NTSB CAROL · Event
Event WPR21LA032
Aircraft involved
Probable cause & findings
The pilot’s failure to maintain the proper descent glide path while on final approach for reasons that could not be determined from available evidence.
Factual narrative
HISTORY OF FLIGHTOn October 30, 2020, about 1905 mountain daylight time (MDT), a Cessna 172M airplane, N124TW, was substantially damaged when it was involved in an accident near Billings, Montana. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 cross-country flight. The pilot departed at 0739 central daylight time earlier in the day from the Dallas, Texas area and had flown four legs under visual flight rules before departing on the accident flight leg about 1652 MDT from Sheridan County Airport, Sheridan, Wyoming. According to air traffic control, the pilot reported windshear and turbulence and had difficulties continuing the flight at night with strong headwinds. The pilot also reported that he was not able to climb to an altitude to safely navigate mountainous terrain and needed to divert to Billings Logan International Airport (BIL), Billings, Montana. The pilot turned right and continued to BIL where he was instructed to land on runway 28R. As the pilot was approaching BIL, he was asked by the tower controller if he would like runway 25 because it was more aligned with the wind, to which the pilot agreed. As the pilot approached the airport, he advised, “I’m having trouble making out the airport from the rest of the flashing lights.” The controller gave the pilot a position report and the pilot reported that he thought he had the airport in sight. The controller advised the pilot to maneuver as necessary and to maintain an altitude of 4,500 ft mean sea level (msl) or higher. After some maneuvering, the pilot reported that he did not have the runway in sight. The controller then requested that he pass over the top of the airport and the pilot replied he had the runway in sight. The pilot reported that he needed to maneuver to lineup with the runway to which the controller issued wind information and cleared the pilot to land on runway 25 with additional instructions not to descend below 4,000 ft msl. As the pilot was lined up for runway 25, the controller advised the pilot the runway elevation was at 3,600 ft msl and that he could descend at any time. The controller also advised the pilot that the runway had Precision Approach Path Indicator (PAPI) lights, to which the pilot reported that he had them in sight. The controller lost sight of the airplane and lost all communication with the pilot. A security video shows the airplane’s navigation lights travel across the top of the screen at nighttime while on the approach to runway 25 at BIL. Near the end of the video, the airplane pitches downward and view of the airplane’s lights stop. Figure 1-Flight data track and accident site location. PERSONNEL INFORMATIONAccording to a family member, the pilot had flown this multi-leg flight numerous times. The airplane and pilot’s logbooks were not obtained during the investigation. METEOROLOGICAL INFORMATIONA surface analysis chart identified a cold front at 1800 MDT located across central Montana. A high pressure system was also located over western Wyoming. The accident site was located east of the cold front on the warm side of the boundary. Three hours later the cold front had moved through the BIL area and was located east of the accident site. The observations from BIL surrounding the accident time indicated VFR conditions with a southwest wind gusting to 27 knots in the hours leading up the accident time, and the wind becoming northwesterly at 1930 MDT and gusting to 42 knots at the surface at 1944 MDT. The observer also noted alto-cumulus standing lenticular (ACSL) clouds in the distance from the south, west, through the northeast prior to the accident. BIL weather observation at 1853 MDT, wind from 250° at 12 knots, visibility 10 miles or greater, few clouds at 9,000 ft above ground level (agl), few clouds at 13,000 ft agl, scattered clouds at 20,000 ft agl, temperature of 14°Celsius (C), dew point temperature of -2°C, and an altimeter setting of 29.60 inches of mercury (inHg). Remarks: automated station with a precipitation discriminator, sea level pressure 1002.2 hPa, temperature 13.9°C, dew point temperature -1.7°C. BIL special weather observation at 1917 MDT, wind from 240° at 14 knots, visibility 10 miles or greater, few clouds at 9,000 ft agl, few clouds at 13,000 ft agl, scattered clouds at 20,000 ft agl, temperature of 14°C, dew point temperature of -2°C, and an altimeter setting of 29.60 inHg. Remarks: automated station with a precipitation discriminator, temperature 13.9°C, dew point temperature -2.2°C. WRECKAGE