# NTSB SEA98FA101: Piper PA-46-350P, N9247W, Bigfork, MT, April 11, 1998 - Type: NTSB accident investigation - Classification: Accident · Fatal · Field investigation · Final report - Date: April 11, 1998, 02:21 local (08:21 UTC) - Place: Bigfork, MT - Coordinates: 47.740577, -113.740043 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=47.7406&lon=-113.7400&mi=10 - Phase of flight: [Unknown](https://openairdocs.org/ntsb-phases/990) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 2 fatal - Status: Completed, report December 3, 2004 - Report: Approved by Office Director - NTSB case key (mKey): 42719 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA98FA101 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/42719/pdf - Page: https://openairdocs.org/ntsb/SEA98FA101 ## Probable cause The pilot's failure to maintain terrain clearance for undetermined reasons. Contributing factors were the mountainous terrain, trees, dark night conditions, clouds and pilot fatigue. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with terrain/water, unknown - clearance - not maintained (cause) - terrain condition - mountainous/hilly (contributing factor) - object - tree(s) (contributing factor) - weather condition - clouds (contributing factor) - fatigue, pilot in command (contributing factor) - light condition - dark night (contributing factor) - In flight collision with terrain/water, descent - weather condition - clouds (contributing factor) - light condition - night (contributing factor) - proper altitude - not identified, pilot in command (cause) - fatigue, pilot in command (contributing factor) - terrain condition - mountainous/hilly (contributing factor) ## Analysis The aircraft disappeared from ATC radar immediately after being cleared to descend from 12,000 feet to 10,000 feet. ATC radar data showed the aircraft at 11,900 to 12,000 feet for approximately the last 6 minutes prior to the disappearance, with the last Mode C altitude and discrete transponder code 2402 (at 0221:03) reported as 11,800 feet. The last three returns, 12,000, 11,900, and 11,800, are consistent with the start of a descent from 12,000 feet. Due to construction at the radar antenna site, the area where the aircraft disappeared was blocked from radar coverage. Subsequent attempts by the controller to contact the aircraft were unsuccessful. A 7,000- to 7,500-foot overcast was reported at the destination, along with lower clouds and precipitation. Documentation at the accident site indicated an approximate level flight path from the broken treetops to the area of ground impact into a northwest-facing 60-degree mountain slope at approximately the 5,600-foot level. The wreckage was not located for approximately two months. Post-accident examinations of the aircraft's Bendix/King KEA-130A (United Instruments 5035PB-P57) encoding altimeter revealed needle impressions on the indicator face and pointers consistent with an altitude indication of 12,620 feet. The internal components of the unit were severely damaged and a functional test was not possible. The aircraft was equipped with a copilot's altimeter. Only the faceplate was recovered and examined. One impression on the main faceplate revealed a needle impression by the 100-foot pointer consistent with 560 feet. The position of the 1,000-foot pointer could not be determined. The pilot's 4-day activity history showed that he was returning from a demanding 3-day work assignment, that his recent sleeping schedule was irregular, and that he had been awake about 20 hours at the time of the accident. There was no evidence found of a mechanical failure or malfunction at the time of the accident. ## Factual narrative This report was modified on December 3, 2004. HISTORY OF FLIGHT On April 11, 1998, at 0221 mountain daylight time (MDT), a Piper PA-46-350P Malibu Mirage airplane, N9247W, registered to CMSystems, Inc., of Polson, Montana, and being flown by an airline transport pilot (who held commercial pilot privileges for single-engine land airplanes), disappeared from radar 20 nautical miles east-southeast of Glacier Park International Airport, Kalispell, Montana. Visual meteorological conditions were reported at Glacier Park International at 0156, and an instrument flight rules (IFR) flight plan from Bismarck, North Dakota, to Glacier Park International was in effect. The business flight was operated under 14 CFR 91 and had departed