An air carrier medium large transport crew descended in response to a TCASII command.

Attributes
ACN	240349
Time
Date	199304
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : lga
State Reference	NY
Altitude	msl bound lower : 3700 msl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : n90
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 200 flight time total : 20000 flight time type : 5000
ASRS Report	240349
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 : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 400 vertical : 400
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While level at 4000 ft MSL, during vectors for a visual to lga runway 22, ATC called VFR traffic 'over manhattan' at 4500 ft MSL. We did not see the called traffic. Shortly thereafter our TCASII picked up the target at 12 O'clock at 3 NM, closing. A 'descend' TCASII RA was signaled, followed by our compliance and a descent to 3700 ft MSL. After 'clear of conflict' was issued, we climbed back to 4000 ft MSL and informed ATC of our TCASII RA.

Original NASA ASRS Text

Title: AN ACR MLG CREW DSNDED IN RESPONSE TO A TCASII COMMAND.

Narrative: WHILE LEVEL AT 4000 FT MSL, DURING VECTORS FOR A VISUAL TO LGA RWY 22, ATC CALLED VFR TFC 'OVER MANHATTAN' AT 4500 FT MSL. WE DID NOT SEE THE CALLED TFC. SHORTLY THEREAFTER OUR TCASII PICKED UP THE TARGET AT 12 O'CLOCK AT 3 NM, CLOSING. A 'DSND' TCASII RA WAS SIGNALED, FOLLOWED BY OUR COMPLIANCE AND A DSCNT TO 3700 FT MSL. AFTER 'CLR OF CONFLICT' WAS ISSUED, WE CLBED BACK TO 4000 FT MSL AND INFORMED ATC OF OUR TCASII RA.

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.