Date: 201707
Local time of day: 1201-1800
Location: CHS.Airport, SC
Light: Daylight
Aircraft: B737 Next Generation Undifferentiated
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Ground CHS
Second aircraft: Helicopter
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Confusion
Second reporter function: Pilot Not Flying; First Officer
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Other / Unknown
Detector: Person Flight Crew
When detected: Taxi
Result: Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Human Factors; Procedure
Primary problem: Ambiguous

Narrative: We pushed back from gate on time and contacted Ground Control for taxi to Runway 21. We were cleared to taxi via Taxiways Bravo; Charlie; Alpha; hold short of Runway 15. We complied with the directions and came to a stop short of the hold short line at Runway 15. As we were waiting; we could see that there was a helicopter on Taxiway A on the north side of Runway 15. After another aircraft departed on Runway 15; Ground Control cleared us to cross Runway 15; taxi to Runway 21 via Alpha. We turned on our exterior lights and began crossing Runway 15. About halfway across the runway; we were able to see that the helicopter was on Alpha facing south; leaving us nowhere to go. We stopped the aircraft on the runway; informed Ground Control that we could not proceed further; and asked for instructions. We were told to 'hold position; the helicopter should be departing any second.' However; rather than departing from the Taxiway; the helicopter taxied further south to the hold short line southbound on Taxiway Alpha. Again; we asked Ground what was going on; and were told to hold position on Runway 15. The helicopter then taxied onto Runway 15 in front of us; stopping about 50 ft away at our 10 o'clock position facing south into the wind. The helicopter was on Tower frequency while we were on Ground; so we had no idea what they were doing; and the Ground Controller seemed confused as well. We could not maneuver away; as the helicopter was so close to us that our aircraft exhaust could have caused him damage. After 30 seconds on the runway together; the helicopter suddenly lifted off; just off our left wing; and departed southbound. The entire encounter was marked by confusion on the part of the Ground Controller; who seemed to be unaware of what the helicopter planned to do. The fact that we were on different frequencies on the same piece of pavement at the same time made the entire event very uncomfortable and unsafe. After the helicopter departed; we were cleared to continue taxi via Alpha to Runway 21; and subsequently departed without further incident.Better coordination between Ground Control and Tower Control is essential. Each aircraft was on a different frequency and no one seemed to know what the plan was. The helicopter should have departed from the runway; or from the taxiway while we were being held short of 15. The diverse operations at CHS are often challenging; but clear communication of intentions is a must!


Second narrative: As we proceeded across Runway 15 (Clear left; clear right; and turning on all exterior lighting) we observed a helicopter on the opposite side of the runway on A. We stopped on Runway 15 as we are blocked from continuing across onto A on the North side. We ask GROUND what to expect. Ground advised us to hold position ON Runway 15 and that he was not certain about the helicopter; and he was on Tower frequency. After several long and awkward minutes sitting on Runway 15 in the middle of HS1; the helicopter crossed the hold short; proceeded directly to our 10 o'clock position on Runway 15 at very close range; coming to a momentary stop; and in amazement; he rotated and climbed out directly above our left wing. I made clear on Ground frequency that his proximity to us was far too close for our comfort. Ground advised that he would make a report. We continued taxi for a normal departure on Runway 21It seems to me that the helicopter likely misunderstood his takeoff clearance. There may have been a disconnect between Ground and Tower; but there could be no chance that the helicopter executed his takeoff clearance correctly. When unsure of a clearance; ask for clarification.


Synopsis: B737 flight crew reported being cleared to cross CHS Runway 15; but had to stop on the runway after being blocked by a helicopter on the other side. The helicopter taxied onto the runway and took off over the B737.