N90 controller was vectoring an aircraft at 5000 feet. The aircraft descended in response to an RA f...

Attributes
ACN	1377727
Time
Date	201608
Local Time Of Day	1201-1800
Place
Locale Reference	N90.TRACON
State Reference	NY
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Small Transport Low Wing 2 Turboprop Eng
Operating Under FAR Part	Part 135
Flight Phase	Cruise
Route In Use	Vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Medium Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Person 1
Function	Approach
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 28
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance

Narrative:

While working the isp radar position 312; I was vectoring aircraft X who was approximately 13 miles east of isp northbound at 5000 feet. There was a second aircraft approaching aircraft X and that aircraft was level at 4000 feet. Aircraft X stated that he was responding to a TCAS alert with a VFR aircraft and descended into the flight path and altitude of aircraft Y which resulted in a loss of separation. I did advise aircraft X not to descend and he did not listen to my instructions.although aircraft are expected to listen to their TCAS the VFR aircraft was no factor and this time around the aircraft X pilot should have listened to me and not descended into aircraft below him. If the TCAS showed traffic below him then the TCAS should have advised pilot to turn or climb; not descend.

Original NASA ASRS Text

Title: N90 Controller was vectoring an aircraft at 5000 feet. The aircraft descended in response to an RA for VFR traffic into an aircraft the Controller was vectoring at 4000 feet.

Narrative: While working the ISP radar position 312; I was vectoring Aircraft X who was approximately 13 miles east of ISP northbound at 5000 feet. There was a second aircraft approaching Aircraft X and that aircraft was level at 4000 feet. Aircraft X stated that he was responding to a TCAS alert with a VFR aircraft and descended into the flight path and altitude of Aircraft Y which resulted in a loss of separation. I did advise Aircraft X not to descend and he did not listen to my instructions.Although aircraft are expected to listen to their TCAS the VFR aircraft was no factor and this time around the Aircraft X pilot should have listened to me and not descended into aircraft below him. If the TCAS showed traffic below him then the TCAS should have advised pilot to turn or climb; not descend.

Data retrieved from NASA's ASRS site 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.

N90 controller was vectoring an aircraft at 5000 feet. The aircraft descended in response to an RA for VFR traffic into an aircraft the controller was vectoring at 4000 feet.