airbus 320 fly by wire

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Quick Start Guide Airbus A320-200 with full Fly-By-Wire and Airbus EFIS For X-Plane 9.xx Program Version: 0.9.5.1 Document Version: 1.0.2 Author: Torsten Liesk Date: 13.11.2009

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Page 1: Airbus 320 Fly By Wire

Quick Start Guide

Airbus A320-200 with full Fly-By-Wire and Airbus EFIS

For X-Plane 9.xx

Program Version: 0.9.5.1 Document Version: 1.0.2 Author: Torsten Liesk Date: 13.11.2009

Page 2: Airbus 320 Fly By Wire

Introduction This is the first release of the Airbus A320 with full Fly-by-wire and realistic Airbus EFIS. This version also features the first aircraft systems simulated according to the A320 system architecture, namely pneumatics (ATA36), and Air Conditioning (ATA21). I started developing this Aircraft in 2005 for X-Plane 8 with the key focus on a realistic panel (that’s after all what you’re seeing during most of the flight, no?), genuine Fly-by-Wire and a realistic Auto-Pilot. However, this aim only got feasible with the introduction of X-Plane 9 and the creation of generic instruments. Thanks to the X-Plane developers for this great feature! The plugin development started beginning 2008, and now – over 15000 lines of C-source-code later – the first official release is completed! My thanks here go to the entire crew from xsquawkbox for there great examples, most notably thanks to Sandy Barbour, Ben Supnik and Marginal. The cross-platform compiles have been created with the valuable help of Phillip Münzel and Jörg Hermann from the vasFMC team. A big thank you to those guys. Mid 2009, the engineering service supplier QualityPark AviationCenter GmbH expressed its interest in this X-Plane add-on. QPAC will use the add-on for visualisation of aircraft systems-simulations that have already been done and others that will still be done as part of the on-going R&D at QPAC. (They want to do a bit of marketing too, I assume.) Hence, QPAC has become a sponsor of this project, but don’t worry, we will always keep a freeware-version, at least with simplified system simulation.

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Installation Installation is easy, just unzip the content into an aircraft folder of your choice (E.g. “Heavy Metal”).

Getting started Quite a few things are different from the X-Plane standard. In the following, I’ll quickly explain the most important bits. If you prefer “trial and error”, I think, you should be able to figure most of it out anyway. ;-) Engine start-up FBW-Airbus aircraft have an automatic start-up feature. That means you, as the pilot, don’t need to worry about things like switching on ignition and fuel in a certain order etc. To start up the engines, you just need to turn the engine-mode-switch into the “Ignition/Start” position while the associated Engine Master Switch is off. Then move the Engine Master Switch for the engine you want to start into the “on” position:

The computer then takes care of opening the start valve, switching on the ignition and putting fuel into the combustion chamber, once N2 has come up to enough speed. (In the current version, the EGT during start reaches over 700 degrees. this is a bug that I still need to solve by overriding X-planes native fuel flow.) As bleed air simulation is now part of the add-on, your engine won’t start, if the respective side of the aircraft does not receive bleed air. If you have your APU running, just switch APU Bleed on, using the switch on the Overhead Panel. If one engine is already running, you can also choose to open the Cross-Bleed Valve to start the second engine using Bleed air from the first. (Switch the Cross-Bleed Valve back to AUTO afterwards!)

Engine-mode switch in position „Ignition/Start”

Engine Master Switch 2 from “Off” to “On” to start Number 2.

APU-Bleed Pushbutton Cross-Bleed-Valve Switch

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After having started both engines, turn the Engine mode switch back to Norm, unless you fly in icing conditions or other conditions, where it is recommendable to have the ignition on. And guess how to shut down the engines after landing? Exactly, just switch off the master switch.

