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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Arfa Daily wrote:
Seems that today, an Air France Airbus A330 en route from Rio to Paris with 238 people on board, has gone down without warning over the Atlantic. Hard to see what the pilot might have done wrong with the thing at 38000 ft in the cruise ... Apparently, it disappeared off African trans-atlantic ATC radar, at around 3am, our time. This is not instilling a lot of confidence in me, regarding flying on one of these things in October, instead of my usual Boeing ... :-| Electrical and turbulence problems reported. Aircraft was sending distress signals so it may have made a decent ditch. Air France's last air disaster was the Concorde in 2000. I've flown the 320-100 several times and the Mulhouse crash never entered my mind. We actually had a 5 hour delay one time after a hydraulic pump failed on the ground and had to be replaced. I wouldn't worry about the 330 considering the number of those things in the air at any given time and it's wonderful track record. Yeah, I know what you're saying. It just bothers me a little that on say a 747, the driver has got a triple redundancy control system which hydraulically links his yoke and pedals directly to the control surfaces, and a robot driver that can be thoroughly switched off, such that in an unusual set of circumstances, a quick-thinking and experienced guy sitting behind those controls, might be able to recover a potentially catastrophic situation by thinking outside the box, and doing something which maybe puts the airframe outside of the 'safe' envelope. From what I can understand of the FBW systems, they are never going to allow you to do this, and in the event of a total electrical systems collapse, your little joystick, and the computer(s) that it's connected to, are not going to be of any use to control the aircraft, anyway. My pilot friend rang me yesterday when all this was going down (honestly, no pun intended). He felt that there had to be more to it than just flying into a storm. He says that in general, if lightning hits an aluminium-bodied plane, it tends to pass around the outside, and re-discharge and carry on its way from the opposite side or wherever. He questioned whether the same would happen on a carbon composite bodied plane, as the A330 apparently is, or whether the higher electrical resistance of such a material, would cause the lightning to 'stick around' as it were, and just fry the internal systems, or even heat the material to the point where it just exploded. He reckons that unless there was an absolutely catastrophic failure of the airframe, a distress signal should have been able to be broadcast almost all the way down, as the last voice transmitter is battery powered to ensure that it can still operate, even in the event of a catastrophic electrical or systems failure. Sobering thoughts ... From reading the boards, it appears that, rather than flowing arond the outside of the aircraft, lightning is more inclined to punch holes right through composite skins, thereby getting into the metalwork and wiring. Ron(UK) |
#2
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![]() "Ron" wrote in message ... Arfa Daily wrote: Seems that today, an Air France Airbus A330 en route from Rio to Paris with 238 people on board, has gone down without warning over the Atlantic. Hard to see what the pilot might have done wrong with the thing at 38000 ft in the cruise ... Apparently, it disappeared off African trans-atlantic ATC radar, at around 3am, our time. This is not instilling a lot of confidence in me, regarding flying on one of these things in October, instead of my usual Boeing ... :-| Electrical and turbulence problems reported. Aircraft was sending distress signals so it may have made a decent ditch. Air France's last air disaster was the Concorde in 2000. I've flown the 320-100 several times and the Mulhouse crash never entered my mind. We actually had a 5 hour delay one time after a hydraulic pump failed on the ground and had to be replaced. I wouldn't worry about the 330 considering the number of those things in the air at any given time and it's wonderful track record. Yeah, I know what you're saying. It just bothers me a little that on say a 747, the driver has got a triple redundancy control system which hydraulically links his yoke and pedals directly to the control surfaces, and a robot driver that can be thoroughly switched off, such that in an unusual set of circumstances, a quick-thinking and experienced guy sitting behind those controls, might be able to recover a potentially catastrophic situation by thinking outside the box, and doing something which maybe puts the airframe outside of the 'safe' envelope. From what I can understand of the FBW systems, they are never going to allow you to do this, and in the event of a total electrical systems collapse, your little joystick, and the computer(s) that it's connected to, are not going to be of any use to control the aircraft, anyway. My pilot friend rang me yesterday when all this was going down (honestly, no pun intended). He felt that there had to be more to it than just flying into a storm. He says that in general, if lightning hits an aluminium-bodied plane, it tends to pass around the outside, and re-discharge and carry on its way from the opposite side or wherever. He questioned whether the same would happen on a carbon composite bodied plane, as the A330 apparently is, or whether the higher electrical resistance of such a material, would cause the lightning to 'stick around' as it were, and just fry the internal systems, or even heat the material to the point where it just exploded. He reckons that unless there was an absolutely catastrophic failure of the airframe, a distress signal should have been able to be broadcast almost all the way down, as the last voice transmitter is battery powered to ensure that it can