Learjet 45 landing

[avbuff58]

here is my 2cents, I have flown the lear about 50+ times and I've found that if the airspeed gets to low is when you have this problem of taking off again. You have anose high attitude the air gets under the wings and you start to lift off again.If you carry a bit more speed on final the approach is flatter and you don't have such a nose up attitude. I also dont flare to much just hold the j'stick level all the way down.

[neoncarrot]

I came across this intersting thread while browsing and thought I'd offer my tuppence worth. My own experiences are in the Lear in FS9, but the principle should be much the same.

I've only been playing FS for about 6 months, and often use London City Airport as it's local to me in the real world and I did a number of flights into the airport in the jump seat of Dash 7's some years ago. While I could pull creditable looking landings in the lear at Gatwick, Heathrow etc etc, for some reason I always ended up touching down halfway down the (short!) runway at LCY/EGLC. It annoyed me enough to try and work out why. The glideslope just "looked" steep on approach, and a bit of digging eventually confirmed that LCY is something of a rarity at 5.5 deg (was once 7.5 deg!!), as opposed to the more normal 3ish degrees, and it appears this is modelled in FS9, accounting for my problems.

So I did some tests and flew a lot of approaches to LCY to try and nail it down, and what I found pretty much concurs with the other posters who suggest getting the approach (especially speed) right is the key in the lear. All my approaches mentioned were ILS approaches flown on autopilot to 500ft AGL with autothrottle engaged, after which it's manual stick and throttle for the last part.

Once you "tip" over onto a normal glideslope in the Lear, your speed is going to rise by 6-10 knots (depending on flaps), but drag will generally bleed this off by touchdown on a 3 deg GS angle. On the 5.5 deg GS the speed gained was sticking all the way down - especially crucial as you seem to need a lower airspeed in any case on the steeper GS. Even taking it off autothrottle and retarding the throttles makes little difference. If you retain this extra speed you're going to do some floating, and at LCY theres not much tarmac to do it.

Theres an odd additional problem re floating; the spoilers. Pop the spoilers in level flight on the Lear (or most FS9 jets) and the nose tends to rise. I don't know if this is realistic, but it does seem reasonable. Problem is that when the autospoiler engages on wheels down, this causes the nose to lift, and if your speed is already a little over you might well go airborne again. Irrespective, you'll have to give the nose a little help to come down.

So the trick seems to be to ensure you get to the glideslope intercept with everything ALREADY correctly configured just beforehand. In my case, to set down at the right point at LCY with 40 percent fuel and 50 percent passenger load, this comes to;

- flaps 40
- airspeed 110 - 115
- gear down
- autospoilers armed

Accounting for the increased speed gained on the GS and disengaging AP/AT at 500ft AGL, this gives me a airspeed of approx 112-117kts at the threshold, which, after fully retarding the throttle and adding 2 or 3 degrees of pitch to flare, bleeds the speed down to 107-110 kts at which point the Lear settles nicely with a descent rate of around 150 fpm. The nose needs a bit of nudge to stop it rising after the spoilers pop up, but without using too much force, to avoid the nose wheel coming down too hard.

The FS9 notes for the Lear suggest hitting the glide at about 140kts, but if I tried that I'd float down the runway end up in the Thames. The numbers given for many of the stock AC seem not to work, or in some cases actually contradict between the notes given in the 'help' section to those given on the kneeboard.

With that in mind I tried testing the Lear's stall speed* in level flight @5000 ft with various flap configurations to try and work out what the 'safe' speeds were for a given weight etc. I just basically backed off the throttle slowly till the stall warning sounded and the aircraft dropped. These are pretty approx and hardly scientific, but what I got was;

clean - 90kts
Flaps 20 - 87kts
Flaps 40 - 84 kts

So a glideslope speed of 115kts or better seems to leave a good margin for error on a steep GS, and 120 seems to work OK on a normal 3 deg GS.

Hope this is of interest to someone .


* I tried this same test in the 747 in FS9, and ended up with a stall speed of 120 kts with the AC fully loaded and fuelled.

[Slotback]

The Learjet 45 that comes with FSX has a pitch-up motion when the spoilers are extended. Very annoying and can cause you to jump back into the air.

[Brett_Henderson]

neoncarrot.. describes the landing well.. He illustrates that you have to understand what's happening .. has taken steps to strengthen his understanding .. an demonstrates how important the airspeed is.

You cannot just steer-n-fly jets to the runway. Your landing technique needs to be well polished (best accomplished in slow, forgiving airplanes).

And.. simply hitting the runway, while not over-running it, does not constitute a good.. realistic landing.. if it would have the airplane owner taking the keys from you; the virtual FAA taking your license; the tower guys wanting to talk to you; the mechanics cursing you, and a plane full of passengers who will never again step foot onto an airplane..

[Slotback]

Also, make sure Throttle sensitivity is FULL, with NO null zone. It will be difficult to idle the throttles otherwise.

[dacair]

Hi,
I am glad so many people discus here about the subject.
Many real good answers I found here from you all.

After I read your posts here, and after some tests I've made with my FSX LearJet 45 I think in my case the spoilers are exteded