Scavenging a crashed 777: for a book
 

Hi, I'm writing a book of fiction that involves a slightly damaged 777 that landed on a primitive island. I've been lucky to be in contact with a 777 pilot to get his input, but there are a lot of technical questions he doesn't know. Hopefully, some of you experts will answer my questions.

Appropriate title for an aircraft engineer?
One of the PAX is on the 777 in order to fix a 757 that is broken elsewhere. What is this person's correct title? Is it "Aircraft Engineer"? Or, Maintenance Engineer or something else? I'm assuming the person is about 35 years old and would be fairly knowledgeable regarding all the plane's systems.

Emergency radios on the raft - can you talk with them?
I know each raft has a radio set to 121.5Mhz, the question is if they just emit a homing signal or if you can talk to anyone else using one of these?

Galley hot water boiler
I'd like to use the hot water boiler as a pressure vessel to generate steam. My question is how large are these boilers (gallons) and how many a 777 is likely to have.

Cabin printer, cockpit printers
Are these regular 8.5 x 11 inkjet printers? Or dot-matrix? Or what? They would be valuable, at least until their ink ran out. Are supplies typically carried on board?

thanks!

LAME, Licensed Aircraft Maintenance Engineer, AMT Aircraft Maintenance Technician in the USA.

No they beep only. This is called an ELT, there is generally one on the aircraft and others in emergency rafts.

Maybe a few liters, not sure about quantity in craft.

Probably 8 1/2 wide but it is on a roll with perforated seams. They are thermal printers.

Thanks for the feedback.

Do you know if there is a hand-held VHF radio typically on the aircraft? I see the ground-crew with them, but does a unit remain on the aircraft?

Typically not, yet on battery power a static inverter converts dc to ac and one ships radio may be operational.

There are variants of emergency radio which do have built in microphones and allow voice on 121.5. The use of the option is not encouraged, as it eats battery life. Some variants of 777 may have them fitted. Most modern units transmit location (GPS co-ordinates) on 406 MHz also, although some still don't - the odds are that anything fitted to a 777 will.

Typical units:-

http://www.transair.co.uk/sp+Kannad-...egra-ELTs+4010

http://www.sportys.com/pilotShop/product/16431

G

I like where your imagination is taking you :cool: Except 1 thing: B777's don't crash unless you make it crash :)

But to continue with your story, you'll have to decide how damaged it is (and what caused it), do you still have battery power (for a short time anyway)?
If so, you'll have radio.
BTW they say the battery lasts about 30mins on a flying/systems powered plane.

Coffee makers have a boiler of about 1ltr, depending on aircraft configuration there are about 10-14 on board. They run on electricity (unless you want to boil the water on a campfire :8)

Good luck

Some more background:
- The plane doesn't crash, they try to land it with wheels up on the water and "slide" it up onto the beach. It mostly works, except for the tail section which fractures, but remains attached. Minimum loss of life.

- Some fuel remains, they didn't ditch it all. Possibly 1,000 gallons.

- Engines are DOA, but the RAT and APU should be functional, the engines remained attached and were shut down on impact, but they did take in quantities of seawater and beach sand. I don't expect them to be operational and I can't imagine the value of getting them to work.

- They have used the alternator and a bike from cargo to build a windmill. Doesn't produce much, but enough.

- They will have to figure out how to build a steam-powered electrical generation eventually. I'm figuring the boilers might work for that. I was hoping that the tanks used for water/waste could be turned into boilers, but it seems they are made of carbon-fiber? They don't seem to be aluminum or SS.

- Are the reservoirs used for oil and the fuel tanks made of carbon-fiber too? Any large containers that might be made out of SS?

- Thanks for the details on the 121.5Mhz. My pilot friend that flies 777 mentioned he thought they had voice, I didn't know if he was mistaken or not. I guess my 777 will have those types of 121.5Mhz radios/beacons.

Again, I like your thinking, mate :ok:
You're not stupid and doing the research, I hope we can help (don't count on me too much;) )

Watertanks (3 of on 777-300) are fibreglass
Wastetanks (2 of) are carbon fibre, so both are good for storage (although wastetanks???) or as floating devices.

The RAT might survive the impact/landing but only if it remains retracted (it deploys from the bottom of the plane).The RAT deploys automatically when both engines stop....so be aware.
Bare in mind the APU needs fuel to work (they use about 200+ kilograms per hour) the fuel pipe runs under the floor so you might want too leave that intact.

The oiltanks, sit on the engines, are made of casted aluminium, probably melts.....

O, and about the fuel; they dump it (jettison) and ditch the plane

I probably go too much into details and I keep thinking about a movie i.s.o. a book (hope for you one day they'll make a movie of it), forgive me for that.

And again, my beloved Triple doesn't fail :}

Thanks for the clarifications. Too bad the APU uses so much fuel to run, that would be an easy win.

I wonder if the APU could eventually be converted to run off steam power? It's a turbine after all. Maybe with some modifications? Of course, the modifications would have to be made with a limited set of tools.

Kenpimental - Hmmmm ... you do know this plot has been done before, in both book and film form, don't you?? :rolleyes:

http://media.apunkachoice.com/image/...mage-37157.jpg

Yes, familiar with that. Of course, my plot is very different. I haven't revealed it completely. There is certainly not going to be any effort to make another airplane to fly people off the island. They are stuck where they are and must make the most of it.

