Narrative:

While tracking the localizer inbound from vectors for the ILS [runway] 08 at bur; ATC pointed out traffic at our 11 o'clock; maneuvering at 4;500 ft MSL. Both myself and the pilot not flying spotted two small single engine aircraft in this position converging on us and they also appeared on TCAS as blue targets. The pilot not flying reported 'in sight' to ATC. A few seconds later we received an RA from the closest target. Although the pilot not flying said; 'got 'em;' to me; I no longer had this aircraft in sight as it had disappeared from my view underneath the left front side of our aircraft. I disconnected the autopilot and complied with the RA and requested the pilot not flying advise ATC of our action; which he did and they acknowledged. This resulted in a climb of approximately 300 ft at which time the 'monitor vertical speed' command was issued and I leveled off. A few seconds later 'clear of conflict' was issued and we advised ATC and returned to 5;000 ft MSL and re-engaged the autopilot. We were then cleared for the ILS approach. The remainder of the approach and landing were completed normally without unusual events. As a note; while descending on the glideslope over vny; we received a TCAS TA. We spotted traffic that appeared to be in the pattern at vny. This is a very common occurrence while on this approach in VMC. Probable cause may have been the other aircraft starting to climb and/or possible detected closure rate by the TCAS. I believe this is a VFR practice area and is also a common arrival route and altitude range for IFR and VFR traffic into the area airports. Possibly extending the bur class C airspace further west and at a higher altitude and keeping controlled aircraft inside this airspace would help prevent these occurrences.

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Original NASA ASRS Text

Title: A large corporate jet's First Officer reported near miss at 5;000 FT on the BUR Runway 08 ILS after responding to TCAS traffic maneuvering at about 4;500 FT.

Narrative: While tracking the localizer inbound from vectors for the ILS [Runway] 08 at BUR; ATC pointed out traffic at our 11 o'clock; maneuvering at 4;500 FT MSL. Both myself and the pilot not flying spotted two small single engine aircraft in this position converging on us and they also appeared on TCAS as blue targets. The pilot not flying reported 'in sight' to ATC. A few seconds later we received an RA from the closest target. Although the pilot not flying said; 'Got 'em;' to me; I no longer had this aircraft in sight as it had disappeared from my view underneath the left front side of our aircraft. I disconnected the autopilot and complied with the RA and requested the pilot not flying advise ATC of our action; which he did and they acknowledged. This resulted in a climb of approximately 300 FT at which time the 'monitor vertical speed' command was issued and I leveled off. A few seconds later 'clear of conflict' was issued and we advised ATC and returned to 5;000 FT MSL and re-engaged the autopilot. We were then cleared for the ILS approach. The remainder of the approach and landing were completed normally without unusual events. As a note; while descending on the glideslope over VNY; we received a TCAS TA. We spotted traffic that appeared to be in the pattern at VNY. This is a very common occurrence while on this approach in VMC. Probable cause may have been the other aircraft starting to climb and/or possible detected closure rate by the TCAS. I believe this is a VFR practice area and is also a common arrival route and altitude range for IFR and VFR traffic into the area airports. Possibly extending the BUR class C airspace further west and at a higher altitude and keeping controlled aircraft inside this airspace would help prevent these occurrences.

Data retrieved from NASA's ASRS site as of April 2012 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.