Air Traffic Control Fully Certified
Communication Breakdown; Situational Awareness
ATC Issue All Types
Air Traffic Control Issued New Clearance
Procedure; Human Factors
I plugged in for a relief briefing. A helicopter was approximately 3 northwest climbing out of 2;500 FT when I first observed the RADAR display. A CRJ9 was departing Runway 2; northwest bound. I was not aware of what heading was assigned to either aircraft. During the relief briefing; Departure Control requested Tower stop the CRJ9 at 2;000 FT. Controller giving relief briefing may not have heard this request because another aircraft was calling at the same time. I heard the request and told Controller working Local Control to stop the CRJ9 at 2;000 FT. Instructions were relayed to pilot. No loss of separation occurred. Local Control did not coordinate with Departure to make sure they knew we had issued instructions to pilot of the CRJ9. Local Control could have maintained better awareness of current traffic while conducting relief briefing. Departure Control could have used phraseology 'break for control' to interrupt the 'RELIEF BRIEFING.'
Tower Controller described a potential conflict event when; during the relief briefing; the Controller being relieved failed to maintain awareness of current traffic.