Auto-Pilot-Interface:

The Auto-Pilot on the A320 is a bit different from what you were used to so far. The whole thing is described in Airbus’ Flight Crew Operating Manual on over sixty pages. I’ll try to keep the whole thing short, if you’re interested in more detail, go to www.smartcockpit.com and download for the A320 family the System description “AutoFlight”. In there it is pages 154 to 353 . But don’t worry, it’s not 200 pages, they just have every page 3 times in there for applicability reasons. The key philosophy in the A320 Auto-Pilot usage is the distinguishing between selected and managed modes. In selected mode, the Pilot directly chooses Heading, Speed, Altitude or Vertical Speed on the Autopilot interface, which is called FCU (Flight Control Unit) on the Airbus. In Managed mode, the autopilot automatically selects these values according to the flight plan in the FMGS (the Airbus version of the FMC) or Aircraft performance data. Another difference is that you cannot switch on the AP for only the vertical or only the lateral motion. On the Airbus, you either switch the Autopilot on, and it controls the aircraft around all three axes, or you fly the aircraft yourself. (In FBW normal law.) If you move your joystick more than half way around any axis while the AP is engaged, the AP disengages. (In real life, the sidestick gets locked in the central position, if the AP is on. If the pilot exerts more than a certain force on it, the AP gets disengaged and the side stick is free to move again.) The Auto-Pilot can be engaged from 5 seconds after lift-off. To engage, just press the button “AP1” or “AP2” on the FCU. AP1 works with the data on the Captain’s PFD, AP2 works with the data on the Co-Pilot’s PFD. Keep this in mind, in case you have different Baro-Settings on the left and on the right side. Only one AP can be engaged at a time, except for during the approach phase, during which both APs can be engaged simultaneously. (Has currently no effect except that it looks cool with all the green lights. In a later version, this will give you CAT 3 DUAL landing capability instead of CAT3 SINGLE.) To disengage the AP, in real life, you would normally use the “instinctive disconnect button” on the side stick. To get this feature, program any button of your joystick to either of the X-Plane commands “autopilot/fdir_servos_down_one” or “autopilot/servos_and_flight_dir_off”. Otherwise you can also just click again on the button on the FCU. To get rid of the subsequent Warning (Master Warning lit and “AP OFF” message on ECAM), either push again the “instinctive disconnect” button or click on the Master Warning light. If the AP disengages due to a failure or because you push the joystick too hard, the warning sound is not going to stop, until you take some action! Now to the interface. The FCU looks like this:

Page 5: Airbus 320 Fly By Wire

Most noticeably, the windows for SPD, HDG, and VS show dashes. What does this mean? As you can see, for each entry, the associated white dot is lit up, that means, SPD, HDG, and VS are in managed mode – the computer sets the targets. Here, the aircraft is in final approach, and the computer selects the heading and vertical speed targets such that the aircraft follows the ILS. The speed in controlled according to the flap setting, so that the pilot can slowly extend the flaps until position “FULL”. If the pilot turns any of the selection knobs for SPD, HDG, or VS, the dashes in the associated window will disappear, and the current value will appear, which the pilot can then modify. However, as long as you don’t push the associated selection knob, the AP mode will not change. If you don’t push the button at all, your selection will disappear after 10 seconds for the SPD, and after 45 seconds for HDG or VS. The Auto-Pilot will continue doing what it did before. After choosing a new target altitude, you need to confirm the new target within 5 seconds, by pulling (=clicking on) the altitude selection knob, otherwise the old target will remain active. The FCU only gives you very limited information, so how do you know, what the Auto-Pilot is doing? For this, you should look at the top of your PFD (Primary Flight Display.) It displays the “Flight Mode Annunciator” (FMA):

AP and A/THR on/off

Turn to select AP Speed

Click to toggle managed and selected speed

The white dot visible indicates “Managed mode” for SPD (left)

HDG (center) and VS (right)

Turn to select AP HDG

Click for: In mode HDG: Arm NAV mode In any other mode: Revert to HDG mode

Arm or disengage LOC mode

Turn to select AP ALT

Click to: - Engage OP CLB or OP DES mode - Confirm new ALT

Arm or disengage APPR mode

Turn to select AP VS

Click to: Set VS to zero (if in mode VS) Engage VS mode (if in any other mode)

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The FMA shows what mode the Auto-Thrust and the Auto-Pilot are in, and what mode is armed to be engaged automatically (if any.) A description of the different modes can be found in the appendix, here I just want to give the sequence of modes for a

Standard flight with flight plan: Take-off run: Vertical guidance: The vertical mode SRS engages (guides the aircraft to maintain lift-off speed +8kts or Lowest selectable speed +10kts, whichever is higher.) Lateral guidance: If the Localizer/ILS for the used runway is tuned into Nav1, the mode RWY engages laterally. It provides yaw commands to maintain the Runway centreline. If a flight-plan is entered into the FMC which starts at the departure airport, the NAV mode arms during the Take-off run. Auto-Thrust: The Auto-Thrust is armed, when the Thrust levers are moved into the FLX TO or the TOGA detent. The chosen thrust setting is shown in the first column of the FMA.

