A320 Captain experiences loss of PFD information climbing through FL180; followed quickly by ECAMs for IR1 fault and multiple computer failures. IR1 switch is discovered to be in the off position. After switching Captain's PDF to the #3 IR and placing the #1 IR switch in ATT position systems return to normal and flight continues to destination.

Narrative

This report concerns the loss of IR1 and both autopilots. We also had communication difficulties initially with Dispatch and Maintenance. During our climbout; shortly before 18000 feet; I lost all information on my PFD (Primary Flight Display) (attitude; airspeed and altitude). Shortly thereafter; we got an ECAM for an IR1 fault. I looked up and the switch was in the off position! This was then followed by multiple ECAM's for A/THR OFF; THRUST LOCK; YAW DAMP 1 (I think) and GPWS TERR. My First Officer was hand flying at the time and continued to fly. I worked through the ECAM's and switched my PFD to the No. 3 IR and displayed good information. I selected IR1 to ATT. When I reached the status page; I saw that both autopilots (AP) were inoperative (AP 1+2) as well as the yaw damper; GPWS TERR (A/THR?) and Cat 2. Both FMGC's seemed to be working with normal map displays that worked independently. We could select direct to a station but NAV would not engage (we had the dashed line on the map display). [We did a] position cross-check with the VOR's which we could tune with the RAD/NAV page. When we realized that neither autopilot would engage; I sent an ACARS to Dispatch to call me. I soon saw ACARS call on the upper ECAM; but could not retrieve the frequency from either box. Since I do not have an FOM in my ship set; I took the aircraft and radios while my First Officer looked up the frequency. We established a phone patch with Dispatch; although at first he could not hear us. We finally established the connection and described what was going on. The symptoms really didn't match anything. With one IR inoperative; we should have had the right autopilot; but we had none. Nor did we have either FD. There were No FMA's on either PFD. There was an FD flag on my side; and the FD flag was intermittent on the First Officer's side. We were hoping that Maintenance would have some ideas for a reset; but he was stumped also. He asked if we were ok to continue to destination; we conferred with Dispatch about any changes in en route and destination weather and decided we were ok to continue. We terminated the phone patch and were about to let ATC know our autopilot situation to see if we could continue at our altitude when the FMA's came back; we selected autopilot 2 and it worked; as did the auto thrust. We had no further problems during the flight. Before writing this; I saw that Maintenance deferred the DMC 3 and changed it. How would this have kept the autopilots from working? After reviewing the FM; IR faults; one can get loss of autopilots with one IR failure if the ELAC's (Elevator Aileron Computer) lack confidence in the other two IR's; but if this was the case; I think we should have also degraded to direct law. The crew coordination throughout this event was very good and once we established contact with Dispatch and Maintenance that went well also. In hindsight; probably should have let ATC know what was going on sooner. I knew that when I sent a call me to Dispatch and we didn't get back to him quickly; he would be concerned. I called once we were on the ground and he said was about to send a confirm ops normal. Since we were not able to retrieve ACARS messages for several minutes; we would not have gotten that one either.