EMB190 first officer reports a near midair collision with a single engine cessna during approach to ...

Narrative:

Bos approach control vectored us and we joined the 4R localizer at approximately 25 DME. We were then cleared to descend from 10;000 to 6;000 ft. Descending through 8;700 ft a TCAS target suddenly appeared on the mfd TCAS display within approximately 3 miles and 300 ft vertically below. We slowed the descent and then received a climb RA. [We] followed [the] TCAS RA command bars (flight director) until clear of conflict. During the RA maneuver the captain visually acquired contact with the target aircraft (high-wing cessna single engine) and estimated our separation as 100 ft vertical and 0 ft lateral. The captain then relayed to bos approach that we had just responded to an RA. The controller ignored the transmission. The controller seemed extremely busy at the time. There would certainly have been a collision had we not responded immediately to the RA. This was partly due to us being vectored into the primary class B airport while outside of the class B airspace. Perhaps another controller 'watching' might have been able to at least give us a traffic alert or issue an advisory stop descent instruction.

Original NASA ASRS Text

Title: EMB190 First Officer reports a NMAC with a single engine Cessna during approach to BOS; while outside the Calss B airspace. A TCAS RA commanded a climb alerting the crew.

Narrative: BOS Approach Control vectored us and we joined the 4R localizer at approximately 25 DME. We were then cleared to descend from 10;000 to 6;000 FT. Descending through 8;700 FT a TCAS target suddenly appeared on the MFD TCAS display within approximately 3 miles and 300 FT vertically below. We slowed the descent and then received a climb RA. [We] followed [the] TCAS RA command bars (flight director) until clear of conflict. During the RA maneuver the Captain visually acquired contact with the target aircraft (high-wing Cessna single engine) and estimated our separation as 100 FT vertical and 0 FT lateral. The Captain then relayed to BOS Approach that we had just responded to an RA. The Controller ignored the transmission. The Controller seemed extremely busy at the time. There would certainly have been a collision had we not responded immediately to the RA. This was partly due to us being vectored into the primary class B airport while outside of the class B airspace. Perhaps another Controller 'watching' might have been able to at least give us a traffic alert or issue an advisory stop descent instruction.

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.

Attributes
ACN	939375
Time
Date	201103
Local Time Of Day	1201-1800
Place
Locale Reference	BOS.Airport
State Reference	MA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	EMB ERJ 190/195 ER&LR
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Aircraft 2
Make Model Name	Cessna Single Piston Undifferentiated or Other Model
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Conflict NMAC
Miss Distance	Horizontal 0 Vertical 100

EMB190 first officer reports a near midair collision with a single engine cessna during approach to bos; while outside the calss B airspace. A TCAS RA commanded a climb alerting the crew.