S46 TRACON controller conducting on-the-job training reported an aircraft they were vectoring to the...

Narrative:

I was conducting training when the trainee took radar contact on aircraft X at 5;000 feet. Aircraft X asked for lower and once he was clear of the 5;000 foot minimum vectoring altitude; my trainee issued a descent initially to maintain 3;000 feet. Moments later; the trainee issued an ILS clearance to aircraft X and to maintain 2;000 feet until established. After the clearance; my trainee continued to work his other traffic and by the time his scan got back to aircraft X; the VFR traffic was issued but no control instruction was given. Aircraft X advised he was responding to an RA (resolution advisory) and began to climb and turned westbound. The trainee instructed aircraft X when able to fly a 340 heading to rejoin the ILS and to maintain 2;000 feet. Once the pilot was on his heading and descending he was advised traffic was no factor and issued another traffic call for another VFR target over the final approach fix at 1;500 feet. The second VFR target began to climb and aircraft X responded to another TCAS RA. At this point I took control of the frequency and climbed aircraft X to 5;000 feet on 020 heading.this area is known for its complexity with VFR traffic due to the surrounding airports and that's why initially aircraft X was only given 3;000 feet. I've discussed with my trainee to stay at or above 3;000 feet until established on final so the VFR traffic could be assessed better. 3;000 feet keeps the aircraft in class bravo airspace with a less likely chance of an encounter with a VFR target. I would also recommend that further review of the airspace configuration be assessed so better procedures could be put in place to protect for this. For example; a VFR corridor would help the VFR pilots navigate in and out of busy airspace. The traffic keeps increasing; both IFR and VFR; and I feel it's being left unaddressed. S46 has always had issues with TCAS events on the finals due to VFR traffic not being aware of inbound IFR traffic. The other thing that could've been a factor was having three sectors combined.

Original NASA ASRS Text

Title: S46 TRACON Controller conducting on-the-job training reported an aircraft they were vectoring to the ILS responded to a Resolution Advisory to avoid unidentified VFR traffic.

Narrative: I was conducting training when the trainee took radar contact on Aircraft X at 5;000 feet. Aircraft X asked for lower and once he was clear of the 5;000 foot Minimum Vectoring Altitude; my trainee issued a descent initially to maintain 3;000 feet. Moments later; the trainee issued an ILS clearance to Aircraft X and to maintain 2;000 feet until established. After the clearance; my trainee continued to work his other traffic and by the time his scan got back to Aircraft X; the VFR traffic was issued but no control instruction was given. Aircraft X advised he was responding to an RA (Resolution Advisory) and began to climb and turned westbound. The trainee instructed Aircraft X when able to fly a 340 heading to rejoin the ILS and to maintain 2;000 feet. Once the pilot was on his heading and descending he was advised traffic was no factor and issued another traffic call for another VFR target over the final approach fix at 1;500 feet. The second VFR target began to climb and Aircraft X responded to another TCAS RA. At this point I took control of the frequency and climbed Aircraft X to 5;000 feet on 020 heading.This area is known for its complexity with VFR traffic due to the surrounding airports and that's why initially Aircraft X was only given 3;000 feet. I've discussed with my trainee to stay at or above 3;000 feet until established on final so the VFR traffic could be assessed better. 3;000 feet keeps the aircraft in Class Bravo airspace with a less likely chance of an encounter with a VFR target. I would also recommend that further review of the airspace configuration be assessed so better procedures could be put in place to protect for this. For example; A VFR corridor would help the VFR pilots navigate in and out of busy airspace. The traffic keeps increasing; both IFR and VFR; and I feel it's being left unaddressed. S46 has always had issues with TCAS events on the finals due to VFR traffic not being aware of inbound IFR traffic. The other thing that could've been a factor was having three sectors combined.

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.

Attributes
ACN	1545134
Time
Date	201805
Local Time Of Day	0001-0600
Place
Locale Reference	S46.TRACON
State Reference	WA
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	Challenger 300
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Route In Use	Vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	Climb
Route In Use	None
Flight Plan	VFR
Person 1
Function	Instructor Approach
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 4
Person 2
Function	Approach
Qualification	Air Traffic Control Developmental
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict

S46 TRACON controller conducting on-the-job training reported an aircraft they were vectoring to the ILS responded to a resolution advisory to avoid unidentified VFR traffic.