BIGFORK, MT, USA
N9247W
Piper PA-46-350P
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.
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 of the airplane when it departed Bismarck. AIRCRAFT INFORMATION The accident aircraft, a Piper PA-46-350P Malibu Mirage (serial number 4622168), was issued a standard airworthiness certificate on August 25, 1994. The aircraft's last annual inspection was on October 3, 1997, at 691.5 hours tachometer time. The last entry in the airframe logbook, indicating compliance with Piper Service Bulletin 1014 and dated March 25, 1998, indicated that the aircraft's hour meter read 781.1 hours at that time. According to the Piper equipment list for the aircraft, at the time of delivery the aircraft was equipped with autopilot/flight director, area navigation (RNAV), pilot's horizontal situation indicator (HSI), copilot's pitot/static system (per Piper drawing 82233-7) and flight instruments, radar, Bendix/King KLN 90A global positioning system (GPS), Bendix/King KAS 297B altitude selector, and dual vacuum pumps. (NOTE: The KLN 90A GPS is FAA-approved as class A2 GPS equipment under FAA Technical Standard Order [TSO] C129a. According to TSO C129a, class A2 equipment provides IFR en route and terminal navigation capability, but is not FAA-approved for use on instrument approaches.) The aircraft was also equipped for flight into known icing conditions. The aircraft logbook further indicated that the aircraft had been modified on September 21, 1994, by installation of an Eventide model Argus 5000 moving map display, and on February 3, 1996, by installation of a Terra TRA-3000/Tri-40 radar altimeter system. The aircraft log indicated that both of these installations were performed by Denver Avionics, Inc. of Denver, Colorado, per FAA field approvals. According to information obtained from the manufacturers of the units, the TRA-3000/Tri-40 radar altimeter system provides altitude above ground level (AGL) information from 40 to 2,500 feet AGL, and the Argus 5000 moving map display installed in the accident aircraft (part number 5000-10-15, serial number 003353) did not have the capability to display aircraft altitude. According to Piper's equipment list for the aircraft, the aircraft was delivered with a Bendix/King KEA-130A encoding altimeter (Honeywell [formerly AlliedSignal] part number 066-03064-0005, serial number 3661), an optional installation which replaced the standard encoding altimeter for use with the KAS 297B altitude selector. This altimeter was supplied to the manufacturer, Honeywell, by United Instruments of Wichita, Kansas, and was sold by Honeywell under the Bendix/King name. United Instruments manufactures the altimeter as a model 5035PB-P57; the United Instruments serial number on the altimeter installed in the accident aircraft was 25981. According to information supplied by Honeywell, the KEA-130A altimeter installed in the accident aircraft was manufactured in October 1993. The aircraft log indicated that the second altimeter installed in the accident aircraft was a part number "5934PAD-3" (the manufacturer was not given.) According to the aircraft log, and job records furnished by Denver Avionics (Job Order #20459, dated September 5, 1996), the aircraft's altimeters were noted to be out of tolerance specifications during the aircraft's last altimeter and pitot/static system check. A -50 foot adjustment was made to the encoding altimeter, and a -40 foot adjustment made to the second altimeter, to bring them within tolerance specifications. Both altimeters were subsequently tested and certified to 30,000 feet, on September 5, 1996. The aircraft static system was tested and certified to 30,000 feet on September 6, 1996. Engineering drawings supplied by The New Piper Aircraft indicated that on the accident aircraft, the pitot/static system was constructed such that the pilot's airspeed indicator and the pilot's altimeter were supplied with static air from separate static lines, both of which "T" off of the static air line to the copilot's instruments. A diagram of the aircraft pitot/static system from the PA-46-350P Pilot's Operating Handbook (POH) is attached to this report. According to information supplied by Honeywell, the KEA-130A encoding altimeter furnishes altitude