Aeronca 7AC — Hanson, MA, 2018

Aeronca 7AC — Hanson, MA

1 fatal Low-time pilot

Date	August 24, 2018
Location	Hanson, MA
Aircraft	Aeronca 7AC
Purpose of flight	Personal
Conditions	Day · Visual Meteorological Cond
Phase / occurrence	Standing Miscellaneous/other
Pilot age	33
Pilot total time	195 hrs · Low time
Time in type	4 hrs
Fatalities	1, 1 serious

Probable cause

A loss of engine power due to carburetor icing, the pilot's decision to turn back to the runway shortly after takeoff, and his failure to maintain airspeed during the turn, which resulted in an exceedance of the airplane's critical angle of attack, and subsequent aerodynamic stall.

NTSB findings

Personnel issues-Action/decision-Info processing/decision-Decision making/judgment-Pilot - C
Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot - C
Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Angle of attack-Not attained/maintained - C
Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Airspeed-Not attained/maintained - C
Environmental issues-Conditions/weather/phenomena-Temp/humidity/pressure-Conducive to carburetor icing-Effect on operation - C
Environmental issues-Conditions/weather/phenomena-Temp/humidity/pressure-Conducive to carburetor icing-Contributed to outcome - C

What happened

The commercial pilot and passenger were departing on a local personal flight in the single-engine airplane. Review of airport security video showed the airplane level off about 100 ft above ground level as it passed the departure end of the runway. The airplane then entered a left turn and descended to ground contact. Damage to the propeller blades was consistent with a lack of engine power at the time of impact; however, examination of the wreckage revealed no evidence of preimpact mechanical anomalies that would have prevented normal engine operation. Based on the temperature and dew point about the time of the accident, the conditions were favorable for serious carburetor icing at a glide power setting.

Video showed that the airplane operated on the ground at an idle engine power setting for about 7 minutes before takeoff, and it is probable that carburetor ice formed during this time, subsequently resulting in the loss of engine power during the initial climb. Following the loss of power, the pilot attempted to turn back to the runway with insufficient altitude and, during the turn, failed to maintain airspeed, resulting in an exceedance of the airplane's critical angle of attack, an aerodynamic stall/spin, and impact with terrain.

An editorial "what led to it / how to avoid it" analysis for this accident is generated separately and will appear here.