You are managing a project that is testing a system that manages a newly redesigned...

You are managing a project that is testing a system that manages a newly redesigned jet engine for heavy aircraft. Given the fact that this engine is specifically engineered to reduce noise, it is important that the software maintains enough thrust for lift for a period of 5 minutes without exceeding 87.5dB. The software must achieve this independent of other internal systems such as fuel or navigation management.

Given the risk for the ability of the aircraft to meet the noise abatement regulations while still being able to fly, when is the optimum time in the software lifecycle to apply the performance testing?