Paraphrased from my email conversation with the feeder of Boeing Field, who requested this added frequency.....
" 128.55. That is the frequency for the Los Angeles Special Flight Rules Area, which is the Northwest-Southeast airspace corridor directly above LAX. VFR aircraft use this corridor to cross above LAX at either 3500 ft (southeast bound) or 4500 ft (northwest bound). It is basically a tunnel in the sky above LAX from Imperial Blvd to Marina Del Ray (Ballona Creek).
The frequency is pretty straightforward, as pilots typically report their positions entering, over LAX, and exiting the area. It tends to be one-way conversations, unless pilots fear a collision and they start talking to each other. It’s also a great way to monitor aircraft coming into the LA area (Santa Monica, Hawthorne, and Torrance).
The corridor keeps transitioning VFR traffic out of the way of the heavy LAX traffic just below, but things sometimes become interesting if an LAX aircraft has to do a missed approach or go-around. Obviously they climb, and are “supposed” to stay below the corridor."
Cheers,
Rob
-KLAX Feeder-