The Air Force has imposed limits on its 33 newest C-17 Globemaster III jet transports, limiting them to 92 passengers instead of 109. The problem is that vibration of the aircraft causes breaks in the system that activates the three life rafts in the event the plane has to ditch in the ocean, sometimes preventing the rear raft from deploying on the same switch as the two front rafts. (The third raft will still deploy, but might have to be activated separately.) The Air Force says this will not affect operations as most do not fly with full passenger loads anyway. The 39 older C-17s are unaffected as the problem is caused by a design change that took effect with the 40th aircraft. It is unclear how long it will take to fix the problem.--Stephen V Cole