LR40 captain reports an airborne conflict with a DA42 during a visual approach to bzn. Tower called ...

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.

Original NASA ASRS Text

Title: 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.

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.

Data retrieved from NASA's ASRS site as of July 2013 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	1056805
Time
Date	201212
Local Time Of Day	1201-1800
Place
Locale Reference	BZN.Airport
State Reference	MT
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Learjet 40
Operating Under FAR Part	Part 135
Flight Phase	Initial Approach
Route In Use	Visual Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	DA42 Twin Star
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor Flight Crew Multiengine Flight Crew Instrument
Experience	Flight Crew Last 90 Days 97 Flight Crew Total 12200 Flight Crew Type 240
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Altitude Excursion From Assigned Altitude
Miss Distance	Horizontal 500

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.