Revenue and Expense Recognition In the Aerospace segment, segment revenue is recognized on the accrual basis at the time of shipment of goods and transfer of title. There are no significant contracts allowing for right of return. In the Test Systems segment, revenue of approximately 1% and 62% for the three months ending September 27, 2014 and September 28, 2013, respectively, and approximately 1% and 40% for the nine months ending September 27, 2014 and September 28, 2013 respectively, is recognized from long-term, fixed-price contracts using the percentage-of-completion method of accounting, measured by multiplying the estimated total contract value by the ratio of actual contract costs incurred to date to the estimated total contract costs. Substantially all long-term contracts are with U.S. government agencies and contractors thereto. The Company makes significant estimates involving its usage of percentage-of-completion accounting to recognize contract revenues. The Company periodically reviews contracts in process for estimates-to-completion, and revises estimated gross profit accordingly. While the Company believes its estimated gross profit on contracts in process is reasonable, unforeseen events and changes in circumstances can take place in a subsequent accounting period that may cause the Company to revise its estimated gross profit on one or more of its contracts in process. Accordingly, the ultimate gross profit realized upon completion of such contracts can vary significantly from estimated amounts between accounting periods. Revenue not recognized using the percentage-of-completion method is recognized at the time of shipment of goods and transfer of title. With the acquisition of ATS, a portion of our Test Systems segment sales are recognized as multiple element arrangements, whereby revenue is allocated to the equipment and post installation maintenance service components based upon vendor specific objective evidence, typically pricing established in the contracts for the post installation servic