Air carrier captain reported an RA while on final approach to sea.

Attributes
ACN	1502244
Time
Date	201712
Local Time Of Day	1801-2400
Place
Locale Reference	SEA.Airport
State Reference	WA
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	Skylane 182/RG Turbo Skylane/RG
Operating Under FAR Part	Part 91
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Events
Anomaly	Conflict Airborne Conflict Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance
Miss Distance	Vertical 400

Narrative:

We had TCAS/RA on short final to runway 34L at approximately 800 ft AGL. We started an immediate climb per the RA and subsequently executed a missed approach. We were VFR; descending on an ILS approach with a cloud layer underneath us. The conflicting aircraft came within 400 ft according what I saw on the TCAS. I never saw the other aircraft. Approach control informed me it was a cessna 182.

Original NASA ASRS Text

Title: Air Carrier Captain reported an RA while on final approach to SEA.

Narrative: We had TCAS/RA on short final to runway 34L at approximately 800 ft AGL. We started an immediate climb per the RA and subsequently executed a missed approach. We were VFR; descending on an ILS approach with a cloud layer underneath us. The conflicting aircraft came within 400 ft according what I saw on the TCAS. I never saw the other aircraft. Approach control informed me it was a Cessna 182.

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.