A B757-200 AFTER PUSHBACK RETURNED TO THE GATE DUE TO ALL SYS CONNECTED TO THE #2 AIR DATA COMPUTER WERE INOP CAUSED BY THE PITOT LINE DISCONNECTED.

Narrative

WHILE PERFORMING RVSM MODIFICATION; I WAS REVIEWING THE PAPERWORK TO CONFIRM AND FAMILIARIZE MYSELF WITH THE MODIFICATION REQUIREMENTS. MEANWHILE; MY PARTNER WAS RETRIEVING THE AIR DATA COMPUTERS REQUIRED TO COMPLY WITH THE MODIFICATION. ONCE I HAD FAMILIARIZED MYSELF WITH WHAT STEPS I WAS GOING TO FOLLOW; I PROCEEDED TO COMMENCE THE REMOVAL OF THE #2 AIR DATA COMPUTER. AT THAT TIME MY PARTNER RETURNED TO THE ACFT AND TOLD ME THAT THERE WAS ONLY 1 COMPUTER IN STOCK; MEANING THAT WE WOULD NOT BE ABLE TO COMPLY WITH THE MODIFICATION. I HAD ALREADY TWISTED THE QUICK DISCONNECT WHEN MY PARTNER HAD TOLD ME THE NEWS. I RESECURED THE QUICK DISCONNECT ON THE PITOT LINE; GATHERED MY TOOLS; TURNED OFF THE LIGHT AND CLOSED THE E&E ACCESS DOOR. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS A B757-200 AND SHORTLY AFTER PUSHBACK THE ACFT TAXIED BACK TO THE GATE WITH ALL SYS CONNECTED TO THE #2 AIR DATA COMPUTER INOP. THE RPTR SAID THE PITOT LINE QUICK DISCONNECT WAS FOUND DISCONNECTED FROM THE #2 AIR DATA COMPUTER. THE RPTR STATED THAT HE REMEMBERS DISCONNECTING THE QUICK DISCONNECT FITTING BUT CANNOT RECALL RECONNECTING THE FITTING. THE RPTR STATED THE FAA HAS MADE NO CONTACT.