still operate, even in the event of a catastrophic electrical or systems failure. Sobering thoughts ... From reading the boards, it appears that, rather than flowing arond the outside of the aircraft, lightning is more inclined to punch holes right through composite skins, thereby getting into the metalwork and wiring. Ron(UK) So, perhaps not the best choice of material to make a long haul aircraft from, given that it is going to fly to areas of the world where thunderstorms are prevalent, and at cruising altitudes where it is well up amongst the crap, as it were. I have actually flown in and out of both Orlando and Las Vegas, with thunderstorms in the area, without giving them a second thought. But then that was in a nice 747 aluminium cigar tube ... If it is true that CC skins are not good in areas of electrical storm activity, I'm sure pilots regularly flying such planes, must be aware of this, so if the weather radar on this flight showed that he was heading into bad air and storms, I wonder why he didn't go around it, or see if it was possible to climb above the worst of it ? I understand that thunderheads can extend above the maximum ceiling of airliners, but I would have thought that there might have been a 'way through' between cells ? Fuel constraints maybe ? Looking on a map, the path from Rio to Paris looks awfully long for a plane of this size. BTW, is that Ron ex LVA ? If so, you haven't by any chance got a schematic set for a Warwick Sweet 25.1, have you ? Or anyone else reading this ? Warwick have refused to even acknowledge requests for assistance, let alone supply info. Arfa |
#3
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Posted to sci.electronics.repair
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Arfa Daily wrote:
"Ron" wrote in message ... Arfa Daily wrote: Seems that today, an Air France Airbus A330 en route from Rio to Paris with 238 people on board, has gone down without warning over the Atlantic. Hard to see what the pilot might have done wrong with the thing at 38000 ft in the cruise ... Apparently, it disappeared off African trans-atlantic ATC radar, at around 3am, our time. This is not instilling a lot of confidence in me, regarding flying on one of these things in October, instead of my usual Boeing ... :-| Electrical and turbulence problems reported. Aircraft was sending distress signals so it may have made a decent ditch. Air France's last air disaster was the Concorde in 2000. I've flown the 320-100 several times and the Mulhouse crash never entered my mind. We actually had a 5 hour delay one time after a hydraulic pump failed on the ground and had to be replaced. I wouldn't worry about the 330 considering the number of those things in the air at any given time and it's wonderful track record. Yeah, I know what you're saying. It just bothers me a little that on say a 747, the driver has got a triple redundancy control system which hydraulically links his yoke and pedals directly to the control surfaces, and a robot driver that can be thoroughly switched off, such that in an unusual set of circumstances, a quick-thinking and experienced guy sitting behind those controls, might be able to recover a potentially catastrophic situation by thinking outside the box, and doing something which maybe puts the airframe outside of the 'safe' envelope. From what I can understand of the FBW systems, they are never going to allow you to do this, and in the event of a total electrical systems collapse, your little joystick, and the computer(s) that it's connected to, are not going to be of any use to control the aircraft, anyway. My pilot friend rang me yesterday when all this was going down (honestly, no pun intended). He felt that there had to be more to it than just flying into a storm. He says that in general, if lightning hits an aluminium-bodied plane, it tends to pass around the outside, and re-discharge and carry on its way from the opposite side or wherever. He questioned whether the same would happen on a carbon composite bodied plane, as the A330 apparently is, or whether the higher electrical resistance of such a material, would cause the lightning to 'stick around' as it were, and just fry the internal systems, or even heat the material to the point where it just exploded. He reckons that unless there was an absolutely catastrophic failure of the airframe, a distress signal should have been able to be broadcast almost all the way down, as the last voice transmitter is battery powered to ensure that it can still operate, even in the event of a catastrophic electrical or systems failure. Sobering thoughts ... From reading the boards, it appears that, rather than flowing arond the outside of the aircraft, lightning is more inclined to punch holes right through composite skins, thereby getting into the metalwork and wiring. Ron(UK) So, perhaps not the best choice of material to make a long haul aircraft from, given that it is going to fly to areas of the world where thunderstorms are prevalent, and at cruising altitudes where it is well up amongst the crap, as it were. I have actually flown in and out of both Orlando and Las Vegas, with thunderstorms in the area, without giving them a second thought. But then that was in a nice 747 aluminium cigar tube ... If it is true that CC skins are not good in areas of electrical storm activity, I'm sure pilots regularly flying such planes, must be aware of this, so if the weather radar on this flight showed that he was heading into bad air and storms, I wonder why he didn't go around it, or see if it was possible to climb above the worst of it ? I understand that thunderheads can extend above the maximum ceiling of airliners, but I would have thought that there might have been a 'way through' between cells ? Fuel constraints maybe ? Looking on a map, the path from Rio to Paris looks awfully long for a plane of this size. There`s a lot of stuff, some useful some 'not so' on the PPrune boards about this accident. Many of the posts are from people who fly these birds everyday for a living, it`s a good read. BTW, is that Ron ex LVA ? If so, you haven't by any chance got a schematic set for a Warwick Sweet 25.1, have you ? Or anyone else reading this ? Warwick have refused to even acknowledge requests for assistance, let alone supply info. Well LVA is still alive and well, I just don't do many repairs any more, I`m concentrating more on live sound production. Sorry Arfa I don`t have a diag for that amp. Ron(UK) |
