which probably means that wet performance is being used far more than it was before and I am not convinced that safety has been improved.
Evergreen International Airlines believes it does.
Aero 11 - Rejected Takeoff Studies
"About 2 percent occur at speeds in excess of 120 kt. The overruns and incidents that occur invariably stem from these high-speed events."
"Approximately 80 percent of the overrun events were potentially avoidable by following appropriate operational practices."
"Using the Boeing data, we initially approached the FAA with a proposal to call a reduced V1 the "decision speed" and treat it as a V1 speed. The flight crew would remove their hands from the thrust levers, and the takeoff would continue. The initial proposed speed was 10 kt less than published V1."
"In late 1992, after we received the Boeing Takeoff Safety Training Aid in draft form, we decided to again seek approval of the "decision speed" concept. This time we chose a speed of 8 kt for a reduction, which added approximately 2 seconds of recognition time. In the worst case the screen height was degraded to approximately 15 to 20 ft."
"We believe that this reduced V1 procedure provides a valuable increase in the safety margin over that provided in the AFM in the event of an RTO."
In order to reduce the chance of an over run from a poorly handled RTO, a reduced V1 (use of wet figures) helps.