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[F4UCorsair]

I think I may have said this in an earlier post, but perhaps not as directly, so here it is:

A FBW aircraft is conventional in every way, i.e., it is essentially the same as a non FBW aircraft EXCEPT that it has no physical connection between the pilots' control columns/side sticks and the flight control surfaces. There may be a few cosmetic things, but otherwise the two are essentially the same; they fly the same and the same inputs cause the same effect, i.e., pull back it goes up, push forward and it goes down.

A conventional aircraft has cables (mostly) from the flight deck to the hydraulic/electric actuators whereas a FBW has electrical wiring that transmits signals to the actuators. Even some conventional aircraft have limited FBW to activate what are generally emergency/backup systems, e.g., TE flaps and LED's on a Boeing.

FBW aircraft still have multiple systems, hydraulic, electric, pneumatic, anti icing, etc., so still stand to suffer faults in those systems. The electric/electronic impulses transmitted via the wires do not activate control surfaces, undercarriage, etc., contrary to what seems to be popular belief. That is done by the impulses activating conventional systems to control surfaces.

The navigation systems are conventional, multiple GPS's feeding Flight Management/Performance Computers, Flight Data Computers and Symbol Generators feeding the instrumentation, conventional navigation aids are used (newer generation aircraft [and not just FBW aircraft] have auto selection though), they both have auto throttles, multiple brake and hydraulic systems and enormous redundancy built in, and a whole lot of other common installations.

The FBW technology is only a small part of the overall complex machine, so a FBW failure will almost inevitably impact on other systems.

Edited by F4UCorsair, 2009-08-06 17:12:33.

[F4UCorsair]

I attempted to edit my earlier post, but couldn't add the following:

Even some conventional aircraft have limited FBW to activate what are generally emergency/backup systems, e.g., TE flaps and LED's on a Boeing.

sibeymai, you said:

The only difference between FBW and direct control backup in this situation is the tactile feedback a pilot receives from a direct control system.

Well, that's not a difference; FBW aircraft have 'feel computers' (because control is thorugh hydraulic systems) as do conventional aircraft for a number of functions so there is feedback.The earliest form of 'feel computers' was the stick shaker stall warning because the approaching stall couldn't be felt through the hydraulic system.

We'll have to wait and see what the cause of the crash was before we can determine whether a conventinal aircraft would have saved the day over a FBW, and we may never know. If it was iced up pitot tubes, and an erroneous airspeed was sent to the FDC, and the aircraft entered severe turbulence at higher than the optimum penetration speed, then nothing would have saved it from an in flight breakup, but there's even some conjecture now as to whether that happened.

Edited by F4UCorsair, 2009-08-06 17:39:29.

[jackdanielsesq]

Having watched electronics in action for an awful long time, and observed how it has been elevated from a mere tool status to a primary, or means to an end, is it small wonder when exceeding its given, design envelope parameters, there are not more, larger catastrophic failures. The hostile work environments are not conducive to its reliability and well being either.
Two glaring FD errors come to mind - the inability of the PIC to override extraneous flawed data expeditiously, when the system has reached critical-mass, prior to shutdown - where manual control/input is absolutely essential for craft survival, and the spatial cocoon these flyboy of ours are made to live in, where there is little, relative cognitive reference, and the ability to make rational, logical decisions is reduced to zero. We are still three dimensional. The FBW in its current form, might indeed be more hindrance than help.
BR>Jack

[LaoPo]

Air France crash remains a mystery
December 17, 2009 - 6:59am EST

PARIS (Reuters) - Investigators are still unable to pinpoint why an Air France passenger jet crashed into the Atlantic on June 1, killing all 228 people on board, France's official BEA aviation accident authority said on Thursday.

The BEA said in its latest report into the disaster that speed probes on Air France flight AF 447, which was flying from Rio de Janeiro to Paris, were one factor in a string of events that led to the crash but not the sole cause.

"At this stage, despite the extensive analyses carried out by the BEA on the basis of the available information, it is still not possible to understand the causes and the circumstances of the accident," the report said.

The 'black box' flight recorders are still missing and only small parts of the wreckage have been found of the Airbus A330. However, a string of automated messages just before the crash showed there were problems with data from the speed probes.

"The BEA confirms that the phenomenon of inconsistency in the measurement of airspeeds was one of the elements in a chain of events that led to the accident, though this alone cannot explain it," the BEA said in a report.

Noting that planemaker Airbus had recommended replacing Pitot speed probes on A330 and A340 planes and that airlines including Air France had followed the advice, the BEA issued two additional recommendations.

The first one was to improve the effectiveness of the equipment for localizing airplanes and collecting the recorded data for analysis in case of an aviation accident.

The second one was to better characterize the composition of cloud masses at high altitude in which long-range airplanes fly, and to draw conclusions in relation to airplane certification.

http://www.reuters.c...E5BG1U120091217


LaoPo

[manarak]

There is a theory that the turbulences severed the plane's vertical stabilizer and it then went into a plunging spiral, which caused the odd readings of the speed probes which worked normally.
This may be due to a weakness in the plane's design.

[powderpuff]

Non Thailand Related. Close It.

[Crossy]

powderpuff, on 2009-12-17 23:46:40, said:

Non Thailand Related. Close It.

Due to the importance of this incident it was decided to keep it open.

[Old Croc]

powderpuff, on 2009-12-18 00:46:40, said:

Non Thailand Related. Close It.

This unexplained crash was the worst of several recent incidents involving the Airbus A330.
Problems with this widely utilised aircraft are of a concern for all travellers, including those of us that fly to and from Thailand.
Thai Airways run a number of these aircraft.

This thread is very much "Thai related".

[animatic]

Old Croc, on 2009-12-20 15:26:41, said:

powderpuff, on 2009-12-18 00:46:40, said:

Non Thailand Related. Close It.

This unexplained crash was the worst of several recent incidents involving the Airbus A330.
Problems with this widely utilised aircraft are of a concern for all travellers, including those of us that fly to and from Thailand.
Thai Airways run a number of these aircraft.

This thread is very much "Thai related".

Ditto.

[SantiSuk]

I came across some documentary last night about sun radiation getting very close to the earth's surface in an area of the South Atlantic off Brazil. They said it had the capability to screw up communications and wreck electronics big time. Sorry if this repeats some discussion earlier on.

[bkkjames]

SantiSuk, on 2009-12-22 18:45:32, said:

I came across some documentary last night about sun radiation getting very close to the earth's surface in an area of the South Atlantic off Brazil. They said it had the capability to screw up communications and wreck electronics big time. Sorry if this repeats some discussion earlier on.

Is there much radiation from the sun at 11pm local time?

he flight left Rio on Sunday at 7 p.m. local time. About four hours later, the plane sent an automatic signal indicating electrical problems while going through strong turbulence, Air France said.

[LaoPo]

UPDATE

4 April 2011 Last updated at 20:24 GMT

Air France Rio crash dead to be recovered - officials


French ministers promised the wreckage and bodies would be recovered


Specialists could start recovering bodies of those killed in Air France's 2009 plane crash off Brazil within weeks, French officials say.

Undersea robots finally uncovered a large part of the wreckage, including bodies, on Sunday.

The "black-box" flight recorders have not yet been spotted, but investigators have expressed hope they will be found.

The flight went down in the Atlantic, killing all 228 people on board. The cause of the disaster remains unknown.

'Major breakthrough'

Continue reading the main story



From: http://www.bbc.co.uk...europe-12961710

LaoPo

Edited by cdnvic, 2011-04-05 07:00:17.
Closed - Updated topic in travel forum