Possible Pyramid location (and maybe PYR too)

Message posted by Salty on December 28, 2005 at 18:22:55 PST:

Concerning the discussion about the location of Pyramid and Planet, I don't think BTY060030 is Pyramid. After listening to some audio, I repeatedly hear that the gear goes down at or around the Pyramid fix.

One one of the audio segments, Razor 51 calls in to the tower approaching Pyramid, and the field has been in sight already. The BTY060030 fix is some 20-odd miles away, so it seems unlikely to get a visual on the runway from there. Also they must be close to the field to be in contact with the tower vs. (Dreamland) Control. The tower asks to report gear down, and later Razor 51 reports gear down, left base. Left base means they are flying perpendicular to the extended runway line, and will be turning left to line up with the runway for the final approach.

In another example, Razor 09 is cleared for the visual to runway 32 by Control, switches to Tower, and reports "coming in overhead Pyramid for left base 32".

So it would appear Pyramid is either in line with the extended runway line, or at some not terribly far away WSW prior to it.

From what I understand, gear down usually happens at some point around turning on final approach (getting in line with the runway). I've seen more than a few instances that this occurs at the outer marker, which is a 75 MHz beacon a number of miles out and in line with the runway.

For Groom, the outer marker is most likely at 3710'21.94"N 11546'19.35"W, about 3 miles from the runway and it's the furthest building approximately in line with the runway (it's actually between the closed 32L and 32 extended runway lines, more towards 32L). Note that there's also a large shadow along the lower part of the building, which may be a large vertical antenna. An outer marker antenna need not be that big, but an NDB antenna may be a large horizontal array (which would be pretty much invisible on the Google Earth resolution) or a good sized vertical antenna. This may be the location of the 414 kHz NDB antenna PYD. Having the fix Pyramid and PYD at the same place does make sense. This would also provide a good way to approach the 32 approach from a long distance.

One thing to note, Don Davis back in 1997 pinpointed the PYD beacon to 5 miles west of Groom, although I've been told recently with someone with radio direction finding experience that the methods used can induce large errors. What's interesting is a location in that are would be around the flight path of incoming Janets.

There are also a couple of small structures at 37 9'46.28"N, 11546'48.13"W, one of which is too reflective to be identified, the other is just too small. These are about 0.8 miles west from the presumed outer marker. Perhaps this is Pyramid, although it could be Planet, but that seems unlikely given the small distance. I would imagine Planet would be some further distance away. Perhaps the BTY fix is Planet.

Suggested topics for further research (meaning it's pretty unlikely I'm going to be able to make the haul out there anytime soon, and if anyone is feeling especially bored):

1) What is the actual time between clearances to Planet/Pyramid and upon reaching Pyramid?

2) Observation of the Janets and radio transmissions to see when they approach Pyramid, or at least gear down (although this may be a stretch considering the distances involved).

3) Can the two sites mentioned above (outer marker and structures 0.8 miles away) be photographed from Tikaboo? What looks to be the Desert Range blocks some of the view far south of the base, but I don't think it obscures it that far south.

4) Do Runway 14 landings include clearances to Pyramid? This would only make sense if they were making a left downwind. They would be flying a few miles south of the runway, turning north at some point east of the runway, flying parallel to the runway at some distance, then turning left to base, then left to final. This may already be in the audio clips, but I haven't gone through them all in detail yet. If they do get a Pyramid routing for runway 14, and get a right downwind/right base, then Pyramid is likely not in line with the extended runway line, but instead some distance west of the base.

Because inquiring minds of trivial matters want to know ;-)


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