aterpster,
Many thanks for the links to the current Jeppesen and FAA charts for KLAX ILS Rwy 06L and ILS Rwy 24R, and FAA documentation for the procedures prior to the resiting of the DME station used for the ILS 06L.
For others, and in confirmation of my
previous post, the latter show that the old DME for Rwy 06L was withdrawn, and the ILS 06L now uses the same DME as the ILS 24R. This means that, on the ILS 06L, the DME reading at the threshold changed from 2.1 (falling) to 0.5 (rising). That is because, whereas the old siting was beyond the far end of the runway (near the localiser antenna), the new one is 0.5 nm before the threshold (near the 24R localiser antenna). So the DME reads zero at a point 0.5 nm before the threshold, reads 0.5 at the threshold, and about 0.7 at the touchdown point.
The ILS 24R is unaffected, because the DME siting has not changed. The reading remains about 2.0 at the threshold, and about 1.9 at the touchdown point. The change of DME siting seems to have been repeated on the three other reciprocal runways at KLAX, halving the number of DMEs needed.
For those who haven't been following this discussion, the Aruba DME station is sited to the side of the runway, close to the touchdown point and the GS antenna. It has only one approach to serve: ILS Rwy 11. It reads 0.2 at the thresold and zero at the touchdown point.
Quote:
"(The FAA never has biased DME transmitters, so these had to be two separate transmitters.)"
Yes, the biased systems are a device in some other countries to enable one, airfield-sited DME not only to serve two reciprocal runways, but also to read zero at the touchdown points (
see my post above). The DME is normally sited equidistant from the two thresholds, so that the bias does not need to be changed when the duty runway is switched. However, it can lead to a surprise, because the DME may be reading a negative value as you vacate the runway, or (briefly) during a missed approach.