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How to get a new database for the earth's magnetic field

Started by Hardy Heinlin, Sun, 14 Feb 2021 23:52

Bluestar

Quote from: cavaricooper on Sun, 16 Oct 2022 22:00Thanks for the reminder Will- ditto!

C

Carl,

Glad to see you are back.  I was afraid you were going to get blown away.  :)

Bode
Grace and Peace,

Bode

DougSnow

Just looked on MBF, Boeing is targeting Fall 2023 for the Service Bulletins to be available for operators to update their MagVar tables for the 744 and 747-8...

Jeroen Hoppenbrouwers

Such a table is either hard part of the FMC software (inseperable) or else has the same certification requirements  ("Parameter Data Item"). This means that it has the same impact as a program code change. And after Boeing's recent goofs with certification, the FAA has clamped down (also on itself) to all players in industry to get this right. So changing the very base of what determines the aircraft's heading knowledge is sort of heavy impact.


Hoppie
Not involved at all in any of this

DougSnow

I was reading the FTD, this is a remove and replace item, a new FMS is getting installed with the new datatable.  The Service Bulletins are not yet available with all the painful details, and since we no longer operate/own any 747s (I guess we owned the TNT 47s on paper), I wont be able to see the service docs once they are available.

cavaricooper

Quote from: Bluestar on Sun, 16 Oct 2022 22:49Carl,

Glad to see you are back.  I was afraid you were going to get blown away.  :)

Bode

Thanks Bode!  We were VERY lucky... unfortunately South of us, not so much.

C
Carl Avari-Cooper, KTPA

Hardy Heinlin

I think the FMC gets its mag var data from its monthly loaded nav database, and that just for the locations of the loaded database VORs etc. -- if at all.

Each IRU has a fixed mag var table which provides the MAG HDG data when the IRU is in NAV mode, i.e. when the IRU knows the aircraft's present position so that the IRU can look up the variation from the table. This MAG HDG data from the IRU also goes into the FMS and from there to the ND. When the IRU is in ATT mode, the IRU doesn't know the present position and thus can only provide its pure platform heading to the FMS and ND (the platform heading drifts and therefore requires mag heading entries in the FMC from the crew every few minutes) even when the FMS itself operates normally.


|-|ardy

Bluestar

Quote from: DougSnow on Mon, 17 Oct 2022 01:34Just looked on MBF, Boeing is targeting Fall 2023 for the Service Bulletins to be available for operators to update their MagVar tables for the 744 and 747-8...

Has Boeing updated the MagVar tables?

If so, which data does Boeing use?
Grace and Peace,

Bode