Global Express (BD700)
Flight Crew Air Transport Pilot (ATP)
Flight Crew Total 3215
Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
Air Traffic Control Provided Assistance
Airport; Procedure
We requested to taxi for departure from the FBO at KLAX; ATC's initial response was for us to taxi via A; hold short of Taxiway F. While taxiing on Taxiway A; the ATC called us back and told us to switch and monitor the Tower frequency; as well as to expect the Runway 25L for departure. We were busy in the cockpit with taxi checklist. In this process; the pilot flying did not clearly hear the last part of the transmission. I called back the Ground asking to repeat the last part of the transmission. The Ground Controller responded indicating that we can expect to depart from the Runway 25L. I then switched to the Tower frequency to monitor. Shortly after; while we were still taxiing on Taxiway A; the Tower called us indicating 'continue taxi to Runway 25L; hold short of Runway 25L.' The clearance was read back. I continued to proceed with checklist items on the electronic checklist. When I raised my head; the aircraft was moving past the hold short line. When I saw this I addressed 'hold short' to the pilot flying; but it was too late. The aircraft lined up on Runway 25L and stopped on the runway. The Tower called us indicating that we were told to hold short and not line up.
Bombardier BD-700 flight crew reported crossing the hold short line of the runway while they were preoccupied with the checklist.