Did I do this correctly?

[Ryan B]

I like to do things and ask for forgiveness later hehe

Tonight I flew KONT PRDO7 TRM KPSP - given 130 as a final.

When xferd to socal near PSP I asked for GPS-B approach. I was cleared for the approach while flying the PRDO7 to TRM (the leg after NIKKL). Is it legal to look at the enroute charts, and note that the route I was filed is the same as the V64 airway and descend on my own, ensuring my altitude is at or above the MEA? Example. At 130 I was cleared for the approach. After crossing HEMET I descended to 110. After BALDI I descended to 8000, and then I just waited to cross TRM for the full procedure and descended in the hold to 4000.

Is this a legal way to do it?

[Peter Grey]

Yes, if you look on the chart it even tells you it's V64.

[Ryan B]

Sweetness!

[Peter Grey]

So after further review it ends up we may not have gotten this one correct.

While counter intuitive the purpose of charting airways on the DP is to provide general orientation information, not to amend it's altitudes onto the DP.

My reference on this is going to be FAA Order 8260.46E.

(1) Limit the number of altitude requirements to the minimum necessary. ATC
operational restrictions are not permitted on ODPs.

And

d) When ATC requests an altitude restriction for a fix located on a transition
route, it must be at or above the specified minimum en route altitude (MEA) for the route. See
note in paragraph 2-1-1e(1)(b).

(b) When ATC requests a minimum “at or above” altitude restriction at a fix in an
initial SID routing (prior to reaching the SID termination fix) that is higher than the required
procedure design minimum altitude at the same fix, the higher requested ATC altitude then
becomes the minimum altitude at that fix. This altitude must support all procedure design and
criteria requirements [i.e., obstacle clearance/procedure design constraints/navigation solution
and the ATC requirement(s)].

So in simple terms being on the PRADO DP does not allow you to use V64 altitudes in any situation.

The obvious solution is to be cleared via V64, or a direct TRM which removes the PRADO altitude restrictions from the equation.

Sorry about that. Obviously this one ended up being a bit more complex then the first look.

[Ryan B]

So wouldn't you have to issue me an altitude to cross TRM at?

I'm by no means an expert on this exact scenario.... But if you you just say cleared GPS-B approach and I'm at 130, I can't descend until crossing TRM... I'll need one or two holds to descend. That doesn't seem reasonable when the terrain is getting lower as I reach TRM. I wonder if socal would descend me along the route then clear me when I'm a lot closer (and lower) to TRM?

[Peter Grey]

So wouldn't you have to issue me an altitude to cross TRM at?

In theory no as you are correct in the sense that you can descend down to MEA. The trick here is that we were using the wrong MEA. In this case you would have to stay at or above 11000' (the DP MEA).

Obviously as you allude you this is 100% impractical. SOCAL would bring you down to a lower altitude to make this approach possible.

[Ryan B]

Yeah.... hmmm ... I'm curious - what is the MVA along V64 as one approaches TRM?

[Peter Grey]

The MVA starts at 9000 and begins a rapid descent to 1500 about 15 miles West of TRM.