Aviation Accident Summaries

Aviation Accident Summary LAX97FA067

LAKE TAHOE, CA, USA

Aircraft #1

N6056M

Beech V35B

Analysis

The pilot was advised of moderate turbulence below 18,000 feet msl, with a freezing level reported to be 9,300 feet and rime icing expected. En route the pilot changed his destination to Lake Tahoe instead of Truckee. He was requested to hold at the Squaw Valley VOR at 13,000 feet and to expect a clearance into Lake Tahoe. The pilot stated that he was in rime icing and requested 12,000 and, unable to hold at 12,000 feet, requested 11,000 feet. He was given a heading change and requested to maintain 11,000 feet. He then requested a 180-degree turn and later reported that he was now out of the clouds and in the clear, but he had a lot of ice. He then stated 'we're declaring an emergency I'm going down.' ATC provided the pilot with a heading change to which he acknowledged. That was the last communication with the pilot.

Factual Information

HISTORY OF FLIGHT On December 7, 1996, about 1121 hours Pacific standard time, a Beech V-35-B, N6056M, collided with mountainous terrain in the Granite Chief Wilderness Area of the Lake Tahoe National Forest, California. The aircraft was en route from Smith Ranch, California, to Truckee, California. The aircraft was destroyed and the pilot received fatal injuries. Instrument meteorological conditions prevailed for the personal flight and an instrument flight plan was filed. The pilot reported airborne from Smith Ranch at 1030. The Oakland Air Route Traffic Control Center (ARTCC) requested the pilot climb and maintain 13,000 feet msl. The pilot responded at 1109, with a request for the VOR A approach into South Lake Tahoe and requested 11,000 feet msl. The controller advised the pilot to hold at the Squaw Valley VOR at 13,000 feet and expect a clearance into South Lake Tahoe. At 1113, the pilot stated that he was picking up light rime ice. The controller amended the previous altitude and requested the pilot maintain 12,000 feet msl. At 1114, the pilot advised the controller that he was unable to reach 12,000 and requested 11,000 feet. The controller approved 11,000 feet and gave the pilot a 250-degree heading. The pilot acknowledged the heading and the altitude. At 1118, the pilot requested a 180-degree turn and to start the VOR approach. At 1119, the pilot stated "I need a 180 immediately." About 16 seconds later the request was approved. Four seconds later, the pilot reported "out of the clouds now but we're ah got a lot of ice." The controller acknowledged the pilot and asked if he wanted to start the approach now over Squaw Valley at 11,000 feet, or did he want a higher altitude. Seven seconds later, the pilot said "we're declaring an emergency and im going down." Eight seconds later, the controller acknowledged the pilot and provided a heading of 240 degrees. Six seconds later, the pilot acknowledged the heading. That was the last recorded communication with the pilot. At 1123, another pilot in the area reported receiving an emergency locator beacon signal for a short period of time. PERSONNEL INFORMATION The pilot's logbook was not recovered. According to the pilot's last flight physical, he reported a total flight time of 1,450 hours. According to a flight instructor's statement, the pilot complied with the requirements of a biannual flight review on January 11, 1996, and in October 1996, the pilot had taken an instrument currency flight check. AIRCRAFT INFORMATION According to FAA records, the pilot was the registered owner as of October 21, 1996. The aircraft records were not recovered. According to the dealer specification sheet, at the time of sale the aircraft had a total flight time of 2,477 hours, the engine had 625 hours since a major overhaul, and the propeller had 276 hours since overhaul. The annual inspection date was listed as February 1996. A statement obtained from the maintenance shop that performed the annual inspection indicated that the annual inspection was signed off on February 18, 1996, at a total flight time of 2,436.8 hours. WRECKAGE AND IMPACT INFORMATION The crash site was located in the Tahoe National Forest about 6,200 feet msl. The GPS location of the accident site was 39 degrees 12 minutes 00 seconds north by 120 degrees 21 minutes 00 seconds west. According to the FAA radar information, the last radar hit was at 39 degrees 12 minutes 28 seconds by 120 degrees 22 minutes 27 seconds. The accident site was snow covered mountainous terrain with pine trees. During the on-scene examination, it was determined that the first point of contact was with a pine tree measured to be about 100 feet tall. The tree indicated damage about 54 feet up from the tree base. The wreckage path was measured to be about 159 degrees magnetic. The right wing section was located along the wreckage path. Examination of the wing revealed imbedded bark to the leading edge, which severed the wing spars and control cables. Along the wreckage path were the left wing tip, right stabilator, elevator, and trim tab. At 150 feet from the first tree strike were located the inverted engine, fuselage, and empennage. A postcrash fire occurred, burning from the engine compartment aft half way to the empennage. Both of the propeller blades were found broken from the propeller hub and revealed chordwise striations, burnishing, leading edge damage, and blade twisting. Examination of the instrument vacuum pump revealed the vanes were intact, along with the vane block. The postcrash fire destroyed the splined drive coupling. The fire and impact damaged emergency locator beacon (ELT) was located with the ELT antenna buried in the ground. Examination of the ELT battery revealed a replace battery date of November 1996. The ELT battery voltage was measured to be 10.3 volts. METEOROLOGICAL INFORMATION At 0919 on the morning of the accident, the pilot telephoned the Oakland AIFSS to file an IFR flight plan. He obtained a preflight weather briefing for the flight from Marin Smith Ranch, via Skaggs Island VOR and Squaw Valley VOR to Truckee, California. The pilot's preflight weather briefing (Airmet Sierra) forecasted the mountains east of Sacramento to have moderate turbulence below 18,000 feet msl with a freezing level reported to be at 9,300 feet msl, and moderate rime icing expected because of the temperatures. At 1145, the Truckee-Tahoe Airport Automated Weather Observation System (ASOS) was reporting: winds 140 degrees at 10 knots gusting to 22; surface visibility 20 miles; sky condition 3,500 feet scattered, 4,500 feet broken; temperature 43 degrees Fahrenheit; dew point 33 degrees Fahrenheit; altimeter 30.14 inches inHg; and total sky cover was 7/10. At 1147, the South Lake Tahoe Metars weather observation was reporting: wind 210 degrees at 12 knots with gusts to 25 knots; visibility 40 miles; broken clouds at 4,000 feet agl; temperature 45 degrees Fahrenheit; dew point 30 degrees Fahrenheit; altimeter 30.09 inHg; and the sky cover was 5/10. MEDICAL AND PATHOLOGICAL INFORMATION On December 16, 1996, the Placer County Medical Examiner performed an autopsy on the pilot's remains. Due to the intense postcrash fire, limited toxicology samples were available for analysis. The analyses that were performed were negative for alcohol and drugs. ADDITIONAL INFORMATION The Safety Board did not take possession of the aircraft wreckage. The insurance company recovered the wreckage to Plain Parts in Sacramento, California.

Probable Cause and Findings

the pilot's intentional flight into adverse weather and improper in-flight planning and decision making.

 

Source: NTSB Aviation Accident Database

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