Approach Problems

[willg]

After cracking my landing problems my latest problems the approach.

im following my flight plan (i always edit them so that itll  guide right in line with the runway)

im at 4000 foot(30 miles or so away ferom the runway) bang in line with the runway by following the line in my flight plane (nav hold) so i switch to 'nav' then select approach hold, but this does absolutely nothing, the plane might make a vain attempt to line up with the runway, but it doesnt intercept the glidepatch one bit, the plane will just nose down, leaving me to control the altitude. ive even tried getting the red rectangles up and flying through them so i know im definetely in the right position but the plane still wont capture the glidepath. ive even tried this closer to the airport but the same thing.

it must work cuz ive done it before, about 40 miles out of Copenhagen, all this approach hold business seems very hit and miss, its pot luck whether youy lucky enough for the aircraft to capture the glidepath.

[eno]

At 40 miles you're too far out for the approach hold to work .....and at 4000 ft too high for the glideslope.

Most localisers for ILS only send a useable signal out for 20-25nm and to capture the glideslope properly you really need to be below it .... usually 1500-3000 ft  above the terrain.

Line up 40miles out but get lower and don't hit the approach hold till 15 miles out to be sure to capture properly.

[commoner]

..mmmm.....eno has it, you are way too high. Imagine the GS as a laser beam coming from the start of the runway upwards at an angle equal to the correct decent angle but only for maybe as eno says 20-25nm..........makes sense then that at your approach altitude you are well above it and with no chance of making contact....once you are above it you would find it impossible to get back in touch.........commoner

[willg]

how do I know when I can put approach hold on then??

do I just fly at like 300 foot for a while then when im 15 miles out jsut hit APP. ive tried that but as ive said, soon as approach hold is such a pot luck feature it only seems to work about 50% of the time.

[willg]

what im saying is, if i keep flying at 3000 foot eventually i'll be above the glidepath, so how do I know when its the right point to actually put approach hold on?

also, even though im following the line, im well of course, when I put visual flight path on its a few hundred metres to my left or right, and at 15 miles out ive got no chance of getting back on course.

[ashaman]

When approaching, following a Flight plan that brings you directly on the runway you chose, you should not directly go for the APR switch, but at about 25 miles from the runway switch the nav hold from GPS to NAV, being sure you dialled the ILS frequency in the NAV1 radio.

The switching from the LNAV of the GPS to a normal NAV function would keep you (onche the localizer is found) to begin aligning to the runway.

Keep in mind that in a ILS the first signal that is received is always the LOC, the GLIDE having a shorter range.

In FS9 (and FS8 as well) if you lock in the localizer with the APR button but the glidescope signal has yet to show (ie, the LOC needle moves away from the center but the GLIDE needle is still in neutral center position) the autopilot will go insane thinking you already caught the glidescope and will begin making nose down at a random pitch that will bring you crashing down in nowhere land.

NEVER activate the APR switch before the glidescope needle leaves the inactive center position.

[Reap]

You can hit your APP button as soon as you are on course to intercept the localiser. The Heading hold light will stay on until it picks up the approach path, then it will turn off and APP stay on at that point you are established. As long as you approach from under the glideslope then when you intercept that then your alt light will go out. At that point you are FULLY established.

Read NAV's excellent tutorial to get the full picture available here http://www.simviation.com/cgi-bin/yabb/YaBB.cgi?board=COF;action=display;num=1111322151

[willg]

so i set alt hold to 3000 as well as having APP hold on, well that sorts out that problem, but how do I get set up on the localizer.

[RollerBall]

I just did all this only a couple of days ago

http://www.simviation.com/cgi-bin/yabb/ ... 1111666911

What was wrong with that?

[willg]

k, im make sure once aligned with the line on the flight plan im going to put ALT hold on, (at 3000foot-20 miles away) and IAS (160knots), then put approached hold on, and then when the ILS needles come down to the right position, I'll know im on the glide path, and hopefully alt hold should automatically go off and approach hold should take over, from there it'll be a piece of cake Really, its far far harder to actually get set up on the glidepath than it is to land, landings the easy part, i guess the key to a good landing really is a good approach.

please could someone tell me if im doing this right.

thanks for all the guides and stuff, ive read them and theyve helped too.

[Marlin]

Are you using an add-on plane? If so, some won't follow the glideslope to the runway.

Try useing a default plane to see if you are getting everything correct.

The app. button can be depressed as far out as you want. I usually hit it right when ATC starts to vector me in for approach along with the NAV switch and the HDG button. When you get close enough the HDG light will go out and the APP will stay on.

[willg]

problem sorted, just done a lovely little flight from Zurich (cessna grand caravan), taking off runway 34 and heading into the alps before turning back and doing a perfect approach and landing, then flying over to my own favourite little bay at the end of the airport  :)

i got the approach hold perfect, i think ive mastered it now, i might put some screenies up of my flight later  :)

by the way, is this one of those fuel pumps I can fill my tanks up from? :