FLIGHT SIMULATION FORUMS

[99jolegg]

The approach hold is just that - an approach hold function so will not land the aircraft for you because it's not designed to do so. Disengage the autopilot and autothrottle at 200-500ft and hand fly the remainder.

As for not intercepting the glidesope...make sure you have intercepted the localiser first and then approach the glideslope from below at 180kts - if you do so, you should have no issues.

If you can give us a bit more info about your speed and profile, it'll help.
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[eater1234]

thanks for help it works fine now

[KenTel]

Hey Jon, what a lot of knowledge you have imparted to me and a lot of other land lubbers... Must have a lot of patience also, I have thoroughly enjoyed the post, though has taken me into the wee small hours reading it all.

Anyway I felt impelled to add my appreciation, for your time, work, knowledge and patience.

Thanks Jon!
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[99jolegg]

No problems! Glad it helped.
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[Blade Brown]

Hi there, thx first for this incredible tutorial.. But still... I have big troubles when landing..I think I just make a tiny mistake somehow... Or maybe I forgot something...

My approach is always fine.. I get ATC orders and follow them.. Once I have my ILS Runway Info, I punch it into the GPS with vectors-to-final.. The red line is there then and I perfectly align with the runway and i can see it..

Then I am coming in, flaps full, gear down, speed between 145 and 150 knots.. before the airport usually at around 2000 - 2500 feet.. I then descend using the althold button cause i have no joystick and flying with the keyboard is a mess... However, I wanna land manually.. I see during my final approach that these 4 lights that are next to the runway start to change color.. (I dunno must have something to do with the ILS)... Then at around 500 feet i disengage A/T but then as soon as i disengage the althold button or autopilot, my nose shoots up in the air and i miss... i tried it a different altitudes during final approach... always the same.. and whether i fly the lets say 737-800 or the airbus 321.. it s always the same... so where is the problem? It even does it sometimes when I disengage AP during the normal flight..

(I did the tutorials in MSX incl transition to jets and flew some missions..never had problems there)

I tried to learn...read books etc before i started with msx so i was thinking i was theoretically prepared lol... mistake i guess

Thx

Seb

[99jolegg]

It's the stabiliser trim that usually causes that problem. In the real world, autopilot systems are designed so that "snatching" doesn't occur on engaging or disengaging the autopilot. In the sim, it's hit and miss as to whether it'll snatch to the last known trim position when flying manual.

The best solution I can think of is it stabilise the aircraft as best as you can and re-trim for the current speed / configuration.

By the way, the four lights you're seeing are the Precision Approach Path Indicators (PAPIs) and they denote your rough whereabouts on the vertical axis on the approach i.e. the glideslope. Roughly a 3 degree glideslope is denoted by 2 white lights and 2 red lights. Higher than that indicates 3 or 4 white lights. Lower than the optimum is indicated by 3 or 4 red lights and no white lights.

Let us know how that goes.
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[Blade Brown]

Thx my friend... This time I used the whole ILS Configuration.. Meaning entering the ILS frequency.. This case Flying Guangzhou to Hong Kong..Quick jump... I punched in ILS Frequency.. And turned on NAV Button on the Com Console..Heard the Morse Code as soon as i approached.. I was flying a 737-800 Singapore Airlines.. Changed display to Approach... Configured my plane for final approach... Vectors-to-final ILS 7L Perfect alignment..as I hit the localizer I pushed the APP Hold Button and my plane started to descend and turned off AltHold Button.. Perfect... As i hit 200 ft. I disengaged AP and again..nose up..Really have to work on that trim..Maybe I leave on the AP until I am on the runway... Gotta try that... Config was okay.. flaps full 150 knots..gear down... and the Boeing descended by itself... at the end I had 4 white lights..During the approach, I was at 1.700 ft as given by ATC..She was going down perfectly... Centerline... But when I hit the AP Button at 500 ft.. bam..Nose up... damnit..lol... Let me see if I land ILS leaving AP on until I touchdown..nose down and then hit the Reverse Thrust.. Maybe then it s ok.. She lands beautifully, announcing perfeclty from 100 to 20 ft.. I have the PM Sound Add On.. then I put Thrust on Idle in order to land... no Retard Retard though.. Let me try not to disengage the AP until touchdown and Thrust Reverse..

Thx

[Blade Brown]

P.S.

I solved the trouble for the Airbus....Although I think no real pilot would do that... Turning of the ELAC Flight Control 1 (3 buttons, right side overhead panel) seemed to disengage this problem..It did it... But I don' t think thats the best way... The Boeing doesn t have that..I will try now leaving AP on until touch down and then see...

