Accurate simulation of unsteady turbulent flow is critical for improved design of greener aircraft that are more fuel-efficient. We will demonstrate the application of PyFR to petascale simulation of such flows. Rationale behind algorithmic choices, which offer increased levels of accuracy and enable sustained computation at up to 58% of peak DP-FLOPs on unstructured grids, will be discussed. A range of software innovations will also be detailed, including use of runtime code generation, which enables PyFR to efficiently target multiple platforms via a single implementation. Finally, results will be presented from fullscale simulations of flow over low-pressure turbine blades, along with scaling results, and performance data demonstrating sustained computation at up to 13.7 DP-PFLOPs.