AND IMPACT INFORMATIONDue to the Covid-19 pandemic, the National Transportation Safety Board did not travel to the accident site. Local law enforcement and the Federal Aviation Administration (FAA), responded to the accident site, and onsite photographic documentation was accomplished. The airplane impacted trees and rolling terrain about 3/4-mile east of BIL, near the approach end of runway 25. The accident site revealed that the airplane collided with a large tree before it impacted the ground. The wings and engine separated from the airplane during the accident sequence. The debris field was about 200 ft long and on a magnetic heading of about 277o. Multiple propeller blade strikes were found on broken branches near the large tree. All major structural components of the airplane were located within the debris field. The postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. ADDITIONAL INFORMATIONAccording to a local news article, on the evening of the accident, at about 1900, a memorial procession involving emergency vehicles and tow trucks for a light display were lined up on Highway 3, located just to the south of BIL. At 1915 the procession was scheduled to move through town. MEDICAL AND PATHOLOGICAL INFORMATIONThe pilot had reported having had coronary artery bypass procedures in 2004 and 2010 to the FAA. He had also reported having hypertension, cataract surgery (bilateral), and vascular surgery. At his last exam, he reported using losartan, amlodipine, aspirin, meloxicam, atorvastatin, and metoprolol to control his diseases. These are not considered impairing. At the time of the accident, the pilot was certified under BasicMed. According to the autopsy performed by the Department of Justice, Forensic Science Division, the cause of death was multiple blunt force injuries and the manner of death was accident. In addition, severe atherosclerotic stenosis (>75%) of left anterior descending coronary artery and moderate (<75%) atherosclerotic stenosis of right coronary artery was identified. A single patient graft to the left marginal artery was identified. The pathologist reported the presence of hypertensive cardiovascular disease based on elevated heart weight (wall thicknesses not described) and on the appearance of the kidneys. Toxicology testing identified losartan, amlodipine, and metoprolol, which are prescription blood pressure medications, in cavity blood and urine; metoprolol is also used to reduce the risk of recurrent heart attack. None of these medications is considered impairing. Zolpidem, a prescription sleep aid, was also identified in cavity blood and urine. Zolpidem carries warnings, including the potential for altered behaviors, agitation, hallucinations and performing complex behaviors. The level identified in the pilot’s specimens was at a level below that thought to cause effects. TESTS AND RESEARCHAn airplane performance study revealed that airspeed and airplane attitude information estimated from automatic dependent surveillance broadcast equipment (ADS-B) and winds aloft data indicate that the airplane impacted a tree and terrain while in a controlled descent and that an aerodynamic stall was not likely a factor. The airplane was operating at altitudes between 7,000 and 11,000 ft msl for most of the 2 hour 6-minute accident flight, and it was night for the last half hour with the airplane largely operating between 4,000 and 9,000 ft msl. It is not known whether the pilot was using supplemental oxygen; however, air traffic control communications indicate that he was having difficulty finding the airport at night. The FAA Airplane Flying Handbook, FAA-H-8083-3B, 2016, recommends using oxygen at night due to a “significant deterioration in night vision” at cabin altitudes as low as 5,000 ft. The handbook goes on to say that “flying over terrain with only a few lights makes the runway recede or appear farther away. With this situation, the tendency is to fly a lower-than-normal approach. If the runway has a city in the distance on higher terrain, the tendency is to fly a lower-than-normal approach.” Figure 11 shows the ADS-B ground track for N124TW and the surrounding terrain on final approach into Billings. The pilot departed on the last leg of a multi-leg cross-country flight during dark night conditions. Air traffic control communications indicate he reported encountering wind shear, turbulence and difficulties continuing the flight at night with strong headwinds. The pilot also reported that he was not able to climb to an altitude to safely navigate mountainous terrain and needed to divert to another airport. During the approach the pilot was unable to identify the runway from other flashing lights that were likely part of a planned