ILS problems in the Lear Jet 45

[Pc-Shark]

My ILS system works in the Lear Jet 45 but this is what it does, I am about 40 miles away from the airport and I am already set up basicly heading right at the rwy then when I get aprox. 20 miles out and the ILS Freq. picks up and I turn on the approuch hold switch and my ILS indicater shows just about lined up when all that needs to be done is just a small turn to become aligned with the glide scope then the auto pilot starts turning sharp and keeps missing the glide scope bouncing back and forth till I get real close to the rwy then it lines me up but by that time I am to close and I over shoot the rwy. why would the Lear Jet 45 ILS approuch be messing up like that?

[tsunami_KNUW]

Try turning the autopilot off and land manually

[nickle]

Make sure you intercept the GS from below.  You can be far enough out, say 20 mi, but still be above the GS.  Check that the GS bug is above the center of the ADI.

[YodaNYC]

First, you should not be trying to line up with the runway at 40 miles out.  For the best approach, you should come into the approach at a 30 degree angle to the final approach course (this will most likely be 10 miles from the runway).  For instance, if the final approach is 40 degrees, enter from a heading of 70 degrees.  If using the autopilot (which it appears you are) to fly the approach, the plane will make a smooth left turn toward the runway.

Also, make sure that you establish on the glideslope from the proper altitude.  A quick check of the approach plate for the airport will show you the appropriate altitude for the outer and middle markers.  Too high and you'll miss the runway altogether.

I fly 737's and 777's so have not experienced your particular issue.

[Nexus]

Hey Yoda, what if the runway is actually straight ahead from his descent point. Doesn't make sence to create a route offset and then do an intercept turn?

[YodaNYC]

Agree with you on all that regarding real world flying.

Problem is FS, as you pointed, is that the system doesn't react well to larger turns.  I find that the plane often overturns du to the steep bank angle and then has to revor back to the proper approach path.

[Flapsup]

You can intercept the ILS from the last vector that ATI and gives you but you need to be established on autopilot altitude and heading. Do not switch altitude off before switching to APP. Also make sure you have set the ILS frequency into NAV1 and not a VOR frquency. Also chec to be sure you have the NAV/GPS switch set to NAV. The aircraft will follow the glideslope down and align with the runway. on Short final get off autothrottle and establish your approach speed manually. Remember that in FS9, landing speed is just that LANDING SPEED AT TOUCHDOWN not a mile out. Many of the aircraft will loose altitude rapidly if you get down to that speed too early. Have spoilers and auto brakes armed and switchoff the autopilot at about 50 feet, retard throttle, flair and brake and apply thrust reversers if necessary. If you remembered to lower the gear you should have a smooth landing. By the way ILS approaches from 15 miles or so are the norm for FS9 and in real life they allow you to get everything accomplished before you reach the airfield. Look at the article on good approaches in this months Flying Magazine.  

[nickle]

If the [autopilot] isn't satisfactory, in the aircraft config file you can dampen A/P oscillations by inserting a value in nav_derivative_control and boundry.  For starters use the same value as the integrator settings.

nav_proportional_control=11.00
nav_integrator_control=0.20
nav_derivative_control=0.00
nav_integrator_boundary=2.50
nav_derivative_boundary=0.00

[Billerator]

Yeah I suspect the problem was that you were not capturing the GS from below.
This will cause the AP to freak out ( sometimes ) and it will not land you on the runway.
( I found that out the hard way  :P )

[Pc-Shark]

[quote]
Yeah I suspect the problem was that you were not capturing the GS from below.
This will cause the AP to freak out ( sometimes ) and it will not land you on the runway.
( I found that out the hard way

[nochus]

If the approach speed is too high, then the AP cannot catch up with the ILS fast enough.

Try it with high speeds and low speeds and you will undersatand AP versus speed versus ILS sensitivity behaviour, on any aircraft.

Good luck

[nickle]

Lear 45 is a problem due to speed control on approach.
Download fuel to 25 percent.
Set 125kts A/S control.
Be dirty at 12 mi  ILS with G and some flap.
Full flap prior to GS.
Deploy spoilers for speed control on GS.
Anticipate need for some power in close with spoilers deployed.
POC