Aviation Accident Summaries

Aviation Accident Summary SEA95FA175

SWAN LAKE, MT, USA

Aircraft #1

N8014R

BEECH F33A

Analysis

The pilot reported via radio to Cedar City Flight Watch that he was VMC and climbing through 11,400 feet. Flight Watch provided weather information and approximately 1 minute later the pilot responded 'OK, roger that ah understand---.' A recording of this transmission revealed the pilot breathing heavily and forcefully and his rate of speech had slowed noticeably. Radar data at the time of this transmission showed the aircraft peaking in the climb and transitioning into a high rate of descent which continued until ground impact in mountainous terrain. Post-mortem examination revealed severe sclerosis with over 60% occlusion of the right artery and over 90% occlusion of the left anterior descending and circumflex branches. The examination revealed ankle fractures but no hand/wrist/finger fractures. The pilot was 36 years old and his twin brother reported a 'heart issue' 8-10 years earlier.

Factual Information

HISTORY OF FLIGHT On August 7, 1995, at 1534 mountain daylight time, a Beech F33A, N8014R, being flown by an instrument-rated, private pilot, was destroyed when it collided with terrain during an uncontrolled descent following a loss of control while in a climb. The aircraft crashed near Swan Lake, Montana. The pilot and passenger were fatally injured. The aircraft was to have been operated under 14CFR91 as a personal flight, and originated from Cut Bank, Montana, approximately 1440. The meteorological conditions at the accident site were unknown, and a VFR flight plan had been filed. The pilot obtained a weather briefing prior to departing Cut Bank and had been advised that VFR flight was not recommended. A non- correlated radar target squawking 1200 with a mode "C" altitude readout was recorded by the Salt Lake Air Route Traffic Control Center (ARTCC) with the first target placing the aircraft approximately 14 nautical miles south-southeast of the Cut Bank airport climbing through 8,100 feet above mean sea level (msl) at 1448. The target tracked generally west-southwest. The last target was received at 1533:53 and was located approximately one- half mile west of the ground impact site. At 1530:53, the pilot of N8014R contacted Cedar City Automated Flight Service Station (AFSS) Flight Watch and reported "I'm about seventy miles ah east of Mullan at ah I'm VFR I'm climbing ah now above the cloud layer climbing through eleven thousand four hundred and the cloud layer seems to be the tops about ten thousand through here or ten thousand five hundred and ah the ride is pretty calm. There's not much turbulence and ah the visibility ah up here is pretty good. It's better than fifty probably" (refer to ATTACHMENT CT-I). The radar track of the aircraft placed it 87 nautical miles and bearing 050 degrees magnetic from Mullan at 1531. The radio communication from the pilot concluded approximately 1530:30 and was followed by a discussion of the weather by the Cedar City flight watch briefer at 1531:44. The briefing lasted slightly less than one minute and was followed at 1532:30 by the pilot responding "OK, roger that ah understand ----." During this transmission of eight seconds the pilot was heard breathing heavily and forcefully. Approximately this point in time the mode "C" altitude readout from the aircraft showed the aircraft transitioning from a shallow climb to a rapid descent (refer to GRAPH I). A re-recording of the pilot's radio communications was reviewed by the investigator and a marked difference was noted between the 1530:53 transmission and the 1532:30 transmission. His rate of speech had slowed noticeably and he sounded pre-occupied or distracted. No further transmissions were received from the aircraft. PERSONNEL INFORMATION The 36 year old pilot received an FAA third class airman's medical certificate on February 7, 1995. Copies of the submitted paperwork relating to this medical examination revealed that the pilot checked the "NO" block in item 18g on FAA Form 8500-8 which inquires into the medical history of the pilot, i.e., "Have you ever had or have now any of the following? - Heart or vascular trouble." Additionally, the "NO" block in item 19 was checked which inquires into the pilot's medical history, i.e., "Visits to Health Professionals Within (the) Last 3 years" and the associated data blanks (should the "YES" block be checked) were left unfilled. These same findings were noted on the paperwork associated with the previous medical issued December 8, 1992, with the exception of block 19 whereby there was a single reference to the "repair (of a) torn bi-cep tendon (sports injury)." The