memorial procession and light display that was lined up near the airport. The controller gave the pilot a position report and the pilot reported that he thought he had the airport in sight. The controller advised the pilot to maneuver as necessary and to maintain an altitude of 4,500 ft mean sea level (msl) or higher. After some maneuvering the pilot reported that he did not have the runway in sight. The controller then requested that he pass over the top of the airport and the pilot replied he had the runway in sight. During the approach the pilot impacted trees and terrain about 3/4 mile from the runway. The accident site examination revealed that the airplane impacted a large tree and then terrain which was located along the runway centerline. Branches surrounding the large tree revealed propeller strike marks, suggesting an undetermined amount of engine power during the accident sequence. The postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. An airplane performance study revealed that airspeed and airplane attitude information estimated from automatic dependent surveillance-broadcast equipment and winds aloft data indicate that the airplane impacted a tree and terrain while in a controlled descent and that an aerodynamic stall was not likely a factor. The airplane was operating at altitudes between 7,000 and 11,000 ft msl for most of the 2 hour 6-minute accident flight, and it was night for the last 30 minutes with the airplane largely operating between 4,000 and 9,000 ft msl. The pilot’s severe cardiovascular disease placed him at increased risk of an acute cardiac event such as ischemia or arrhythmia that can cause sudden incapacitating symptoms and leave no evidence at autopsy. Whether the pilot was impaired or incapacitated by his cardiac disease or some other medical condition at the time of the accident could not be determined by this investigation. However, whether the cause of the airplane’s behavior was due to an incapacitating medical condition, distraction, wind shear, or some other factor is not known from the available operational information. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12
NTSB Findings
Hierarchical cause / factor breakdown from the FAA bulk avdata database. Each finding tagged C (Cause) or F (Factor).
- — Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Descent/approach/glide path-Not attained/maintained
- — Not determined-Not determined-(general)-(general)-Unknown/Not determined
Verbatim from NTSB's published report. Source file
NTSB_2020_WPR21LA032.txt.
Findings + structured fields enriched from FAA avall.mdb.
Full investigation docket on
data.ntsb.gov ↗.
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Related research
What the literature says.
Academic papers and agency reports matching this event's aircraft type or causal vocabulary (wind shear, stall, turbulence). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
- NASA NTRS 2019 · Conference Paper
Crash Testing and Simulation of a Cessna 172 Aircraft: Pitch Down Impact Onto Soft Soil
During the summer of 2015, NASA Langley Research Center conducted three full-scale crash tests of Cessna 172 (C-172) aircraft at the NASA Langley Landing and Impact Research (LandIR) Facility.
- NASA NTRS 2019 · Technical Memorandum (TM)
Simulating the Impact Response of Three Full-Scale Crash Tests of Cessna 172 Aircraft
During the summer of 2015, a series of three full-scale crash tests were performed at the Landing and Impact Research Facility located at NASA Langley Research Center of Cessna 172 aircraft.
- NASA NTRS 2019 · Contractor Report (CR)
An Examination of Aviation Accidents Associated with Turbulence, Wind Shear and Thunderstorm
The focal point of the study reported here was the definition and examination of turbulence, wind shear and thunderstorm in relation to aviation accidents.
- Embry-Riddle Scholarly Commons 2021 · Journal article (IJAAA)
Comparative Study on the Prediction of Aerodynamic Characteristics of Mini - Unmanned Aerial Vehicle with Turbulence Models
When dealing with CFD simulations the turbulent nature is seen on most of the engineering flows and these flows need to be solved.
- arXiv 2020 · arXiv preprint
Numerical Simulation of Iced Wing Using Separating Shear Layer Fixed Turbulence Models
Aerodynamic prediction of glaze ice accretion on airfoils and wing is studied using the Reynolds-averaged Navier-Stokes method.
- NASA NTRS 2019 · Conference Paper
Optimal recovery from microburst wind shear
The flight path of a twin-jet transport aircraft is optimized in a microburst encounter during approach to landing. The objective is to execute an escape maneuver that maintains safe ground clearance …
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