# NTSB DEN05FA126: Cessna 425, N425SG, Lone Tree, CO, August 14, 2005 - Type: NTSB accident investigation - Classification: Accident · Fatal · Field investigation · Final report - Date: August 13, 2005, 20:20 local (Aug 14, 2005, 02:20 UTC) - Place: Lone Tree, CO - Coordinates: 39.502223, -104.83583 - Nearby events: https://openairdocs.org/map.md?lat=39.5022&lon=-104.8358&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 4 fatal - Status: Completed, report October 3, 2006 - Report: Approved by Office Director - Parties: Cessna Aircraft Company, Federal Aviation Administration, Pratt & Whitney - NTSB case key (mKey): 62261 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN05FA126 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/62261/pdf - Page: https://openairdocs.org/ntsb/DEN05FA126 ## Probable cause The pilot's failure to properly execute the published instrument approach procedure, which resulted in controlled flight into terrain. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with terrain/water, approach - faf/outer marker to threshold (ifr) - ifr procedure - not followed, pilot in command (cause) - proper glidepath - not maintained, pilot in command (cause) - lack of certification, pilot in command ## Analysis During an ILS approach in night instrument meteorological conditions, the airplane impacted terrain and was destroyed by impact forces and postcrash fire. Prior to departure, the pilot obtained a weather briefing, which reported light rain, mist, and instrument meteorological conditions at the destination airport. After approaching the terminal area, the pilot received radar vectors to intercept the localizer for the Runway 35R ILS approach. The pilot's keying of the microphone and the timing of his speech exhibited decreased coordination during the approach phase of flight. After crossing the outer marker and at altitude of 7,700 feet, the pilot asked the controller what the current ceilings were at the airport, and the controller stated 500 feet. With the airplane at an altitude of 6,800 feet, the controller informed the pilot of a "low altitude alert" warning, at which the pilot responded, "Yeah, I am a bit low here." Approximately 20 seconds later, the pilot stated, "I'm back on glideslope." No further communications were received from the accident airplane. The controller issued another low altitude warning, and the radar target was lost. The accident site was located on a hilly, grass field at an elevation of 6,120 feet approximately 2.6 nautical miles from the runway threshold near the extended centerline of the runway. At 2027, the weather conditions at the airport were reported as wind from 360 degrees at 10 knots, visibility 2 statute miles with decreasing rain, scattered clouds at 500 feet, broken clouds at 1,100 feet, and an overcast ceiling at 2,800 feet. An acquaintance of the pilot, who had flown with him on other occasions, provided limited information about the pilot's proficiency, but stated, "a night ILS in IFR conditions would not be [the pilot's] first choice if he had an option." The pilot's logbooks were not located. The pilot did not hold a valid medical certificate at the time of the accident, and post-accident toxicological test revealed the presence of unreported prescription medications. No anomalies were noted with the airframe and engines. Ground inspection and flight testing of the airport's navigational equipment revealed that the equipment functioned satisfactorily. ## Factual narrative HISTORY OF FLIGHT On August 13, 2005, approximately 2020 mountain daylight time, a Cessna 425 twin-engine turboprop airplane, N425SG, was destroyed when it impacted the terrain near Lone Tree, Colorado, during an instrument approach to the Centennial Airport (APA), near Englewood, Colorado. The private pilot and three passengers were fatally injured. The airplane was registered to SGavit Aviation LLC, Littleton, Colorado, and operated by the pilot. Night instrument meteorological conditions (IMC) prevailed, and an instrument flight rules (IFR) flight plan was filed for the Title 14 Code of Federal Regulations Part 91 personal flight. The cross-country flight departed Sandpoint (SZT), Idaho, at 1627 pacific daylight time. A review of the air traffic control communications and radar data from the Federal Aviation Administration (FAA) revealed that during the en route portion of the flight, a radar target identified as the accident airplane maintained all assigned altitudes and headings. The