Cockpit

Anyone, even those who don’t like planes, will surely be hooked when they enter the cockpit for the very first time. There’s just too many things to see and touch. Buttons are everywhere, dials, guages, screens all displaying meaningless information, the whole layout and ambient lightning is just so captivating. Today I’ll show some shots from the cockpit and throw in some explanation.


Overview of the 737-400 cockpit.

Basically from the cockpit, you can control EVERYTHING on the plane. From how much thrust you want from the engines to whether you want the “No smoking” sign to be switched on or not. There are countless buttons and dials and pilots and engineers should know each and every button and what they do and the consequences of pressing the buttons.


Overhead control panel. Click for large version (652KB).

The overhead control panel controls most of the acessories on the plane. From pneumatic air supply, battery power, apu and engine starting, to condition monitoring gauges, lights and cabin temperature. Today I will explain briefly on some of these controls.


Air cond controls. Controls the cabin temperature. Similar to a car’s climate control. Except that this is more advanced. In order to get the right temperature, the plane mixes cold and hot air. Hot air comes from the bleed air from the engine and can be as hot as 232C. Cold air comes from the aircond pack and can be below 0C.


The temp gauge shows the temperature in the cabin. Yes, it is close to 40C because all equipment are running and they generate a lot of heat.


Bleed means bleed air from the engines or the APU. It’s called bleed because there is a pipe that channels some of the hot air from the compressor section for pneumatic use. The pipe “bleeds” some of the air from the engine, hence the name “bleed air”. This section of the control panel also controls the GPU (ground pneumatic unit) input.


The pneumatic gauge has 2 needles, one indicating the left pack and the other indicating the right pack. You can see the top needle with a “L” on it.


AC supply control panel. AC supply on the plane can come from 3 sources: the engines, the apu or the inverters. Each engine has its own AC generator that generates 115V 400Hz AC when the engine is running. The APU also has its own generator. The inverters uses 28V dc voltage from the batteries to generate 115V 400Hz AC. Now it’s showing 0 amps for obvious reasons.


Engine starting. Unlike the car’s engine, you can’t start a turbine engine by a turn of the key. The engine has to spin up to approximately 20% N1 before ignition and fuel can be introduced so it will reach its self-sustaining speed. More on this next time because this is complicated.


Self-explanatory. For the emergency lights, if it’s set to OFF, it will stay off no matter what. If it’s armed, when power is severed, it will come on. If it’s ON, it will stay on no matter what. Emergency lights are powered by their own rechargable batteries.


Electrical power control panel. Top-left: DC +- 50V. When the needle is pointing at the -ve portion, that means the battery is supplying current but it’s not being charged. If it’s at the +ve portion, it means the battery is charging (note: not too sure about this though, will reconfirm). Top-right: CPS (cycles per second). It should be showing around 400Hz. Middle-left: DC volts. Should be 28volts. Middle-right: AC volts. Should be around 115V AC. I’m not sure what the dials below are used for.


Showing 28V dc.

That’s all for today. More to come next time!

ps: don’t come into this field if you have no interest in any of these because you’ll be dealing with this for the rest of your life. Continue reading