ACR Y CLB THROUGH OCCUPIED ALT; HAD LTSS FROM ACR X. SYS ERROR.

Narrative

THE SECTOR WAS MODERATELY BUSY VOLUME WITH VERY COMPLEX TFC SIT. THERE WAS TRAINING ON THE H (HDOF ASST POS) AND TRAINING ON THE R (RADAR POS). ABOUT 1/2 OF THE SECTOR TFC WAS ON A NON-STANDARD RTE THROUGH THE MIDDLE OF THE SECTOR (INCLUDING ACR X) TO ACCOMMODATE SPACING REQUIREMENTS TO IAD WITH OTHER HIGH ALT TFC THAT WE DON'T TALK TO. THERE WERE ABOUT 5 PHL DEPS THAT NEEDED TO BE CLBED ABOVE THE IAD TFC (INCLUDING ACR Y). BECAUSE OF THE HVY CONCENTRATION OF TFC IN ONE AREA; THE DATA BLOCKS HAD TO BE CONSTANTLY MOVED TO PREVENT OVERLAP. ONE TIME WHEN THE RADAR TRAINEE WAS MOVING A DATA BLOCK; HE ACCIDENTLY DROPPED ACR X DATA BLOCK COMPLETELY DUE TO A KEYBOARD STICKING. I DID NOT NOTICE ACR X DATA BLOCK DROP OFF DUE TO THE OTHER DATA BLOCK CONGESTION. ACR Y WAS CLBED FROM 13000 FT TO 15000 FT WITHOUT BEING GIVEN A RESTR TO MISS X AT 14000 FT WHO HAD NO DATA BLOCK AND WAS NOT NOTICED. THE CONFLICT ALERT WENT OFF AND I ASKED ACR Y HIS ALT AND HE REPLIED THAT HE WAS LEVEL AT 15000 FT. CONTRIBUTING FACTORS: STICKING KEYBOARD EQUIP IS VERY OLD AND STICKY KEYS ARE GENERALLY ACCEPTED. THE MAIN AND BIGGEST PROB WAS THAT THERE WAS TRAINING ON THE HDOF POS AT THE SAME TIME AS THE RADAR POS. THIS REQUIRES THE RADAR TRAINER TO WATCH THE RADAR TRAINEE AND COORDINATE WITH THE RADAR TRAINEE; THE HDOF TRAINEE; AND THE HDOF TRAINER; MAKING IT VIRTUALLY IMPOSSIBLE TO SEE EVERYTHING THAT IS HAPPENING.