Narrative:

Clear VFR - unlimited ceiling - I was flight instructor in right seat. We contacted hhr tower just south of hhr class D. We received instructions to make left traffic - cleared to land. We proceeded down hawthorne blvd to just north of alondra park then executed aim 45 degree entry to left downwind. Abeam the tower I requested a short approach to give student a simulated engine out arrival. The tower controller had cleared another aircraft 'left traffic'. He told me later that he thought we would beat the aircraft to the runway. Just past abeam the runway end the other aircraft established not on a downwind but perpendicular to the runway on a left base streaked in front of us (this was just inside the houses that populate the corner of the golf course - way inside normal power on base leg area). I took the controls and executed an evasive 50 degree banked turn to the right away from the traffic. I continued around and rejoined downwind and executed a normal landing. Not sure how this was allowed to occur. The other aircraft clearly didn't follow instructions to enter the traffic pattern for left traffic and instead headed directly on a left base entry - not caught by the controller. We received no traffic advisories advising of the conflict and came very close to colliding with the other aircraft. We saw and avoided - fortunately. [I] wouldn't really like to come that close to a mid-air again.

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Original NASA ASRS Text

Title: A light aircraft Instructor reported an airborne conflict with another light aircraft on approach to HHR.

Narrative: Clear VFR - Unlimited Ceiling - I was flight instructor in right seat. We contacted HHR Tower just south of HHR Class D. We received instructions to make left traffic - CLEARED TO LAND. We proceeded down Hawthorne BLVD to just north of Alondra Park then executed AIM 45 degree entry to left downwind. Abeam the Tower I requested a short approach to give student a simulated engine out arrival. The Tower Controller had cleared another aircraft 'left traffic'. He told me later that he thought we would beat the aircraft to the runway. Just past abeam the runway end the other aircraft established NOT ON A DOWNWIND but perpendicular to the runway on a LEFT BASE streaked in front of us (this was just inside the houses that populate the corner of the golf course - way inside normal power on base leg area). I took the controls and executed an evasive 50 degree banked turn to the right away from the traffic. I continued around and rejoined downwind and executed a normal landing. Not sure how this was allowed to occur. The other aircraft clearly didn't follow instructions to enter the traffic pattern for left traffic and instead headed directly on a left base entry - not caught by the Controller. We received no traffic advisories advising of the conflict and came very close to colliding with the other aircraft. We saw and avoided - fortunately. [I] wouldn't really like to come that close to a mid-air again.

Data retrieved from NASA's ASRS site as of April 2012 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.