Standby RMI

[J D ADAM]

Hi All

Just out of interest (and because I wasn't quite certain what an ISFD was!!!!) I Googled and found as below. Not related to the Queen but I found it very interesting.  Note that the ISFD cannot be switched off from the cockpit.  

http://www.b737.org.uk/flightinsts.htm

Cheers
Derek

[Will]

I noticed the ILS/MLS switch... will PSX be able to receive MLS signals, and fly MLS approaches?  Related question: are any of those curved-path MLS approaches still in use anywhere?

[Qavion]

I thought ISFD's were MAG only.

I guess they are designed to mimic the whiskey compass... Unfortunately, the compass information only lasts as long as the Main Batteries do.

Note that the ISFD cannot be switched off from the cockpit.

If this were really the case, Derek, the ISFD dedicated battery would go flat on a dead ship after a few hours The Main Battery Switch provides the logic to shut down the ISFD.
The ISFD dedicated battery recharge time is quite long. If the battery went flat just prior to departure, we would have to delay the aircraft.

Not sure about the MLS these days, but GPS approaches have been trialled by our airline. We are modifying our FMC's to become GPS approach-capable.

Cheers.
Q>

[Hardy Heinlin]

I noticed the ILS/MLS switch... will PSX be able to receive MLS signals, and fly MLS approaches?  Related question: are any of those curved-path MLS approaches still in use anywhere?

PS1 has MLS, PSX has MLS. In the current airac cycle, however, there's no MLS facility. I think Heathrow is just starting with its brandnew MLS.


Cheers,

|-|ardy

[delcom]

That's right Q.

Derek,
the ISFD is NOT powered trough the battery switch, it seeks only ground through the battery switch. This provides an enable signal regardless of main battery status. If you have flat main batteries (or they are removed) with battery switch ON, the ISFD will still display its basic functions attitude, altitude and airspeed for about 150 minutes from its own dedicated battery. All the extra goodies like ILS and HDG info are removed (because their data sources are not powered).

cheers,
d

[Phil Bunch]

Hi All

Just out of interest (and because I wasn't quite certain what an ISFD was!!!!) I Googled and found as below. Not related to the Queen but I found it very interesting.  Note that the ISFD cannot be switched off from the cockpit.  

http://www.b737.org.uk/flightinsts.htm

Cheers
Derek

Thanks for the link - I was surprised to read that an HUD display is available for the 737.  Makes me think about adding some missiles and guns, and chasing bad guys around the skies (grins).  Who needs fighter planes?!  (more grins)

[Will]

(Mixing up topics within one thread)  Hardy, do you know if the Heathrow MLS is going to have a track that's in more than two dimensions?  I.e. legs, or curves?

[J D ADAM]

Hi All
Thanks guys for your descriptions. I was only repeating what was mentioned in

http://www.b737.org.uk/flightinsts.htm  regarding the ISFD

and this of course related to the 737.

Cheers
Derek

[Hardy Heinlin]

(Mixing up topics within one thread)  Hardy, do you know if the Heathrow MLS is going to have a track that's in more than two dimensions?  I.e. legs, or curves?

I don't think they use a changing azimuth. From what I've read they prefer the MLS just because microwaves are not subject to interferences caused by vehicles on the ground or aircraft in the far end of the runway, so traffic separation can be tighter and safer.

The Anchorage MLS approach in PS1 also uses a fixed azimuth. I don't know how you could create curves. You certainly can change the azimuth (like a VOR radial) and change your heading to intercept the new azimuth.


|-|ardy


P.S.: The MLS switch on the panel is for the APP mode on the standby instruments. The normal instruments on the EFIS are controlled via the CDU NAV RAD page as usual. You simply enter MLS data instead of ILS data.

[John H Watson]

All the extra goodies like ILS and HDG info are removed (because their data sources are not powered).

It's ironic that such a sophisticated instrument is fed with unheated pitot/static probes under emergency conditions.

[Jeroen Hoppenbrouwers]

The idea is/was that an onboard computer can read the MLS elevation and azimuth continuously, much like the FMC reads the VOR radials and GPS and DMEs continuously. The computer knows the intended curved approach much like the FMC knows the intended LNAV/great circle and VNAV trajectories. The result of the continuous comparison between "where am I" and "where should I be" is translated to steering commands and displayed on the traditional ILS GS/LOC pointers -- but these now do not guide the plane along a straight line.

I suppose that all curved MLS approaches were intended to always be flown by the A/P but with a good F/D this isn't even required.


Jeroen

[Hardy Heinlin]

Hardy,
watch the "weight" of the vertical separator line on P2-4 lightplate. That line should be as thick as the rest of the separators on your overhead (which you've already painted correctly, btw). One more little thing...the to circles around S3 and S5 under no circumstances may touch each other.

with respect,
d

New attempt:




|-|

[delcom]

Well done...that's a lot better.

regards,
d

EDIT: amazing texture on the glareshield padding, btw.

[Jeroen Hoppenbrouwers]

Challenge: find the source of that padding texture  

[delcom]

One shot with a macro lens.


cheers,
d

[Hardy Heinlin]

One possible source