Narrative:

The crew of a B-737 were cleared in position and hold, runway 25R, caution wake turbulence departing heavy (md-11).. When in position on the runway, we were told 'cleared for takeoff, maintain runway heading, 7 mi in trail of a heavy.' our TCASII (and my eyeballs) revealed that the md-11 was only 3 mi away. I said 'how far away is the heavy?' the controller replied 'approaching 7 mi.' I said 'he looks like 4 mi.' the controller replied, he will be at 7 mi.' when we observed the md-11 at 5 1/2 mi on the TCASII, we commenced our takeoff. Although I climbed at an angle that I thought would put me above the md-11's flight path, I still experienced light wake turbulence. It appears that controllers are under pressure to 'move 'em out' and they are ignoring wake turbulence requirements. Fortunately, we had TCASII (and visual acquisition) to tell us that we did not have this separation.

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Original NASA ASRS Text

Title: FLC REFUSED TKOF CLRNC WHEN THEY DISCOVERED THE PRECEDING WDB WAS ONLY 4 MI AHEAD OF THEM.

Narrative: THE CREW OF A B-737 WERE CLRED IN POS AND HOLD, RWY 25R, CAUTION WAKE TURB DEPARTING HVY (MD-11).. WHEN IN POS ON THE RWY, WE WERE TOLD 'CLRED FOR TKOF, MAINTAIN RWY HDG, 7 MI IN TRAIL OF A HVY.' OUR TCASII (AND MY EYEBALLS) REVEALED THAT THE MD-11 WAS ONLY 3 MI AWAY. I SAID 'HOW FAR AWAY IS THE HVY?' THE CTLR REPLIED 'APCHING 7 MI.' I SAID 'HE LOOKS LIKE 4 MI.' THE CTLR REPLIED, HE WILL BE AT 7 MI.' WHEN WE OBSERVED THE MD-11 AT 5 1/2 MI ON THE TCASII, WE COMMENCED OUR TKOF. ALTHOUGH I CLBED AT AN ANGLE THAT I THOUGHT WOULD PUT ME ABOVE THE MD-11'S FLT PATH, I STILL EXPERIENCED LIGHT WAKE TURB. IT APPEARS THAT CTLRS ARE UNDER PRESSURE TO 'MOVE 'EM OUT' AND THEY ARE IGNORING WAKE TURB REQUIREMENTS. FORTUNATELY, WE HAD TCASII (AND VISUAL ACQUISITION) TO TELL US THAT WE DID NOT HAVE THIS SEPARATION.

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.