Seb

[99jolegg]

You could try that but just as an aside, it's illegal to do that in the real world unless the aircraft and runway (they're not in the sim) are certified for a CAT IIIB/C approach i.e. the runway and aircraft (and crew) must be certified to land with the autopilot still on.

I'd still try and counteract the pitch up, which certainly becomes so much easier with a joystick.
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[Blade Brown]

hmmm..i get the feeling it might not be the sim itself... but the add on i downloaded

it was a texture download for the original planes... however the airplane.cfg changed as well.. somehow i think this person altered the autopilot in a way it is not flyable anymore....

the settings are:

Airbus 321:

[flight_tuning]
cruise_lift_scalar=1.0
parasite_drag_scalar=1.0
induced_drag_scalar=1.0
elevator_effectiveness=1.0
aileron_effectiveness=1.0
rudder_effectiveness=1.0
pitch_stability=1.0
roll_stability=1.0
yaw_stability=1.0
elevator_trim_effectiveness=1.0
aileron_trim_effectiveness=1.0
rudder_trim_effectiveness=1.0


static_pitch=0.3 //degrees, pitch when at rest on the ground (+=Up, -=Dn)
static_cg_height=9.2 //feet, altitude of CG when at rest on the ground
gear_system_type=1 //Hydraulic

[gear_warning_system]
gear_warning_available=1 //Normal
pct_throttle_limit=0.1 //Percent throttle that activates warning
flap_limit_idle=5.0 //Flap angle that activates warning at idle
flap_limit_power=25.5 //Flap angle that activates warning at above idle

[autopilot]
autopilot_available=1
flight_director_available=1
default_vertical_speed=1800
autothrottle_available=1
autothrottle_arming_required=1
autothrottle_max_rpm=90
autothrottle_takeoff_ga=1
pitch_takeoff_ga=8;
max_pitch=10.0
max_pitch_acceleration=1.0
max_pitch_velocity_lo_alt=2.0
max_pitch_velocity_hi_alt=1.5
max_pitch_velocity_lo_alt_breakpoint=20000.0
max_pitch_velocity_hi_alt_breakpoint=28000.0
max_bank=25.0
max_bank_acceleration=1.8
max_bank_velocity=3.00
max_throttle_rate=0.10
nav_proportional_control=12.00
nav_integrator_control=0.25
nav_derivative_control=0.00
nav_integrator_boundary=2.50
nav_derivative_boundary=0.00
gs_proportional_control=25.0
gs_integrator_control=0.53
gs_derivative_control=0.00
gs_integrator_boundary=0.70
gs_derivative_boundary=0.00
yaw_damper_gain=1.0


And Boeing 737-800

[flight_tuning]
cruise_lift_scalar = 1.0
parasite_drag_scalar = 1.0
induced_drag_scalar = 1.0
elevator_effectiveness = 1.0
aileron_effectiveness = 1.0
rudder_effectiveness = 1.0
pitch_stability = 1.0
roll_stability = 1.0
yaw_stability = 1.0
elevator_trim_effectiveness = 1.0
aileron_trim_effectiveness = 1.0
rudder_trim_effectiveness = 1.0

[autopilot]
autopilot_available=1
flight_director_available=1
default_vertical_speed=1800
autothrottle_available=1
autothrottle_arming_required=1
autothrottle_max_rpm = 90
autothrottle_takeoff_ga=1
pitch_takeoff_ga = 8;
max_pitch=10.0
max_pitch_acceleration=1.0
max_pitch_velocity_lo_alt=2.0
max_pitch_velocity_hi_alt=1.5
max_pitch_velocity_lo_alt_breakpoint=20000.0
max_pitch_velocity_hi_alt_breakpoint=28000.0
max_bank=30,25,20,15,10
max_bank_acceleration=1.8
max_bank_velocity=3.00
max_throttle_rate=0.10
nav_proportional_control=12.00
nav_integrator_control=0.25
nav_derivative_control=0.00
nav_integrator_boundary=2.50
nav_derivative_boundary=0.00
gs_proportional_control=25.0
gs_integrator_control=0.53
gs_derivative_control=0.00
gs_integrator_boundary=0.70
gs_derivative_boundary=0.00
yaw_damper_gain = 1.0


The problem must be in here somehow.... I think..

However..the AP On did it..I landed using ILS funstions etc.. and at the end just leave the AP on until I touched down..Reverse Thrust..and then turn it off..It worked...

