reported B/E Mag and BRA True (+ weird HUD Command Heading indicator)

[Tusky]

Hi all!

Motivated by a post in the general F/A-18 section I've run a test and here is what I found..

Scenario (Picture 1+2)
NTTR Map (magnetic variation about 12°E)
Aircraft on the runway (Nellis 03R)
B/E aligned with runway centerline at 5.3nm and selected as WYPT
True bearing to B/E: 40°
Mag bearing to B/E: 28°

HSI + RADAR page  Picture (3)
WYPT: 28°/5.3 (magnetic)
B/E: 208°/5.3 (magnetic reciprocal of WYPT)
BRA: 39°/5.3 (true >>> mag+mvar >>> 28°+11°E)

Question: shouldn't BRA be magnetic and be the same as WYPT?

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Command Heading indicator - Speed 0kn (Picture 2 to 4)
I noticed that when not moving on the runway (parking brake or brakes engaged), the Command Heading indicator on the HUD was way off to the left or sometimes jumping to the right and back to the left. As you can see, the WYPT indicator on the HSI correctly points upwards aligned with the aircraft...

Command Heading indicator - Speed > 0kn (Picture 5)
As soon as i started moving, the Command Heading moved right on my nose below the heading caret.

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I'll add the mission, too.

Thank you!

P.S. Easy to reproduce but let me know if you need a track

Test BRA.miz

Edited February 16, 2023 by Tusky

[MARLAN_]

Yea BRAA should definitely be magnetic, this also conflicts with the true/mag mode set in the aircraft.

[Mikaa]

Pretty sure this has been brought up before. There are lots of discrepancies for in-cockpit indications on the Radar as well as AWACS callouts. Needs some TLC to ensure correlation between cockpit, AWACS, and map to account for mag variation. 

 

[BIGNEWY]

please PM any unclassified evidence 

thank you

[Tusky]

Hi Bignewy!

I sent you a PM.

Basically, it seems there is a correlation between the value indicating the heading of the aircraft (on top of the radar screen) and the value used as BRA: they share the same North reference (whether true or magnetic).

If you confirm it is a True bearing, better to indicate it in the manual since is seems that the common understanding is that the B is a magnetic bearing. 

Edited February 23, 2023 by Tusky

[Viking.VFA103]

On the A/A Radar Screen, the BRA indication in the lower left quadrant indicating the BRA of either the radar cursor or currently designated contact is showing bearing in TRUE.
All other instruments (SA page, HSI, HUD heading tape) switch between MAG/TRUE based on the setting in the HSI->DATA->A/C  sub page.
Is the BRA indication on the radar screen always showing TRUE by design or should it switch between TRUE/MAG with everything else?

[Tusky]

Already pointed out some time ago: 

 

[Harker]

I reported this recently as well. All indications, including BRA, should either be in True or Magnetic, depending on the selection in the A/C subpage of the HSI.