Airbus 319 ques

[nptguy]

Since Northwest is the only airline that flyes non-stop to LGa from memphis their my first choice. I have a few ques about the plane I fly on,which I love the A319. When the cabin's main doors close a sound starts which sounds like my 1993 Grand AM trying to start in the winter, it sounds like a dead battery. When still in thr air during bumpy weather I notice the airalons [SP] come up when the plane rocks around, why does this not happen in the 737? Well guess thats it for now , thanks for taking the time to answer my ques.

 

[JBL]

nptguy,

I haven't flown the bus in over a year and a half, but I'll take a shot at this. The sound you're probably hearing is probably the sound most people notice. After the first engine is started, the hydraulic systems run a test of what's called a PTU. It stands for power transfer unit. This was two airplanes ago so I'm a little rusty, but the airplane has three hyd systems that can use either engine pumps or electric pumps to generate hyd pressure to run the flight controls and the gear (among other things). The PTU links two of them together so that the motive flow of hyd fluid in one system can generate flow via a mechanical linkage to another system who's pump(s) have failed. Some people have said it sounds like a barking dog in the cargo hold.

As far as the spoliers are concerned, the flight control computers automatically command their positions relative to what the pilot or autopilot are asking of them. There is a certain amount of aileron deflection needed before the spoilers will act to assist them in roll control. Just like in any other airplane, more control inputs are necessary to maintain desired position of the airplane when experiencing turbulence. I never flew the 737, but having ridden on them countless times, they seem to handle turbulence much better than the Airbus.

I hope this answers your questions. All you current bus guys chime in, but please be kind to me...it's been a long time and allot of beers since I flew it and I'm a little fuzzy on the details.



JBL

 

[side stick-n]

In addition, doesn't Northwest have LAF (Load Alleviation Function) installed.

"In addition to their normal functions, the ailerons and spoilers are used to reduce wing
loading in turbulence. Operation is completely automatic and does not limit the pilot’s
control authority. This feature is called the Load Alleviation Function (LAF).

"When LAF is activated by turbulence, it moves the ailerons and outboard pair of spoilers in a rapid upward motion."

True, the PTU would probably be the sound. Three systems, two engine driven (one with electric), one electric only. Either engine driven system can power opposite system if loss of fluid is not involved.

Stick-n