The altitude restrictions depicted in the profile view are valid IF, AND ONLY IF, you are established on the approach (I read that as LOC alive) once that is true, check the DME, if inside of MERCE (<16.2) then start down to cross FAF @2200, or GS intercept, make sense? Otherwise, in the turn, you may not have obstacle clearance or be above min vectoring altitude(not your problem, since you can't tell what it is). Thats most likely why it says maintain 4000 till MERCE on the segment from PERMS to MERCE. There must also be a reason why there is no PT allowed on this approach, perhaps not enough protected airspace with associated obstacle clearance in the LOC path.

Might not be wrong to start down but, not a good idea, IMO. I must first confess, I fly cargo, so I don't really give a hoot about how the boxes feel in the descent, but if planned for, the whole thing should be able to be done smoothly and comfortably for most any aircraft. I have not been to LAX lately, but isn't the speed limit there just 200 KIAS?

I'd maintain 4000 till MERCE or LOC intercept (alive) then descend to the next restriction. I think if you were to do that, you could not be wrong, you just might be intercepting the GS from above, and you should have 10-12 DME to fix it, but maybe only 4-6 DME to meet your carrier's stabilized approach requirements so, your milage may vary.

ImperialxRat

A good question, if you need the extra 80', and you just might on those crappy days with GS inop. As for the when would you use the arbie fix minimums (S-LOC 24R) as opposed to the normal S-LOC mins of 540.?

I think, one uses the ARBIE mins of 460 vice 540 when you are flying the S-LOC 24R and have DME, being careful of the runway lighting status for the RVR restrictions prior to commencing. In other words, you must cross ARBIE at 540, if you can identify ARBIE (has to be with DME at 3.4, and DME is not required equipment for the approach in general, there is the matter of that timing thing ), then and only then, you can continue down to 460 on the LOC. Have I missed anything here?

JMHO, standing by to be corrected.