Medium Transport; High Wing; 2 Turboprop Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 2
Situational Awareness
Deviation - Speed All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Runway
Procedure
I was working Final for SEA when the speeds of two IFR aircraft with visual approaches proceeded to land at SEA. The first aircraft was Aircraft X. This aircraft was on a Visual Approach following Aircraft Y to Runway 34C at SEA. The next aircraft was Aircraft Y who reported the previously mentioned aircraft in sight and was instructed to follow that aircraft to the same runway and then cleared on a Visual Approach. I then restricted the speed of this aircraft to 180 knots to the Final Approach Fix; to insure adequate spacing before talking to SEA Tower. Both aircraft landed and at the time it seemed to be a normal operation. I was told that Tower had a runway incursion with these two aircraft. Upon facility review the QA Specialists had mentioned that they noticed Aircraft X had slowed quite a bit in short distance for a stable approach but nothing you could notice in real time updates. The OM and QA Supervisor reviewed video and voice playback and they said that the speeds were too great and the reason Tower had and incursion was speeds and spacing with these two aircraft. I had been on Final a relatively short time when this transpired.I recommend that the people in positions of QA maintain a level of familiarity of air traffic at the locations they are responsible for. I don't feel that maintaining a rating on that position is necessary to give their opinion of potential events.
S46 Final Controller reported a loss of separation due to speeds on final for SEA and as a result the Tower had a runway incursion due to the lack of speed control on Final.