This paper presents an experimental evaluation of a prototype jet engine controller intended for Unmanned Aerial Vehicles (UAVs). The controller is implemented with commercial off-the-shelf (COTS) hardware based on the Motorola MPC565 microcontroller. We investigate the impact of single event upsets (SEUs) by injecting single bit-flip faults into main memory and CPU registers via the Nexus on-chip debug interface of the MPC565. To avoid the injection of non-effective faults, automated preinjection analysis of the assembly code was utilized. Due to the inherent robustness of the software, most injected faults were still non-effective (69.4%) or caused bounded failures having only minor effect on the jet engine (7.0%), while 20.1% of the errors were detected by hardware exceptions and 1.9% were detected by executable assertions in the software. The remaining 1.6% is classified as critical failures. A majority of the critical failures were caused by erroneous booleans or type conversions involving booleans.