Large Transport; Low Wing; 2 Turbojet Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 31
Training / Qualification; Troubleshooting
ATC Issue All Types; Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Requested ATC Assistance / Clarification
Weather; Procedure; Human Factors; Airport
Aircraft X started takeoff roll before Aircraft Y had exited runway. There were two Front Line Managers in the tower and one was monitoring Local Control when this occurred.Arrivals; which formerly landed on the Right runway; were now landing on the Center runway. Adding to the complexity of the operation; the ceiling was such that restrictions were imposed on Line-Up-And-Wait operations (LUAW) in that landing clearances had to be withheld until the LUAW aircraft was cleared for takeoff; causing more transmissions than normal.Intending to launch Aircraft X after Aircraft Y and another aircraft on final; Local Control tried to hustle Aircraft Y off the runway but gave the wrong taxiway designator; with his exit instructions. Aircraft Y had already passed the taxiway and was coming up on the next taxiway; which he had slowed enough to exit. Unfortunately; Aircraft Y must have been confused and continued his roll out to an even further away taxiway.Local Control anticipating Aircraft Y's runway exit; issued a takeoff clearance to Aircraft X without ensuring that Aircraft Y had; in fact; exited the runway. After realizing that Aircraft Y was still rolling down the runway; Local control tried to cancel Aircraft X's takeoff clearance. This was not effectively communicated and Aircraft X continued his takeoff roll. The subsequent arrival; continued his approach to landing. The distance between Aircraft X and Aircraft Y was over 6000 feet when Aircraft Y was at their runway exit point. This did not meet ASDE-X parameters for an alert.Local Control's incorrect exit instructions caused this loss of separation.1) Using the correct taxiway designator with runway exit instructions (instead of saying next exit or next high speed) has been emphasized at this facility -- as per 7110.65. That presumes that the controller knows his airfield geography. Maybe 'next high speed' would have worked better. Perhaps the FAA needs to re-examine the 7110.65 in this regard.2) The controller needs to be told how to command the frequency in these situations -- using pause; inflection; and emphasis. 'Aircraft X; Dulles TWR; cancel takeoff clearance!' This was not effectively communicated by Local Control.
Working Local Control; landing and departing a wet runway; I had north bound departures. Aircraft Y was cleared to land and asked to exit as soon as feasible upon landing. Aircraft Y replied he would. After Aircraft Y cross the landing threshold Aircraft X was told to line up and wait and that traffic was on a six mile final. An aircraft on a six mile final had not checked in and I attempted to contact him numerous times. Aircraft Y was told to turn right at a taxiway and he replied turning right at [taxiway]. Using Anticipating Separation (7110.65 3-9-5) Aircraft X was cleared for takeoff. Scanning the runway I realized that Aircraft Y had not exited at [taxiway] but had continued down the runway to [taxiway]; Aircraft Y never advised me that he had passed [taxiway] and had continued down the runway to [another taxiway]. I cancelled Aircraft X take off clearance; he had just started his departure roll. Arrival traffic was told to go around for traffic on the runway. There was no response from Aircraft X; I once again told Aircraft X stop your departure roll; still no response from Aircraft X. Aircraft X departed without acknowledging any of my instructions. The arrival was cleared to land and landed with no separation lost. Aircraft X was asked did he hear the cancel take off clearance and his response was no. Aircraft X checked back on the frequency a time later and stated there was some confusion and he thought that he was told to continue take off roll. I recommend assistance to Local Control positions during heavy arrival and departure banks when landing and departing the same runway.
A report from a Front Line Manager; a Controller and a flight crew about a Local Controller that used non-standard phraseology 'stop your roll' which was not understood by foreign flight crew.  The foreign aircraft was originally cleared for takeoff while another aircraft was clearing the same runway after landing.