AP/ILS questions

[jgf]

This is probably ridiculously simple but nothing I've read has given me the answer.  When I enable the Approach function on the AP, do I disable the Altitude and Heading hold functions?  or have all three enabled?  (trial and error hasn't provided a definitive answer)

Also, my normal procedure is to come in at 2000-2200ft AGL and engage Approach when I intersect the ILS;  at some airports the plane will descend to 1500-1800ft AGL then overfly the airport at that altitude;  I disengage the AP, go around and try again - same results.  Go around once more and land manually.  (I usually let the AP fly approach til around 1000ft AGL, perhaps 500ft for small aircraft, then disengage.)  What would be causing this odd behaviour?

[Pablo]

I always find its best to contact ATIS* when approaching the Airfield, to obtain which runway is in use, and which end of the runway I must use, (take-off and landing, depending upon the wind direction, etc), and any other important information.

It is very easy to dial in the ILS frequency and find oneself descending to the wrong end of the runway, (the far-end, back-course)... ...!

* http://en.wikipedia.org/wiki/Automatic_ ... on_Service

[Sir_Crashalot]

Keep the heading and altitude buttons enabled. It should turn off automatically when the ILS kicks in and take your plane right down to the runway.

Carlo

[Nav]

Hi! again, jgf.

You MUST contact ATC once you are within 30 miles, to get clearance and also to be advised as to which runway to use. If it's a small airport with no ATC, ATIS should give you the wind direction and 'runway in use,' then check the map for the precise runway direction etc.

Further, as Crash says, leave Altitude Hold and Heading Hold engaged and wait for the autopilot to turn them off at the right points.

More advice here:-

http://205.252.250.26/cgi-bin/yabb2/YaB ... 1111322151

[microlight]

One important thing to remember is that when you've captured the localizer, you must then intersect the glideslope from beneath, or else the default FS autopilot won't capture the GS, and you will stay at your set altitude.

[jgf]

One important thing to remember is that when you've captured the localizer, you must then intersect the glideslope from beneath, or else the default FS autopilot won't capture the GS, and you will stay at your set altitude.

I was advised that 2000ft was a reasonable approach altitude for ILS, so have used that since.  When the gauge indicates I've intersected, I hit the approach button on the AP.  I don't recall ever seeing the AP disengage the heading or altitude functions (the indicators remain lit);  thought perhaps I'm taking control before the point where this would happen, but have let the AP bring the Baron all the way to touchdown with all three indicators lit.

[jgf]

...
You MUST contact ATC once you are within 30 miles, to get clearance and also to be advised as to which runway to use. If it's a small airport with no ATC, ATIS should give you the wind direction and 'runway in use,' then check the map for the precise runway direction etc.
...

Usually contact my destination as soon as it appears on the 'nearest airport' list, since ATC has the irritating habit of, no matter from which direction I'm approaching, sending me to the most difficult to reach runway from my current course (they also take great delight in directing me to the one runway at the airport with no ILS).

[elite marksman]

Usually contact my destination as soon as it appears on the 'nearest airport' list, since ATC has the irritating habit of, no matter from which direction I'm approaching, sending me to the most difficult to reach runway from my current course (they also take great delight in directing me to the one runway at the airport with no ILS).

This is where the "request different runway" feature is nice... Like today when ATC decided to send me to a 5000' rwy with no ILS in <5nm visibility when there was a parallel 12000' rwy with ILS... :-?

[dave3cu]

..When the gauge indicates I've intersected, I hit the approach button on the AP....

The [APP]roach hold should be engaged once you are established on the HDG and ALT to intersect with the ILS, and well before intercepting the ILS glide path/slope.

APP will then automatically disengage the HDG and ALT holds as it locks on to path and then slope.

Dave

[Nav]

[quote]

I was advised that 2000ft was a reasonable approach altitude for ILS, so have used that since.

[Stewy44]

I use the NAV (not HDG) button on the AP to line up with the correct runway allignment when I've picked up the ILS signal. I alse have the "ALT" button on as well

Once I've picked up a glideslope, I'll watch the glidepath descend until it reaches the centre notch and then I'll hit the "APP" button to "catch" the glideslope.

[jgf]

Thanks for all the input.  After years of just flying around (all the way back to the early days of FS98) I've been trying to learn to do things "by the book".

[Gringo6]

It's also a good idea to use the approach plates to determine what altitude and headng to use.

Frequently the approach plate will have the instrument approach to the airport begin at some fix (such as a VOR) and not just a long straight-in shot.

The aproach to Juneau AK comes to mind.

[Stewy44]

Fly into Geneva, Switzerland - I think if you're coming from the north, the approach is huge!