|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||airport : den|
|Altitude||agl bound lower : 0|
agl bound upper : 0
|Operator||common carrier : air carrier|
|Make Model Name||Large Transport, Low Wing, 3 Turbojet Eng|
|Flight Phase||ground : holding|
ground other : taxi
|Affiliation||company : air carrier|
|Function||flight crew : captain|
oversight : pic
|Qualification||pilot : atp|
|Experience||flight time last 90 days : 150|
flight time total : 12000
flight time type : 6000
|Function||controller : local|
|Qualification||controller : non radar|
|Anomaly||non adherence : published procedure|
non adherence : clearance
|Independent Detector||other controllera|
|Resolutory Action||controller : issued new clearance|
|Primary Problem||ATC Human Performance|
|Air Traffic Incident||other|
|ATC Facility||procedure or policy : unspecified|
We refused to takeoff in our large transport X immediately behind a heavy transport Y as not enough time had elapsed and we could still see tight vortices formed in the heavy, dark jet exhaust at his rotation point. We had a slight tailwind and a large temperature/dew point spread (50 degrees), 66 degrees/16 degrees, also high clouds. We were heavy for an large transport also. So, all conditions were set up for a difficult takeoff at best (not mentioning any engine failure). So, there was no doubt in the minds of all 3 of us that we needed to wait at least another minute and watch the vortices dissipate before taking off, which is what we did. So, what's the problem, you ask? Den tower said, 'go now or clear the runway,' after we told them the problem. We taxied clear and waited for about 11 mins while several aircraft took off ahead of us. We could have taken off before the first one next behind us took off if we had been allowed to wait about 1 min. The problem is: this is strong pressure brought to bear on the first one to go after a heavy. The next one after the first has cleared has no problem due to the time that has gone by.
Original NASA ASRS Text
Title: AFTER TAXIING ONTO RWY, LGT REFUSED TKOF CLRNC DUE TO WAKE TURBULENCE FROM HVT THAT JUST DEPARTED. WAS TOLD BY TWR TO CLEAR THE RWY.
Narrative: WE REFUSED TO TKOF IN OUR LGT X IMMEDIATELY BEHIND A HVT Y AS NOT ENOUGH TIME HAD ELAPSED AND WE COULD STILL SEE TIGHT VORTICES FORMED IN THE HEAVY, DARK JET EXHAUST AT HIS ROTATION POINT. WE HAD A SLIGHT TAILWIND AND A LARGE TEMP/DEW POINT SPREAD (50 DEGS), 66 DEGS/16 DEGS, ALSO HIGH CLOUDS. WE WERE HEAVY FOR AN LGT ALSO. SO, ALL CONDITIONS WERE SET UP FOR A DIFFICULT TKOF AT BEST (NOT MENTIONING ANY ENG FAILURE). SO, THERE WAS NO DOUBT IN THE MINDS OF ALL 3 OF US THAT WE NEEDED TO WAIT AT LEAST ANOTHER MINUTE AND WATCH THE VORTICES DISSIPATE BEFORE TAKING OFF, WHICH IS WHAT WE DID. SO, WHAT'S THE PROB, YOU ASK? DEN TWR SAID, 'GO NOW OR CLR THE RWY,' AFTER WE TOLD THEM THE PROB. WE TAXIED CLR AND WAITED FOR ABOUT 11 MINS WHILE SEVERAL ACFT TOOK OFF AHEAD OF US. WE COULD HAVE TAKEN OFF BEFORE THE FIRST ONE NEXT BEHIND US TOOK OFF IF WE HAD BEEN ALLOWED TO WAIT ABOUT 1 MIN. THE PROB IS: THIS IS STRONG PRESSURE BROUGHT TO BEAR ON THE FIRST ONE TO GO AFTER A HVY. THE NEXT ONE AFTER THE FIRST HAS CLRED HAS NO PROB DUE TO THE TIME THAT HAS GONE BY.
Data retrieved from NASA's ASRS site as of August 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.