Question about 747 manual

[AirbusA340300 0]

i read that the manual will be about 400 pages so im sure that what im asking will be included but just to make sure. will the manual have a detailed explanation of each system? like some manuals for other products just say, push ON for this and OFF for this, but dont really explain the system and what happens when u push it on or off. and another question, will it include limitations, like EGT, N2, N1, VIB, ect.? thanksAdam

[michal 44]

I think the key word here is "detailed". Did you see Flight1's ATR manual? I think this is the level of detail you can expect in any well written manual but not more. Some schematics/diagrams are shown, some explanation given as to interaction between subsystems but no engineering in-depth knowledge. It is basically the diagram and you staring at it. Pilots are not engineers anyway. By the way, it is much easier to understand for example pneumatics than 'electrics'. Just looking at pneumatics diagram I can get the picture what is going on but I have been looking at electrical diagrams of 747-400 and things look really complicated. Even some terminology is alien ("synchronous buses"). I do not count on getting any in-depth knowledge of this stuff from the manual, instead I am sure some resident experts on this forum (like Ian R.) who actually know this aircraft very well from their daily practice will be here to shed more light on the subject and answer specific questions.Michael J.WinXP-Home SP2,AMD64 3500+,Abit AV8,Radeon X800Pro,36GB Raptor,1GB PC3200,Audigy 2

[Guest Buck Bolduc]

>I think the key word here is "detailed". Did you see>Flight1's ATR manual? I think this is the level of detail you>can expect in any well written manual but not more. Some>schematics/diagrams are shown, some explanation given as to>interaction between subsystems but no engineering in-depth>knowledge. It is basically the diagram and you staring at it.>Pilots are not engineers anyway. By the way, it is much easier>to understand for example pneumatics than 'electrics'. Just>looking at pneumatics diagram I can get the picture what is>going on but I have been looking at electrical diagrams of>747-400 and things look really complicated. Even some>terminology is alien ("synchronous buses"). I do not count on>getting any in-depth knowledge of this stuff from the manual,>instead I am sure some resident experts on this forum (like>Ian R.) who actually know this aircraft very well from their>daily practice will be here to shed more light on the subject>and answer specific questions.>>Michael J.>WinXP-Home SP2,AMD64 3500+,Abit AV8,Radeon X800Pro,36GB>Raptor,1GB PC3200,Audigy 2If your talking about AC busses "Synchronuos" means the sine waves would mach if viewed on a scope. in another words the phases would match up.Otherwise, it seems to me anyhowe, when you threw a bus tie swith you would end up with a 3 phase system or 1 1/2 or whatever.No electrical engineer?Just guessing here!I do know one can adjust the Power Factor, make the voltage lag/lead depending on the application. For example elec. AC moters generally use from 7-9 the running voltage to start. So you give it a voltage kick. Helps prevent the windings from getting hot.Enough allreadyBest

[michal 44]

Ok, since we are on the subject - what exactly is "bus tie" switch? I suspect (?) it has to do with transfering power from one bus to another but can't somehow visualize the actual current flow. Is it equivalent to say two batteries powering the same piece of wire?Michael J.WinXP-Home SP2,AMD64 3500+,Abit AV8,Radeon X800Pro,36GB Raptor,1GB PC3200,Audigy 2

[Guest Matthew Murray]

The two engine generators provide power for AC Generation for their respective busbar. The AC Generation provides AC and DC through the Static Invertor for normal flight conditions. The transfer circuit allows current from one busbar, through the transfer circuit to the opposite busbar. The transfer circuit allows supply of either/both AC circuit from one of four sources (GEN1, GEN2, APU, EXT) through and BTC (bus-tie-contactor) within the transfer circuit. The BTC is just a relay which connects both busbars, or allows independant operation, as in normal flight. The Bus-Tie is normally an automatic system, if the system senses say GEN1 dropping offline during flight, thus you are on one source (GEN2), the BTC will switch allowing current to flow from one bus-bar to the next. However, operation of the BUS TIE SWITCH allows you, the pilot (or us, the engineer/ground crew) to cycle this BTC connecting or disconnecting both busbars. This is a bit specific to the Airbus A320 Series, I don't work on our B737's. Shouldn't be too radically different. Hoep that makes sense.Matthew Murray,[bR]British Airways Maintainence Glasgow.