Typical FMA Display during the TO Run for a flight with flight plan and FLX TO Thrust.

Indicates A/THR armedA/THR will engage, when the Thrust levers are retarded into the CLB detent.

Indicates Flight Directors on PFD 1 and 2 engaged.

Indicates Manual Thrust selection. Thrust levers in the FLX TO detent.

Indicates Vertical AP mode: SRS (Speed reference system)

Indicates Lateral AP mode: RWY (Yaw orders to maintain RWY centerline). NAV mode is armed and will engage at 30ft RALT.

1st column: A/THR

mode and status 2

nd column: Vertical AP mode

1st line: Active mode (green)

2nd

line: Armed mode (blue)

3rd column: Lateral AP mode

1st line: Active mode (green)

2nd

line: Armed mode (blue)

Indicates A/THR engaged

Indicates AP1 engaged A/THR operates in SPEED mode, i.e. the thrust controls the speed

The AP operates vertically in Glide Slope mode (Maintain the Glide Slope)

The AP operates laterally in Localizer mode (Maintain the Localizer beam)

Typical FMA display during an ILS approach with AP1 and ATHR engaged.

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At 30ft Radio Altitude: Vertical guidance: Remains unchanged SRS mode. Lateral guidance: If the NAV mode is armed, it engages now, otherwise the mode RWY TRK engages. RWY TRK guides the aircraft to maintain the track it was flying when passing through 30ft RALT. (You need actively end this mode by engaging the Heading mode, whenever you wish.) Auto Thrust: Remains armed with FLX TO or TOGA thrust. At thrust reduction altitude: Vertical guidance & lateral guidance: Unchanged. Auto Thrust: The FMA flashes “LVR CLB” in the 3rd row of the first column, asking the pilot to retard the thrust levers into the “Climb” detent. (The thrust levers are in the climb detent, if the red “instinctive disconnect” button is just above the letters “CL” on the thrust levers. See figure below.) If one lever is in the climb detent, and the other is not, the warning “LVRASYM” is displayed in amber.

At acceleration altitude: Vertical Guidance: Changes to “OPEN CLIMB” to increase speed to allow flap retraction. After flap retraction, the mode maintains Greendot-Speed+x. (x depends on the altitude.) Lateral guidance: No changes. Auto-Thrust: No changes. (A/THR commands Climb thrust. Speed is controlled by the vertical guidance.) At reaching the altitude selected on the FCU: Vertical guidance: Changes to ALT* to reduce Vertical Speed in order to reach a VS of zero when reaching the desired altitude. Lateral guidance: No changes. (Continues to follow flight plan in mode NAV) Auto-Thrust: Changes to mode SPEED (or MACH at high altitude) to maintain the desired speed by changing engine thrust. Now you are basically enroute. You can change your altitude by selecting a new altitude on the FCU and then clicking on the ALT selection knob. If you want to fly parts of your route with mode heading just click on the HDG selection knob to active

Thrust Levers in climb position during a flight where AP1 follows the flight plan (Mode NAV) and maintains 3000ft. (Mode ALT). The A/THR controls the speed.

