Fly By Wireless?

[EconomyClass]

I was soooooo tempted to make that "Die By Wireless", but a grabber title like that is only useful once.

http://www.newscientist.com/article/mg20327245.300-flybywireless-set-for-takeoff.html

Some wi-fi setups seem rock solid, whereas others really depend on how good your wireless card is. Hence, the proviso that it must be a "robust" system. I don't know what the alternative would be except more and more kilometers of cable. That seems a dead-end road to me.

[MCM]

Why do you need kilometers of MORE cable? Fly By Wire control systems are established, and I can't see how you need to add more cable going into the future?

I'm sure as time goes on wireless will make its way into aircraft, however I doubt it will be as a cruicial system. It isn't just a matter of making it work, its proving that it is inunterruptable by normal means, and that it won't interfere with radio navigation systems. At the moment, the risk is worn for PED's in cruise because you know that if you get false indications you can turn them off. To prove that it will never interfere will be very very difficult.

[EconomyClass]

They did specify a "robust" system. Can't be what you have on your Blackberry. As for connectivity, I'd say they would build in a heartbeat to detect interruptions in connectivity. That's old networking stuff.

Unmanned aircraft are controlled via wireless. Seems like it has proven itself pretty well. In fact, the deep space aircraft and Mars Rovers have worked via wireless for decades.

[MCM]

So what happens when the system DOES detect an irregularity or disconnection? You lose command of your flight controls until it re-establishes?

This isn't deep space, where a small period of down time can be worn. It also isn't unmanned aircraft, where wireless is used to control from a large distance.

The wired flight control systems are established. In the future more wires will not be required, in fact possibly less.

By all means, wireless is great for other aircraft functions and will probably be introduced... but there is no real reason to do it for flight controls. If they can do it for the inflight entertainment system the savings could be huge.

I wonder why you would want this introduced... I cannot see how it improves safety... it merely improves financials by making the aircraft lighter.

[EconomyClass]

I wonder why you would want this introduced... I cannot see how it improves safety... it merely improves financials by making the aircraft lighter.

Let's see. Didn't wires get severed in that AA plane that flipped? And in the DC-10 that crashed in Paris. Didn't they ignite in the Halifax crash? Wires are an accident waiting to happen. Truth is, I don't see how, without redundancy, wires can even be trusted. Snap one and lose control. I can't believe that this wasn't in the engineers thoughts when the very first FBW control was being conceived. And if there ever was an actual study on the ultimate reliability of wired vs. wireless. I think there are wires simply because it could be done. Where wireless control is used today, the wire option simply isn't there. And whaddyaknow. Despite all the worriers, it worked fine.

[Highkeas]

..........Truth is, I don't see how, without redundancy, wires can even be trusted. ...............

Fly-by-wire control systems are triple redundant - they are routed as far apart as practical so that any localized damage does not impact redundancy.

[SYDCBRWOD]

Let's see. Didn't wires get severed in that AA plane that flipped? And in the DC-10 that crashed in Paris. Didn't they ignite in the Halifax crash? Wires are an accident waiting to happen. Truth is, I don't see how, without redundancy, wires can even be trusted. Snap one and lose control. I can't believe that this wasn't in the engineers thoughts when the very first FBW control was being conceived. And if there ever was an actual study on the ultimate reliability of wired vs. wireless. I think there are wires simply because it could be done. Where wireless control is used today, the wire option simply isn't there. And whaddyaknow. Despite all the worriers, it worked fine.

The one thing that worries me is that wireless can be jammed. Right now you cannot take more than 100mls of liquid onto an aircraft, people are metal detected and luggage is x - rayed and probably 'sniffed' by an explosives detector (depends on the security situation I guess). A narrowband jammer wouldn't need to take up much room - a reconfigured laptop? All a terrorist would need to do is switch on the device at a critical phase (takeoff/landing) and the signals controlling the aircraft could be blocked or interrupted. Then the situation would be no electronics on board at all which would stuff up most business travellers.

I like well shielded wires with redundancy thanks.

[TeeVee]

The one thing that worries me is that wireless can be jammed. Right now you cannot take more than 100mls of liquid onto an aircraft, people are metal detected and luggage is x - rayed and probably 'sniffed' by an explosives detector (depends on the security situation I guess). A narrowband jammer wouldn't need to take up much room - a reconfigured laptop? All a terrorist would need to do is switch on the device at a critical phase (takeoff/landing) and the signals controlling the aircraft could be blocked or interrupted. Then the situation would be no electronics on board at all which would stuff up most business travellers.