and barometric correction information to the KAS 297B altitude selector, and also supplies the KLN 90A GPS with "gray code" altitude information. METEOROLOGICAL INFORMATION Information supplied to the FAA by GTE Government Systems of Chantilly, Virginia, indicated that the pilot of N9247W received a computer preflight weather briefing via the GTE Direct User Terminal Access System (DUATS) approximately 1649 Central daylight time on April 10, 1998. Records of the briefing indicated that the pilot was furnished with AIRMET Sierra Update 4, issued at 1345 MDT on April 10 and valid until 2000 MDT on April 10, during that briefing. AIRMET Sierra Update 4 advised that mountains in western Montana would occasionally be obscured in clouds and precipitation, and that these conditions would continue beyond 2000 MDT through 0200 MDT on April 11. The area forecast for the western third of Montana valid until 0200 MDT on April 10, given in the DUATS briefing, was for scattered to broken clouds at 9,000 to 10,000 feet, broken clouds at 14,000 feet, cloud tops at flight level 180, and widely scattered rain showers. The area forecast gave an outlook of visual flight rules conditions for the time period from 0200 MDT to 0800 MDT. Cloud cover and visibility information in the Terminal Aerodrome Forecast (TAF) for Glacier Park International for the time period 0200 MDT to 0800 MDT, as given in the DUATS briefing, was: prevailing visibility 6 statute miles; scattered clouds at 2,000 feet; ceiling 4,500 feet overcast; with 40% probability during that time period of 4 statute miles visibility in light rain and snow showers and ceiling 1,500 feet broken. An updated AIRMET meteorological advisory issued at 0145 MDT on April 11 (approximately 36 minutes before contact was lost with N9247W), AIRMET Sierra Update 1, advised that mountains in western Montana would occasionally be obscured in clouds and precipitation during the time frame in which contact with N9247W was lost. The 0156 automated METAR observation at Glacier Park International Airport (approximately 21 nautical miles west-northwest of the accident site; elevation 2,972 feet above sea level) reported wind from 010 degrees at 3 knots; visibility 10 statute miles; light rain; few clouds at 300 feet; scattered clouds at 3,400 feet; ceiling 7,000 feet overcast; temperature 4 degrees C; dewpoint 3 degrees C; altimeter setting 29.72 inches Hg; and that rain began at 2 minutes past the hour. The 0256 automated Glacier Park International Airport METAR observation reported calm winds; visibility 9 statute miles; ceiling 6,000 feet broken; overcast at 7,500 feet; temperature and dewpoint 3 degrees; altimeter setting 29.68 inches Hg; rain ended at 0159; and pressure falling rapidly. Astronomical data calculation indicated 100% moon illumination (a full moon) at the latitude and longitude of the accident site at the time contact with the aircraft was lost. Local officials reported that the mountains in which the crash occurred were covered with snow at the time of the disappearance. AIDS TO NAVIGATION The FAA conducted a special flight inspection of the Kalispell VOR/DME facility on July 27, 1998, with satisfactory results. Segments checked during this flight inspection included the 15 nautical mile (NM) arc from the 093 degree radial clockwise to the 145 degree radial, the 148 degree radial of the VOR from 12.0 NM inbound to the VOR, and the 316 degree radial of the VOR from the VOR out to 8.0 NM. AERODROME AND GROUND FACILITIES The Kalispell runway 30 VOR approach incorporates an initial approach fix (IAF) at the Kalispell VOR/DME 093 degree radial/15-mile distance measuring equipment (DME) fix. The approach procedure specifies that from this IAF, the Kalispell 15-DME arc is flown to the southwest at an altitude of 8,600 feet to the Kalispell 148 degree radial. A right turn to an inbound course of 328 degrees is then made to the VOR/DME, which is the final approach fix (FAF). Once established on the 148 degree radial inbound, a descent to a stepdown altitude of 7,500 feet is made; this altitude is maintained until 10 miles from the VOR/DME, at whi
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.
Source: NTSB Aviation Accident Database
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