CL600 crew was given a defacto lahso clearance while on rollout at dfw.

Attributes
ACN	569669
Time
Date	200212
Day	Sat
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : dfw.airport
State Reference	TX
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tower : dfw.tower
Operator	common carrier : air carrier
Make Model Name	Challenger CL600
Operating Under FAR Part	Part 121
Flight Phase	landing : roll
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tower : dfw.tower
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	landing : go around
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 9000 flight time type : 900
ASRS Report	569669
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	non adherence : published procedure non adherence : far
Independent Detector	other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance controller : separated traffic flight crew : executed go around
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	other

Narrative:

On rollout on runway 17C dfw, we planned an M3 or M5 high-speed exit. We were a little fast for M3 so I told first officer (PF) to let it roll to next high-speed M5. As I was turning onto M5 (starting to turn), about 25-35 ft off centerline of runway 17C the tower controller said, 'air carrier X (our call sign) take next high speed.' I missed next part and I heard 'bravo hold short runway 17R.' the rapid speaking and high workload at that moment made it hard to understand. Since I was moving towards M5 at the time, and committing to it when controller said take next high-speed, I could only assume he meant M6. So, I continued to roll on runway and caused another aircraft to go around. Too many instructions and spoken too quickly at a high workload time. Also, atl tower will tell you particular high-speed if they want you on the one you are approaching. In this case, dfw controller said (next) high-speed (to me, M6), so that's what I did. This has happened to me before when I was an first officer. The captain I was with did the same thing, same instruction, same runway. Was M5 blocked by another aircraft? Was it closed? It was dark. When he said next high-speed to me, it was M6.

Original NASA ASRS Text

Title: CL600 CREW WAS GIVEN A DEFACTO LAHSO CLRNC WHILE ON ROLLOUT AT DFW.

Narrative: ON ROLLOUT ON RWY 17C DFW, WE PLANNED AN M3 OR M5 HIGH-SPD EXIT. WE WERE A LITTLE FAST FOR M3 SO I TOLD FO (PF) TO LET IT ROLL TO NEXT HIGH-SPD M5. AS I WAS TURNING ONTO M5 (STARTING TO TURN), ABOUT 25-35 FT OFF CTRLINE OF RWY 17C THE TWR CTLR SAID, 'ACR X (OUR CALL SIGN) TAKE NEXT HIGH SPD.' I MISSED NEXT PART AND I HEARD 'BRAVO HOLD SHORT RWY 17R.' THE RAPID SPEAKING AND HIGH WORKLOAD AT THAT MOMENT MADE IT HARD TO UNDERSTAND. SINCE I WAS MOVING TOWARDS M5 AT THE TIME, AND COMMITTING TO IT WHEN CTLR SAID TAKE NEXT HIGH-SPD, I COULD ONLY ASSUME HE MEANT M6. SO, I CONTINUED TO ROLL ON RWY AND CAUSED ANOTHER ACFT TO GAR. TOO MANY INSTRUCTIONS AND SPOKEN TOO QUICKLY AT A HIGH WORKLOAD TIME. ALSO, ATL TWR WILL TELL YOU PARTICULAR HIGH-SPD IF THEY WANT YOU ON THE ONE YOU ARE APCHING. IN THIS CASE, DFW CTLR SAID (NEXT) HIGH-SPD (TO ME, M6), SO THAT'S WHAT I DID. THIS HAS HAPPENED TO ME BEFORE WHEN I WAS AN FO. THE CAPT I WAS WITH DID THE SAME THING, SAME INSTRUCTION, SAME RWY. WAS M5 BLOCKED BY ANOTHER ACFT? WAS IT CLOSED? IT WAS DARK. WHEN HE SAID NEXT HIGH-SPD TO ME, IT WAS M6.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.