The non-compliance with applicable Airworthiness Directives which required wing spar inspections, and the continued operation of the aircraft beyond the compliance time extension granted as per the approved alternate means of compliance (AMOC). Also causal was the operation of the aircraft outside of its flight "G" load limitations. Contributing factors were the misunderstanding between the Federal Aviation Administration (FAA) ACO and maintenance personnel in regard to AD/AMOC compliance, the insufficient AMOC’s, and failure of the operator to adequately comply with CFR Part 91 subpart E, maintenance.