Why do aircraft cockpits have so many buttons and switches? What do all those actually control and are they all used?


Why do aircraft cockpits have so many buttons and switches? What do all those actually control and are they all used?

In: 26

They all have a function yes – aircraft builders aren’t in the habit of including buttons et al just for decoration. But bear in mind that redundancy / duplication is a key safety feature in aircraft, so you can pretty much divide the number you see by two to get the number of distinct functions.

Some of them are “just” monitoring different states (fuel, hydraulics, electricical systems etc) in order to give informationm should anything not be as it should, rather than having a direct purpose in flying the aircraft. Some are for navigation, others for flight control…

Throttle-engine power. Maybe different throttles for different engines

Anti collision lights

landing lights

Buttons for modifying the instruments, setting airfield local air pressure or control areas designated air pressure-this is so the aircraft is assuming the same pressure as all other aircraft and therefore altitude if not accurately reported is atleast good in reference to other planes.

Navigational buttons all the way from the old VOR beacons to modern GPS etc.

Control surfaces for adapting the trim of the aircraft, adjusting the amount of pressure a pilot needs to exert on the controls.

Fuel mixture levers allow you to set the amount of oxygen mixing.

Engine priming allows you to inject fuel into the engine to start it up.

The on switch.

Fuel tank switches.

Radio buttons. Larger aircraft may be able to tune into more than one radio frequency. These needs controls to change the frequency, volume etc.

Source_ am a small aircraft pilot, I imagine there are a lot more in bigger planes, but the big commercial aircraft will have something similar to all this and with more sophistication

It’s actually dependent on what flight you are using. But a common comercial flight uses these buttons to communicate or to enable and disable the seat belt signs, to control the engine , speed to signal the cabin crew , to talk with the passengers etc.
There are lots of buttons to talk about.

Ohhh what does this button do??

If your car is having trouble, you can pull over, pop the hood, and take a look at the engine.

If your plane is having trouble, you can only work from inside the plane (until you land it, which might be hours away). So the cockpit must have additional troubleshooting/diagnostic tools to allow the pilots to either fix the problem or to accurately determine what the problem is in order to find a safe solution (temporary fix then fly to original destination, call nearby airport for emergency landing, or attempt a crash-landing). The cockpit instruments are therefore made to provide a lot of information readily at hand to the pilots so that they can troubleshoot the plane quickly mid-flight.

What everyone else has said, but also: a fair number of the switches are circuit breakers, especially on airliners. And there can be a lot of circuits on an airliner.

Airplanes are simply different than cars that you are likely used to. For example car lights can have headlights, running lights, high beams, cabin lights, etc all on one control. For my plane I have beacons, nav lights, strobes, panel lights, instrument lights, cabin lights, two separate landing lights (one is in the retractable nose gear, one is on the cowl). Each of these has a separate switch.

Why all on separate switches? Well if I have a failure, say a short, I can isolate that one system super easy while I let the others run. It is also super easy to only run the one system I want if that is all I want. I can run the fixed landing light without running the one that is retracted (some planes have systems that supposedly turn the retracted light off, some don’t). I can turn on the navigation lights without the strobe if I am in clouds or fog, or just taxiing past someone so I don’t blind them.

Also, if I have an alternator failure I can shed load to let my battery last longer to keep things like my radios running while turning off things I don’t need.

Next, my plane has basically three radios, your car has one. I also have an audio panel that works as your cars radio’s built in fader. That panel also allows me to decide which radio is in what condition. For example I can listen and talk on one radio while I just listen to the second radio. I can also set my panel up so I am talking and listening on one radio and my FO is talking and listening on another radio totally independently of me.

In your car you don’t need more than one radio I need several. (Two communications radios, two nav radios, one or two transponders, at least one GPS, and a radio panel).

I have to have equipment you don’t need in a car. I have a radio that is called a transponder that responds to ATC with a code. So when I contact ATC they give me a code and I have to dial it into that radio… Say they give me 3434. Then when ATC sends out a pulse, my plane responds back with ‘3434 altitude 20,000 feet’. Think of it as playing ‘Marco Polo’ where you respond with your name so the person who is blindfolded knows where you are.

Next I have engine instruments that are on the dash instead of hidden on the floor. And you have gas and brake, I have throttle, mixture, and RPM. Your car does your mixture for itself, I have to do my own mixture. I have a set of three levers for each engine.

But not all planes are like this. Google a J3 Cub instrument panel. https://foxbatpilot.files.wordpress.com/2014/12/j-3-panel.jpg

It has engine RPM, Airspeed, a compass, Altimeter, and an oil pressure and temperature gauge.

Speaking of compass. I have two. One wet compass and one gyro compass. The wet compass is subject to certain errors like moving when I speed up or slow down, or actually turning the wrong way when I make a turn at first! So I have a gyro stabilized compass and I use the wet compass only on level flight to set the gyro one.

Lastly, when you look at a plane that has to have two pilots, each pilot has to have their own set of flight instruments. So each pilot is going to have an airspeed indicator, altimeter..etc. And these are redundant systems. So my airspeed indicator and my co-pilots are independent. If mine breaks, his will still work and vice versa. My artificial horizon one is powered by the vacuum system, the other is electric.

Oh and unlike your car, I have immediate access to all of my circuit breakers (ok most). I’ll bet you it takes a second or two to even find them in your car. I have to know where they are and check them before every flight.

Trust me, none of those switches are ignored.

It’s mainly redundancy. There are two or three of everything and although the buttons aren’t touched routinely they’re needed to isolate and reconfigure systems if there’s a fault.

On older aircraft at least half the “buttons” on the overhead panel are actually circuit breakers, which makes it look a lot more complicated. These are replaced with reset buttons (A350, A380) or virtual circuit breakers on one of the computer displays (B787).

They work on “lights out” concept where the buttons are unlit if everything is working normally, and illuminated only if there’s a fault or it’s been turned off. Top tip – you can get an Airbus 99% of the way to being ready to fly simply by pushing every button with a white light in it.

Most of the controls needed to fly the plane are the ones in front of the pilot and in the centre console. But that’s still quite a lot. You have a the yoke and throttle, of course, but there’s also landing gear, flaps, and a couple of other essential controls.

Then you have a radio. At the very least this needs a numeric pad to set the frequency. You also need controls for autopilot and navigation.

In an airliner, you also have a bunch of other non-essential controls. The “Please fasten your seatbelts” sign needs a switch. There’s an intercom for giving pilot announcements to the passengers, cabin lights and things like that. It all adds up.

Don’t forget the dramatic flashing indicator for when a heat seeking missile is locked into you.

Pareto’s 80/20 principle probably applies here too: 80% of the tasks are done by 20% of the switches, and the rest hardly ever get used! It’s a bit like my wife’s wardrobe… 20% of her clothes get used daily and the other 80% never see the light of day… and STILL she keeps buying more!! 🤣🤣