The design of the Tiger includes a high degree of crash worthiness; many of the onboard systems have redundancies and are segregated to minimise the effect of damage. Components of the propulsion system, such as the rotors and drive shaft, were deliberately designed for greater ballistic tolerance than traditional designs; the gearbox is rated for a 60-minute dry run capability if lubrication is lost. Fuel is contained in two main internal fuel tanks, and an additional two smaller tanks are housed inside the stub wings. Fuel tanks have self-sealing capability to decrease the vulnerability. In the inhospitable conditions of the Afghanistan theatre, the Tiger had a reported operational availability of 90%.