Helicopter
Air Traffic Control Fully Certified
Communication Breakdown
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance
General None Reported / Taken
Human Factors; Procedure
I was working Local East combined with Local Helicopters and monitoring Local West. The West Controller needed a bathroom break so I had to combine West with my positions. While working the 3 separate frequencies; there were some blocked transmissions. I heard an aircraft check in on final and I heard Aircraft X calling at the same time; hearing only him checking in with his call sign. I said 'Aircraft X; Boston Tower; go ahead' but there was no reply. The West Controller returned and I briefed him on West and continued working the other two locals. When I was then relieved I briefed my relief on Aircraft X's call. He confirmed with me that Aircraft X had no clearance to enter BOS B airspace. I affirmed he did not; but added (somewhat tongue in cheek) 'unless he took 'go ahead' as a clearance.' My relief (also tongue in cheek) noted that perhaps he did. In my 2 minute post brief; I heard the relieving controller call Aircraft X and asked if he'd called. Aircraft X answered he did not. I joked to the controller 'then why is he on frequency?' Aircraft X then did ask for confirmation that he'd been cleared in to the BOS B via the PIKER route (a published helicopter route). Some sort of notification should be made to pilots (ATIS?) that frequencies are combined and to be aware that transmissions may not be heard and they may hear us talking to aircraft on other frequencies. Specific clearances for specific requests must be issued; authorizations to enter airspace should not be assumed or inferred.
BOS Controller described an airspace entry event when Tower positions were combined and frequencies were experiencing multiple 'blocked' transmissions. The reporter suggested some type of pilot notification be establish to alert pilots to multiple frequency use.