We investigate the feasibility of obtaining highly trustworthy results using crowdsourcing on complex engineering tasks. Crowdsourcing is increasingly seen as a potentially powerful way of increasing the supply of labor for solving society's problems. While applications in domains such as citizen-science, citizen-journalism or knowledge organization (e.g., Wikipedia) have seen many successful applications, there have been fewer applications focused on solving engineering problems, especially those involving complex tasks. This may be in part because of concerns that low quality input into engineering analysis and design could result in failed structures leading to loss of life. We compared the quality of work of the anonymous workers of Amazon Mechanical Turk (AMT), an online crowdsourcing service, with the quality of work of expert engineers in solving the complex engineering task of evaluating virtual wind tunnel data graphs. On this representative complex engineering task, our results showed that there was little difference between expert engineers and crowdworkers in the quality of their work and explained reasons for these results. Along with showing that crowdworkers are effective at completing new complex tasks our paper supplies a number of important lessons that were learned in the process of collecting this data from AMT, which may be of value to other researchers.