Before taking off at atl airport, an MD80 crew requested 2 mins separation after a B757 departure.

Attributes
ACN	457689
Time
Date	199912
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : atl.airport
State Reference	GA
Altitude	agl single value : 0
Aircraft 1
Controlling Facilities	tower : atl.tower
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Flight Phase	ground : position and hold
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tower : atl.tower
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	climbout : takeoff climbout : initial
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	457689
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : multi engine pilot : commercial
Events
Anomaly	non adherence : published procedure
Resolutory Action	controller : issued new clearance controller : issued advisory flight crew : took precautionary avoidance action
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance

Narrative:

ATC facility: atl tower. Location: runway 8R. We were sequenced for takeoff behind a B757 which was following an L1011. ATIS reported no significant winds and with clouds at 300 ft and reported visibility at 1 1/2 mi I elected, in the interest of safety, to take the 2 min separation behind the B757. Tower cleared us into position and hold runway 8R. The first officer advised the controller that we needed the 2 mins for separation. No response. 1 min after the B757 started his takeoff roll, we were cleared for takeoff. I advised the controller that we needed 1 min. After a short moment, a different controller indicated that we had to take off or clear the runway. As I cleared the runway, I advised him that we had told the other controller that we needed 2 mins prior to taking the runway. He then stated 'we don't do 2 mins here.' it is my understanding that I may request 2 mins when I deem it necessary. Have the rules changed, or is atl just pushing margins? I do not believe the initial takeoff clearance would have provided the minimum takeoff separation, much less what I deemed appropriate for the given conditions. Safety can only be pushed so far in an attempt to facilitate departures.

Original NASA ASRS Text

Title: BEFORE TAKING OFF AT ATL ARPT, AN MD80 CREW REQUESTED 2 MINS SEPARATION AFTER A B757 DEP.

Narrative: ATC FACILITY: ATL TWR. LOCATION: RWY 8R. WE WERE SEQUENCED FOR TKOF BEHIND A B757 WHICH WAS FOLLOWING AN L1011. ATIS RPTED NO SIGNIFICANT WINDS AND WITH CLOUDS AT 300 FT AND RPTED VISIBILITY AT 1 1/2 MI I ELECTED, IN THE INTEREST OF SAFETY, TO TAKE THE 2 MIN SEPARATION BEHIND THE B757. TWR CLRED US INTO POS AND HOLD RWY 8R. THE FO ADVISED THE CTLR THAT WE NEEDED THE 2 MINS FOR SEPARATION. NO RESPONSE. 1 MIN AFTER THE B757 STARTED HIS TKOF ROLL, WE WERE CLRED FOR TKOF. I ADVISED THE CTLR THAT WE NEEDED 1 MIN. AFTER A SHORT MOMENT, A DIFFERENT CTLR INDICATED THAT WE HAD TO TAKE OFF OR CLR THE RWY. AS I CLRED THE RWY, I ADVISED HIM THAT WE HAD TOLD THE OTHER CTLR THAT WE NEEDED 2 MINS PRIOR TO TAKING THE RWY. HE THEN STATED 'WE DON'T DO 2 MINS HERE.' IT IS MY UNDERSTANDING THAT I MAY REQUEST 2 MINS WHEN I DEEM IT NECESSARY. HAVE THE RULES CHANGED, OR IS ATL JUST PUSHING MARGINS? I DO NOT BELIEVE THE INITIAL TKOF CLRNC WOULD HAVE PROVIDED THE MINIMUM TKOF SEPARATION, MUCH LESS WHAT I DEEMED APPROPRIATE FOR THE GIVEN CONDITIONS. SAFETY CAN ONLY BE PUSHED SO FAR IN AN ATTEMPT TO FACILITATE DEPS.

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.