Narrative:

In takeoff position behind B757 departing. B757 turned left to 140 degrees which is arcing 2.8 DME arc about 20-30 degrees to left from me. Tower cleared me for takeoff with less than 4 mi and less than 2 mins. I delayed a few seconds to get spacing. Tower said; 'start your takeoff roll or I will cancel your takeoff clearance...state intentions.' I saw 6-8 aircraft holding for takeoff. I said 'there is a B757 ahead of me and put that on the tape.' tower said 'I need 4 mi and there is 8 and let's put that on the tape.' at this point; 8 mi was an outright lie. I delayed a few seconds more and started takeoff roll when I felt there was enough time and spacing. My concerns are: 1) controller misinfo about the actual distance behind the B757. Perhaps he lied or the equipment is mis-calibrated or my TCASII is inaccurate or he was liberally anticipating the 8 mi. 2) when there is an immediate significant turn after takeoff; different performance characteristics of different aircraft could cause the following aircraft to turn inside the leader and close the distance significantly (turning rejoin). 3) as PIC; I have final authority/authorized to decide whether it's safe to take off. Being threatened to be put back into line because I choose to use the full 2 mins and/or 5 mi is unacceptable. It is harassment that could influence pilots to make bad decisions. The controller's concept of how he wants the pattern to work is not the definitive parameter. I waited in line; I had the runway; and it may not even be legal for the controller to take the runway away from me; especially not for the 20 seconds needed.

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Original NASA ASRS Text

Title: MD80 DEP FROM BOS DISPUTES TWR CTLR'S APPLICATION OF WAKE TURB SEPARATION FROM PRECEDING B757.

Narrative: IN TKOF POS BEHIND B757 DEPARTING. B757 TURNED L TO 140 DEGS WHICH IS ARCING 2.8 DME ARC ABOUT 20-30 DEGS TO L FROM ME. TWR CLRED ME FOR TKOF WITH LESS THAN 4 MI AND LESS THAN 2 MINS. I DELAYED A FEW SECONDS TO GET SPACING. TWR SAID; 'START YOUR TKOF ROLL OR I WILL CANCEL YOUR TKOF CLRNC...STATE INTENTIONS.' I SAW 6-8 ACFT HOLDING FOR TKOF. I SAID 'THERE IS A B757 AHEAD OF ME AND PUT THAT ON THE TAPE.' TWR SAID 'I NEED 4 MI AND THERE IS 8 AND LET'S PUT THAT ON THE TAPE.' AT THIS POINT; 8 MI WAS AN OUTRIGHT LIE. I DELAYED A FEW SECONDS MORE AND STARTED TKOF ROLL WHEN I FELT THERE WAS ENOUGH TIME AND SPACING. MY CONCERNS ARE: 1) CTLR MISINFO ABOUT THE ACTUAL DISTANCE BEHIND THE B757. PERHAPS HE LIED OR THE EQUIP IS MIS-CALIBRATED OR MY TCASII IS INACCURATE OR HE WAS LIBERALLY ANTICIPATING THE 8 MI. 2) WHEN THERE IS AN IMMEDIATE SIGNIFICANT TURN AFTER TKOF; DIFFERENT PERFORMANCE CHARACTERISTICS OF DIFFERENT ACFT COULD CAUSE THE FOLLOWING ACFT TO TURN INSIDE THE LEADER AND CLOSE THE DISTANCE SIGNIFICANTLY (TURNING REJOIN). 3) AS PIC; I HAVE FINAL AUTH TO DECIDE WHETHER IT'S SAFE TO TAKE OFF. BEING THREATENED TO BE PUT BACK INTO LINE BECAUSE I CHOOSE TO USE THE FULL 2 MINS AND/OR 5 MI IS UNACCEPTABLE. IT IS HARASSMENT THAT COULD INFLUENCE PLTS TO MAKE BAD DECISIONS. THE CTLR'S CONCEPT OF HOW HE WANTS THE PATTERN TO WORK IS NOT THE DEFINITIVE PARAMETER. I WAITED IN LINE; I HAD THE RWY; AND IT MAY NOT EVEN BE LEGAL FOR THE CTLR TO TAKE THE RWY AWAY FROM ME; ESPECIALLY NOT FOR THE 20 SECONDS NEEDED.

Data retrieved from NASA's ASRS site as of January 2009 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.