Extra EA-500/failure dialog

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The Extra500 incorporates a dialog that enables you to produce failures (and to repair them) in various aircraft systems through a graphical interface. The dialog is accessible through Extra 500 - Failure Dialog.

Canvas/Nasal background information

For some background information on writing this Canvas dialog please have a look here.

Extra500: only two greens


The failure system in the Extra500 model is far from complete. It incorporates a mixture of failures that are interesting and/or fun. They are in not selected on if they are likely to occur. It is to test your pilot skills, try out different approaches handling these failures or just to see what happens.

Personal note:
One of the first failures I implemented was 'gear jammed' and is still my favorite. Just to try out to land on two gear legs and keep the aircraft reasonable free from damage. What is the best strategy? High or low speed landing, flaps extended or up, or maybe just a belly landing.

The dialog

Failure dialog - first page

The dialog features a menu on top. You can select the aircraft system or on the far right choose to REPAIR ALL. Note that all failures are present if the the dialog is open or not. However all failures are resetted with each flight session.

On the initial screen you can trigger a Random Failure. Set the maximum delay with the mouse wheel. It can happen earlier, but never later.
There are a lot of failures that can happen (approx. 100) and some you might not notice. For instance if you are flying in summer and one of the wing boots has failed. Other you will notice directly (autopilot servo runaway) or at the exact time you don't want it to happen (flaps jammed at approach).

If you want to see a dedicated failure go the the system and click on the component you want to break. The component color will change to red and a text will appear stating the exact failure. Also the menu-system button will have a red field with a number in it, representing the number of failures of that particular system.

There are 3 kinds of failures:

  • The most common failure is you click on it and there is a failure, on/off, no in between-s.
  • The fuel system has some 'analogue' failures. For instance the fuel filters can be set clogged 0-100% with 10% steps.
  • Progressive failures start with no error, but the error increases over time. There are several misleading indications like this.

In the left lower corner is a timer which counts down to the failure to become active (or in-active). To set this timer hover with your mouse over the field and scroll your mouse wheel. It is limited 0 - 60 seconds. Progressive failures cannot be timed.

The systems you can choose from are:

  • GEAR
  • FUEL
  • DE-ICE

Gear window

In the gear window you can see a schematic view of the landing gear. The failures include gear jammed, brake failures and flat tires.
Extra 500 - Failure Dialog - Gear

Fuel window

The fuel window is a bit more complicated. Here you can clog/block filters, check valves and jet pumps, make tanks leak, let pumps fail. Basically everything that will let your engine fail (no fuel at the right flow and pressure). In the background the fuel flow due to the pressure loss in the system and the pressure gain due to the pumps is calculated. This means that at low power (low fuel flow) the engine might get enough fuel, but at high power setting the pressure drop will be too high and the engine will fail.
Also be careful of other effects like fuel unbalance and reduced range.
Extra 500 - failure dialog - Fuel

Controls window

The control system of any aircraft is redundant, thus a single failure won't have you loose control entirely. You can always land your aircraft safely. The rudder backs up the ailerons (and the other way around) and the pitch trim system backs up the elevator system. Actually for aircraft certification, you need to show you can land the aircraft with pitch trim. As the Extra500 has a real pitch trim system, you can actually play test pilot and try!
Extra 500 - failure dialog - controls

De-ice window

All de-ice systems you can fail here. Ranging from the pitot heat to a single de-ice boot. Of course when there is no icing, there is no effect. But in winter take care. Make sure to checkout an Ice Contaminated Tail Stall (ICTS) just to find out why you should not set the flaps to 30 deg with ice on your horizontal stabilizer.
Extra 500 - failure dialog - de-ice

Avionic window

Use it to induce indication failures (roll, pitch, heading, altitude, airspeed) and the failure of other avionics. Note that the roll, pitch and heading faults are 'progressive'. So you won't notice it at first, but the indication error gets worse and worse.
Extra 500 - failure dialog - avionic

Autopilot window

The most interesting failures here are the servo runaways. Make sure you give yourself some time to prepare, so use the timer to the delay the runaway. The servo runaway will drive the servo at full speed to a random direction. Especially at high airspeeds, this can be quite problematic. Remember you can overpower the servos while pressing o and disconnect the autopilot by pressing d.
Extra 500 - failure dialog - autopilot

Pressing the REPAIR ALL button will repair all instantly.
However, if the Random failure has not occurred yet, you won't be able to stop it until it is triggered.

Have fun and take care!