Well, I found the missing 5ft:
Also, those elevations are all wrong. In the interests of reducing confusion when people went from A Pad to B Pad, the numbers in use for A were faithfully reproduced over on B. But the pad deck on B was five feet higher, so every one of those numbers is five feet too low. A small thing, to be sure, but a very real thing, too.
Source (warning, the author has a colorful language)
So it should be:
> bottom FSS level (level 75), 75ft AMSL pad A, 80ft at pad B
27ft gap
> pad surface 48ft AMSL pad A, 53ft at pad B
42ft deep flame trench
> bottom of flame trench at 6ft AMSL pad A, 11ft at pad B
---------- Post added 10-21-19 at 02:34 AM ---------- Previous post was 10-20-19 at 02:13 PM ----------
Turns out the MLP pedestal pins, and probably the north end, aren't exactly correct: to visually align the water pipes I loaded both the pad and MLP meshes into blender, and decided to check that the actual error was between the pins and pedestals, and there is a 2 inch error on the 4 north pins. Re-checked things and the pad is OK, but the MLP has the distance between the center and south pins 2 inches too short, and I think I know where it comes from. The MLP was probably sized using the dimensions of the side panels, and in the area in question they are almost all 8 feet wide, except for the 3 center ones which are 8 feet 8 inches. Thus our MLP has 8 * 12 = 96 feet between the pins instead of the correct (9 * 8) + (3 * 8.6666) = 98 feet indicated in several diagrams.
For now things should remain as is, as it is a small error and nothing depends on it. The MLP/pad were aligned analyticaly using the south pedestals as reference, so those match, and the others will match as well by "just" shifting the north end of the MLP. So it is good task for SSU 5.1.
In other news, after finding the missing 5ft in the morning, the flame trench is now fully corrected, as well as the flame deflector and water pipes. The only missing part on the hardstand mesh is cleaning, and correcting the position and animation of the side flame deflectors.