Whats The Differance?

[SWAFO]

Questions, questions. Alright, here we go:

APPROACH TYPES
ILS approaches are split up into 3 categories depending on conditions at the arrival airport. You need to reference
approach charts for specific procedures, as they vary based on airports, etc. However, I'll give you some simple
reference points as to when a specific approach type is acceptable. Note that there are more complex issues
when deciding on the approach in use (at airports equipped with CAT II and CAT III systems, the airport will tell
you what approach is in use in real life... I don't think CAT II and III approaches are modelled in FS9) . Here are the
basic, simple guidelines of when you can use the different categories of ILS approaches:

CAT I ILS - This is the normal ILS approach, used usually when the visibility is no less than 1800 FT RVR (runway
visual range), and you can see the runway with no problem at least 200 FT above it. As I mentioned previously,
the acceptable conditions for a CAT I ILS will vary quite a bit, and you need to reference approach charts. For
example, occasionally you'll see a CAT I ILS that has a specified minimum RVR value of higher than 18 (quite
often actually). For example, the ILS to runway 28R at KPDX has a RVR requirement of 50 (5000 FT). This means
that the visibility must be at least 5000 ft (near a mile) as measured by transiometers on the runway to use this
published approach. As an additional note, my airline (Southwest) will always use 200 feet as the Decision
Height on CAT I ILS procedures, and won't go by the decision height referenced on the approach plate.

CAT II ILS - If runways are equipped with CAT II or III systems, they must have a seperate approach plate for each
of the three applicable approaches. Normally, CAT II ILS approaches will have a decision height of 150 or 100 FT,
and a minimum RVR of 12 or 16 (1200 or 1600 feet).

CAT III ILS - There are three types of CAT III ILS approaches. They are designated as CAT IIIA, CATIIIB, and
CATIIIC. Their minimums are described below:

CATIIIA- This is the only CAT III approach that Southwest Airlines will perform. It can only be done on certified
aircraft, that have the HGS (Heads Up Guidance System... like a HUD). It has no decision height, and a minimum
RVR value of 07 (700 FT).

CATIIIB- Same as CATIIIA, however with stricter guidelines and a minimum RVR of 06 (600 FT).

CATIIIC- VERY STRICT GUIDELINES, requires full autoland operation, and has no DH, as well as no minimum
RVR conditions. A landing could literally be performed in zero visibility conditions.

SIDS AND STARS

Simply put, these are published procedures that allow for uniform routing to/from an airports terminal area. SIDS
are Standard Instrument DepartureS, while STARS are Standard Terminal ARrivalS. They're pretty self
explanatory, and if you look at a SID/STAR chart, you'll instantly understand it.



CAT II Landing Capability simply means that the aircraft in question is certified down to CAT II ILS minima.

Hope this helps.

EDIT: Just noticed your username... keep flying the 737's!