# NTSB SEA06LA029: Piper PA-28-181, N4350F, Butte, MT, December 17, 2005 - Type: NTSB accident investigation - Classification: Accident · Fatal · Limited investigation · Final report - Date: December 16, 2005, 17:50 local (Dec 17, 2005, 00:50 UTC) - Place: Butte, MT - Coordinates: 45.849166, -112.450553 - Nearby events: https://openairdocs.org/map.md?lat=45.8492&lon=-112.4506&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 1 fatal - Status: Completed, report August 29, 2006 - Report: Approved by Office Director - Parties: Helena FSDO - NTSB case key (mKey): 62958 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA06LA029 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/62958/pdf - Page: https://openairdocs.org/ntsb/SEA06LA029 ## Probable cause The pilot's failure to maintain clearance from the terrain during low-level maneuvering at night. Factors included the pilot’s improper in-flight decision to continue into an area that was forecasted to possibly contain snow, fog, and low ceilings. Additional factors included his failure to obtain a weather update while en route, a dark night, mountainous terrain, trees, snow showers, fog, and the pilot’s inadvertent flight into instrument flight rules conditions while on a visual flight rules flight. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight encounter with weather, maneuvering - in-flight planning/decision - improper, pilot in command (contributing factor) - light condition - dark night (contributing factor) - weather condition - snow (contributing factor) - vfr flight into imc - inadvertent, pilot in command (contributing factor) - weather condition - low ceiling (contributing factor) - in-flight briefing service - not obtained, pilot in command (contributing factor) - weather condition - fog (contributing factor) - In flight collision with object, maneuvering - object - tree(s) (contributing factor) - clearance - not maintained, pilot in command (cause) - terrain condition - mountainous/hilly (contributing factor) ## Analysis When the pilot, who was not instrument rated, departed his point of origin, the area forecast for his destination was indicating the possibility of marginal VFR and locally IFR conditions due to fog, snow showers, and low clouds. He did not make use of FAA weather updating services while en route, and when he arrived in the area near his destination, it was already dark, and the weather at the airport had deteriorated to one-half mile visibility, freezing fog, moderate snow, and a ceiling of 800 feet broken. As he maneuvered toward the airport through mountainous/hilly terrain, he inadvertently entered IFR conditions, and then reversed course in order to return to VFR conditions. During his attempt to maneuver through the area of a mountain pass, the aircraft collided with trees on a steep snow-covered slope. ## Factual narrative On December 16, 2005, approximately 1750 mountain standard time, a Piper PA-28-181, N4350F, impacted trees in mountainous terrain about eight miles southeast of Bert Mooney Airport, Butte, Montana. The private pilot, who was the sole occupant, received fatal injuries, and the aircraft, which was owned and operated by the pilot, was destroyed. The 14 CFR Part 91 personal pleasure flight, which departed Miles City, Montana, about three hours prior to the accident, was en route to Bert Mooney Airport. No flight plan had been filed. The ELT, which was activated by the accident sequence, aided in the location of the accident site. On the day of the accident, the pilot departed Miles City around 1500 in order to fly to Butte, where he was going to meet a friend that he was going to go hunting with. According to his wife, he had earlier checked the weather through the Meteorlogix on-line aviation weather service, and he also had topped off the fuel tanks of his aircraft. After departure, he climbed to about 10,000 feet, and then by use of his cell phone, he contacted the individual in Butte that he was going to go hunting with. The pilot told this individual what altitude he was at, and said that he was above the clouds. He then asked if it was snowing in Butte at that time, and the hunting partner told him that it was not snowing, and that the sky was partly cloudy with areas of blue. The pilot then stated that he hoped to arrive there in about two and one-half hours, and then that was the end of the conversation. About the same time, the pilot used his cell phone to call Butte Aviation at Bert Mooney Airport. He had contacted Butte Aviation earlier in the week to advise them that he would be coming to Butte on that Friday, and that he would need a hanger for one or two nights. During the subject in-flight call, he advised Butte Aviation that he was on his way, and that he would arrive around 1800. There were no other known contacts with the pilot after those two phone calls. He did not contact the FAA Air Route Traffic Control Center for flight-following, nor did he contact Flight Watch for updated weather at Butte. About 1740, an airline transport pilot, who was standing outside of his home, which is located just west of Pipestone Pass (about four miles west of the accident site), heard a single-engine aircraft flying at what sounded to him like a low altitude at a point south of his location. Although