Date: 201212
Local time of day: 1201-1800
Location: BZN.Airport, MT
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: Learjet 40
Operator: Air Taxi
Operating under: Part 135
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class E ZLC
ATC / advisory: Center ZLC; Tower BZN
Second aircraft: DA42 Twin Star
Reporter organization: Air Taxi
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude
Detector: Automation Aircraft RA; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action
Contributing factors: Airspace Structure; Aircraft; Procedure
Primary problem: Ambiguous

Narrative: Descending toward the airport; being vectored by Salt Lake City ARTCC (SLC) onto a high right downwind; anticipating a visual approach; following a commuter aircraft. Due to fresh snow cover and white aircraft (commuter) we were unable to visually locate the commuter traffic to enable a Visual Approach. SLC gave us vectors and gradual descents toward the airport. Once acquiring the commuter on short final we were issued a visual approach to follow the commuter. We continued our descent passing though approximately 8;500 MSL; 195 KTS; on a high right downwind (airport elevation 4;500 MSL). During the time both the commuter and we were being worked by SLC; the Center Controller advised the commuter of several targets in the airport area. My co-pilot and I discussed some targets that were located on our TCAS. Center did not advise us of traffic prior to the hand-off to Bozeman Tower (BZN). Upon initial contact with BZN; we were given a sequence to the airport; BZN Tower told us they would call our base turn. The Tower then advised another aircraft of our position (the DA42 listed above). BZN also quickly gave us their position; crossing at approximately 12 o'clock; less than a mile; 7;700 FT. We had no indication of his position on TCAS; and the TCAS did not give us a Traffic Alert. My co-pilot announced traffic in sight; but before he had a chance to tell me to avoid the traffic; we received a Resolution Advisory (RA). I immediately complied with an auto-pilot disconnect and a climb. We passed within 500 FT horizontally (or less); of the other aircraft. The pilot of the DA42 replied to the Tower; 'that was close'. After landing I instructed the co-pilot to tell BZN of the RA. BZN asked us to call the Tower after securing our aircraft. I spoke with the Tower; gave them the information above; and answered a few questions. One question was whether or not SLC had informed us of the traffic. I replied; negative. The following day I again spoke with the Tower Operator; who had talked to SLC after the incident. SLC indicated they did not see the traffic. I am not placing blame on anyone. I only question if there is a 'blind spot' in Center's radar. Had we not been anticipating traffic; the outcome may have been different.




Synopsis: LR40 Captain reports an airborne conflict with a DA42 during a visual approach to BZN. Tower called the traffic and TCAS commanded an RA climb without showing the traffic or announcing a TA first.