In-Flight Electronic Foolproof Systems

Can we do anything to mitigate the human factor risks in aviation? The answer is: Yes, we can

In-Flight Electronic Foolproof Systems

Due to the recent tragic event, one question arises: How can we be assured of in-flight safety if one of the pilots is mentally unstable? Can we do anything to mitigate the human factor risks? The answer is: Yes, we can, with a wide-scale commercial deployment of the system co-developed by Boeing and Honeywell, one of the largest developers of aerospace technologies.

The system is based on a very simple principle: Once the situation in the cockpit is critical or unknown, all cabin piloting systems are switched off and are no longer operable. A pilot could push any button or try to operate any gear, but would find himself in a situation much like this cute squirrel: all piloting would be done by the ground service operators.

How does it work? Of course there are no geeky dispatches armed with a joystick and VR helmet. All of the flight parameters are uploaded to FMC, or Flight Management Computer, beforehand. The system is then capable of operating the flight entirely from the ground. As you can imagine, many electronic systems need to be in place to make this happen, and they are already here.

Flying by wire

In today’s aircrafts, the digital Fly-by-wire technology is increasingly becoming widely used. The first aircraft to ever deploy it was an Airbus A320, back in 1980s. The essence of this tech is very straightforward: electric gear is used to operate the aircraft instead of mechanical gear, e.g. pushrods, tension cables, hydraulic circuits, transmit load amplifiers, and so on. Those electric gears are controlled by a computer and connected by wires, hence the name.

The benefits of deploying this tech are simple: the aircraft becomes lighter, less expensive, and more reliable, particularly in terms of foolproof security features. Why hadn’t the Germanwings pilot just sent the aircraft into the nosedive? The automatics control the flight; not allowing a high negative pitch and descent at an excessive sink rate.

When the speed gets lower than the limit, or the sink rate is excessive, a smart electronic system makes corrections automatically.

For this reason, it’s impossible to allow the modern airliner to get into a stall or spin accident: when the speed gets lower than the limit, a smart electronic system automatically accelerates to a higher speed.

The higher the degree in which the in-flight systems are managed by a computer, the more capable the automatic pilot system is. For instance, it might take over the task of operating direction, speed and altitude parameters of the flight, as well as set the flaps at the required angle, extend the landing gear, activate automatic breaking, or, to put it simply, land the aircraft in a fully automatic mode not involving any action from pilots.

It would be enough to remotely upload the flight parameters into the in-flight systems and provide a necessary landing approach pattern, and everything would self-govern from there.

Beacons of Hope

As many might guess, in order to work this magic, super-precise navigation is paramount. Luckily, the aviation industry already has access to the majority of necessary positioning assets. Classical aeronautics use ground radio beacons, whose location and frequency is already known to the piloting systems. By setting the receiver onto a certain frequency, a pilot can define the aircraft’s location based on the range of the beacon.

The most primitive beacon called Non-Directional Beacon, or NDB, is equipped with a single antenna and in-flight systems are capable of only defining where the beacon is positioned in relevance to the aircraft’s position.

Another kind of beacon, a VOR, or VHF Omni-directional Radio Range beacon, is based on a more complex concept. It has a number of antennas located circle-wise and, thanks to the Doppler effect, allows to define the aircraft’s relevant location along with the beacon’s magnetic radio bearing — or, in other words, the aircraft’s current course in relevance to the beacon.

Frequently, VOR beacons are combined with another type of beacon — DME, or Distance Measuring Equipment beacon, in order to define the distance to them. The in-flight systems send requests, the beacon sends responses, and the difference in timing required to get the signal through serves to define the distance. With all this data at hand, it is possible to define the air position with maximum precision.

Landing somewhere suitable

For landing, azimuth and elevation transmitters are used. Together, both of them form ILS, or Instrument Landing System.

This is how it works: the azimuth transmitter serves to form two ‘fields’ with different radio signal frequencies (one on the left-hand side and one on the right-hand side of the runway). If the signal power is equal for both, then the aircraft is positioned straight along the central axis of the runway, and everything works like a Swiss clock. If one of two signals is stronger, then the aircraft should shift left or right in order to adjust the course.

The elevator transmitter works according to the same principle, but the ‘fields’ are, respectively, used to identify the position on the vertical axis in relevance to the glide slope line — it is the ‘vertical track’ on which the aircraft positions itself when landing. The principle remains the same: once one signal gets stronger than the other, the pilot has to adjust the vertical velocity in order to return onto the track.

Land us, ye Satellite

There is an alternative approach and landing system which employs SatNav and is called GLS (GNSS Landing System). The principle of this technology lies within defining the air position by satellite coordinates supplied by a SatNav system like GPS, Glonass, or any other.

As the precision of satellite geopositioning is not high enough for the landing approach, GBAS, or Ground Based Augmentation System beacons are established on the ground to transmit a high-precision signal.

Unlike the satellite, ground stations are fixed in relevance to runways and are located closer to the aircrafts. As a result, the aircraft’s position coordinates error does not exceed 10 ft (or 3 m). The main advantage of this system is its affordability (there’s no need to have separate beacons for each runway), reliability, and increased precision of guiding the airplane down the glide-slope line.

All of these technical solutions are available and operating now, but when all of it would enable fully automatic flight, remains an unanswered question. In theory, all tech needed is available right now, and today’s pilots, in fact, take over the control from the in-flight systems solely in emergency cases.

The problem is that if an emergency situation happens, one cannot entrust the electronics with the task of fully controlling the situation. That is why a human is unlikely to be excluded from the piloting process anywhere in the foreseeable future. Moreover, it would require an immense capital investment to refit all airplanes in the world to deploy such systems, so it won’t be possible to quickly upgrade every single aircraft with fully-automatic pilotless systems.

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