Narrative:

I had aircraft X departing off runway 16L with a 140 heading issued leaving 1500 feet and aircraft Y departing off runway 16C straight out on the SID. Both aircraft were given traffic with intentions on the roll. With both of these aircraft on departure roll; departure keyed in and told me to stop 140 turns. I advised him that I already had one on the roll with the turn issued. He replied leave him straight out. I advised that I was unable because of a jet that was also rolling that would be straight out. He replied that I had to leave the prop straight out. As soon as I could I advised aircraft X that departure now needed him to fly straight out and issued traffic on aircraft Y so that I could get pilot visual with these airplanes. At this point aircraft Y is just off the departure end but below aircraft X; so aircraft X was unable to see them. At the point I see aircraft Y stop his climb to get away from aircraft X. Departure then keyed in and advised that I could turn aircraft X to the 140 heading. I issued the turn and shipped aircraft X to departure. Aircraft Y then advised that he had to respond to a TCAS RA from aircraft X and had to descend to get away. He continued his climb without further incident. Looking back at the event; I believe that departure shut off the 140 headings reference a jet off that he had already turned and climbed into the area they are supposed to protect for our turns. The departure controllers lack of insight into the effect that they have on our operation put two of my aircraft into unsafe proximity. When I said that I needed the turn he should have come up with another plan or asked if I could provide visual with his jet that was above my prop.reference the letter of agreement section which states we must turn props that are eastbound to a 140 heading. We don't have guidance for the TRACON turning them off except in the SOP (standard operating procedure). It says we must use the placard. TRACON should never be allowed to use this airspace unless first coordinated and agreed upon by both controllers. Right now they turn them off when needed and often never call to turn them back on until we call and ask if we can use them again. It is my understanding that there is no memory aid for them that reminds them when they are on or off. This is a disservice to the customer as aircraft behind these props are having to wait on the ground longer for us to ensure separation behind these slower aircraft.

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Original NASA ASRS Text

Title: SEA Tower Controller reported the TRACON could not accept an aircraft on a previously agreed to heading which placed the aircraft into confliction with parallel runway departure traffic.

Narrative: I had Aircraft X departing off Runway 16L with a 140 heading issued leaving 1500 feet and Aircraft Y departing off Runway 16C straight out on the SID. Both aircraft were given traffic with intentions on the roll. With both of these aircraft on departure roll; departure keyed in and told me to stop 140 turns. I advised him that I already had one on the roll with the turn issued. He replied leave him straight out. I advised that I was unable because of a jet that was also rolling that would be straight out. He replied that I had to leave the prop straight out. As soon as I could I advised Aircraft X that departure now needed him to fly straight out and issued traffic on Aircraft Y so that I could get pilot visual with these airplanes. At this point Aircraft Y is just off the departure end but below Aircraft X; so Aircraft X was unable to see them. At the point I see Aircraft Y stop his climb to get away from Aircraft X. Departure then keyed in and advised that I could turn Aircraft X to the 140 heading. I issued the turn and shipped Aircraft X to departure. Aircraft Y then advised that he had to respond to a TCAS RA from Aircraft X and had to descend to get away. He continued his climb without further incident. Looking back at the event; I believe that departure shut off the 140 headings reference a jet off that he had already turned and climbed into the area they are supposed to protect for our turns. The departure controllers lack of insight into the effect that they have on our operation put two of my aircraft into unsafe proximity. When I said that I needed the turn he should have come up with another plan or asked if I could provide visual with his jet that was above my prop.Reference the letter of agreement section which states we must turn props that are eastbound to a 140 heading. We don't have guidance for the TRACON turning them off except in the SOP (Standard Operating Procedure). It says we must use the placard. TRACON should never be allowed to use this airspace unless first coordinated and agreed upon by both controllers. Right now they turn them off when needed and often never call to turn them back on until we call and ask if we can use them again. It is my understanding that there is no memory aid for them that reminds them when they are on or off. This is a disservice to the customer as aircraft behind these props are having to wait on the ground longer for us to ensure separation behind these slower aircraft.

Data retrieved from NASA's ASRS site 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.