#4
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![]() "Ron" wrote in message ... Arfa Daily wrote: "Ron" wrote in message ... Arfa Daily wrote: Seems that today, an Air France Airbus A330 en route from Rio to Paris with 238 people on board, has gone down without warning over the Atlantic. Hard to see what the pilot might have done wrong with the thing at 38000 ft in the cruise ... Apparently, it disappeared off African trans-atlantic ATC radar, at around 3am, our time. This is not instilling a lot of confidence in me, regarding flying on one of these things in October, instead of my usual Boeing ... :-| Electrical and turbulence problems reported. Aircraft was sending distress signals so it may have made a decent ditch. Air France's last air disaster was the Concorde in 2000. I've flown the 320-100 several times and the Mulhouse crash never entered my mind. We actually had a 5 hour delay one time after a hydraulic pump failed on the ground and had to be replaced. I wouldn't worry about the 330 considering the number of those things in the air at any given time and it's wonderful track record. Yeah, I know what you're saying. It just bothers me a little that on say a 747, the driver has got a triple redundancy control system which hydraulically links his yoke and pedals directly to the control surfaces, and a robot driver that can be thoroughly switched off, such that in an unusual set of circumstances, a quick-thinking and experienced guy sitting behind those controls, might be able to recover a potentially catastrophic situation by thinking outside the box, and doing something which maybe puts the airframe outside of the 'safe' envelope. From what I can understand of the FBW systems, they are never going to allow you to do this, and in the event of a total electrical systems collapse, your little joystick, and the computer(s) that it's connected to, are not going to be of any use to control the aircraft, anyway. My pilot friend rang me yesterday when all this was going down (honestly, no pun intended). He felt that there had to be more to it than just flying into a storm. He says that in general, if lightning hits an aluminium-bodied plane, it tends to pass around the outside, and re-discharge and carry on its way from the opposite side or wherever. He questioned whether the same would happen on a carbon composite bodied plane, as the A330 apparently is, or whether the higher electrical resistance of such a material, would cause the lightning to 'stick around' as it were, and just fry the internal systems, or even heat the material to the point where it just exploded. He reckons that unless there was an absolutely catastrophic failure of the airframe, a distress signal should have been able to be broadcast almost all the way down, as the last voice transmitter is battery powered to ensure that it can still operate, even in the event of a catastrophic electrical or systems failure. Sobering thoughts ... From reading the boards, it appears that, rather than flowing arond the outside of the aircraft, lightning is more inclined to punch holes right through composite skins, thereby getting into the metalwork and wiring. Ron(UK) So, perhaps not the best choice of material to make a long haul aircraft from, given that it is going to fly to areas of the world where thunderstorms are prevalent, and at cruising altitudes where it is well up amongst the crap, as it were. I have actually flown in and out of both Orlando and Las Vegas, with thunderstorms in the area, without giving them a second thought. But then that was in a nice 747 aluminium cigar tube ... If it is true that CC skins are not good in areas of electrical storm activity, I'm sure pilots regularly flying such planes, must be aware of this, so if the weather radar on this flight showed that he was heading into bad air and storms, I wonder why he didn't go around it, or see if it was possible to climb above the worst of it ? I understand that thunderheads can extend above the maximum ceiling of airliners, but I would have thought that there might have been a 'way through' between cells ? Fuel constraints maybe ? Looking on a map, the path from Rio to Paris looks awfully long for a plane of this size. There`s a lot of stuff, some useful some 'not so' on the PPrune boards about this accident. Many of the posts are from people who fly these birds everyday for a living, it`s a good read. BTW, is that Ron ex LVA ? If so, you haven't by any chance got a schematic set for a Warwick Sweet 25.1, have you ? Or anyone else reading this ? Warwick have refused to even acknowledge requests for assistance, let alone supply info. Well LVA is still alive and well, I just don't do many repairs any more, I`m concentrating more on live sound production. Sorry Arfa I don`t have a diag for that amp. Ron(UK) No sweat. I've found the problem now. Some moron had pinched a wire to the fans under a board mounting pillar when reassembling after some previous repair. It had nicked the insulation, resulting in an intermittent short to the metal pillar. Very odd symptoms this caused. Sometimes, when you flicked the "ground lift" switch on the back panel, the fans would start up at full chat, and a sound that can best be described as a drone pipe on a set of bagpipes, ramped up as the fans ran up. Very odd indeed. So, where do I find this PPrune board ? Arfa |
#5
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