Cessna landing runway 33 at oak experienced an near midair collision with pattern traffic for runway...

Narrative:

Following ATC instructions; I was in a right downwind for runway 33; cleared to land runway 33. Suddenly; another cessna cut in front of us at the same altitude. I estimate that there was only 100 ft of horizontal separation; and no vertical separation; at the nearest point. The plane looked as though it was turning from a right crosswind for runway 27R into a right downwind; but the pilot had turned crosswind before the end of runway 27R. I heard the other pilot advise ATC that he had spotted us; but was not previously aware of us. I was also not aware that another plane was in the pattern for runway 27R. After landing; I asked oakland tower for their landline number. I called the tower and advised the tower that there had been a loss of separation; and that neither of the cessna pilots appeared to have been advised of the presence of the other; and neither reported the other in sight. The cessna in the 27R pattern should have been instructed to continue upwind until I was clear of the pattern and had landed on 33. The controller I spoke to said that we were in class C and so we were being separated; but we were at the same altitude and there did not appear to be sufficient horizontal separation. I am not sure that the controller understood how close the near-miss was. This incident could easily have resulted in a mid-air collision. Because runway 33 and 27R are both right traffic patterns; it is possible for planes to converge in the patterns if both are in use. At a minimum; ATC must ensure that each pilot is aware of other aircraft and that the pilots can apply visual separation. If not; then ATC should ensure that a pilot in the 27R pattern extends his/her upwind until separation is assured.

Original NASA ASRS Text

Title: Cessna landing Runway 33 at OAK experienced an NMAC with pattern traffic for Runway 27R; no ATC traffic advisories were issued to either aircraft.

Narrative: Following ATC instructions; I was in a right downwind for Runway 33; cleared to land Runway 33. Suddenly; another Cessna cut in front of us at the same altitude. I estimate that there was only 100 FT of horizontal separation; and no vertical separation; at the nearest point. The plane looked as though it was turning from a right crosswind for Runway 27R into a right downwind; but the pilot had turned crosswind before the end of Runway 27R. I heard the other pilot advise ATC that he had spotted us; but was not previously aware of us. I was also not aware that another plane was in the pattern for Runway 27R. After landing; I asked Oakland Tower for their landline number. I called the Tower and advised the Tower that there had been a loss of separation; and that neither of the Cessna pilots appeared to have been advised of the presence of the other; and neither reported the other in sight. The Cessna in the 27R pattern should have been instructed to continue upwind until I was clear of the pattern and had landed on 33. The Controller I spoke to said that we were in Class C and so we were being separated; but we were at the same altitude and there did not appear to be sufficient horizontal separation. I am not sure that the Controller understood how close the near-miss was. This incident could easily have resulted in a mid-air collision. Because Runway 33 and 27R are both right traffic patterns; it is possible for planes to converge in the patterns if both are in use. At a minimum; ATC must ensure that each pilot is aware of other aircraft and that the pilots can apply visual separation. If not; then ATC should ensure that a pilot in the 27R pattern extends his/her upwind until separation is assured.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1106353
Time
Date	201308
Local Time Of Day	1801-2400
Place
Locale Reference	OAK.Airport
State Reference	CA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	Landing
Flight Plan	None
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	Final Approach
Route In Use	Other Traffic Pattern
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Private
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 130 Flight Crew Type 110
Events
Anomaly	ATC Issue All Types Conflict NMAC
Miss Distance	Horizontal 100 Vertical 0

Cessna landing runway 33 at oak experienced an near midair collision with pattern traffic for runway 27R; no ATC traffic advisories were issued to either aircraft.