VFR C172 on base leg for hef experienced conflict with traffic inbound to same complex runway.

Attributes
ACN	665195
Time
Date	200507
Place
Locale Reference	airport : hef.airport
State Reference	VA
Altitude	agl single value : 500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : hef.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	VFR
Aircraft 2
Controlling Facilities	tower : hef.tower
Operator	general aviation : personal
Make Model Name	Cessna Aircraft Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Route In Use	approach : traffic pattern
Person 1
Affiliation	other
Function	instruction : trainee
Experience	flight time last 90 days : 30 flight time total : 120 flight time type : 120
ASRS Report	665195
Person 2
Affiliation	other
Function	instruction : instructor
Events
Anomaly	conflict : airborne critical
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance
Miss Distance	horizontal : 500 vertical : 200
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	Ambiguous

Narrative:

Was talking to hef tower controller. Told him 2 mi out inbound for runway 34R. He said cleared to land. I repeated cleared to land runway 34R. I was on base leg at the time with my instructor in the right seat. As I turned to final; raising the wing; my instructor looked right and said 'wow; where is he going?' I looked right and saw the other aircraft on my right with 500 ft horizontal and about 200 ft above me. I turned away (right) in a circle under him -- a full 360 degrees; as he was then told by ATC to land on runway 34L. Thus; either he had been cleared on the same runway and was switched to runway 34L after he called ATC and asked 'do you see that other aircraft?' or he was cleared to cross paths with me on the base leg. Both are serious safety issues. Manassas has had problems with this controller before; but nothing happens. Does someone have to die before we respond?

Original NASA ASRS Text

Title: VFR C172 ON BASE LEG FOR HEF EXPERIENCED CONFLICT WITH TFC INBOUND TO SAME COMPLEX RWY.

Narrative: WAS TALKING TO HEF TWR CTLR. TOLD HIM 2 MI OUT INBOUND FOR RWY 34R. HE SAID CLRED TO LAND. I REPEATED CLRED TO LAND RWY 34R. I WAS ON BASE LEG AT THE TIME WITH MY INSTRUCTOR IN THE R SEAT. AS I TURNED TO FINAL; RAISING THE WING; MY INSTRUCTOR LOOKED R AND SAID 'WOW; WHERE IS HE GOING?' I LOOKED R AND SAW THE OTHER ACFT ON MY R WITH 500 FT HORIZ AND ABOUT 200 FT ABOVE ME. I TURNED AWAY (R) IN A CIRCLE UNDER HIM -- A FULL 360 DEGS; AS HE WAS THEN TOLD BY ATC TO LAND ON RWY 34L. THUS; EITHER HE HAD BEEN CLRED ON THE SAME RWY AND WAS SWITCHED TO RWY 34L AFTER HE CALLED ATC AND ASKED 'DO YOU SEE THAT OTHER ACFT?' OR HE WAS CLRED TO CROSS PATHS WITH ME ON THE BASE LEG. BOTH ARE SERIOUS SAFETY ISSUES. MANASSAS HAS HAD PROBS WITH THIS CTLR BEFORE; BUT NOTHING HAPPENS. DOES SOMEONE HAVE TO DIE BEFORE WE RESPOND?

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