Flight Crew Air Transport Pilot (ATP)
Communication Breakdown
Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Runway
General None Reported / Taken
Procedure; Human Factors
After starting engines on the ramp; I announced on the CTAF frequency (118.45) that we were taxiing out for takeoff to Rwy 4L (tower closed). I noticed that all airport lights were extinguished; so I activated all lighting on 118.45 using PCL procedures. No vehicular/aircraft traffic was observed on the surface of the airport; and no movements of same were heard on the CTAF. Just prior to taking the selected runway for departure (4L); I announced that we were taking the runway for departure. After brake release; I announced on the CTAF that we were commencing takeoff roll on 4L. All aircraft / taxi lights were on full bright. Just after the aircraft began to accelerate; I heard on the CTAF; 'Airport maintenance one is crossing all airport taxiways/ runways at Baton Rouge; use caution for vehicle.' Apparently this was an inspection vehicle for the airport prior to the tower opening. After the aircraft accelerated through approximately 90 knots; I noticed the silhouette of a vehicle crossing our active runway (4L) right to left approximately 3;000 ft in front of the aircraft; most likely the vehicle was crossing the runway on taxiway G. There was never a conflict with the aircraft and vehicle; and we were airborne well prior to where the vehicle crossed the runway; and the vehicle was clear of the runway when we passed that position.
Light Transport First Officer reported an airport vehicle crossing the departure runway after the crew had announced several times that they were taxiing to and departing from Runway 4L; on the CTAF frequency. The crew had also activated the airport lighting prior to taxi.