OzExpat- Our flight dept./fleet capt. seems to agree with the ATC interpretation of the PANS OPS., or if not agree, have anyhow issued instructions to pilots to follow the ATC interpretation. I wanted to basically find out and get views on the ATC inerpretation.
keithl-
"I thought that some level segment was always necessary (though maybe not over a specified distance) in order to ensure the GP was intercepted from below. Thus avoiding false lobes. "
The Boeing737 FCTM says that the Glideslope may be captured from above or below. Besides there are numerous ways to detect if you are on a false glideslope (also mentioned in the Boeing FCTM):
1. Abnormal altitude range distance relationship (Normal would be aprox. 300ft HAT per NM of distance from the runway for a 3 degree glideslope)
2. Abnormal pitch and ROD would be apparent on a flase glidepath.
Also don't have my GSP handy at the moment, but remember reading that the first false lobe of the glideslope would be occur at a sufficient height, that it would be very obvious that your are getting a false glideslope. Infact, I remember getting a false glideslope at an altitude of about 8000ft at a distance of some 17nm to touchdown on the localizer ( please don't ask how we got there
)
DFC- totally agree with you.
Cheers....
