SimHelp - Full Flight Simulator Maintenance ServicesRecently SimHelp team had to change the red CRT tube in the Airbus A320 Full Flight Simulator situated at BAA-Training. Team of qualified engineers wants to give valuable advice, which could help engineers-beginners to save time, health and nerves while changing the CRT tube.

Colored pictures – how are they created?

Nowadays Full Flight Simulator is an integral part of aviation. By realistically imitating aircraft’s flight it helps to learn to operate aircrafts by not breaking the real one, which of course helps to save money. The feeling and vision of a real flight is built not only on full motion, but on the visual part too.

Three calligraphic projectors compose the entire Visual System picture to fill up visual field of view by 180 degrees in horizontal direction and 40 degrees in vertical direction. Each calligraphic projector has 3 CRT tubes. Each tube represents single primary color: Red, Green and Blue, which are projected in the same area to create white color. The intensity of each primary color can be varied dynamically during image generation by different proportions, and the nice colored picture is created in such way.

CRT tubes tends to ‘die’

Unfortunately, tubes are consumable parts and they are aging and loosing intensity while using them. Furthermore visual system defects are the most obvious for any visitors and usually those defects can mislead someone to underrated evaluation of overall simulator condition. When CRT tube ‘dies’ the visual picture colors are being distorted. Depending from which color the tube ‘ends’ its lifetime, the image may become more cyan, yellow or magenta colored. In order to avoid such inconvenience, CRT tube must be changed.

Usual lifetime for a CRT tube is up to 15 000 hours, which equals to about 1.5 years of non-stop work. Considering that simulators are used for a long time, normally up to 20 years or even more, tube replacement procedure will happen many time during the entire lifetime of the simulators.

SimHelp team suggests

Changing the CRT tube is not a simple job, but can be easily managed by FFS engineers if the precise preparation is done. Thought it may appear ‘same old song’ but we will ‘sing it’ again: do your homework and be cautious!

  • Once again check if all the accessories from your hands are taken off: watch, rings, bracelets and any other jewelry can be trapped inside of tight space of projector and disturb your work.
  • Just in case, we want to remind you that 36 000 volt power is used inside of the Calligraphic projector to accelerate electrons flow inside each tube. This is way more than 240 volts or 110 volts, normally considerated as dangerous in every domestic electricity network.
  • Some parts can heat up significantly inside of a projector during normal operation. Mind this fact before touching any internal component to avoid burn.
  • Some components like tubes and power supplies are quite heavy and sensitive to the physical shock – be prepared to manage them properly before undoing screws of the projector.
  • When assembling the tool kit required for the tube replacement, don’t forget to add a torch – the amount of light may be quite limited at the workspace.
  • Always do your homework. Read the specific procedures in the manufacturers’ manual to be familiar about what’s going on and how to perform desired procedure correctly. Sometimes it happens that mistakes are done when performing a “well-known procedure”.

SimHelp team is wishing all the engineers good luck in your daily jobs. You can always ask us for helping you with your simulators by dropping a line at 

To see how SimHelp engineers replace the red CRT tube on the Airbus A320 FFS, please follow the link:

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