Flight Crew Multiengine; Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 142; Flight Crew Total 11331; Flight Crew Type 9384
Communication Breakdown
Conflict Ground Conflict; Critical
Flight Crew FLC complied w / Automation / Advisory; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Aircraft; Procedure
I was the PIC; and I was in the right seat.  We were taxing for takeoff to Runway XX at ZZZ.  Upon reaching the end of Runway XX; we were cleared for takeoff on Runway XX. As my co-captain took the runway; he used all the runway and made a hard 90 degree turn to line up on the centerline.  As he was about to add takeoff power; I noticed a plane on TCAS not far from the end of the runway at 600 ft. AGL and warned the other pilot.  We looked out of the windshield and got a visual on the other aircraft which appeared to be heading towards the airport.  When the plane quickly turned down the runway opposite direction to us and appeared to be descending rapidly; I keyed the mike and asked on Tower frequency is that plane landing on our runway. I did not get an answer; and the plane was now about to land opposite direction on Runway XA.  I told the other pilot to get off of the runway; he powered up and exited at the next runway exit about 400 ft. down the runway. The plane appeared to be a Cessna 172 and exited the runway around midfield; still nothing was said on the radio.  The Cessna asked if he could taxi to [the FBO] and Tower responded yes for him to taxi to [the FBO].  The emergency vehicles then exited the fire station; and I heard Tower tell the emergency responders that he reported engine trouble; I guess he reported it to departure.  It was not on Tower.  We were eventually cleared to taxi back to the end and cleared to take off with nothing else said to us from the Tower.
Captain reported that another aircraft landed on the opposite direction runway after they were cleared for takeoff.