Date: 201907
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Regional Jet 200 ER/LR (CRJ200)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
Airspace: Class E ZZZ
ATC / advisory: CTAF ZZZ
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Communication Breakdown; Situational Awareness
Anomaly: Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Runway
Detector: Person Flight Crew
When detected: Taxi
Contributing factors: Airport; Human Factors; Procedure
Primary problem: Human Factors

Narrative: We were waiting short of the runway for our release from ATC at an uncontrolled airport for approximately 20 minutes; at the runway with a 4-8kt headwind which was required for our performance due to high DA and winds. All aircraft were using the favorable wind runway except the firefighting aircraft which appeared to be due to their base location. We would make a radio call every 5 minutes or so and continuously monitored the traffic advisory frequency. After we received our release from ATC we made 1 more radio call that we were holding short of the runway while we completed our before takeoff check. We heard an aircraft call in from 20 miles away inbound for landing; and heard him make 1-2 more subsequent radio calls. He was the only traffic radio call we heard in the vicinity at that time or for the previous 5-10 minutes. There were firefighting exercises with multiple single engine firefighting airplanes in and out of the airport and we had thoroughly briefed the threat to include making more radio calls; continuously monitor CTAF if we had to communicate with ATC; and to take an extra search for aircraft opposite us before we departed. After we made a radio call that we were taking the runway for departure; I asked the FO (First Officer) to look again at the opposite end of the runway where the firefighting airplanes seemed to be parking and departing. Myself and the FO spent at least 10 sec searching to make sure no airplane was at the other end of the runway. As I began to taxi; I had the FO make one more radio call just to be sure. As he made the radio call; I looked one more time at the opposite end of the runway and saw landing lights turn on. I stopped immediately and had crossed the hold short line by maybe 10-15 ft. As the airplane passed we made another radio call with no response from them. I checked to make sure we were on the correct frequency and radio; which we were. The airplane passed maybe 400-500 in the air and we were again about 10-15 ft beyond the hold short line. After again looking at the departure end of the runway; we then departed and when airborne we were able to contact the aircraft. Although we never heard a single radio transmission from them; they claimed they made radio calls and also claimed they never heard our radio calls. We had monitored CTAF the entire time; using both radios at times when communication with ATC required Comm 1 but only during those short periods of time and we transmitted on comm1 as well as comm2 multiple times while we were holding short of the runway and had no issues communicating with or hearing other traffic on either radio. The traffic also informed us that he saw us crossing the hold short line during his takeoff; but continued the departure anyway.The cause of the event was two main factors; either the other aircrafts lack of radio usage; or failure either partially or fully on either theirs or ours parts; although our radio exhibited zero signs of malfunction. The other contributing factor is the layout of the airport seemed to almost have a slight crown in the middle; possibly causing interference with radios and definitely contributed to not seeing the aircraft when we spent a very adequate amount of time looking at the opposite end of the runway for traffic.I have thought about what else we could have mitigated this threat; and I feel the FO and myself did everything we could have leading up to; and took prompt and effective actions to avoid any further incident. We used both radios; made more than normal radio communications; took extra time to look for traffic prior to departure; departed the runway with a significant headwind; and briefed the threat of the firefighting aircraft using the opposite runway. The only thing I can think of is in the future I will establish communication with any firefighting airplane in the pattern or area and ask if they have any aircraft close to departing as to minimize any radio issues with two aircraft on opposite ends of a runway.




Synopsis: CRJ Captain reported as they entered the runway to depart a non-towered airport they observed an aircraft taking off from the opposite direction.