MVAR entry should not be required for GND INS alignment

[some1]

According to real manuals, magnetic variation entry is required only for SEA alignment:

 

d. DDI — CHECK A/C LAT/LONG (input correct position if required).

Plus:

Magnetic variation (MVAR) for Gyro Align SHIP DATA for MANSEA align.

 

 

For GND alignment, only position entry is required. In Razbam AV8 alignment process won't start until magvar is entered.

 

This is also incorrectly depicted in the startup tutorial.

[Frederf]

Procedure is more clear with line breaks:

7.1.7 Before Taxiing

All Aircraft:

1. INS — ALIGNMENT.

a. Parking brake — SET.

With C1+ or OMNI 7.1:

b. DDI — DTX, UNBOX TRUE.

With H4.0:

c. MPCD — SDAT--DTX/OLX/GPSX.

All Aircraft:

 

d. DDI — CHECK A/C LAT/LONG (input correct position if required).

Plus:

Magnetic variation (MVAR) for Gyro Align

SHIP DATA for MANSEA align.

OMNIBUS 7.1 -- Box MVAR if MAD input may be invalid.

 

e. INS Switch — GND ALIGN.

f. Waypoints — CHECK/ENTER.

Day and Night Attack Aircraft:

2. DMT — ON.

Not sure why MVAR is called out for the Plus (Harrier II+). Is it because it has to use Gyro Align and thus MVAR is needed for all Gyro Align for all models or is it that Gyro Align specific to the Plus model needs MVAR input?

 

But confidence is had that N/A variant does not require MVAR input (or receives it from DSU) for ground, SEA SINS, and IFA alignments. Possibly it doesn't require MVAR input for any alignment. No part of NFM-000 procedure meantions MVAR for any possible alignment. It is likely that all alignments which can discover true heading simply need MVAR value to display instruments referencing magnetic north.

 

What differences exist for different variants that procedures differ? DSU? MAD?

 

The phrases "All Aircraft:" "With C1+ or OMNI 7.1:" "Plus:" "With H4.0:" refer to specific sub variants of AV-8B. For extra information the following phrases correspond to different phases between NFM-000 and NFM-500.

[table=head]NFM-000|NFM-500

All Aircraft|All Aircraft

With C1+ or OMNI 7.1|Before ECP-285

With H4.0|After ECP-285

Plus|Plus

Day Attack|Day Attack

Night Attack|Night Attack

Day and Night Attack|Day and Night Attack

Radar Aircraft|Radar Aircraft[/table]