Airplane Talk

[Huntn]

Anyone familiar with the Boeing 787 Dreamliner electrical system? After reading this article: Dreamliner's Nightmare and this quote:

In other jets, the power for flight controls and other systems comes from the engines. In the 787, critical parts of the system depend on electrical power generated by equipment in two bays beneath the cabin.

I'm not sure what is being referred to. I suspect this is just another example of poor aviation reporting by people not familiar with aviation. The airplanes I know about usually use electrical generators and/or hydraulic pumps powered by the engines to run the controls and devices like landing gear retraction/extension. Some aircraft (like Airbus) use primarily engine driven generators to handle electric and to run electric hydraulic pumps. This Boeing article says there are engine driven generators, so I think the issue with the 787 is associated with it's electrical buses located in the electronics bay. The emergency landing described in the Newsweek article where the crew was totally dependent on the RAT- Ram Air Turbine to provide the soul and limited source of electrical power is not a good thing.

[jdechko]

Originally Posted by Huntn

I'm not sure what is being referred to. I suspect this is just another example of poor aviation reporting by people not familiar with aviation.

I'm not sure what they're referring to either. And while I don't know a lot about airplanes, I do know that most electronics run off of either 5v or 12v DC power.

I'd assume that what ends up happening in airplanes is similar to cars. The battery provides a limited supply of 12v DC power to the electronics, but since it is capable of providing juice for only a small amount of time, it must constantly be recharged. The alternator serves the purpose of taking mechanical energy from the engine (RPMs) and, using an electric motor, creates DC current, thereby charging the battery- which is why a car with a bad alternator can start, but not run very long (<- I've had this issue 2x on 2 different vehicles).

I'm sure that I got some terminology wrong here, but I think the theory behind it is correct and that airplanes use something very similar.

[Apple Hobo]

Boeing has stepped away from the traditional hydraulics/pneumatics systems with the 787.

Boeing 787 electric architecture

And Page 20 here

[JoshMKB24]

Poor reporting or not it seems to be a real problem as I think they grounded any US based airlines using it and are trying to do the same over in Japan until its fixed.