ASK is an abbreviation for
available seat kilometer. In parallel with the
RPK, it is used in judging the size of
airlines. Where the RPK measures an airline's actual traffic, the ASK measures an airline's
potential traffic: how many RPK's the airline would pull if every airplane were full of paying passengers.
The main drawback with the ASK is that it doesn't give any indication of whether an airline's load factors are good. An airline with a high ASK figure but few passengers could well be driving itself into the ground. However, since the advent of computerized reservation systems like Sabre and Apollo, as well as web sites like Priceline, RPK and ASK figures tend to be fairly close, since most airlines can fill their seats with little difficulty.
See also FTK.