Originally Posted by
AtoBsafely
For RPLL, the MVA to the east is 3500' from 10-20nm.
You must be looking at a different MVA chart than mine. To the East it looks like 3500 from 10 to 15 on mine, > 15 nm MVA is 7000 MSL. 3500 at D20 would place you 327 ft above a 3173 MSL mountain peak out there.
Originally Posted by
AtoBsafely
In this case, you can capture the glidepath outside 10nm, as the 3.1 degree glide slope is 3550' at 10nm.
Looks to me like 3500 MSL would put you about 180 ft above the GS at 10 IMA. SIN 3.06 X 10 X 6076 = 3243 add 75 ft TDZE = 3316 GS alt at D10 IMA
Originally Posted by
AtoBsafely
If you aren't certain of the math, just stay at 3500' and capture the glide path at 10nm (from 3500', which is what your ATC clearance would be).
You may only descend on the GS if you're established on the localizer. You may have assumed that was understood, but it's worth clarifying for those readers for whom it's not obvious.
Anyway, it looks to me like it's not geometrically possible for ATC to issue a vector that complies with the MVAs, and intercepts the localizer at an angle of 30 degrees or less, below the GS. Even if they brought you in from the southeast on a vector that clips the D15/R080 point, aiming directly for D10 on the localizer, (shallowest possible LOC intercept angle within the 3500 MVA sector) you're still going to intercept the localizer at about 50 degrees, (yes, I did the math, I'm bored) as well as be above the glide slope.
There is another place which, IME is like this; Fairbanks, Alaska (PAFA) ILS 19R (now 20R) I used to fly for an airline based there, and we did all the training and checking in the airplane. So, I did a lot of ILS19R procedures, and every single time, approach would put you on the localizer, close in to the FAF, at a steep intercept, and above the GS .... every time. I haven't ever seen an MVA chart for Fairbanks, but I have to assume that they were up against some MVA sectors which didn't really work, geometrically. Either that, or they were just really consistently bad at vectoring, because I don't think I ever got a vector that intercepted the LOC at less than 30 degrees, 2 miles from the FAF and below the GS.