Mechanical & Engine Failure · NTSB CEN12FA601
AERONCA 7AC — Brighton, MI
| Date | September 1, 2012 |
| Location | Brighton, MI |
| Aircraft | AERONCA 7AC |
| Purpose of flight | Personal |
| Conditions | Day · Visual Meteorological Cond |
| Phase / occurrence | Initial climb Loss of engine power (partial) |
| Pilot age | 79 |
| Pilot total time | 2,686 hrs · Experienced |
| Time in type | Unknown |
| Fatalities | 1, 1 serious |
Probable cause
NTSB findings
- Aircraft-Aircraft power plant-Engine (reciprocating)-(general)-Not specified
- Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Airspeed-Not attained/maintained - C
- Aircraft-Aircraft oper/perf/capability-Performance/control parameters-(general)-Not attained/maintained - C
- Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot - C
- Aircraft-Aircraft systems-Equipment/furnishings-Flight compartment equipment-Failure - F
What happened
Witnesses observed the airplane make a normal engine run-up before takeoff followed by a normal takeoff from the runway. Shortly after takeoff, the engine did not sound like it was developing full power, and the airplane was struggling to climb. Subsequently, the airplane made a 180-degree turn and then descended toward terrain in a nose-down attitude. Postaccident examination of the airplane revealed no evidence of any preimpact mechanical failures or anomalies that would have precluded normal operation. Although the weather conditions at the time of takeoff were conducive to the formation of carburetor ice at glide and cruise power, it could not be determined whether carburetor ice was a factor in the loss of engine power. It is likely that the pilot failed to maintain airspeed during the turn back to the airport, which resulted in a stall.
Postaccident examination of the airframe revealed that the pilot's shoulder harness failed during the accident. Material examination of the shoulder harness webbing and stitching showed that they failed due to an overload event. The occupants' injuries suggest that both occupants were using the four-point shoulder harnesses at the time of the accident and were exposed to strong deceleration forces. If the pilot's shoulder harness had not failed, he likely would not have suffered the brain injury he received, which caused permanent disability. However, it is possible that an intact shoulder harness could have led to more severe chest, abdominal, or cervical injuries. The investigation could not determine whether the pilot would have died or sustained a permanent disability from some other injury if the shoulder harness had remained intact.