Madison, Wisconsin, at 1945 central daylight time (CDT) on the evening of April 10, making an intermediate fuel stop at Bismarck. The aircraft wreckage was located on June 16, 1998 in the Swan mountain range approximately 10 nautical miles east-northeast of Bigfork, Montana. The aircraft was destroyed, and the pilot and sole passenger were found to have sustained fatal injuries. Federal Aviation Administration personnel reported that at the time of the accident, the radar site located in Lakeside, Kalispell, Montana, was under construction to upgrade the facility from an ARSR-3 system to an ARSR-4 system. Due to this construction at the site, the reception of radar signal was inhibited to the northeast of the facility site. The Salt Lake City ARTCC radar tracked the aircraft, which was assigned a transponder code of 2402. The flight path indicated that the aircraft approached this area of blocked radar coverage from the north at an altitude of 11,900 feet then was dropped as it entered the area of blocked radar coverage at 0221:03. One additional secondary return was noted at 0221:14, with a code of 2002, at 11,800 feet. According to FAA ATC records, the pilot's filed route of flight from Bismarck to Glacier Park International was from Bismarck to the Havre, Montana (HVR), VOR 160 degree radial/34 DME fix, thence direct to Glacier Park International. N9247W was cleared for takeoff from Bismarck at 2358 CDT on April 10, and was cleared to an altitude of 10,000 feet after takeoff. The aircraft was subsequently instructed to climb to 12,000 feet for terrain by Salt Lake City Air Route Traffic Control Center (ARTCC) at 0155 MDT on April 11, approximately 26 minutes prior to loss of contact with the aircraft. Approximately 0213, the pilot was asked by a Salt Lake City ARTCC controller which approach he wanted into Glacier Park International, and the pilot replied that he wanted to plan the VOR approach to Glacier Park International runway 30 "for now." At 0217, the Salt Lake ARTCC controller cleared the aircraft to join the Kalispell VOR 15 DME arc from the east and arc south, and told the pilot to expect the approach in about 10 miles. At 0220:57, Salt Lake ARTCC cleared the pilot to descend from 12,000 to 10,000 feet. The pilot's acknowledgement of the descent clearance at 0221:00 was the last radio transmission received from the accident aircraft. At 0223:41, the Salt Lake ARTCC controller advised N9247W that radar contact was lost and asked which radial from the Kalispell VOR the aircraft was crossing, without response. Subsequent attempts by the Salt Lake ARTCC controller to reestablish contact with the accident aircraft were unsuccessful. The Salt Lake ARTCC radar depicted the aircraft's track during the last 6 minutes of radar contact as being generally westbound directly toward Glacier Park International, approximately on the filed route of flight at 11,900 to 12,000 feet, then turning onto a southbound track at a point approximately 14 nautical miles from the Kalispell VOR/DME. The aircraft then tracked generally southbound toward the Kalispell 093 degree radial/15 DME fix (an initial approach fix for the VOR runway 30 approach), reporting its Mode C altitude as 11,900 feet, for about 8 nautical miles before loss of radar contact. The southbound portion of the aircraft's track was not on the 15 DME arc, but was up to approximately 3 miles inside the arc. The aircraft's average ground speed between the last two air traffic control (ATC) radar plots was computed to be 191 knots (normal cruise true airspeed at 12,000 feet is 190 knots, according to a performance chart in the PA-46-350P pilot's operating handbook.) The aircraft's last radar position, as recorded by Salt Lake ARTCC, was at 0221:03, at the Kalispell 087 degree radial/14 DME fix, at a Mode C-reported altitude of 11,900 feet. According to air traffic control (ATC) communications records furnished by the FAA, there were no reports of difficulty by the pilot to ATC prior to the disappearance, nor did the pilot report canceling IFR. Following the last Salt Lake ARTCC radar contact with the aircraft, a military radar site near Malmstrom Air Force Base (AFB), Great Falls, Montana, recorded a series of 11 primary radar returns in the accident area from 0222:19 to 0226:43. The Malmstrom AFB primary radar returns in this area were recorded in an azimuth sector between 285.3 and 286.6 