Flight crew of a DC8 freighter, on departure climb, made an evasive action turn to assure separation with a descending ATR42. ATC issued a TA and cleared the DC8 to a higher altitude which further reduced the opposite direction separation. The ATR42 also made an evasive action turn when meeting the DC8 head-on.

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Attributes
ACN	382452
Time
Date	199710
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : bdl
State Reference	CT
Altitude	msl bound lower : 15000 msl bound upper : 15000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	DC-8F
Flight Phase	climbout : intermediate altitude
Route In Use	enroute airway : zbw
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	ATR 42
Navigation In Use	Other
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 155 flight time total : 10000 flight time type : 6500
ASRS Report	382452
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	other other : other pilot : atp pilot : cfi
Experience	flight time last 90 days : 100 flight time total : 5000 flight time type : 100
ASRS Report	382565
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 1500 vertical : 300
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

The ATR was pointed out as traffic (to the DC8) by ZBW controller and the DC8 was also pointed out to the ATR. The ATR responded to the traffic call by stating the DC8 was on TCASII. When the DC8 saw the ATR traffic from approximately 2 mi and called 'traffic in sight' to ATC, the center controller then issued a clearance (DC8) to 'climb at pilot's discretion to 17000 ft.' neither aircraft had leveled at 15000 ft, 'ATR descending and DC8 climbing.' the ATR appeared at first sighting to be on a parallel course to the DC8 so no evasive action was taken on either part. The TCASII on the ATR must have urged the ATR crew to take evasive action and by the time a close course was near both aircraft turned right to avoid a collision. I believe the clearance by ATC for both aircraft at 15000 ft and the clearance for pilot discretion to climb (DC8) to 17000 ft were confusing and ambiguous and led to this near midair or near-miss. I believe the TCASII was the saving grace on the ATR and wish TCASII was installed on DC8 freighters. This would have provided earlier detection and avoidance.

Original NASA ASRS Text

Title: FLC OF A DC8 FREIGHTER, ON DEP CLB, MADE AN EVASIVE ACTION TURN TO ASSURE SEPARATION WITH A DSNDING ATR42. ATC ISSUED A TA AND CLRED THE DC8 TO A HIGHER ALT WHICH FURTHER REDUCED THE OPPOSITE DIRECTION SEPARATION. THE ATR42 ALSO MADE AN EVASIVE ACTION TURN WHEN MEETING THE DC8 HEAD-ON.

Narrative: THE ATR WAS POINTED OUT AS TFC (TO THE DC8) BY ZBW CTLR AND THE DC8 WAS ALSO POINTED OUT TO THE ATR. THE ATR RESPONDED TO THE TFC CALL BY STATING THE DC8 WAS ON TCASII. WHEN THE DC8 SAW THE ATR TFC FROM APPROX 2 MI AND CALLED 'TFC IN SIGHT' TO ATC, THE CTR CTLR THEN ISSUED A CLRNC (DC8) TO 'CLB AT PLT'S DISCRETION TO 17000 FT.' NEITHER ACFT HAD LEVELED AT 15000 FT, 'ATR DSNDING AND DC8 CLBING.' THE ATR APPEARED AT FIRST SIGHTING TO BE ON A PARALLEL COURSE TO THE DC8 SO NO EVASIVE ACTION WAS TAKEN ON EITHER PART. THE TCASII ON THE ATR MUST HAVE URGED THE ATR CREW TO TAKE EVASIVE ACTION AND BY THE TIME A CLOSE COURSE WAS NEAR BOTH ACFT TURNED R TO AVOID A COLLISION. I BELIEVE THE CLRNC BY ATC FOR BOTH ACFT AT 15000 FT AND THE CLRNC FOR PLT DISCRETION TO CLB (DC8) TO 17000 FT WERE CONFUSING AND AMBIGUOUS AND LED TO THIS NEAR MIDAIR OR NEAR-MISS. I BELIEVE THE TCASII WAS THE SAVING GRACE ON THE ATR AND WISH TCASII WAS INSTALLED ON DC8 FREIGHTERS. THIS WOULD HAVE PROVIDED EARLIER DETECTION AND AVOIDANCE.

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.