Aircraft landing vny received TCASII ATC alerts regarding unknown C172 traffic on short final.

Attributes
ACN	600673
Time
Date	200311
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : vny.airport
State Reference	CA
Altitude	msl single value : 800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : vny.tower
Operator	general aviation : corporate
Make Model Name	Medium Transport
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tower : vny.tower
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	None
Person 1
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 200 flight time total : 6000 flight time type : 400
ASRS Report	600673
Person 2
Affiliation	company : corporate
Function	flight crew : first officer
Events
Anomaly	conflict : airborne critical
Independent Detector	aircraft equipment : tcas other controllera other flight crewa
Resolutory Action	controller : issued advisory flight crew : took evasive action
Miss Distance	horizontal : 400 vertical : 400
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

On short final to runway 16R at vny, tower advised immediate climb or turn for traffic at our altitude converging. At the same time we received a TCASII command to climb, which we did. We cleared the traffic without further incident and completed the landing. The traffic came out of nowhere. It crossed the extended centerline for runway 16R in a wnw direction, it looked like a C172. It was a maneuver that we reported to tower and they advised no problem and nice job. Thanks for TCASII.

Original NASA ASRS Text

Title: ACFT LNDG VNY RECEIVED TCASII ATC ALERTS REGARDING UNKNOWN C172 TFC ON SHORT FINAL.

Narrative: ON SHORT FINAL TO RWY 16R AT VNY, TWR ADVISED IMMEDIATE CLB OR TURN FOR TFC AT OUR ALT CONVERGING. AT THE SAME TIME WE RECEIVED A TCASII COMMAND TO CLB, WHICH WE DID. WE CLRED THE TFC WITHOUT FURTHER INCIDENT AND COMPLETED THE LNDG. THE TFC CAME OUT OF NOWHERE. IT CROSSED THE EXTENDED CTRLINE FOR RWY 16R IN A WNW DIRECTION, IT LOOKED LIKE A C172. IT WAS A MANEUVER THAT WE RPTED TO TWR AND THEY ADVISED NO PROB AND NICE JOB. THANKS FOR TCASII.

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.