Bjorn’s Corner: Flight simulators

By Bjorn Fehrm

By Bjorn Fehrm

22 July 2016, ©. Leeham Co: Last week at the Farnborough Air Show I had the chance to try three flight simulators: The MC-21 airliner simulator, the SAAB Gripen fighter simulator and a special simulator for testing some new 3D synthetic vision ideas for a future avionics system. I’ve now tried some dozen different aircraft simulators of different generations, not counting the PC-based ones.

The simulators were different types. Some were fixed with displays that wrapped around and covered the peripheral vision like the Irkut MC-21 and SAAB Gripen ones. Others were full motion with complete surround vision display like the Airbus A350 simulator that I trained in ahead of flying A350 MSN002 last April, Figure 1. A third type were closed full motion simulators that lacked a vision system.

A350 simulator

Figure 1. Airbus full motion A350 simulator in Toulouse. Source: LNC

Compared with the very advanced Airbus simulator, I was surprised how realistic it felt with the simpler fixed simulators I tried last week. It made me wonder why.

What human senses are important

The many different types of aircraft simulators all try to fool one’s senses that one is actually flying. The first I flew was to train flying in bad weather; you trained flying only on the instruments. They were not as crude as the classical Link simulator, Figure 2, but not far from it.


Figure 2. The classical aircraft simulator, the Link trainer. Source: Wikipedia

The key attributes were that one was closed off from the surroundings in a moving aircraft cockpit, flying on the classical instrument T, Figure 3. The simulators movements should model the G-forces that the manoeuvres generated, thereby giving one the feeling of flying.


Figure 3. The classical bad weather (IMC) flight instruments, with the essential ones (speed, attitude, altitude, course) forming the T. Source: Wikipedia

They were not very convincing despite being very expensive. I remember the SAAB Draken ones we had in the Swedish Air Force. They were large installations, used for instrument flying training (bad weather take-off and landing procedures) and also for aircraft intercept training, Figure 4. These were big installations, often a separate part of a building with the simulator cockpit in a big hall and a control room outside.

J35f simulator

Figure 4. The cockpit of a Draken J35F simulator used for training IMC flying and intercepts. Source: Swedish Air Force.

Yet despite all the investment, the feeling when using the simulator was not of high realism. One trained the mechanics of the flying and the use of the systems but there was no doubt that one was in a simulator.  These early simulators lacked an external vision simulation. They had motion and sound, but the lack of a synthetic external environment visible through the canopy made them artificial to ones senses.

The power of vision

When I flew the fixed simulators last week with good surround visions systems, Figure 5, the feeling of realism was much better. Despite these being non moving simulators, the display of a realistic surrounding out the cockpit windows (canopy for the Gripen) more than compensated for sitting still.

MC-21 simulator

Figure 5. The simple but effective display system for the MC-21 simulator. Three large HD TV screens feed by the simulator software. Source: LNC

When I flew the MC-21 aggressively to make the final after a too tight a circuit or considered a half roll to get in after an enemy passing underneath in the Gripen, the immersive feeling of the situation and the manoeuvre being real was there. It shows that the most important sensor to feed (and fool) is the human vision. Adding a good sound also helps. Feed these with good trustworthy information and it will overpower the part of the body that says, “I’m not moving; we are sitting still.”

Bang for the buck

Full motion simulators with realistic surround vision like the A350 in Figure 1 will of course be the best solution. But the cost of these is an order of magnitude different to the Embraer KC-390 or MC-21 simulators that I flew, both being fixed with surround vision. And these felt realistic enough to be good for a lot of training cases.

When home PC simulators are equipped with three big screens like in Figure 5, fed with good synthetic landscape simulation, the home PC simulator will come close to the real thing for almost no investment at all.  Like Desktop publishing took over the dedicated publishing systems, the desktop airline simulator can replace expensive dedicated simulators for a number of roles. It will only require three good screens coupled to a high end PC and a good simulation of the cockpit interior.

The realistic PC-based flight simulation software is already there. Read my preparations for the A350 flight; the quality of certain PC simulator software is amazing. Now we just need the screen display to cover three screens, configured like in Figure 5, and we are close to the real thing.

7 Comments on “Bjorn’s Corner: Flight simulators

  1. Good morning Björn,

    I was lucky to fly the SAAB Gripen at FIA last week too and I was really astonished, how realistic it felt besides being in a fixed simulator. In the end I was really surprised how a good visual realisation can fool one’s perception and senses as I felt a bit dizzy when I climbed out of the cockpit after a couple of rolls and manoeuvres. All in all I was pretty impressed by SAAB’s FIA presence.

    • Yes I agree. The Simulator was a fixed cockpit with a good external screen. I didn’t take any pictures in the SAAB Gripen simulator but they had a darkened room with a really nice projection of the outside world on a half dome type screen in front of the cockpit. It made for a very good feeling when flying. Once again, get the visual and sound right and it will be surprisingly real. Doing a wooden cockpit mock-up with a good internal and external screen arrangement is not so expensive, the thing that costs is the hydraulics involved in moving cockpits. It is also hard to program the motions that shall induce a G force sensation with such a system.

      Re SAAB’s presence. What I find really good is the attitude of their personnel. Richard Ljungberg is the chief test pilot of the group. He did not go home Friday when the schools were there. He said they all stay the whole show, they are there to show what SAAB can do regardless if it’s professionals or public who are the visitors.

  2. It won’t be long before with mass produced basic cockpits and 3D glasses / smartphones w’ll have realism better then big simulators years ago.

    I know years ago groups were working on in-flight simulation for the JSF package. Threats / targets were simulated into the real world / systems for practice. A bit like Pokémon GO 🙂

  3. This thing about simulators reminds me on AF 447. It seems that the pilots did not have a good view just like in a Link trainer.

    I do not want to send pilots into Link trainer. I would recommend something else: the aircraft need a simulated view. Maybe a simulated horizon on all real windows could have been sufficient.

    • We are on the way to something like that. The third simulator I tested was with an experimental synthetic outside terrain model projected both on the pilots Primary Flight Display (PFD) and on the Head Up Display (HUD). Projecting on all six cockpit windows would be more difficult, on the HUD is sufficient. It is much easier to fly in bad weather with such aids, you fly exactly the same as if you were in good weather and could see the terrain. This is the future and it will eliminate accidents like AF447.

  4. I’m in the process of reviewing international best practice for the gliding world (big aeroplanes during the week; 15m silent wings on the weekend). I recently had the chance to use a gliding simulator with Oculus Rift VR goggles. It has convinced me that – at the simple end of flying at least – the days of the expensive and fixed based simulators are over. I found it quite immersive, albeit a little nauseating at first, but then increasingly realistic.

    • Agree these affordable units have been progressing over the last few years.

      Simple cockpits, when available for thousands iso hundreds of thousands of dollars will come in. Proffesional simulation is no longer leading. Commercial gaming is a much bigger world with more specialists and R&D money spent and quick live cycles.

      When I was a student programming a moving base 3D FS nearly 30 yrs ago (OMG..) we had a new mass storage for our Gold supercomputer. Sized a fridge and a whopping 300MB. Compare that to the nail sized memory card in the Iphone I’m typing on here..

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