IRS vs. IRS

[martiben81]

I was wondering if somebody could enlighten me on the difference between an IRS and an INS system, if there is a difference. Also, am I correct in thinking Direct Lift Control is not on any of the current CX fleet, only on the old L-1011?

[spannersatcx]

I think this is in the wrong forum.

Have a search in tech log or engineers & technicians forums. It has been asked many times there.

[404 Titan]

martiben81

Generally speaking IRS is a solid state unit using Ring Laser Gyros, i.e. no moving parts, and is incorporated in a FMS system. An INS unit on the other hand generally uses mechanical gyros and is a stand alone item, i.e. no FMS.

You are correct that Direct Lift Control only existed on the L1011.

[martiben81]

Thanks for the information. That clears up my confusion with the systems.

[spannersatcx]

Can of worms opened!

INS navigates (tell it where you want to go and it will tell you how to get there - usually via the flight director and almost always can be coupled to the autopilot. The heading and attitude outputs are a useful by product of the stable platform (either virtual or physical) used to supply the navigation circuits with groundspeed and direction information) The system is stand alone.
IRS only supplies reference information (attitude, heading, speed, acceleration, etc,etc,etc. This is then fed to other systems which calculate a navigation solution (FMGS) or display the output as a compass rose or attitude ball.) The system cannot navigate, it can only provide present position information.
The details of the internal mechanisms are irrelevant(IRS not always solid state). There are INS's that use RLG's and IRS's that use standard rate gyros.