Don Tuite writes:

No. It's all about flying under the Bravo. The letters refer to the
Echo and Golf airspace.

Suppose I want to depart Half Moon Bay with a passenger and show her
the sights of the city -- fly over the Golden Gate Bridge and
Alcatraz.

For the first part of the flight, I know that if I want to hug the
shoreline (stay in I), I have to fly below 1500 feet. But if I stay
more than 7 nautical miles DME from the SFO VORTAC while flying up the
coast, I'll be in F, so I'll be clear of the Bravo as long as I am
below 2100 feet. Once I'm more than 10 nm DME from the VORTAC (or
halfway between the north end of Lake Merced and the south windmill at
Golden Gate Park, I'm clear of the Bravo if I stay below 3000 ft.

The letters run well past E and G. It looks like they go at least
through K.

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