Seb

[99jolegg]

Glad it worked - I'm afraid I don't know anything about the config file side.
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[Blade Brown]

Thx my friend... Great Tutorial anyways.... Now I can manage to land ILS using the AP.. although as you said... AP landing no good.... Seems that the AP is kind of watching over your shoulder in that case...I still have full control over the plane though..but these add ons %^#$!!! my system somehow... I will change the accuracy in the config file...

I know that turning of the ELAC FTL Ctrl 1 is definatley NO WAY!!!.... but if it helps for the Airbus though....ok... btw.. Didn t have an add one for the 747.. Works perfectly..even with AP Off... So it s the config file...

Will try it with a pure 767 and an A 380.... lol.... oh no... Look at us.... amateur whatever wannabe pilots going with an A380 hehehe..

However... My license is in planning... Will work out the financial stuff...I wanna fly.. And at the end get certified on a 737-800 and an 320/321 cause those are the most used ones in the world... So I am training already right now...

I also tried flying a VFR instead of IFR... and guess what... no problem.. although I used the GPS Vector and the ILS for the VFR.. and it worked... really means it s the config file altered...

By the way... I never flew a complete Visual Approach.. I remember when I was flying as passenger in a real plane.. I recognized they were descending and climbing using the throttle... Like flying kind of a sinus rhythym... Is that when they use a map and certain waypoints and marks to descend?

Thx

[99jolegg]

Good luck with the licenses.

[Blade Brown]

I mean it seemed to be kind of a stair type approach.. They reduced speed and descended...increased speed and kept the altitude...reduced again and descended..like a stair... Seemed to me as they were going down..keeping..down..keeping..down..keeping etc..

plus i also read many tutorials saying to extend the flaps step by step..i never saw that except on the vids of the a380...

always seemed to me that they reduced speed and descended... and that at a certain speed and altitude..they extended the landing gear and full flaps which had an immense breaking power while i was seat-belted and then descended...

i also did it like this...i reduced approach speed to 210 knots..once i was ordered to descend i descended and then reduced speed to 200 knots..extended landing gear and full flaps while reducing to 180 knots..and then down to 145.. and then landing...

it s so complicated though.. lol

take off was easy..punched in all info into the AP panel..not activated... teaking off..positive climb..retracting gear and then activate Ap with AltHold..then A/T Cruise speed and then HDG Hold when ATC gave me a heading after climbing following runway heading climb...

Thx

Seb

[99jolegg]

[Blade Brown]

Ok Thx...

I also think I found my problem....

First.. For my approach, landing in HK (54 ft above sea level), ATC assigns me 1.700 ft... according to the usuall 2500 feet to catch the glideslope from below, that mean I would catch it later than if I would be at 2500 ft... I saw it cause on the primary display, once I hit the glideslope, which i think was the green arrow on my gps, the pink square in my flight display told me i m too low..it came down by itself after time..probably coz of the 1.700 ft.. once it was in the middle, i hit the approach button..

I saw all of a sudden, during my approach (which probably never happens in real life) that the runway etc was all of a sudden covered with a green grid and green outlines... then I pressed approach button (according to glideslop on the flight display) and the plane started to descend, turning off the auto-heading (cause I put the heading of 73 in the crs according to flightplan) and it turned of the althold switch...

However... it did not turn off the flight director.... and there was the trouble... after turning off the flight director and then A/T and then the AP, voila...whoop whoop, but no nose up anymore..and i landed very smoothly by going to idle with thrust at 20 ft and flaring the nose...

seems like the FD is not for landing and as you said, disengaging the AP might set the plane to the settings of the FD...... If that was the problem and not just coincidence..that was a stupid beginner mistake from my side.. lol

[99jolegg]

No not your mistake - the FD doesn't do that in real life and shouldn't - when AP is off, it's merely a guide to the pilot; it's not an automatic function of the aircraft and doesn't control the aircraft.

2500ft is just a guide for ILS interception - all airfields are different. I suggested a height just so people didn't have to check the runway plates for the airfield they're attending but you can do it that way if you wish. Some intercept at 2000ft, some 1500ft, some 3000ft - depends on the airfield and its elevation.
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[Blade Brown]

Ok..Thx..I got it..

It seemed like having the FD on and then turning off AP pushed my nose up because they were still the 1700ft. in the AltHold that ATC assigned me..seemed as the plane simply tried to get up to that level again..And due to the fact that A/T was turned off..I heard the horrible sound of the Stickshaker after 5 seconds cause I was about to stall... I tried it during cruising..same thing... FD on... AltHold Off..there goes the plane... FD off, ALTHold off.. or AP off... it kept perfectly flying... Maybe a flaw in the Sim.. I dunno... However... It works now..and I will put vids of it tomorrow on Youtube..hehehehe...

Thx again...

Seb