Narrative:

Working gr/jr/ar combined; average traffic volume and complexity. A C560 was handed off from N90 at 5;000 ft landing gon; as appropriate to the LOA. The C172 had previously been receiving radar advisories from me enroute to an airport within N90's airspace. A radar hand off was accomplished on the C172 and the aircraft was in communication with N90 at the time of the incident. Upon entering my airspace; I issued the C560 a 10 degree left turn and a decent to 3;000 ft and informed the aircraft to expect the visual approach. As I finished issuing those instructions; and scanned ahead of the C560; I observed that the C172 I had already switched to N90 could possibly be a factor given those instructions. I immediately issued traffic to the C560 and instructed the aircraft to expedite to 4;000 ft. The aircraft acknowledged the traffic and expedite instructions. A moment later; it was clear the expedited descent was not enough and I instructed the C560 to turn a further 20 degrees left to avoid the traffic. At that time; the C172's altitude read out was still level at 4;500 ft and the C560's altitude read out was 4;700 ft. I then observed the altitude read out for the C560 begin to climb and the pilot responded to my instruction to turn with the information that they were responding to a TCAS RA and climbing. I acknowledged the instruction and waited until the aircraft were well clear before issuing another descent to the C560. The supervisor was in the TRACON at the time of the incident and upon receiving notification from the C560 of the TCAS RA; I immediately informed him and he acknowledged the event. The C560 subsequently received a visual approach to gon and landed without further incident. I am unaware of any communication between the C172 and N90 with regard to the incident. This event was the result of a poor scan. The most appropriate action would have been to scan ahead of the control instruction; which would likely have resulted in simply leaving the C560 at 5;000 ft until passing the C172. The descent was not absolutely necessary given that gon was landing on runway 23 at the time and the aircraft had plenty of time to descend after it had passed the traffic. Additionally; a turn to the right (particularly had it been 20 or 30 degrees instead of 10) as opposed to the left would have likely caused the C560 to pass behind the traffic even with the descent.

Related reports:

Google
 

Original NASA ASRS Text

Title: PVD Controller described a TCAS RA event when altitude adjustments and vector headings were simply not given in sufficient time to secure separation.

Narrative: Working GR/JR/AR combined; average traffic volume and complexity. A C560 was handed off from N90 at 5;000 FT landing GON; as appropriate to the LOA. The C172 had previously been receiving RADAR advisories from me enroute to an airport within N90's airspace. A RADAR hand off was accomplished on the C172 and the aircraft was in communication with N90 at the time of the incident. Upon entering my airspace; I issued the C560 a 10 degree left turn and a decent to 3;000 FT and informed the aircraft to expect the Visual Approach. As I finished issuing those instructions; and scanned ahead of the C560; I observed that the C172 I had already switched to N90 could possibly be a factor given those instructions. I immediately issued traffic to the C560 and instructed the aircraft to expedite to 4;000 FT. The aircraft acknowledged the traffic and expedite instructions. A moment later; it was clear the expedited descent was not enough and I instructed the C560 to turn a further 20 degrees left to avoid the traffic. At that time; the C172's altitude read out was still level at 4;500 FT and the C560's altitude read out was 4;700 FT. I then observed the altitude read out for the C560 begin to climb and the pilot responded to my instruction to turn with the information that they were responding to a TCAS RA and climbing. I acknowledged the instruction and waited until the aircraft were well clear before issuing another descent to the C560. The Supervisor was in the TRACON at the time of the incident and upon receiving notification from the C560 of the TCAS RA; I immediately informed him and he acknowledged the event. The C560 subsequently received a Visual Approach to GON and landed without further incident. I am unaware of any communication between the C172 and N90 with regard to the incident. This event was the result of a poor scan. The most appropriate action would have been to scan ahead of the control instruction; which would likely have resulted in simply leaving the C560 at 5;000 FT until passing the C172. The descent was not absolutely necessary given that GON was landing on Runway 23 at the time and the aircraft had plenty of time to descend after it had passed the traffic. Additionally; a turn to the right (particularly had it been 20 or 30 degrees instead of 10) as opposed to the left would have likely caused the C560 to pass behind the traffic even with the descent.

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.