Alpha-Protection speed range

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heading mode. Bring your aircraft close enough to the Flightplan and press the HDG selection knob again, and the NAV mode will get armed. It will engage automatically, as soon as you intercept the flightplan. Descent for landing: Vertical guidance: Choose your new altitude on the FCU and click on the altitude selection knob. The mode “OPEN DESCENT” will engage and the aircraft will start descending with the engines at idle. (If you don’t have Auto-Thrust on, don’t forget to pull the levers back, otherwise you’re not gonna go down!) Lateral guidance: If your flight plan brings you to the start of the Localizer – no need to change anything. Otherwise engage the HDG mode and guide the aircraft to the start of the ILS approach by choosing appropriate headings. Auto-Thrust: If it is on, it will reduce thrust to idle automatically. Initiating the approach: Tune the ILS you want to land on into NAV1. As soon as you are within 15NM of this ILS, you can arm the Approach mode. However, even with the approach mode armed, make sure to guide the aircraft laterally and vertically to the beginning of the ILS. Upon reaching the localizer, the mode LOC* engages. After that, the mode G/S* engages, if the aircraft is close enough to the glide-slope. (The mode G/S* will never engages before the mode LOC*). Initial approach: Vertical guidance: The mode G/S* or G/S guides the aircraft along the glide-slope. Lateral guidance: The mode LOC* or LOC guides the aircraft along the localizer. Auto-Thrust: Operates in mode “SPEED”. During the intial approach, any of the modes can be changed by pushing any of the selector knobs or the APPR or LOC button. Final approach: Vertical guidance: The mode G/S guides the aircraft along the glide-slope. Lateral guidance: The mode LOC guides the aircraft along the localizer. Both modes are shown together on the FMA as “LAND”. Auto-Thrust: Operates in mode “SPEED”. Now, the mode cannot be changed anymore via the FCU. The only possibility to get out of this mode is by pushing the thrust levers to the TOGA detent. (Fully forward.) This engages go around mode. Flare and Roll-out: Vertical guidance: At 40ft RALT, the vertical mode changes automatically to FLARE. The aircraft reduces the descent rate to reach a nice smooth touch-down. After touch-down the vertical guidance disengages. Lateral guidance: At about 20ft RALT, the aircraft decrabs, i.e. aligns the aircraft axis with the runway. It lowers the windward wing a little to minimize drift. At touch-down the mode ROLL-OUT engages keeping the aircraft on the runway centreline using yaw-commands. Caution: For whatever reason, the plugin cannot address the nose-wheel steering. At low speeds, you might have to help with the stick to follow the yaw command, as the rudder doesn’t work anymore. Auto-Thrust: At 20ft RALT the Auto-Thrust commands idle and disengages on touch-down. IMPORTANT: Pull the thrust levers back to idle during the flare. Otherwise the engines will spool up to Climb thrust after touch-down. Normally,

Page 9: Airbus 320 Fly By Wire

the “retard” call-out reminds pilots to do this, I haven’t figured out yet how to play custom sounds from a plugin yet, though. There are tons of different possibilities to fly with the Auto-Pilot, just play around with it, and you’ll learn it quickly.

Auto-Thrust:

The most important bits of the Auto-Thrust have already been describe above. I just want to add an explanation on the use of the thrust levers. With both thrust levers forward of the CL detent, the A/THR can only be armed. The Thrust is controlled by the levers. If the thrust is armed in this configuration, and you retard both levers to the Climb-detent or below, the A/THR will become active. The thrust levers now determine, the maximum amount of thrust, that the A/THR can command. That’s why they are normally in the CLB-Detent, as this gives the A/THR maximum authority. If you pull them back to close to idle, there is not much thrust, the A/THR can give. If you pull the levers into idle, the A/THR will disconnect. The other options to disconnect the A/THR are the button on the FCU or the instinctive disconnect button, that you programmed on your joystick. (See Appendix.)

Fly-By-wire:

Find flying with the AP boring? Then just don’t engage it and just follow the flight director instead. The model comes with the Airbus “Normal” fly-by-wire law. (Degenerated laws may be implemented in later versions.) The normal fly-by-wire law includes the full set of protections (no stall, no bank beyond 67 degrees, no pitch above 30 degrees and below –10 degrees, low-speed protection and high-speed protection.) If you are not close to one of the protections, the roll command of the joystick gives a desired roll rate and the pitch command a desired load factor. If you don’t touch your stick, the aircraft automatically maintains the current attitude. (Except for wind gusts that may throw it into a different attitude, which it then maintains again.) No need for trimming or pulling in turns to keep the nose up. Protections: If you get slow (in the amber-black-striped band of the IAS indicator) and reach the maximum angle of attack, the Alpha Protection function sets in. This function means that pulling the stick fully aft will bring you close to the angle of attack of CLMax – you can’t stall while having as much lift as physically possible. To deactivate the Alpha Protection function, you need to push the side-stick forward for a bit, when the aircraft has accelerated enough. (faster than the amber-black band.) The ECAM shows that the Alpha Protection is active! The Alpha Floor function of the Auto-Thrust ensures, that the aircraft accelerates by commanding TOGA thrust, if the aircraft got too close to stall-speed. (The red band on the IAS indicator.) After leaving the Alpha Protection zone, the mode reverts to “TOGA LK” which you can disengage by disengages the A/THR. (I.e. press the instinctive disconnect, pull the throttle levers to idle, or push the button on the FCU.) The rest is pretty intuitive.

