Light Transport; Low Wing; 2 Turbojet Eng
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 45; Flight Crew Total 5200; Flight Crew Type 800
Situational Awareness; Confusion
Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
Airport; Human Factors; Weather
We landed FTW RWY 31L. Tower stated we were allowed to vacate right on upcoming taxiways E; or C4. As we slowed down; we noted there were two right turns off of the runway; one which was clearly marked C4 and the one closest to us; which was not clearly marked. The visibility was low and the windshield was covered with water. Pilot Flying assumed the exit was E and started a right turn to vacate the runway. As the turn was completed; we realized this was in fact not a taxiway; but a closed off part of either an apron or old runway. There were no signs or runway edge lights to prevent us or warn us that this area cannot be used; instead there was red lights some 80 feet ahead; so we pretty much knew this was a dead end prior to fully vacating the runway. Crew realized we had made wrong turn and proceeded to turn back to the adjacent taxiway (C4); to vacate. As we completed the turn we realized ATC had cleared another aircraft who announced we were still in use of the runway and was requested to abort rollout. We contacted Ground once cleared of runway and were given taxi instructions and a phone number to call due to deviation. The PIC contacted them and was advised there would be an investigation on the matter. I question some aspects that possibly lead to this incident. The fact that there are no visible runway edge lights or signs to prevent aircraft from entering this part of the runway. The lack of information on the taxiway plate; though there is a X mark; there is not a hotspot highlighted as high risk for deviations; and ATC's decision to clear another aircraft for takeoff during precipitation and low visibility conditions without the certainty that us (the landing aircraft) had fully cleared the runway.
Air taxi First Officer reported inadvertently exiting the runway into a non-movement area rather than a taxiway.