In my Wilco CRJ I put the arrival information in my FMC during my descent after I get the info from the ATIS. When I choose the runway it gives me options for each runway on the left in the "arrival" section. For example I put in 25L for KLAX and get this:

 

LEENA4

MOOR3

OLDEE2

RDEYE2

 

now I know these are all arrivals but then there's:

 

I25L

R25LY

R25LZ

 

What are these? IT gets more confusing at KLGA:

 

MIP4

R04-Z

S04

 

I tried to land at LGA earlier and couldn't figure out how to just put ILS in....For instance I was on the Korry3 arrival and at some point I got cleared direct GRENE which is the IAF for the ILS rwy4 and I coudn't figure out how to get it in the FMS.

The first four are arrival procedures called STAR, that guide you from your route to approach procedure.

 

Next three are approach procedures which guide you down to the runway: I25L means ILS approach on 25L, R25L means RNAV 25L, X and Y means there are two somewhat different RNAV approach procedures.

 

MIP4 is a STAR, R04-Z - runway 04 RNAV approach, S04 also some kind of approach.

 

So for KLGA to fly ILS first you select STAR (KORRY3) and then the approach procedure (I04).

 

To fly direct to:

as far as I know in CRJ FMC you press DIR INCT button, choose point you want to fly directly and put it into the line called DIR and execute.

 

I'll try to give a brief explanation. When you approach to destination you'll be flying throught this stages: route-STAR transition-STAR-approach transition-approach-landing. Transitions, STARs and approaches are selected in FMC to fly them automatically. Sometimes some of this stages are not present. There is a lot of information on this topic so it worth to search what does every stage means and check airport charts for correct routing.

I should have been more specific...I am very familiar with STAR's and ILS and RNAV approaches, but the way these are labeled in the FMC makes no sense.There is no ILS4 available in the FMC for LGA...but there is for other airports with ILS approaches and this makes no sense. I'm even up to date with Navigraph.

 

The fact that you look at S04 the same way I do and think "it's some kind of approach" but don't know what backs this up.

 

If I go to SFO and put in I28L it puts every fix for the ILS 28L into the FMC, but this isn't available for every airport with an ILS which I'm trying to figure out why, and why an ILS isn't labeled the same at another airport in the FMC.

Here are the ARINC approach types...

 

 

Here is the list of the valid ARINC424 approach route types:

 

B = Loc/Backcourse approach

 

D = VORDME approach

 

F = Flight Management System (FMS) approach

 

G = Instrument Guidance System (IGS) approach

 

I = Instrument Landing System (ILS) approach

 

J = GNSS Landing System (GLS) approach

 

L = Localizer Only (LOC) approach

 

M = Microwave Landing System (MLS) approach

 

N = Non-Directional Beacon (NDB) approach

 

P = Global Positioning System (GPS) approach

 

Q = Non-Directional Beacon + DME (NDB+DME) approach

 

R = Area Navigation (RNAV) approach

 

S = VOR approach using VORDME/VORTAC

 

T = TACAN approach

 

U = Simplified Directional Facility (SDF) approach

 

V = VOR approach

 

W = Microwave Landing System (MLS), Type A approach

 

X = Localizer Directional Aid (LDA) approach

 

Y = Microwave Landing System (MLS), Type B and C approach

 

 

DJ

Have you looked at this?  http://www.airnav.com/airport/KLGA

 

Everything you need for KLGA is there, and any other US airport