degrees true from the site, at slant ranges between 107.2 and 109.0 nautical miles. The accident occurred at 48 degrees 6.1 minutes North and 113 degrees 50.9 minutes West. PERSONNEL INFORMATION The accident pilot, who was 48 years old at the time of the accident, was the owner of CMSystems (a company which produced software for the airline and banking industries, and which owned the accident aircraft) and was also the president of Security State Bank and Trust, a Polson, Montana, bank founded by the pilot's grandfather. He was a resident of Aurora, Colorado, and (according to interviews conducted by NTSB human performance investigators) visited Polson for approximately one week each month to conduct bank business. He held an airline transport pilot (ATP) certificate with a date of issue of December 16, 1983. His ATP certificate carried airplane multiengine land and Boeing 727 type ratings, and commercial pilot privileges for single-engine land airplanes. The pilot had also previously held a flight instructor certificate with airplane single engine, airplane multiengine, and airplane instrument ratings. His flight instructor certificate was issued on August 17, 1982, and expired on August 31, 1984. Additionally, the pilot held a ground instructor certificate with advanced and instrument ratings, with a date of issue of October 8, 1975. According to the pilot's wife, the pilot worked as a pilot for Frontier Airlines from 1978 to 1986, and also flew for 2 years for Continental Airlines before beginning his own software development company. The accident pilot's logbooks were not recovered by the NTSB. According to information provided to the NTSB by AIG Aviation, Inc. of Northglenn, Colorado, the pilot's total flight time as of June 24, 1997, was 11,450 hours, including 920 hours in the PA-46, and the pilot had flown 59.2 hours between January 12, 1998, and the accident date. AIG Aviation furnished documentation to the NTSB which indicated that the pilot had satisfactorily completed type-specific flight and ground training on the PA-46-350P through Aviation Sales Inc. of Englewood, Colorado. This training, completed on June 21, 1997, included an FAA biennial flight review and instrument competency check. It could not be established whether or not the pilot met 14 CFR 61.57 recency-of-experience requirements for night or IFR flight at the time of the accident. The pilot held a FAA third-class medical certificate dated June 27, 1997. The pilot's medical certificate carried a restriction requiring the wear of corrective lenses. The passenger, an employee of Security State Bank and Trust who worked on bookkeeping and computer operations, was not a pilot, and was reported by a witness to have been observed to be seated in the back ## Aircraft - Registration: [N9247W](https://openairdocs.org/deregistered/N9247W-2013-06-05), registration cancelled 2013-06-05, S/N 4622168, built 1994 (OpenAirDocs) - Reported make and model: Piper PA-46-350P - Registry model: [Piper PA 46-350P](https://openairdocs.org/model/piper-pa-46-350p) (registry code 7104620) (OpenAirDocs) - Registry engine: [Lycoming TI0-540 series](https://openairdocs.org/engine/lycoming-ti0-540-series) (registry code 41533, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 4622168 - Engines: Lycoming TIO-540-AE2A 350 horsepower reciprocating - Damage: Destroyed - Flight: Business, Part 91 - Registered owner: Cmsystems Inc. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, October 3, 1997 - Departed: BIS, BISMARCK, ND - Destination: FCA, KALISPELL, MT - Flight plan: IFR - Airport: FCA, Glacier Park Intl, runway 30 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; airline transport, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 11,450 total, 920 in this make and model, 60 in the last 90 days ## Weather - Conditions: Night/dark - Wind: calm - Visibility: 9 statute miles - Lowest ceiling: 6,000 ft broken - Temperature: 99 °F, dew point 99 °F - Altimeter: 29.00 inHg - Observed at: FCA, 21 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 19980411015239A](https://openairdocs.org/incident/19980411015239A), Apr 11, 1998: Piper PA46350P, Kalispell, MT, Destroyed, 2 fatal. Disappeared from radar fast of fca in mountain terrain. Became missing. (-23) on April 11, 1998 at 0221 MDT a Piper NA-46-350P malibu N9247W registered to cm… 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.