Less than standard separation between 2 air carrier aircraft. TCASII involved.

Attributes
ACN	181540
Time
Date	199106
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : tmu
State Reference	CT
Altitude	msl bound lower : 10000 msl bound upper : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zbw tracon : pvd
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : intermediate altitude descent other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 260 flight time total : 15000 flight time type : 860
ASRS Report	181540
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	controller : issued new clearance flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 3000 vertical : 0
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other other

Narrative:

Aircraft approached each other at about a 70 degree angle of intercept. When opposing air carrier Y was first noticed on TCAS it was 400 ft below our altitude. Ocean approach gave us an immediate descent to 9000 ft. Opposing air carrier Y also descended with us. TCAS resolution then gave a climb command. Later ocean approach gave us a climb to 10000 ft and opposing aircraft banked to right away from us. No thunderstorms from or to opposing aircraft were heard and I assume they were on bos center. Air carrier Y was a company medium large transport type.

Original NASA ASRS Text

Title: LTSS BTWN 2 ACR ACFT. TCASII INVOLVED.

Narrative: ACFT APCHED EACH OTHER AT ABOUT A 70 DEG ANGLE OF INTERCEPT. WHEN OPPOSING ACR Y WAS FIRST NOTICED ON TCAS IT WAS 400 FT BELOW OUR ALT. OCEAN APCH GAVE US AN IMMEDIATE DSCNT TO 9000 FT. OPPOSING ACR Y ALSO DSNDED WITH US. TCAS RESOLUTION THEN GAVE A CLB COMMAND. LATER OCEAN APCH GAVE US A CLB TO 10000 FT AND OPPOSING ACFT BANKED TO R AWAY FROM US. NO TSTMS FROM OR TO OPPOSING ACFT WERE HEARD AND I ASSUME THEY WERE ON BOS CENTER. ACR Y WAS A COMPANY MLG TYPE.

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.