History of Flight
On March 3, 2020, at approximately 0847 central standard time, a Cessna 172S airplane, registration N157SF, was destroyed in an accident near Lincoln, Illinois. The pilot and two passengers were fatally injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as an aerial survey mission.
The operator, Synergy Flight Center, had been contracted by Shoener Environmental to perform aerial surveys of a bald eagle nest near Lincoln. The pilot requested the airplane be topped off with fuel, and at 0759, 27.8 gallons of 100 low-lead fuel were added. The airplane departed at 0804 and traveled south near Le Roy, Illinois, then southwest near Heyworth, eventually heading toward Lincoln.
Northwest of Lincoln, the airplane entered a right descending turn over a heavily wooded area intersected by Kickapoo Creek and Interstate 55. Flight track data showed decreasing altitude and groundspeed during the turn. The last data points, recorded at 0846, indicated an altitude of about 1,150 ft mean sea level (msl) and groundspeed of 80 knots, decreasing to 1,075 ft msl and 50 knots. A witness reported the left wing suddenly drop, and another observed the airplane perform 2.5 rotations while descending vertically. The airplane impacted the southbound lanes of the I-55 and state routes 10 and 121 interchange, followed by a postimpact fire. No ground injuries occurred.
Personnel and Aircraft Information
The pilot's training records and logbook were not recovered. The airplane was equipped with a Garmin GFC 700 digital autopilot, a stall warning system, and onboard weather capability. According to the Cessna 172S Pilot's Operating Handbook, stall speeds (power off) are 53 knots calibrated airspeed (KCAS) with flaps up and 48 KCAS with flaps down, with a stall warning horn sounding 5 to 10 knots above stall. Maintenance records showed no uncorrected mechanical discrepancies.
Meteorological Conditions
The pilot did not request a weather briefing. A flight instructor who flew to the accident site shortly afterward reported light chop, increasing to still light chop at about 1,300 ft msl. An AIRMET Tango issued at 0845 warned of moderate turbulence below 8,000 ft msl for the area. A High-Resolution Rapid Refresh model sounding for 0900 indicated surface wind from 244° at 14 knots, increasing to 20 knots at 500 ft above ground level (agl) and 30 knots at 1,500 ft agl. The Universal RAwinsonde OBservation Program suggested possible light low-level wind shear and light to moderate clear-air turbulence.
Wreckage and Impact
The accident site was on an asphalt highway; the airplane came to rest on a heading of about 280° magnetic at an elevation of 566 ft msl. The airplane impacted in a nose-down attitude, and all structural components were present. Examination revealed no preimpact mechanical failures or bird strike evidence.
Additional Information
The AOPA Air Safety Foundation's Safety Advisor notes that aerial work requires significant division of attention at low altitudes. The FAA Airplane Flying Handbook states that loss of control in-flight is the leading cause of fatal general aviation accidents and emphasizes the importance of stall awareness and angle-of-attack visualization.