History of Flight
On May 11, 2022, at approximately 1235 mountain daylight time, a Cessna 172N airplane, registered N73670, was destroyed in an accident near Broomfield, Colorado. The pilot, who was working toward a commercial pilot certificate under a Part 141 approved course, sustained fatal injuries. The flight was conducted as a personal flight under 14 CFR Part 91.
Data from automatic dependent surveillance-broadcast (ADS-B) showed that the airplane departed from Rocky Mountain Metro Airport (BJC) in Broomfield and flew to the Colorado Air and Space Airport (CFO) in Watkins, Colorado, where it entered the traffic pattern, performed a landing, and then departed to the southeast. The pilot conducted maneuvers south of Bennett, Colorado, before proceeding west back to BJC. After a touch-and-go landing on runway 12R at BJC, the pilot remained in the traffic pattern.
The air traffic controller instructed the pilot to widen the downwind leg for runway 12R due to traffic on runway 12L, then changed the landing clearance to runway 12L. As the pilot turned onto the base leg and established on final for runway 12L, the airplane turned abruptly to the north and descended rapidly. It struck an intersection about half a nautical mile northwest of the approach end of runway 12L, impacting the ground and a traffic light pole before coming to rest on a sidewalk. A postimpact fire ensued, destroying the airplane.
Two witnesses, a designated airworthiness representative (DAR) and an FAA aircraft certification specialist with a background as an aerospace engineer and pilot, observed the accident from a nearby golf course. They reported that the airplane was not in an aerodynamic stall or spin. The DAR noted that the airplane appeared to be in a gentle left-hand turn with about 15–20° of bank and a descent. No flight control movements, smoke, or fire were observed, and the engine sounded normal. The airplane remained structurally intact during flight. Security camera footage confirmed the airplane's abrupt turn to the north and rapid descent.
Pilot Information
The pilot was a student at Western Air Flight Academy, based at BJC, and began commercial pilot training on January 11, 2022. His logbook, partially damaged by fire, indicated he had received a pilot-in-command endorsement for a high-performance airplane on January 5, 2022, and had completed 5 hours of ground instruction for mountain flying and high-altitude operations, though the date of that instruction could not be determined. He had flown the accident airplane multiple times previously. The pilot worked as a professional truck driver and had passed a Department of Transportation commercial driver's license medical examination in April 2020.
Aircraft Information
Examination of the airplane's maintenance records revealed no evidence of uncorrected mechanical discrepancies with the airframe or engine.
Meteorological Information
A High-Resolution Rapid Refresh model sounding indicated possible low-level wind shear near the surface at the accident site. The National Weather Service Area Forecast Discussion, issued at 1115, noted that winds would be the greatest operational impact, with VFR conditions. Southerly winds were forecast to increase to 25 knots, then to 32 knots after 18z for Denver and Aurora airports, with BJC topping out around 25 knots. Winds were expected to shift more westerly after 14z and become due west after 16z with gusts up to 32 knots. The estimated density altitude at BJC at the time of the accident was 8,578 feet above mean sea level.
Wreckage and Impact Information
The wreckage was recovered and transported to a salvage facility for examination. Most of the airframe was consumed by the postimpact fire. No bird remains were found. Flight control continuity was established for all controls. The flaps were found at about 30° with no evidence of asymmetric deployment. The engine separated from the airframe but remained intact, with cylinder No.1 sustaining impact damage. One propeller blade showed chordwise scratching; the other blade was bent approximately 90° rearward at midspan. No preimpact mechanical malfunctions or failures were found that would have precluded normal operation.
Additional Information
Low-level wind shear and density altitude are known considerations at airports near mountain terrain. The FAA has published guidance documents discussing these phenomena, which note that strong surface winds blowing through mountain passes can cause unpredictable wind shear during approach, and high density altitude reduces aircraft performance. However, the investigation did not assign a probable cause.