accident airplane approached APA from the north and west, and the pilot received radar vectors to intercept the localizer course for the Instrument Landing System (ILS) runway 35R approach. At 2016, the controller instructed the pilot to turn left to a heading of 010 degrees to join the localizer for runway 35R, and descend to and maintain 8,500 feet. The pilot asked the controller to repeat the instruction. The controller then instructed the pilot to turn to a heading of 360 degrees, descend and maintain 8,500 feet. The pilot did not respond, and the controller asked if the pilot received the clearance. The pilot responded, "Give me a minute." At 2017, the controller instructed the pilot to descend and maintain 8,000 feet. The pilot acknowledged the instruction, and the controller then cleared the airplane for the ILS runway 35R approach. The pilot read back the clearance, and the controller asked the pilot if he was "starting down on the altitude." The pilot responded affirmatively. The controller then instructed the pilot to contact APA air traffic control tower (ATCT) on frequency 118.9. At 2018:06, with the airplane at an altitude of 8,500 feet and a groundspeed of 170 knots, the pilot reported to APA ATCT that the airplane was at the outer marker (CASSE). The controller then cleared the airplane to land on runway 35R and stated the wind was from 360 degrees at 8 knots. At 2018:47, at an altitude of 7,700 feet and a groundspeed of 190 knots, the pilot asked the controller, "What's the current ceiling...?" The controller responded, "I'm showing a five hundred foot ceiling." At 2019:06, with the airplane at an altitude of 6,800 feet and a ground speed of 170 knots, the controller stated, "And five sierra golf, I am getting low altitude, low altitude alert on you." The pilot responded, "Yeah, I am a bit low here." At 2019:32, at an altitude of 7,200 feet and a ground speed of 150 knots, the pilot stated, "I'm back on glideslope." No further communications were received from the accident airplane. At 2019:56, with the airplane at an altitude of 6,500 feet and a groundspeed of 130 knots, the controller stated, "Twin cessna five sierra golf, check your altitude." At 2020:04, the radar target was lost. At 2020:43, the Denver Approach controller stated to the APA controller, "Everything still okay with five sierra golf, I have low altitude." The APA controller attempted several times to contact the accident airplane with no response. The accident occurred in a hilly grass field at an elevation of 6,120 feet approximately 2.6 nautical miles from the approach end of runway 35R, and near the extended centerline of the runway. Review of the radar data depicting the approach, overlaid on a calculated glideslope and localizer, revealed deviations above and below the glideslope, and left and right of the localizer. PERSONNEL INFORMATION Pilot Information The pilot, age 62, who was seated in the left seat, held a private pilot certificate, issued October 23, 1983, with airplane multi-engine land, airplane single-engine land, rotorcraft helicopter, and instrument airplane ratings. The pilot's most recent third-class medical certificate, dated July 16, 2003, was valid through July 31, 2005. On the medical certificate application form, the pilot estimated his total flight time as 5,000 hours and 40 hours within the previous 6 months. According to an insurance form completed by the pilot in November 2004, he reported 1,423 hours in the accident airplane make and model. The pilot's logbooks were not located. Pilot's Accident History The pilot was involved in three prior accidents, described below. On March 6, 1992, the pilot received minor injuries when an Enstrom F28 helicopter he was flying experience a loss of engine power, and impacted a roadway during the attempted autorotation. The Safety Board determined the probable cause of this accident to be the pilot's premature use of collective during the autorotation. The disconnection and subsequent collapse of the helicopter's induction air line was found to have contributed to the accident. On May 6, 2000, the pilot received serious injuries when a Bell 206 helicopter he was flying impacted a lake while maneuvering at low altitude. The Safety Board determined the probable cause of this accident to be the pilot's failure to maintain control of the helicopter while maneuvering. The high density altitude weather conditions also contributed to the accident. On May 31, 2003, the pilot was not