Date: 202108
Local time of day: 1201-1800
Location: INL.Airport, MN
Flight conditions: VMC
Light: Daylight
Aircraft: Medium Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Landing
Airspace: Class E ZMP
ATC / advisory: UNICOM INL
Second aircraft: Small Aircraft; Low Wing; 1 Eng; Fixed Gear
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Communication Breakdown
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural FAR; Ground Incursion Runway
Detector: Person Flight Crew
When detected: Taxi
Result: General None Reported / Taken
Contributing factors: Airport; Environment - Non Weather Related; Procedure; Human Factors
Primary problem: Human Factors

Narrative: After we landed in INL we had a runway excursion with a GA aircraft. While on approach we heard the GA traffic make radio calls about being inbound about 3-5 miles north of the field. We notified them of our location of about a 10-mile final for Runway 32 and they said they would wait for us to land before landing themselves. They also called us; 'In sight'. After we landed we advised on the radio we were back-taxiing; and as we were turning around we saw the GA traffic landing while we were still on the runway. They stayed well clear of us and were able to exit the runway so we could back-taxi with no issues; and no evasive maneuvering was required at any point.GA traffic apparently not being aware of the risk of landing on a runway we were still on. While he had us in sight I did not have him in sight or on TCAS; and therefore did not know exactly how close behind us he was. Construction in INL requiring back-taxiing and therefore a longer landing time than usual that the GA traffic was probably used to. Try to advise GA traffic earlier if a need to back-taxi is required.


Second narrative: We were flying into an uncontrolled airport and made two-way radio contact with another aircraft north of the field coming into land on the same runway we were. He told us that he would let us go first since we were much faster than him and that he would follow us and be #2 to land. Normal radio calls occurred after that and we landed without incident. Because of construction there are no taxiway turn offs available on the runway and a180 degree turn and back taxi is required. After coming to almost a stop and just about to turn around I made a radio call stating that we would be back taxiing on the runway. Once we just about completed our 180 degree turn we saw the other aircraft about 50 feet off the ground at the other end of the runway in his landing flare. So we pulled as far to the side of the runway as we could just in case he made it down to us. We stayed still until he landed and pulled off on the taxiway about 2;000 feet down the runway where we needed to exit. Once the other aircraft was clear we continued our back taxi to the exit point without incident.The other aircraft stated he saw us on about a one mile final and would be number 2 to land. A contributing factor could be that he never actually saw us or he just disregarded us. Being that he was in aircraft type he might have just assumed he had plenty of runway to land and turn in before us without it being an issue on his end. Poor communication on his end as well; very few radio calls almost all of them were non standard; no tail number; no position reports at all outside of being north of the field; and simply stating 'I'll follow the jet'. A pilot with little regards to aviation safety more or less.The only thing I could think of is maybe more communication. We could have tried getting back on the radio real quick and attempting to have the other aircraft go around. By the time we saw it however; he was basically on the ground


Synopsis: Flight crew reported that after landing at an uncontrolled airport; another aircraft landed on the runway while they were back taxiing causing a runway incursion.