757 VOR lacking AUTO/MAN switch
Thread Starter
Joined: Dec 2001
Posts: 121
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From: Finland
757 VOR lacking AUTO/MAN switch
Hi all,
I'm seeking for an explanation to this: http://www.!!!!!!!!!!!!!!/open.file/0956858/L/
This UAL 757 does not have the AUTO/MAN switch on its VOR control panels. Thus, is one of these three possibilities the explanation to this:
1. The VOR Radios are tuned automatically and can't be switched to Manual. (not likely)
2. The VOR Radios are tuned manually and can't be switched to AUTO. (not likely)
3. The VOR Radios are tuned automatically with Manual remote tuning via the CDU.
This is the first and only of its kind I've ever seen, so any additional information would be good
.
cheers,
Tero
I'm seeking for an explanation to this: http://www.!!!!!!!!!!!!!!/open.file/0956858/L/
This UAL 757 does not have the AUTO/MAN switch on its VOR control panels. Thus, is one of these three possibilities the explanation to this:
1. The VOR Radios are tuned automatically and can't be switched to Manual. (not likely)
2. The VOR Radios are tuned manually and can't be switched to AUTO. (not likely)
3. The VOR Radios are tuned automatically with Manual remote tuning via the CDU.
This is the first and only of its kind I've ever seen, so any additional information would be good
.cheers,
Tero
Joined: Aug 1999
Posts: 1,050
Likes: 4
From: England
Couldn't say for sure, never flown a 75.
But the b737s I used to fly had various avionics fits.
Some had Manual / Auto boxs: Manual = Pilot controlled vor+dme, Auto = assigned by the FMC for FMC radio nav.
Others had the same as on you picture, which worked by having frequency agile DMEs, so VOR and DME permanantly under pilot control, with DME frequency hopping to tune other channels to derive a radio nav fix.
DMEs in use accessable via the NAV STATUS pages if I recall correctly, so you can see if the FMC is either (1) trying to tune the aid, or (2) successfully interrogating the aid, or (3) actually using it for a fix. (a combination of colours and / or inverse video being used to denote which, according to the vintage of the CDU). You can also inhibit the system from using specified DMEs (e.g. if it is notamed unreliable, or clearly pulling your radio fix off), so there is a degree of control over the auto tuning.
Hope that helps,
CPB
But the b737s I used to fly had various avionics fits.
Some had Manual / Auto boxs: Manual = Pilot controlled vor+dme, Auto = assigned by the FMC for FMC radio nav.
Others had the same as on you picture, which worked by having frequency agile DMEs, so VOR and DME permanantly under pilot control, with DME frequency hopping to tune other channels to derive a radio nav fix.
DMEs in use accessable via the NAV STATUS pages if I recall correctly, so you can see if the FMC is either (1) trying to tune the aid, or (2) successfully interrogating the aid, or (3) actually using it for a fix. (a combination of colours and / or inverse video being used to denote which, according to the vintage of the CDU). You can also inhibit the system from using specified DMEs (e.g. if it is notamed unreliable, or clearly pulling your radio fix off), so there is a degree of control over the auto tuning.
Hope that helps,
CPB
