Medium large transport follows TCASII RA has less than standard separation from mdt.

Attributes
ACN	279379
Time
Date	199408
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : n90
State Reference	NY
Altitude	msl bound lower : 3000 msl bound upper : 3300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : n90
Operator	common carrier : air carrier
Make Model Name	DHC-7
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	ATR 42
Operating Under FAR Part	Part 121
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 200 flight time total : 10500 flight time type : 3000
ASRS Report	279379
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : required legal separation non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action flight crew : returned to intended course or assigned course
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 6000 vertical : 200
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

With new york approach, assigned altitude 3000 ft assigned heading 090 degrees. Flight dca -- hpn received a TCASII 'RA' to climb. We followed the TCASII instruction to climb and notified ATC of such action. After the 'RA' was over (we had climbed 300 ft) we notified ATC we were returning to assigned altitude. He informed us we came close to an ATR aircraft. The ATR reported to the controller he had the DHC7 in sight and said that he didn't have to make any deviations from heading or altitude. We never received an additional 'RA' command from TCASII during the incident.

Original NASA ASRS Text

Title: MLG FOLLOWS TCASII RA HAS LTSS FROM MDT.

Narrative: WITH NEW YORK APCH, ASSIGNED ALT 3000 FT ASSIGNED HDG 090 DEGS. FLT DCA -- HPN RECEIVED A TCASII 'RA' TO CLB. WE FOLLOWED THE TCASII INSTRUCTION TO CLB AND NOTIFIED ATC OF SUCH ACTION. AFTER THE 'RA' WAS OVER (WE HAD CLBED 300 FT) WE NOTIFIED ATC WE WERE RETURNING TO ASSIGNED ALT. HE INFORMED US WE CAME CLOSE TO AN ATR ACFT. THE ATR RPTED TO THE CTLR HE HAD THE DHC7 IN SIGHT AND SAID THAT HE DIDN'T HAVE TO MAKE ANY DEVS FROM HEADING OR ALT. WE NEVER RECEIVED AN ADDITIONAL 'RA' COMMAND FROM TCASII DURING THE INCIDENT.

Data retrieved from NASA's ASRS site as of July 2007 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.