I like well shielded wires with redundancy thanks.

I second that! I do not want to give up my laptop, Bose headphones, and Iphone/pod.

[EconomyClass]

Redundancy

Wireless can be introduced on a gradual basis to accumulate experience, in order to be dealing with reality rather than fears. One example would be to stop pulling cable and put NEW data collection on wireless. Another would be to use wireless as one of the levels of redundancy. Another would be to use it as backup in event of wired control failing as has happened in some disastrous crashes. I'm saying that aviation can get some useful experience in wireless by these methods.

As for the terrorist threat? On my last flight I took my laptop on board with me. At each security check, I was told to run the laptop thru the screen by itself, not inside anything. I'm assuming they are specifically looking for things in the laptop case that are security threats. So transportation security has already anticipated the possibility of laptops reconfigured for terrorist purposes. So I'd call that an irrelevant consideration.

[Gabriel]

in event of wired control failing as has happened in some disastrous crashes

Would you please name those? I've never heard of one such an accident. Understand that I don't say that they don't exist. Just I'd like to grab info on accidents of that type.

As for the terrorist threat? On my last flight I took my laptop on board with me. At each security check, I was told to run the laptop thru the screen by itself, not inside anything. I'm assuming they are specifically looking for things in the laptop case that are security threats. So transportation security has already anticipated the possibility of laptops reconfigured for terrorist purposes. So I'd call that an irrelevant consideration.

I guess that a kilo of C4 is easier to detect in x-ray screening than a small jamming circuit board mixed with the circuit boards already there in the laptop. A regular laptop already has receivers, transmitters and antennae for wifi and bluetooth. You could that pair that with some external USB device that looks like a regular device. Have you seen the size of the cellular modems? barely bigger than a pendrive, and they include a receiver, transmitter, antenna and all the elctronics needed to code and decode digital radio signals and communicate with the laptop and get power from it.

[Doug Hughes]

Would you please name those? I've never heard of one such an accident. Understand that I don't say that they don't exist. Just I'd like to grab info on accidents of that type.

Classic case study A/A-1 B707 shorted yaw damper position sensor after take off from one of the New York airports in the early 1960's is one of many.

IMHO, United 585 and USAir 427 were yaw damper LVDT rudder position sensor failures. The 1999-2000 FAA B737 rudder ETEB found such a yaw damper failure resulting in a 11-degree "yaw damper hardover." It's in the report that Boeing tried to have buried.

[Gabriel]

Classic case study A/A-1 B707 shorted yaw damper position sensor after take off from one of the New York airports in the early 1960's is one of many.

IMHO, United 585 and USAir 427 were yaw damper LVDT rudder position sensor failures. The 1999-2000 FAA B737 rudder ETEB found such a yaw damper failure resulting in a 11-degree "yaw damper hardover." It's in the report that Boeing tried to have buried.

About AA flight 1, I could not find any good info on the cause. If you have a link it'll be appreciated.

About the 737 rudder reversal, you are entitled your opinion of course, but after the 1996 loss of control incident (Eastwind Airlines 517) that finally landed uneventfully, and while the investigation of the 1994 accident (USAir 427) was still ongoing, the NTSB re-opened the investigation of the 1991 accident in Colorado Springs (United 585), mixed all three in one investigation, and offered the following as a probable cause for all three events:

PROBABLE CAUSE: "A loss of control of the airplane resulting from the movement of the rudder surface to its blowdown limit. The rudder surface most likely deflected in a direction opposite to that commanded by the pilots as a result of a jam of the main rudder power control unit servo valve secondary slide to the servo valve housing offset from its neutral position and overtravel of the primary slide."

[Alessandro]

Has been discussed before on AD.com, I suggested the WISA system from ABB,
http://library.abb.com/global/scot/scot209.nsf/veritydisplay/4e478bd7490a3f8bc12571f100427dcb/$File/2CDC171017K0201.PDF

[APS]

Loss of control shouldn't be confused with a loss of perceived control. A classic example might be the modern FADEC which, as its name implies, enjoys full authority over the powerplant in its role as interpreting the Pilot's input and making it happen.

The early days of a Pilot manipulating a throttle linked by a mechanical control to the engine while keeping an eye on his TGT and NH readouts are long passed for good reason. Innovation in itself is never a bad thing - it encourages new ideas and new ways of looking at things.

[Highkeas]

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