induction system icing is reduced by the non-icing characteristics of the Bonanza's fuel injected engine and an automatic alternate induction air source. Under certain conditions, however, impact ice can form at several points in the induction system. If the air intake or filter becomes clogged with ice, a spring-loaded door in the air intake duct will open automatically and the induction system will operate on alternate air. If the alternate air source door becomes frozen in the closed position, a pull-and-release T-handle is provided to force the door open. With a completely blocked induction filter, full power can be expected up to approximately 13,000 feet."

The airplane was last refueled at Baker Airport's self-serve pump on November 27, 2013. The amount of fuel was undetermined due to a system recording error. METEOROLOGICAL INFORMATIONA National Transportation Safety Board (NTSB) staff meteorologist prepared a factual report for the area and timeframe surrounding the accident.

The National Weather Service (NWS) regional radar mosaic for 1300 depicted a large area of echoes to the north of the accident site and no significant echoes over the accident site or over the McCall area, which was reporting light rain at the time of the image. The NWS Weather Depiction Chart for 1200 depicted an area of IFR conditions by a shaded contour over the Washington and Oregon coasts, and a separate area of eastern Washington and northern Idaho, surrounded by an area of marginal visual flight rules (MVFR) conditions. A second area of MVFR conditions was depicted extending over eastern Oregon, southern Idaho, and into western Wyoming, which included the accident site. Two small areas of IFR conditions were embedded within the region.

The closest weather reporting facility to the accident site was from McCall Municipal Airport

(MYL), McCall, Idaho, located approximately 27 miles west at an elevation of 5,024 feet and along the immediate route of flight. At 1251, recorded weather conditions were wind from 140 degrees at 11 knots, visibility 9 miles in light rain, ceiling overcast at 2,400 feet above ground level (agl), temperature 2 degrees Celsius (C), dew point 0 degrees C, altimeter 30.04 inches of mercury (Hg), remarks: automated observation system, sea level pressure 1017.9-hPa, hourly precipitation 0.03 inches, temperature 2.2 degrees C, dew point 0 degrees C.

The closest upper air sounding or rawinsonde observation (RAOB) was from the NWS Boise

(BOI), Idaho, located approximately 90 miles south of the accident site at an elevation of 2,867 feet. The 1700 sounding depicted a surface based temperature inversion to 1,500 feet agl with the lifted condensation level (LCL) immediately above at 1,914 feet agl (4,781 feet msl), and a convective condensation level (CCL) 7 at 4,988 feet agl (7,855 feet msl). Th...