RES3 is very complex and ancient mainframe system to work with from a coding perspective. Almost all RES/CRS/GDS systems have them same issue of being unable to fix/update without spending millions of dollars. Website systems, however, are very easy to code and update.

A couple of years ago I saw a presentation given by AC about all their recent and upcomming IT ventures. Everything from Accounting automation to flight pass systems and other revenue enhancing systems was being processed outside of the RES system. As an example, the whole concept of flight pass credits from purchase to utilization is maintained outside of RES in a custom built system. When the flight credit is activated/used, then an entry is made into RES3. This is why getting reservation assistance with flight pass products is difficult. The Reservation agents have access to RES3 but not the flight pass system.

Canada has a lot of experience with failed reservations system upgrades and rebuilds. AC tried for three years to replace the core RES3 system with newer technology. The project was called Polaris and was shelved this year by Calin and co after spending an unconfirmed $70 million. Westjet tried to get a system going and blew their brians out trying to get system performance/capabilities to meet expectations. In the end they spent $40 million and didn't get a thing, that project was called airRes. WestJet's current implementation troubles with Sabre can be sourced back trying to alter the mainframe beast in ways program code gods never intended.