A320 IRS Drift Over Time
 

I am planning on doing an 'Around the world' flight in a Study level A319 Simulator. (which does simulate IRS drift)

I was planning on keeping the IRS's on after each landing to save on time and effort to align them each time, but I am worried about drift adding over time.
I assume most LCC's today probably don't realign the IRS's after each flight, till they secure the plane after the last flight of the day.

Practically, would it be a concern?

If it’s genuinely modelling the IRS as fitted to the aircraft then just do a fast align.

You'll also have plenty of time to do a full alignment if it simulates the actual fuel uplift rate.

Policies at airlines will vary, but it's unlikely a narrowbody will go a whole day on just one alignment.

IRS alignment time is in the order of minutes.
Refuelling and preflight will take longer. You’re not saving any time by skipping it.

Ok guys, thanks a lot for the replies... certainly very grateful for your time :)

Any other considerations/tips for this particular adventure?

If we fly through an area known to be subject ti GPS interference (Cyprus, Eastern Turkey, etc) then it's common sense to perform a full alignment.

Hi,

from a procedural point of view you would perform a complete IRS alignment if it was:

- First flight of the day or
- Crew change or
- Departure airport located between 2° North and South or
- GPS not available and poor NAVAID coverage enroute or
- GPS not available and flight time greater than 3 hours.

Other than that you would perform a fast alignment if the difference between the IRS position and FMGC position is at or above 5 NM.

Bottom line if You want some proper level of realism just do a full alignment every time you fire up your Sim.