Simviation Forums

Hello all.

I was wondering if anyone could advise me as to whether the Approach Hold locks horizontal or vertical movement or both?  

I'm having some difficulty with heavy landings, which are registering as crashes using flight monitoring software.  

I usually use the Approach Hold for the portion of the landing until about 2nm out, those last 2nm are flown by hand.  However, I find that the approach hold starts the descent pretty late, and usually leads to a steep landing (900+ ft per second).  

So if I were to fly the landing by hand, I'd like to know if my correct heading would still be maintained if I did not use the Approach Hold, i.e whether this only controls the vertical portion of the landing?  Of course I have the ILS equipment functioning and it's heading in roughly the right direction but a clarification would be appreciated.

Cheers.

Hussein.

I can't remember the last time I tried to fly an ILS approach, but I believe equipment has the capability to follows both the heading and the glideslope.

I don't know if it can be enabled or disabled with the autopilot system for individual aircrafts.

As for the approach hold starting late, activate it while slightly below the glideslop, otherwise it won't be able to follow it correctly.

Thanks I'll try that and see if I can't soften the landing.

Thanks.

Hi HP......mm...if set up correctly the for an ILS approach and started from a reasonable distance and altitude your aircraft AP will line up exactly for the runway (eventually) and will engage the glideslope and turn off the Altitude hold, but in my experience some corrections with power and trim are neccessary to keep on the glideslope........some guys seem to be able to set up their a/c to hold the glideslope ...but in my personal experience only the heading is held perfectly without interference from me/you.....commoner.

Thanks mate, I'll try that!.

Oh BTW, I know I've said ti before, but I'lll say it again, FSPassengers is GREAT!

Sorry just had to say that.

Hussein.

Ditto the others: standard procedure, with or without the AP on, is to intercept the slope from below- that is, farther out.
Also: I haven't properly let the AP fly an ILS approach yet, but doing so by hand drives home the importance of maintaining the published speed for the approach.

Thanks.  Talking of published speeds, I need to work on that, I stioll come in too fast.  I'm at 190kts when ATC makes the last turn in for the approach (usually about 12nm out) and still at about 160kts within 3nm of the landing with full flaps.

Hussein.

locks both... with some space for rudder corrections.

MSFS's autopilot won't rotate the plane prior to runway and therefore will end up hitting the pavement with too much rate of decent.  You need to manualy flare the plane.  I do this by turning the autopilot off when I hit the last marker and hand flying the little last bit of the approach.

Another neat trick I just started doing (because I have an add on plane which doesn't like to fly AP approaches, see my topic "Airplane questions" below) is to leave the AP set to NAV instead of approach, turn off altitude hold and airspeed hold when it turns on to final, and hand fly just the vertical leaving the AP to fly the horizontal alignment.  Works like a charm.  The plane follows the runway centerline as if it were a VOR course and your job is to just ease the plane down the glide slope.  You can even leave the airspeed hold on (set for approach speed) until you hit the last marker.

The AP is a fun tool to play around with, especially for landings.  

I was wondering if anyone could advise me as to whether the Approach Hold locks horizontal or vertical movement or both?

Approach hold does indeed hold both.

However, I find that the approach hold starts the descent pretty late, and usually leads to a steep landing (900+ ft per second).

That is a perfectly normal glideslope, in fact it sometimes varies acording to airport, some are steeper!. Some AC are solid enough that you can just let it land itself in this way but hitting the rwy at 900fpm is VERY hard! When you are at between 2-300ft you need to 'flare' or bring the nose up, reducing your decent. There are a few AC that do do this automaticaly with an 'autoland' feature but most do not.

Localizer locks horizontal, approach locks vertical.
You can operate them together or individually.
For example you can get the plane to do vertical navigation and you yourself do the horizontal navigation or vice versa.

Ive had bad experiances with the ILS. Autopilot never lined me up properly and I killed it at about 5nm to ge me time to line up. I almost never follow the glideslope, I'm usually low, but most of my landings are so soft that a carrier pilot wouldn't even know we landed. I'll just stick to manual, makes things more interesting.

Again thanks for all your tips and help.  I'll remember those when I next do a landing.  Just downloaded the aircraft checklist multipack which has 67 checklists in it so that will come in really useful.  Thanks.

Hussein.

Ive had bad experiances with the ILS. Autopilot never lined me up properly and I killed it at about 5nm to ge me time to line up. I almost never follow the glideslope, I'm usually low, but most of my landings are so soft that a carrier pilot wouldn't even know we landed. I'll just stick to manual, makes things more interesting.

You've got the autopilot NAV/GPS switch set to NAV, right?

Hussein (and others) you'll always find help and advice here, but it's a good idea, in your first post, to say whiat sort of aeroplane you are flying. It makes it easier to offer advice.

I thought at first that you were flying light aircraft, in which you have to control the speed yourself; in that situation the ILS can't keep the aeroplane on the glideslope unless you give it enough power to work with (and increase the power to compensate for the extra drag as you put down things like gear and flaps).

But you're clearly flying a jet airliner; which means that the problem is almost certainly just that you're getting the speed setting wrong. All the aeroplanes vary slightly, but for a jet airliner, 220 knots while lining up; 180 knots/5 degrees flap/gear down as you intercept the glidepath; reduce to 140 knots/full flap on final; rate of descent 600 feet per minute, will probably be good enough for starters!

Anyway, this will take you through the whole thing, as far as the 737 is concerned. Hope it solves the problem  :) :-

http://www.simviation.com/cgi-bin/yabb/ ... 1129643666