N90 controller described a loss of separation event complicated by a flight check aircraft.

Narrative:

This was a busy combined position. I was working both the feeder and final because we were short staffed. In addition; we had a flight check in the area and sequence was trying to coordinate with me on his handling. An E135 had to be taken out of the final sequence because another aircraft had navigation problems on the approach causing the arrival line to 'bunch up.' I vectored the E135 westbound at 5;000 ft because there was an aircraft on the downwind at 4;000 ft. The next aircraft coming in; an A319 was also descended to 5;000 ft because in my judgment if they had stayed on the arrival the two aircraft would pass no factor. Unfortunately; the A319 'led' the turn on the STAR causing them to pass too closely to the E135. Both aircraft responded to an RA. The unusual situation with flight check and the required coordination was certainly a factor in distracting me. Also; the aircraft that had a navigation problem caused a lot of work all at once. If the position was separated the traffic volume and complexity would have been halved. Additionally; the A319 leading the turn is dangerous and the pilots of those aircraft should be reminded that it is bad practice in such a confined airspace like new york.

Original NASA ASRS Text

Title: N90 Controller described a loss of separation event complicated by a flight check aircraft.

Narrative: This was a busy combined position. I was working both the Feeder and Final because we were short staffed. In addition; we had a flight check in the area and sequence was trying to coordinate with me on his handling. An E135 had to be taken out of the final sequence because another aircraft had navigation problems on the approach causing the arrival line to 'bunch up.' I vectored the E135 westbound at 5;000 FT because there was an aircraft on the downwind at 4;000 FT. The next aircraft coming in; an A319 was also descended to 5;000 FT because in my judgment if they had stayed on the arrival the two aircraft would pass no factor. Unfortunately; the A319 'led' the turn on the STAR causing them to pass too closely to the E135. Both aircraft responded to an RA. The unusual situation with flight check and the required coordination was certainly a factor in distracting me. Also; the aircraft that had a navigation problem caused a lot of work all at once. If the position was separated the traffic volume and complexity would have been halved. Additionally; the A319 leading the turn is dangerous and the pilots of those aircraft should be reminded that it is bad practice in such a confined airspace like New York.

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	1037918
Time
Date	201209
Local Time Of Day	1201-1800
Place
Locale Reference	LGA.Airport
State Reference	NY
Aircraft 1
Make Model Name	A319
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	EMB ERJ 135 ER/LR
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Approach Departure
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Deviation - Track / Heading All Types