injured when the Cessna 425 airplane he was flying, N425SG, was substantially damaged when it encountered hail and severe turbulence during cruise flight. The Safety Board determined the probable cause of this accident to be the pilot's inadvertent flight into adverse weather conditions. Severe turbulence and hail also contributed to the accident. Pilot's Proficiency Safety Board staff interviewed two pilot acquaintances who had flown previously with the pilot. One acquaintance accompanied the pilot on the May 31, 2003, hail encounter flight, and the second acquaintance had flown with the pilot on other occasions. Both acquaintances voiced concern about the pilot's flying skills, with one stating, "a night ILS in IFR conditions would not be [the pilot's] first choice if he had an option." According to an acquaintance of the pilot, the pilot completed recurrent training in the accident airplane in November 2004. Details of the recurrent training were not determined. Pilot's 72-hour History On August 12, 2005, about 0945, the pilot and three passengers departed from APA and flew to Sandpoint, Idaho, for meetings with business colleagues. On August 12 and 13, 2005, the group met with business colleagues. The colleagues stated that the pilot's behavior during the meetings appeared normal. According to one colleague, the pilot said there were poor weather conditions at APA on the day of the accident. The colleague offered the pilot and his passengers a place to stay for the night, but the pilot said he needed to return to the Denver area. A passenger's spouse stated that the group planned to depart SZT for APA at 1300, but did not depart until approximately 1730. AIRCRAFT INFORMATION The accident airplane, a Cessna 425 (Conquest I), serial number 425-0166, was a low-wing, high performance, semi-monocoque design airplane. The airplane was equipped with two 750-horsepower Pratt & Whitney Canada PT6A-135A turboprop engines (serial numbers PCE-PZ0045 and PCE-PZ0044), and McCauley four-bladed, hydraulically operated, constant-speed, feathering-type propellers. The airplane was issued a standard airworthiness certificate on March 24, 1982. The airplane was registered to Accutronics, Inc. (pilot was president/owner of the company), Littleton, Colorado, December 27, 2000, under the registration N425WL. On June 28, 2001, th ## Aircraft - Registration: [N425SG](https://openairdocs.org/deregistered/N425SG-2017-05-22), registration cancelled 2017-05-22, S/N 425-0166, built 1982 (OpenAirDocs) - Reported make and model: Cessna 425 - Registry model: [Cessna 425](https://openairdocs.org/model/cessna-425) (registry code 2076018) (OpenAirDocs) - Registry engine: [Pratt & Whitney Canada PT6A-60A](https://openairdocs.org/engine/pratt-whitney-canada-pt6a-60a) (registry code 52043, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 425-0166 - Airframe hours: 4003.9 - Engines: Pratt & Whitney Canada PT6A-135A 750 horsepower turbo prop - Damage: Destroyed - Fire: On-Ground - Flight: Personal, Part 91 - Registered owner: SGavit Aviation LLC - Airworthiness certificate: Standard, Normal - Last inspection: Continuous airworthiness, May 1, 2005 - Departed: SZT, Sandpoint, ID - Destination: APA, Englewood, CO - Flight plan: IFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 62; injuries: fatal; private; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; last flight review November 1, 2004; seat: left; toxicology performed; flight hours: 5,000 total, 1,450 in this make and model ## Weather - Conditions: Instrument (IMC), Night - Wind: 10° at 9 knots - Visibility: 2 statute miles - Lowest ceiling: 2,800 ft overcast - Temperature: 54 °F, dew point 54 °F - Altimeter: 30.21 inHg - Observed at: APA, 2 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 20050813020569A](https://openairdocs.org/incident/20050813020569A), Aug 13, 2005: Cessna 425, Denver, CO, Destroyed, 4 fatal. (-23) On aug 13, 2005 at approx. 2020 MDT a Cessna N245 twin engine turboprop airplane, N425SG was destroyed when it impacted the terrain near lone tree, CO,… ## Other investigations on N425SG (1) 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. - [NTSB DEN03LA095](https://openairdocs.org/ntsb/DEN03LA095), May 31, 2003: Cessna 425 (N425SG), Pueblo, CO, substantial damage. Probable cause: the pilot's inadvertent flight into adverse weather conditions. Contributing factors include the encounter with severe turbulence and hail. 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.