he initially could not see the aircraft, it sounded like it was getting closer to his location, so he continued to follow the sound as it grew louder. Eventually he saw an aircraft come out of a snow squall and fly past his location. The aircraft, which had its landing light on, continued to the north for a short period of time (toward the airport), and then reversed its course and headed back in the direction it had come from. It eventually went out of sight, but he could still here its engine for a period of time, and the last thing the witness heard was a sudden and significant increase in the engine's rpm/power. Soon thereafter, an ELT signal was detected by satellite, and it was eventually determined to be coming from N4350F, which had impacted a number of trees on a snow-covered steep slope in the mountainous terrain near Pipestone Pass. According to this witness, at the time he saw the aircraft, it was already dark, and there were low clouds and snow falling in the area. He estimated that the visibility was about one-half mile, and he said that the aircraft was going in and out of the snow squalls. The witness further reported that the aircraft's engine sounded normal, and appeared to be running smoothly. He said that he did not see or hear anything that made him think that the aircraft or its engine were malfunctioning in any way. The individual who was going to go hunting with the pilot said that he left his house around 1700, about 50 minutes prior to the accident, in order to drive to the airport. He stated that when he left his house, which is located within a couple of miles of the accident site, there were only a few snowflakes falling, but that by the time he got to Nine Mile (about four miles from the airport), the snow was heavy, and the visibility was reduced to 500 feet or less. The 1753 surface aviation weather observation (METAR) at Butte showed winds from 090 degrees at three knots, visibility of one-half mile, moderate snow, freezing fog, a ceiling of 800 feet broken, overcast at 1,700 feet, a temperature/dew point spread of -10/-12 degrees Celsius, and a barometric pressure of 29.88 inches of Mercury. A review of the METAR's at Livingston, Montana, and Bozeman, Montana, the last two airports the pilot would have flown near en route to Butte, showed that it had been snowing at Bozeman since about 1600, and the snow at Livingston had been falling since 1430, which was prior to the pilot's departure from Miles City. It was also noted that the visibility at Livingston had been at two and one-half miles or less since about 1430. The visibility at Bozeman dropped below two miles about 1640. The National Weather Service Area Forecast in effect for at the time the pilot departed Miles City indicated that the area air mass was remaining very moist in the lower levels, and due to light surface winds, patchy fog would form and persist that evening. It further stated that Marginal Visual Flight Rules (MVFR) conditions would prevail through the area, with areas of local Instrument Flight Rules (IFR) conditions due to low clouds, fog, and light snow. It further stated that up to one inch of snow could accumulate in the mountains as the precipitation moved through. An autopsy preformed by the State of Montana, Department of Justice, Forensic Science Division determined that the manner of the pilot's death was by accident, and that the cause of death was blunt force injuries. The forensic toxicology performed by the Federal Aviation Administration's Forensic Toxicology Research Team, was negative for carbon monoxide, cyanide, ethanol, and listed drugs. ## Aircraft - Registration: [N4350F](https://openairdocs.org/deregistered/N4350F-2013-07-15), registration cancelled 2013-07-15, S/N 28-7790020, built 1976 (OpenAirDocs) - Reported make and model: Piper PA-28-181 - Registry model: [Piper PA-28-181](https://openairdocs.org/model/piper-pa-28-181) (registry code 7102807) (OpenAirDocs) - Category: Airplane - Serial number: 7790020 - Airframe hours: 4950 - Engines: Lycoming O-360-A4M 180 horsepower reciprocating - Damage: Destroyed - Flight: Personal, Part 91 - Operator: Mark N. Irion - Registered owner: RBT Inc. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, October 1, 2005 - Departed: KMLS, Miles City, MT - Destination: KBTM, Butte, MT - Airport: KBTM, Bert Mooney ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 50; injuries: fatal; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review November 1, 2005; seat: left; toxicology performed; flight hours: 258 total, 258 in this make and model, 211 as pilot in command, 7 in the last 90 days, 5 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Instrument (IMC), Night/dark - Wind: 90° at 3 knots - Visibility: 0.5 statute miles - Lowest ceiling: 800 ft overcast - Temperature: 14 °F, dew point 10 °F - Altimeter: 29.87 inHg - Observed at: KBTM, 8 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20051216029729A](https://openairdocs.org/incident/20051216029729A), Dec 16, 2005: Piper PA28181, Butte, MT, Destroyed, 1 fatal. (-23) Aircraft left miles city, Montana, on December 16, 2005. A flight plan was not filed. A witness saw the aircraft at approximately 1740 local. The witness… From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.