I've been attempting the autopilot navigation challenge in chapter 6 of the Sybex guide to FS2004 (page 138). For those of you without the guide, it is a short flight in the Lear using almost exclusively the autopilot. I pick up the glideslope, click APR and the plane then adjusts its course to pick up the ILS localizer, and starts to descend down the glideslope. Thats when things start going wrong. Whatever I do next, the plane dives into the sea short of the destination airport (Vancouver International). I've tried different speeds, intercepting the glideslope earlier/later and various other things, but all without success (I either dive into the sea at some point or miss the glideslope altogether).I realise that I'm probably having the same problems as a lot of others with an ILS landing, but I am following the instructions and I have been through the lessons in FS2004, and searched this forum. I am obviously doing something wrong, but I can't see what.I tried asking the guys on the 'other' forum. Someone suggested reducing the fuel load, but this made no difference.Thanks for any help.Boogie.

Anyone? I can't believe this is a bug in FS2004.Boogie.

I have not had this happen with the Lear or anyother jet using the auto pilot. Let me have the specifics and I will fly the approach and report back.Are you trying to get the autopilot to touch down as well? If so I do not think autoland works. I usually disengage the auto pilot at the DH or say 500ft. and land manually.Bill

Thanks for the reply.The challenge uses the autopilot/ILS to land the aircraft, not using autoland, just the glideslope.The flight is VFR from runway 7 CYAZ to runway 8R CYVR. The idea is to engage the autopilot just after takeoff and use it to control the aircraft until landing. You use GPS at first, but then go to a heading of 55 degrees until the GPS shows a bearing to CYVR of 79, when you change the heading to 80, the direction of the destination runway. You are then instructed to reduce speed from 250 knots to 180 knots (your altitude is 6000'). As you get closer to Vancouver, you toggle Nav/GPS to Nav. When you pick up the ILS glideslope, you click APR. You should then follow the glideslope down onto the runway, lowering your gear, adding flaps and reducing your speed to 120 knots as you go.Hope the above gives you all the information you need.Boogie.

Well I did the flight and its nice country to fly over. I am sure I did it wrong, but anyway, I did a GPS direct VFR 15,000 feet. I wasnt sure where the 6000 ft came in but by the time I got to 6000ft I was above the GS so the AP would not capture and descend on the GS. I think in FS we need to capture the GS from below. I was on the LOC only. Anyway I continued AP only and descended to 2000 ft with the hope that I would be below the GS and have it capture.It did not. I guess once you miss the initial capture its all over. As a result I had to hand fly from 2000 ft down which was ok but not what you want. Since I am now more familiar with the area I will do the flight again but descend to 2000 feet earlier and see if I capture the GS.At what point does your challenge want you at 6,000 feet and also what was your cruising altitude supposed to be?Dont mind doing it again, its a short hop and as I said nice mountains to look at :-)Bill

I fly the Learjet a lot and I always stay at 140Kts while on ILS approach (with 20 to 40 degrees of flaps). Flying at lower speed may not give the plane enough momentum to keep the plane locked on to the GS.Bob

Thanks for the response.6000' is the cruising altitude - the challenge just tells you to climb to that height and stay there until you descend on the glideslope. I think I do capture the glideslope, as the aircraft starts to descend automatically. It then seems to hold the glideslope for a while, then lose it for some reason, and plummet into the sea. Obviously, I could descend manually, but the challenge is to land on autopilot.Regards,Boogie.

Thanks for the response.I'll try that, although I think I may have already tried keeping a higher speed. In any event, the book clearly advises reducing speed to about 120 knots - I presume the author has completed the challenge!Regards,Boogie.

Just tried it with 140 knots and 40 degrees of flaps - same result.Good job my Lear has a liferaft!Boogie.

Ok Boogie I did the flight again and it worked out reasonably well. Let me recap what I did1) Kicked out all the baggage and passengers, only me and you as co-pilot :-)2) Reduced fuel load to 60% all tanks. Just a guess. For such a short trip 100% seems too much3) Took off, cleaned up, engaged auto pilot/NAV/GPS/6000 feet. Quite hairy with all those hills4) Tracked GPS until it intercepted the heading for rwy 8R. Of course I had loaded the vectors for 8R in the GPS and activated same. Not sure if your challenge wanted that but its no big thing.5) As soon as we turned heading 076 (wind corrected), I kept toggling GPS/NAV until I picked up the LOC approx 25 miles. No GS at this point and still at 6,000ft6) Engaged the APR and it tracked the LOC. The GS popped up shortly after that but the AP did not lock on to it.7) I immediately descended below the GS to 2000ft, disengaged the APR and then re-engaged it. VERY important step.8) As soon as the GS reached intercept at 2000ft, it locked on and I descending all the way down to 100 feet, and flared manually onto the rwy. Touch down was @125 kts, stopping without reverse thrust. 9)I had maintained 250kts then 200 kts all the way to the LOC and reduced to approach speed of 145kts. I find this a good speed for the Lear that works for me.Well I hope the above provides some clue as to what maybe different at your end. But the approach was beautiful and right on the numbers.I should also mention that its best to intercept the GS from below rather than above. I think thats real life and works best in FS. Maybe the challenge over looked that. Good luck.Bill

Thanks. I think I've done most of the things you suggest (although this deviates from the instructions in the book), but I'll keep trying.Thanks again for the help.Boogie.

Hi BoogieI tried the Sybex autopilot challenge myself with the default Learjet. I used to have the same problem: becoming a scuba ... until I realised I was in fact doing the ILS approach in GPS mode, instead of the NAV mode.Switching to NAV mode, and doing the ILS approach using the Approach autopilot (IAS 140 kts, flaps 40) landed me safely on the tarmac.Remember: kill the IAS autopilot, just before you land (50 ft QFE) ... else your landing might become a 'touch and go'.Hope it helps ...SergeDublin

Thanks. I think I am in Nav mode, but I'll double check this.Boogie.