Aeronca 11AC N3503E accident near Hoosick Falls, New York

Probable cause

The failure of the left wing attachment bracket weld due to inadequate welding by unknown maintenance personnel.

NTSB analysis

One witness reported observing the airplane "flying sideways" and another witness reported observing the airplane operating "in a large circular motion…losing altitude." The airplane subsequently impacted the ground in a nose-down attitude. Examination of the airplane revealed that the left wing was separated from its aft wing attachment bracket. Further examination of both wings' aft attachment brackets revealed that the welds had not fully penetrated into the base material and that they were of poor workmanship. No maintenance records were found indicating that the brackets had ever been replaced or welded; therefore, it could not be determined when or by whom the welds were made. Due to their location on the attachment brackets, the pilot would not have been able to detect that the welds were inadequate during his visual inspection of the airplane. Based on the evidence, it is likely that the left wing attachment bracket weld failed in flight, which resulted in the pilot being unable to maintain airplane control due to the wing's trailing edge being unattached. Although both wings' aft attachment brackets exhibited evidence of overstress fractures, these likely occurred during ground impact.

Text from the NTSB. Open the NTSB docket for ERA13LA221 for the full record.