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Low-speed protection indications on the EFIS/ECAM

The roll and bank angle protections reduce the pilot stick input when approaching one of the attitude limits, so that you cannot push the nose down more than –10 degrees or higher than 30 degrees. The roll protection requires a full side stick deflection to reach and maintain 67 degrees roll either way. If the side stick is brought back to neutral, the bank angle automatically reduces to 33 degrees, which is the maximum angle that can be maintained with neutral side stick. The high speed protections automatically reduces the stick down authority, if the aircraft exceeds the maximum permissible speed and applies a permanent nose up input. Also, as part of the spiral dive protection, the roll angle will be limited to 45 degrees and with neutral side stick, the wings will become level. High speed protection becomes active at Vne+5kts. Its activation is shown on the Engine Warning Display by the amber text O/SPEED. Current restrictions: The FBW protections work only, once the speed bands are visible on the IAS indicator. When you initiate the flight somewhere in mid-air , it will take 5 seconds for the bands to appear. Before they do, you can stall the aircraft. Sometimes, the AP does weird stuff after an in-flight initalization, in this case you need to reset the AP: Turn of both APs and both FDs (Captain and Co-side). Then turn the FDs back on, and everything should be fine.

ECAM:

The ECAM currently has only some functions. The Engine Warning displays shows the check-lists during take-off and landing and some very few system failures. The amount of failures shown will increase for future updates. The image below shows the landing check-list. Blue action items still need to be done, items purely in green are checked. Concerning the check-item “Cabin ready” I’ll do a guessing game, how to get this one green. Think, what you need to do in real life to get the information from the cabin crew and then perform the one (little) action, that is actually feasible in a flight simulation. The System Display has currently the functional pages: ENG, BLEED, APU, WHEEL, PRESS, COND, FCTL and Cruise. The Status Page can be selected but shows only engine failure or fire, if it occured. The CLR button allows to erase warnings from the E/WD. (Will then be displayed on the Status page of the SD in a future version of the plugin.)

Lowest selectable speed

Alpha Protection speed

Alpha Floor speed

Stall speed (1g)

Indicates Alpha Prot active

Indicates Alpha Floor active

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Acknowledgements:

First of all, I want to thank QualityPark AviationCenter for adopting this project and hence ensuring on-going development (it’s quite time-intensive, you know) as well as maintaining a freeware version. A big thank you also goes to Jörg Hermann and Philipp Münzel from vasFMC, who provided great help with doing the cross-platform compiles. Jörg also helped find some bugs in it. As already said above, I want to thank to X-Plane development team for the introduction of some really cool features with XP9 and XPSDK2.0. As well thanks to the team from Xsquawkbox and all the forum members for the valuable insight into programming plugins for X-Plane. I also want to thank the development team of the GIMP for providing such a cool tool for free; without the gimp, I could never have achieved the result that you see now. Thanks to Reuben Horsley for the nice greater Auckland scenery and to Kevthrev for his Hamburg scenery that you see both on the screenshot on page 1.

Copyright:

The aircraft itself plus all the instrument textures in the current state are freeware. However, if you use parts of this project for your own project, please acknowledge me as the original author. (After all, I spent 1000s of hours creating this) The plugin is also freeware, however, it is not open source meaning you’re not allowed to modify it or distribute it with other aircraft. If you want to use the plugin for other aircraft, contact me, and I’ll be happy to help. (If it can be done with little effort that is.)

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Appendix

The following X-plane joystick commands are mapped in the plugin:

The selection up/down commands for SPD, HDG, ALT, VS should continue to work anyway.

Description of the AP modes:

To be filled later!

AP instinctive disconnect

ATHR instinctive disconnect

ATHR button on FCU Push HDG selector knob on FCU

Push VS selector knob on FCU

Push ALT selector knob on FCU

Push APPR button on FCU