In Flight Alignment

[jasonbirder]

Hi Guys!

Wonder if anyone can enlighten me as to the correct process for using the In-Flight ALignment functionality?

(I have it in mind that flying straight/level/fixed speed for a set amount of time comes into it)

IS there any difference between using it if you haven't performed a Ground alignment compared to using it to update the alignment?

Cheers

[Yurgon]

Haven't used it in ages.

 

I do believe you're required to fly as straight and level as you can for in-flight-alignment to work properly.

 

However, I believe this is not currently modeled in DCS and you can actually fly an airshow program, and the INFLT will still work perfectly fine after a fixed amount of time.

 

In the manual, I couldn't find too much info. Most prominent is this part:

 

INFLT (In Flight) Alignment, R5. If the INS alignment needs to be re-aligned while the

aircraft is in flight or moving on the ground, this option is used. This alignment process

uses current position and velocity measurements from the INS. Before starting an in flight

alignment, EGI, STR PT and ANCHR should be deselected from the Navigation Mode Select

Panel or select HARS. The EGI GPS will then be used to align the EGI INS. This process

can take between 5 and 10 minutes.

[Stuka]

RL you’re actually not supposed to fly as straight as possible, but make gentle turns instead.

[Yurgon]

RL you’re actually not supposed to fly as straight as possible, but make gentle turns instead.

 

Huh, good to know, thanks!

[QuiGon]

RL you’re actually not supposed to fly as straight as possible, but make gentle turns instead.

Interesting. I wonder what are the technical implications behind this? Especially as you stand still during a normal alignment :huh:

[mvsgas]

Interesting. I wonder what are the technical implications behind this? Especially as you stand still during a normal alignment :huh:

 

I don't know about the A -10, for some F-16 INS/EGI versions:

Performing a double-drift maneuver (turn off heading about 45 degrees, then 90 degrees in the opposite direction, then 45 degrees to resume course; maintain each heading change for 1 minute minimum) tends to enhance and hasten the determination of true heading by the master navigation from GPS true course data

 

Keep in mind, in these versions of the INS/EGI, In Flight Alignment (IFA) is for emergencies and will require true heading from Wingman or other outside sources and is just to get you home, not to continue the mission. Additionally, not sure if it relates to the A-10 (any versions) or any other real aircraft.

Edited July 24, 2020 by mvsgas

[QuiGon]

I don't know about the A -10, for some F-16 INS/EGI versions:

 

Keep in mind, in these versions of the INS/EGI, In Flight Alignment (IFA) is for emergencies and will require true heading from Wingman or other outside sources and is just to get you home, not to continue the mission. Additionally, not sure if it relates to the A-10 (any versions) or any other real aircraft.

Thanks, also this still doesn't explaion the technical background on why those maneuvers help with alignment. The ground alignment works fine without any movements, so I wonder what exactly is happening during an IFA that requires maeuvering.

[Biga42]

Look at the page 169 of the manual, HARS Control Panel. Maybe help you figure out.

[Stuka]

Checked it again: the aircraft must be in a straight flight when initiating the INFLT, and you have to stay steady until the flashing asterix becomes steady. Once that is steady, you can speed up the alignment by doing gentle S-turns of approx 30 degrees of bank.