FAA was unable to provide any historical information prior to the December 1992 examination. The pilot's personal doctor was interviewed and reported that he had not seen the pilot since late high school and was unaware of any coronary conditions. The pilot's twin brother was interviewed telephonically and reported that the pilot was in good shape but slightly overweight. He also reported that approximately 8 to 10 years previous, while at Lake Tahoe, the pilot had some kind of "heart issue" and was told not to drink coffee and to be careful about his cholesterol level. AIRCRAFT INFORMATION No aircraft airframe/engine logs were found at the accident site nor could they be located. The tachometer read 325.6 hours at the accident site and the total aircraft time reported in NTSB Form 6120.4 is based on this tach time. It is not known whether the tach time was equivalent to the aircraft total time. METEOROLOGICAL INFORMATION A weather study was conducted by the Safety Board's Operational Factors Division, Office of Aviation Safety, and a weather factual report was issued (refer to attachment). No significant weather was noted in the vicinity of the accident site at the time of the accident. Additionally, the pilot reported in a radio transmission to Cedar City AFSS at 1531, that he was VFR with cloud tops of 10,000 to 10,500 feet, minimal turbulence and visibility better than 50 miles. WRECKAGE AND IMPACT INFORMATION The crash site was located approximately seven nautical miles northeast of Swan Lake, Montana, within the Flathead National Forest. The latitude and longitude of the site was approximately 47 degrees 57.5 minutes north and 113 degrees 40.75 minutes west, and the elevation was approximately 5,250 feet MSL (refer to CHART I). The terrain at the site was characteristic of moderately sloped, heavily-wooded forest land with the downslope toward the northwest. The aircraft was observed at the ground impact site in an upright attitude with its longitudinal axis oriented along a 045/225 degree magnetic bearing [nose northeast] (refer to photographs 1 through 3). The site was ringed by high conifer trees, none of which displayed any broken branches or scrape marks along their trunks (refer to CHART I). The aircraft was basically intact and all control surfaces remained fully attached with the exception of the outboard half of the left elevator which was partially torn free (refer to photographs 4 and 5). Both wings remained attached at the fuselage, however, the right wing was bent upward from root to tip and displayed an approximate 15 degree upward bend from the chordline near the tiptank (refer to photographs 6 and 7). Fragments of glass characteristic of a small light bulb along with fragments of green glass were found 10 to 15 feet slightly outboard of the right wingtip. The engine was observed to be skewed approximately 40 degrees clockwise from the extended longitudinal axis. The propeller remained attached, however, all three blades were loose within the hub assembly. All three blades displayed extensive leading edge scratches and gouging and one blade displayed a tight tip curl (refer to photographs 8 through 11). Several tree branches were found nearby which displayed sharp (near 45 degree) cut ends. MEDICAL AND PATHOLOGICAL INFORMATION Post mortem examination of the pilot was conducted by R. E. Kellenberger, M.D., on August 8, 1995, at the Columbia Mortuary, Columbia Falls, Montana. The report, which was assigned the identification number A-95-21, stated in part: "MICROSCOPIC" "Sections of coronary artery show severe sclerosis. The right artery shows over 60 percent occlusion. The left anterior descending branch shows over 90 percent occlusion as does the left circumflex branch." "SUMMARY" "(The) autopsy revealed multiple injuries which are considered the immediate cause of death." The pathologist also reported "compound comminuted fractures of both ankles" but reported no arm/wrist/hand/digit injuries or fractures. Toxicological evaluation of samples from the pilot was conducted by the FAA's Toxicology and Accident Research Laboratory. All tests were negative (refer to attached report). ADDITIONAL INFORMATION On-site examination of the wreckage was conducted during the afternoon of August 9, 1995. The wreckage was verbally released to Mr. Ed Stewart, USAIG, immediately following the on-site phase of the investigation, and the wreckage remained at the site. Formal wreckage release was issued August 11, 1995 (refer to NTSB Form 6120.15).

Probable Cause and Findings

the pilot's incapacitation due to a heart attack.

 

Source: NTSB Aviation Accident Database

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