Perhaps an
LA pilot can explain this better, but I'll give it a shot. Some of this information was previously posted
here...
In the U.S., helicopter routes can be identified on terminal area charts of major metropolitan areas. However, you can purchase
specific "Helicopter Route Charts" for Chicago, New York, Los Angeles, Boston, Baltimore-Washington, Dallas - Ft. Worth, Houston, and Salt Lake City. These are the
ONLY areas for Helicopter Route Charts (that I know of). They are easier to read than standard charts (blue, brown, and white colors only) and provide a lot of detailed information for low altitude flights.
I don't mean to insult anyone's intelligence, but I'll list the following example anyway. In the Washington area, they put a picture of the Mormon Temple on the chart. It actually looks like a drawing of the Temple, and it says "Mormon Temple" on the chart... very easy. Helicopter routes usually parallel major roads or rivers and there are different frequencies for each route (depends on approach heading to controlling ATC).
Example...
The chart will be very specific about frequencies and instructions. In this case, I rely on the dialogue box for frequencies, because it is specific to helicopters...
Eastbound Contact Washington Tower on 120.75
Also, each route will be highlighted in dark blue with a route number and the frequency of that route along your corridor. Depends on the day of the week, but usually ATC will have dedicated staff for just the helicopter routes. Oh ya,
helicopters entering a route will usually squak a predfined transponder code until you get into Class B (codes found on chart, as well).
Something like this...
You squak 5274 for Civilian Helicopter (as specified on chart) before you even call approach control. You aren't in Class B, yet - but this is like squaking 1200 for VFR (only it tells ATC you are a helicopter and they can tell what route you are following before you even contact them). When you get close to the Class B, you'll have to follow normal procedures to enter Class B.
The call goes something like this...
"Washington, Helicopter N2649D 3 miles west Cabin John for Route One... request Class B, landing Reagan."
At our altitudes, it is doubtful that ATC will have you on radar contact until you get much closer, which is why radio communications/transponder is much more important when using the routes. You wouldn't think it, but there is a LOT of helicopter traffic along these routes. In the U.S., we usually fly on the RIGHT side of the route (road, river, whatever), and hope the other guy coming the opposite direction is doing the same. One more thing... if you aren't in Class B (under ATC control) and switch helicopter routes, make sure you switch over to the right frequency (each route will usually have it's own freq and you self-announce when outside TRACON).