Narrative:

A B757 asked if there was traffic in the near vicinity because they were responding to an RA. I then issued traffic 10 o'clock two miles orbiting at 800 ft. That location was south of class bravo airspace and inside class delta airspace abeam hawthorne airport which lies directly southeast to lax. After issuing the traffic to the B757; he said that he would still be able to make it but that it appeared as if the aircraft was climbing. I then advised that the altitude indicated on him was 900 ft. After the B757 landed; he further elaborated that he only leveled when the RA told him to level but then after receiving the advisories on the traffic still had enough time to land the aircraft. The incident occurred while the B757 was on a three mile final to runway 25L. This is not the first time something like this has occurred. Typically; helicopters orbit in and around that area surrounding the final into lax. The helicopter pilots rarely if ever transgress the bravo airspace unless receiving permission to enter from the helicopter controller. At the time; there was no coordination indicating the fact that a helicopter would transgress bravo airspace. I don't know if the B757's TCAS was extra sensitive or if the helicopter strayed slightly north of course. But when the B757 brought it up; the traffic was approximately two miles south of his position and slowly orbiting which led me to believe it was a helicopter. I never had visual on the traffic.

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Original NASA ASRS Text

Title: A TCAS RA event involving an Air Carrier arrival to the LAX Runway 25 complex. The event resulted from a helicopter operation near Class B airspace.

Narrative: A B757 asked if there was traffic in the near vicinity because they were responding to an RA. I then issued traffic 10 o'clock two miles orbiting at 800 FT. That location was south of Class Bravo airspace and inside Class Delta airspace abeam Hawthorne Airport which lies directly southeast to LAX. After issuing the traffic to the B757; he said that he would still be able to make it but that it appeared as if the aircraft was climbing. I then advised that the altitude indicated on him was 900 FT. After the B757 landed; he further elaborated that he only leveled when the RA told him to level but then after receiving the advisories on the traffic still had enough time to land the aircraft. The incident occurred while the B757 was on a three mile final to Runway 25L. This is not the first time something like this has occurred. Typically; helicopters orbit in and around that area surrounding the final into LAX. The helicopter pilots rarely if ever transgress the Bravo airspace unless receiving permission to enter from the Helicopter Controller. At the time; there was no coordination indicating the fact that a helicopter would transgress Bravo airspace. I don't know if the B757's TCAS was extra sensitive or if the helicopter strayed slightly north of course. But when the B757 brought it up; the traffic was approximately two miles south of his position and slowly orbiting which led me to believe it was a helicopter. I never had visual on the traffic.

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.