Close proximity air carrier-medium large transport GA-unk above N90 TCA.

Attributes
ACN	91042
Time
Date	198807
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : lga
State Reference	NY
Altitude	msl bound lower : 8300 msl bound upper : 8500
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : n90
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent other
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 6400 flight time type : 3330
ASRS Report	91042
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 180 flight time total : 6000 flight time type : 400
ASRS Report	91227
Events
Anomaly	conflict : nmac
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 0 vertical : 200
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

While on descent from 11000' with clearance to 7000', was issued 'VFR traffic at 12 O'clock.' altitude 8500', unverified, wbound. PNF (captain) spotted traffic and was forced, at traffic acquisition, to take control of aircraft and dive below conflicting traffic. Other aircraft, with landing light on, was not participating in VFR advisory. We were able to level at 7000' but vertical speed approached 6000 FPM rate of descent. The conflicting traffic was masked initially by the background city lights of ny due to the descent angle. Also we tried to advise approach control of the aircraft's altitude position, but unacknowledged for approximately 6-8 flying mi. The evasive maneuver caused numerous disturbances in passenger meal service and caused the F/a's (in the aisle collecting the meals) to lose balance. Attempts to advise ATC of near miss was very difficult because of ATC traffic load. This situation evolved due to several factors: descent angle of aircraft looking down at conflicting traffic which blended into background lights, and in crew's opinion lga/ny TCA ceiling is too low (ie, 7000'). A change in course heading and level off might have prevented such a close encounter.

Original NASA ASRS Text

Title: CLOSE PROX ACR-MLG GA-UNK ABOVE N90 TCA.

Narrative: WHILE ON DSCNT FROM 11000' WITH CLRNC TO 7000', WAS ISSUED 'VFR TFC AT 12 O'CLOCK.' ALT 8500', UNVERIFIED, WBOUND. PNF (CAPT) SPOTTED TFC AND WAS FORCED, AT TFC ACQUISITION, TO TAKE CTL OF ACFT AND DIVE BELOW CONFLICTING TFC. OTHER ACFT, WITH LNDG LIGHT ON, WAS NOT PARTICIPATING IN VFR ADVISORY. WE WERE ABLE TO LEVEL AT 7000' BUT VERT SPD APCHED 6000 FPM RATE OF DSCNT. THE CONFLICTING TFC WAS MASKED INITIALLY BY THE BACKGROUND CITY LIGHTS OF NY DUE TO THE DSCNT ANGLE. ALSO WE TRIED TO ADVISE APCH CTL OF THE ACFT'S ALT POS, BUT UNACKNOWLEDGED FOR APPROX 6-8 FLYING MI. THE EVASIVE MANEUVER CAUSED NUMEROUS DISTURBANCES IN PAX MEAL SVC AND CAUSED THE F/A'S (IN THE AISLE COLLECTING THE MEALS) TO LOSE BALANCE. ATTEMPTS TO ADVISE ATC OF NEAR MISS WAS VERY DIFFICULT BECAUSE OF ATC TFC LOAD. THIS SITUATION EVOLVED DUE TO SEVERAL FACTORS: DSCNT ANGLE OF ACFT LOOKING DOWN AT CONFLICTING TFC WHICH BLENDED INTO BACKGROUND LIGHTS, AND IN CREW'S OPINION LGA/NY TCA CEILING IS TOO LOW (IE, 7000'). A CHANGE IN COURSE HDG AND LEVEL OFF MIGHT HAVE PREVENTED SUCH A CLOSE ENCOUNTER.

Data retrieved from NASA's ASRS site as of August 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.