Simviation Forum - ILS Approach

Feb 19^th, 2011 at 9:47pm

D. Miller Offline
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So there I was today practicing my ILS approach in zero visibility. I have been playing with the autopilot trying to figure out the 'APR' button. I had to go missed three times because the plane wouldn't decend correctly or stay in line with the beam. What am I doing wrong. Here is the steps I followed:

1. Flying normally with AP on. Heading and ALT set. A/T on.
2. Entered in ILS freq into Nav 1, set it active.
3. Checked my instuments, the GS was active, and in the middle.
4. Clicked on 'APR'. Noted that 'HDG' and 'ALT' went off. The plane then swayed left to right and didn't decend........

No clue what I am doing wrong.

Thanks.

"The difference between genius and stupidity is that genius has its limits" --Albert Einstein

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Reply #1 - Feb 19^th, 2011 at 9:49pm

D. Miller Offline
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Sorry I forgot to finish. My understanding is that it should keep the GS in the middle of the instrument and keep you decending according to the GS. I made sure my NAV / GPS was set to NAV. I over flew the runway x3 and finally got frusterated and quit. I have been online looking for answers since.

"The difference between genius and stupidity is that genius has its limits" --Albert Einstein

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Reply #2 - Feb 20^th, 2011 at 1:06pm

JoBee Offline
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Make sure you press APR while still below the glideslope, before the GS indicator moves down to the center of the gauge.

If you are a second late, and therefore over the glideslope, the AP will not be able to capture the GS.

Once you are established on the localizer go ahead and press APR. The AP will maintain set altitude until it captures the glideslope.

cheers,
Joe

Don't argue with idiots, they drag you down to their level and beat you with experience.

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Reply #3 - Feb 20^th, 2011 at 3:44pm

-Crossfire- Offline
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Sounds like you're doing everything right. As JoBee said, just make sure you intercept the glideslope from below, not from above.

You can arm APR mode even before intercepting the Loc, if you like. The autopilot in the default jets has no problem intercepting the Loc at a 30 or 45 degree intercept angle.

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Reply #4 - Mar 14^th, 2011 at 12:00pm

sLippd Offline
1st Lieutenant
I Like Flight Simulation!

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You seem to be doing everything right. I would say that your capturing the localizer from an angle and not a straight in. I think your problem is that your catching the G/S too high and that's why you are not descending. Make sure you intercept the G/S under it (Below). Your pink diamond should be on the top and it should say Below G/S.

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Reply #5 - Apr 26^th, 2011 at 1:21pm

Strategic Retreat Offline
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-Crossfire- wrote on Feb 20^th, 2011 at 3:44pm:

You can arm APR mode even before intercepting the Loc, if you like. The autopilot in the default jets has no problem intercepting the Loc at a 30 or 45 degree intercept angle.

Not a good idea. Sometimes, on some ILS, the LOC is WAY more powerful than the GS and the needle of this last remains inactive in the center for a while, before getting alive. Should you happen in a situation like that and press APR or LAND or whatever is called in your plane, the plane would INVARIABLY start IMMEDIATELY a descent at about -700fpm all the way towards a beautiful CFIT. Tongue

This happens because the AP doesn't check the presence of the GS signal (quite the serious AP fault that is there ever since... I remember, and was never addressed by the guys at M$, who always prefer losing themselves after nicer-looking and heavy-on-the-PC graphics instead), gets confused seeing the needle at the center, and thinks THERE AND THEN is the right moment to start descending, and the continuous absence of signal would only serve to deceive it into the false sense of security that it is following correctly a GS that is just not there. Undecided

The correct way, gleaned after thousands of hours on the sim, to avoid disasters in landing is (with the GPS/NAV switch on NAV)to press the NAV, or VOR or whatever button and allow for the plane to begin aligning itself with the runway. As soon s the needle of the GS starts descending from its uppermost position, THEN press APP, APR, LAND or whatever.

Fair winds and soft landings. Wink

There is no such a thing as overkill. Only unworthy targets.

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Reply #6 - Apr 27^th, 2011 at 3:53pm

Tyler012 Offline
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Just dont get to reliant on the autopilot, they do malfunction every now and then so make sure to practice your visual landings as well. Remember, regardless of weather conditions, pilots must always be able to see the runway before making a landing attempt. Otherwise, you might want to start looking for an alternate destination.

Just a sample of my personal art.

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Reply #7 - Apr 27^th, 2011 at 11:01pm

Strategic Retreat Offline
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Wish people were less
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You cannot be completely un-reliant on the autopilot on big irons, especially the kind with big cigars under the wings or hanging under the tail that have almost all the systems actually working (so, no default allowed in this discussion). The same goes about landings.

Visual landings are fine and all, and I'm quite a big fan of them... up to the point I'm always quite nervous in giving the leeway to Otto in landing (if I'm not holding the yoke while landing I get antsy), but not always you can get a gander to your destination runway from distance, that why landings are separated in CATegories, and that's where Otto can help.

Not going to prattle off on said CATegories here and now, as it is almost 5 in the morning here, and I'd be here at midday still, if I wanted to make a serious and complete list. Certain is that, in the real world, if you cannot land there because the minimums don't allow, then you must go elsewhere, but already some CAT II landings, that do not require blind landing equipment and certification of both aircraft and pilots, not always gives you a long distance panoramic of the landing strip.

Some times, and if you don't believe me search on Youtube, some CAT II landings can be quite scary, and the lights of the runway on some airports and in some weather become visible almost on the raw edge of the minimums... and you're alone in the simulated cockpit, not like in real liners, where you can always follow the needles of the ILS and keep track of your altimeter and DME manually while the other pilot looks out for the lights at the end of the tunnel.

It is a good idea not to get DEPENDANT on the autopilot up to the point you can't fly without it, this yes, I'm with you fully, but rely on its help in tight spots is only a good idea, and landings in scarce visibility ARE a tight spot. Wink

There is no such a thing as overkill. Only unworthy targets.

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Reply #8 - Apr 28^th, 2011 at 7:58am

Brett_Henderson Offline
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BE AN NDB

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Fly IMC, ILS, approaches by hand.. and fly them in good weather too, by hand... until it's all so second nature to you, that it will be a seamless event if the autopilot goes goofy..

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