C172 in vny traffic pattern is issued unclear instructions from tower resulting in conflict.

Attributes
ACN	791465
Time
Date	200806
Place
Locale Reference	airport : vny.airport
State Reference	CA
Environment
Flight Conditions	VMC
Weather Elements	Turbulence
Light	Daylight
Aircraft 1
Controlling Facilities	tower : vny.tower tower : mry.tower
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Route In Use	approach : traffic pattern
Flight Plan	None
Aircraft 2
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	climbout : intermediate altitude
Person 1
Affiliation	other
Function	instruction : instructor oversight : pic
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 100 flight time total : 4000 flight time type : 1500
ASRS Report	791465
Events
Anomaly	conflict : airborne critical
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Miss Distance	horizontal : 400 vertical : 500
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	Ambiguous

Narrative:

Aircraft #1 was instructed to fly straight out off runway 34L at vny; crosswind turn will be advised. Turn crosswind now. After established on crosswind turning downwind; we were advised to follow aircraft #2 on crosswind. Aircraft #1 'negative contact.' controller; 'traffic is northbound east of the freeway; stay west of the freeway.' aircraft #1; 'I see the transition traffic; where is the traffic to follow?' we were advised; 'you will see him eventually.'

Original NASA ASRS Text

Title: C172 IN VNY TFC PATTERN IS ISSUED UNCLEAR INSTRUCTIONS FROM TWR RESULTING IN CONFLICT.

Narrative: ACFT #1 WAS INSTRUCTED TO FLY STRAIGHT OUT OFF RWY 34L AT VNY; XWIND TURN WILL BE ADVISED. TURN XWIND NOW. AFTER ESTABLISHED ON XWIND TURNING DOWNWIND; WE WERE ADVISED TO FOLLOW ACFT #2 ON XWIND. ACFT #1 'NEGATIVE CONTACT.' CTLR; 'TFC IS NBOUND E OF THE FREEWAY; STAY W OF THE FREEWAY.' ACFT #1; 'I SEE THE TRANSITION TFC; WHERE IS THE TFC TO FOLLOW?' WE WERE ADVISED; 'YOU WILL SEE HIM EVENTUALLY.'

Data retrieved from NASA's ASRS site as of May 2009 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.