The latest Sukhoi T-50 prototype – PAK-FA – a twin-engine fifth-generation stealth jet fighter aborted a takeoff at the recently held MAKS Air Show outside Moscow on 21 August 2011 after four days of successful demo flights. While two prototypes of PAK-FA have cumulatively made 48 flights since 29 January 2010, it will be important to know the reasons of this mishap.