The Air Force plans to re-engine the C-5 transports with the new GE CF6 turbofan to save money on fuel. They will also save money on spare parts. Indeed, commercial users of this engine replace it much less often than the Air Force predicted. Using commercial rates, the Air Force could cut near-term purchases of spare engines from 73 to only 25, saving $463 million. Even better, the Air Force calculates it will need 90 days to return a removed CF6 engine to service, but commercial airlines do the same job in only 49 days.--Stephen V Cole