Jump to content

Odd ILS behavior


gord96

Recommended Posts

Hello all.

 

Been learning the Aerosoft A319 the last week or so and enjoy it. Have had no issues using the ILS 'autoland' feature the last few days but yesterday, all 3 of my flights I couldn't land at all. I would capture the localiser and glide slope but it would always put me way short of the runway.

 

The first thing I noticed is the plane would struggle to get to my decent altitude. For example I went to land at KLAS last night so set my alt to 3800 as per the runway chart. The plane would decend to about 5000 to 6000 but would struggle to get below that. I thought it might be a speed issue so I tried to slow it down and it would still be struggling to get to 3800.

 

Another thing is on the KLAS flight, and maybe this is supposed to happen, but I can't remember it on my earlier successful landings, is when I armed the localiser it would take the aircraft off of the flight path and turn directly to the runway. I remember before the plane wouldn't do this but maybe I am wrong?

 

Then when I finally get on the glide slope the plane will speed up and slow done all crazy while slowly descending 2000 feet short of the runway.

 

I have gone through my procedures again and can't seem to figure out why Saturday I can land no problem and not on Sunday. Any advice or ideas would be very helpful!

 

Other then the landings the plane is acting normally for takeoff and cruise.

 

Thanks!

 

gord

Link to comment
Share on other sites

Didn't get a screenshot but I think I figured it out. It's just my flightplan it seems. The tutorial flight and the other flights I did were almost direct in so it was easy to catch the glide slope. Last night I did another attempt and failed but it was kind of a u-turn to face the runway and by the time I turned and armed the localizer the glide slope 'diamond' was below me and I was already at the 'capture altitude'. What I am getting from this is I am too high to capture the glide slope. I will try maybe going out a bit further from the waypoint before turning back. 

Link to comment
Share on other sites

  • Deputy Sheriffs

Two things that come to mind here:

- always try to intercept the GS from below. If this is not possible anymore make sure to select an altitude that is below the altitude where you will intercept the GS. Having the altitude set to the intermediate approach altitude in this case will only get you into ALT* and chances of intercepting the GS are becoming slim.

- when arming the LOC it will capture the mode if certain parameters are met, like recieving an LOC signal within a certain offset of the beam. Therefor it is possible for the aircraft to leave the "flightpath" and try to intercept the LOC beam as it seems fit.

Try to intercept the localizer (by arming the LOC or APPR mode) within an 40-45 degree angle and be at the intermediate approach altitude (thats the altitude on the charts) before intercepting the GS. Doing it like this will give you the least problems and the highest chance of a correctly flown ILS by the AFS.

Good luck!

Link to comment
Share on other sites

Also, while descending, keep an eye on the smaller bubble (not the glideslope), making sure you stay below it. Watch out for a notice popping up on the MFD saying "more drag". This means you're not descending fast enough. Apply your speed brakes until you get below the bubble. (Sorry, I've no idea what this bubble is called, but it's found on the same part of the MFD as the glideslope indicator).

Link to comment
Share on other sites

Thanks nealmac! That is helpful. I know what you're referring to! :D

 

Quick question about the air brakes, I have only ever pushed them up for prep for landing. Is that what you do while descending? Or do you pull them down to the other settings?

Link to comment
Share on other sites

  • Deputy Sheriffs

You can use them during the descent by pulling the lever backwards if you need more drag. You first pull them up (arming the groundspoilers) after you have deployed the gear.

Link to comment
Share on other sites

9 hours ago, erick16899 said:

the same question 

I can't get ILS signal

Please login to display this image.

Are you sure you selected an ILS approach for your runway and not some other type of approach (VOR, NDB, etc.)

Link to comment
Share on other sites

Another question if you chaps have time...

 

What exactly does 'activate approach' do? I used it for the first time last night and it seemed to make my approach easier. Slowed down the plane quite a bit anyways.The tutorials I was following no one used that, but last night the sim told me to use it after the approach checklist.

 

When is the best time to use it. Searching various forums and articles it warns you not to use too early.

 

Thanks! :D

 

 

Link to comment
Share on other sites

"Activate Approach Phase" does what it says on the tin -- it puts the FMGS in to the Approach phase from the Descent phase. This configures the aeroplane (particularly in terms of managed speed) appropriately for the approach -- so if you are in managed speed when you activate the approach phase, the speed bug will reduce to the minimum manoeuvring speed for the current configuration (i.e. GD/S speed/F speed/VApp respectively as you extend flap), you'll get GS mini protection and the approach logic works accordingly as well.

 

The approach phase is either activated automatically when you pass the deceleration pseudo-waypoint, or more commonly will need to be activated manually at an appropriate moment.

 

As to when to use it -- my recommendation would be around 25NM (so when you're descending through around 7500ft) out whilst in selected speed (because if you activate the approach phase whilst in managed speed, the bug will immediately drop to GD and will start slowing you down, which you might not want quite at that moment). When you're ready to start slowing and extending flap you can then go back to managed speed.

 

The reason it is inadvisable to activate the approach phase too far out is because in at least some versions of the FMGS software (not sure if it holds true for all versions) the aeroplane uses your gross weight at the moment you activate the approach phase to calculate your VApp speed. Therefore, if you were to activate it several hundred miles out in the cruise, your calculated approach speeds might be wrong (i.e. too high). However, once you're in the initial approach you should be fine.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. Privacy Policy & Terms of Use