An air carrier B-737 demanded more separation behind a B-757 on takeoff.

Attributes
ACN	275787
Time
Date	199406
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : sea
State Reference	WA
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : sea tower : tlh
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	climbout : takeoff
Route In Use	departure other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	climbout : takeoff
Route In Use	departure other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp pilot : commercial pilot : instrument
Experience	flight time last 90 days : 180 flight time total : 12500 flight time type : 1500
ASRS Report	275787
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	faa : reviewed incident with flight crew Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other
Situations
ATC Facility	procedure or policy : unspecified

Narrative:

Prior to departure I asked for 3 mins or 5 mi behind the 757 that was departing prior to my 737-400. Tower said (in a not friendly tone) that they would provide necessary separation. As soon as the 757 departed, I started my clock. We were cleared into position and 1 1/2 mins after the 757 departed and with him only 2 1/2 mi in front of us (as indicated by range marks on our ehsi in map mode, 10 mi range). We were cleared for takeoff. I delayed approximately 15-20 seconds when tower called and stated 'start takeoff now.' the 757 at the start of our roll was no more than 3 1/2 mi in front of us. I had my company's dispatch call and talk to the tower supervisor and dispatch was told that we had 5 mi, but there was no way there could have been that much separation. I realize the tower crew is under a great deal of pressure to get the morning rush out but I feel they should maintain adequate separation, especially since the 757 minimum separation thing is so recent.

Original NASA ASRS Text

Title: AN ACR B-737 DEMANDED MORE SEPARATION BEHIND A B-757 ON TKOF.

Narrative: PRIOR TO DEP I ASKED FOR 3 MINS OR 5 MI BEHIND THE 757 THAT WAS DEPARTING PRIOR TO MY 737-400. TWR SAID (IN A NOT FRIENDLY TONE) THAT THEY WOULD PROVIDE NECESSARY SEPARATION. AS SOON AS THE 757 DEPARTED, I STARTED MY CLOCK. WE WERE CLRED INTO POS AND 1 1/2 MINS AFTER THE 757 DEPARTED AND WITH HIM ONLY 2 1/2 MI IN FRONT OF US (AS INDICATED BY RANGE MARKS ON OUR EHSI IN MAP MODE, 10 MI RANGE). WE WERE CLRED FOR TKOF. I DELAYED APPROX 15-20 SECONDS WHEN TWR CALLED AND STATED 'START TKOF NOW.' THE 757 AT THE START OF OUR ROLL WAS NO MORE THAN 3 1/2 MI IN FRONT OF US. I HAD MY COMPANY'S DISPATCH CALL AND TALK TO THE TWR SUPVR AND DISPATCH WAS TOLD THAT WE HAD 5 MI, BUT THERE WAS NO WAY THERE COULD HAVE BEEN THAT MUCH SEPARATION. I REALIZE THE TWR CREW IS UNDER A GREAT DEAL OF PRESSURE TO GET THE MORNING RUSH OUT BUT I FEEL THEY SHOULD MAINTAIN ADEQUATE SEPARATION, ESPECIALLY SINCE THE 757 MINIMUM SEPARATION THING IS SO RECENT.

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.