Seattle tower and seattle TRACON controllers reported of an operation where the second departure ove...

Attributes
ACN	1354346
Time
Date	201605
Local Time Of Day	1201-1800
Place
Locale Reference	SEA.Airport
State Reference	WA
Environment
Light	Daylight
Aircraft 1
Make Model Name	Medium Transport High Wing 2 Turboprop Eng
Operating Under FAR Part	Part 121
Flight Phase	Initial Climb
Flight Plan	IFR
Aircraft 2
Make Model Name	Medium Transport High Wing 2 Turboprop Eng
Operating Under FAR Part	Part 121
Flight Phase	Initial Climb
Flight Plan	IFR
Person 1
Function	Instructor Local
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 9.5
Person 2
Function	Departure
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 1
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy

Narrative:

Aircraft X departed straight out on the seattle 4 departure and aircraft Y was put into position by lce (local control east). As aircraft Y was going into position S46 called and stopped our automatic turns to 020 heading and I told lce expecting them to cross aircraft in front of the departure with both aircraft now being straight out instead of turning the second aircraft. Lce departed aircraft Y and issued visual separation instructions to the pilot which he accepted. After aircraft Y became airborne I realized that they were going faster and out climbing aircraft X; I told the lce trainee that they needed to do something with aircraft Y; lce then stopped aircraft Y at 2000 ft. I then called departure sector a and told them that aircraft Y was stopped at 2000 ft and was told 'I would expect so' by the departure controller. As I was on with the departure controller I incorrectly assumed lce had climbed aircraft Y to 2100 ft because the altitude readout on the stars showed the aircraft at 2100 ft and they were approaching a 2100 ft MVA area north of boeing field.

Original NASA ASRS Text

Title: Seattle Tower and Seattle TRACON controllers reported of an operation where the second departure overtook the first departure. Controllers used altitude to separate traffic.

Narrative: Aircraft X departed straight out on the Seattle 4 departure and Aircraft Y was put into position by LCE (Local Control East). As Aircraft Y was going into position S46 called and stopped our automatic turns to 020 heading and I told LCE expecting them to cross aircraft in front of the departure with both aircraft now being straight out instead of turning the second aircraft. LCE departed Aircraft Y and issued visual separation instructions to the pilot which he accepted. After Aircraft Y became airborne I realized that they were going faster and out climbing Aircraft X; I told the LCE trainee that they needed to do something with Aircraft Y; LCE then stopped Aircraft Y at 2000 ft. I then called departure Sector A and told them that Aircraft Y was stopped at 2000 ft and was told 'I would expect so' by the departure controller. As I was on with the departure controller I incorrectly assumed LCE had climbed Aircraft Y to 2100 ft because the altitude readout on the STARS showed the aircraft at 2100 ft and they were approaching a 2100 ft MVA area North of Boeing Field.

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.

Seattle tower and seattle TRACON controllers reported of an operation where the second departure overtook the first departure. Controllers used altitude to separate traffic.