And no, it isn't a version of, "Lost" either, though both happened on an island. The island is of no major significance. I plan on making the 777 more of a focus in this story. More McGyver than the impossibilities of Lost. Of course, there is an interesting twist, but that can't be revealed. ;)

Steam engine and bike alternator.... Not alot of current there. I'd go for the generators in the engine or APU. Then you might have enough juice to annoy everyone nearby with a spark gap transmitter. This is assuming the radios are inop.

Well since the airframe is pretty much in one piece, the 406 ELT would have gone off and rescue will be within a day or two at most.

When I traveled a lot, I took a portable printer with me, maybe one of the pax did the same? Check the cargo, maybe someone was shipping a small diesel generator (they will run on jet A) if you want a more "McGyver" kind of thing, and a tight power budget to boot, have a box of thermocouples in the cargo. Strung together with any kind of a heat source and you can get some power.

Check out how the RTG's work in spacecraft like Voyager or even some Russian lighthouses worked for the idea.

There is no hope of rescue. They are on their own. It's not exactly the world as it exists today. Sorry if that's confusing.

There are thermal printers on the plane. I believe there are two of them. I'm not sure about the stability of thermal paper, so it's probably a good idea for someone to bring a portable ink-jet printer.

I'm hoping to convert a gas-powered engine over to steam. I know it can be done. I have to figure out what kind of simple gas-powered engine would make sense in the cargo hold. It seems to be "cheating" to have a small diesel generator sitting on the plane ready to go. I want more McGyver than that.

Thermocouples seem a little forced. It would be pretty random for them to be on the plane.

Right now, I don't think I'll need more thank 1KW per day generation. A windmill will do that. They'll want a steadier power source than wind, which is why steam is the next logical step. Best case would be that steam could drive the APU, but that might require super high pressures and volumes that are difficult to generate McGyver style.

But thanks for the ideas! Please keep them coming.

Don't overlook the possibility of 'scavenge finds', perhaps things from discovered crashed planes from a war in the past, or things that get washed ashore (can be tied in with a storm). Such things could fill in for items not available from the plane to make your story plans work. I'm a sucker for a good realistic story, kudos on doing the research!

Thermal paper actually keeps for quite a long time if kept tightly wrapped, and stored in a cool dark place. I have some that is over 20 years old, and it's still usable.

There will be plenty of intact pressure vessels all around the plane that can be used to store steam (engine oil tanks, potable and waste water tanks even made of fiberglas, and last but not least fire fighting tanks with a squib still under pressure).

The problem is the boiler itself not blowing up. I would use a hydaulic piston as the boiler enclosure.

Course there are also all kinds of stuff in the shipping containers in the hold including tyres under pressure which could power the many micro-turbines like engine starter motors etc.

I bet if you managed to buy a scrapped B777 (Asiana) you could ship it to an island and populate it with volunteers to sort these questions out pretty damn quick.

Q1: Are there fire-fighting equipment on the plane? If so, of what form?

Q2: How big is the hydraulic piston you're talking about? If there are hydraulic pistons, then I think a primitive steam engine might be possible using them?

Q3: Are there any tools that you'd expect to find on a plane in the normal course of events? I'm assuming there aren't any - except for what the AMT is bringing with her to fix a 757. A hacksaw is going to be vitally important to their future...

I'm here at the Smithsonian and there is a museum which shows all sorts of old steam generators, electrical generators and early inventions. Good material!

You'd need a locomotive boiler to produce enough steam to run the apu, even if it runs at all as white hot dry gas requires somewhat different fluid dynamics than warm wet steam. You don't get anywhere near the volume or pressure of steam from a "primitive boiler". Anyway, why do all that when you have 1000gal fuel?

Diesel generators are seldom carried on passenger flights I fear. They are far too heavy- you buy them where you need them.

You deployed the RAT. It will have been destroyed in the ditching.

Aircraft generators are far, far too big, heavy specialised and and complex to run off a heath robinson windmill I think, the RAT gen might just work (if it miraculously survived) but you're going to need a machine shop to modify the gearing/drives and build the windmill which would have to be pretty big to produce the power to drive even the rat gen. Did you have a machine shop in the hold too? Also on a modern aircraft like a 777 gennys are controlled by black boxes elsewhere. They produce 400v ac. Did the inverters miraculously survive the salt-soaking too?

No tools on a 777 unless in baggage. Few aircraft mechanics would carry a hacksaw in the sort of "light" toolkit they'd use on a short fix-it trip. Its just not a tool used in aircraft maintenance.

On a busy 777 someone is going to have a satfone in their pocket

I fear you'll have stretched credibility far enough (and then some) just by ditching at sea and managing to slide it up the beach. All the rest is making it become comedic.

If you have to do the Flight of the Phoenix stuff leave out the seawater at the start is my advice, and even then tread very very gently, a digitally controlled 777 isn't a tin and rivets Boxcar!

I used to operate as a flight mechanic, this could be a charter aircraft, you would have a Maintenance REP (flight mech) on board with a portable personal tool box in a main deck closet and a FAK, fly away kit in one of the belly holds. This has contained in the past several sections of flexible hose, a 60 tonne jack, pipe swaging kits and sections of pipe. And a few belly cans full of every part (mostly electronic boxes) that if failed could ground an aircraft. This is done to allow a charter service to be anywhere at anytime w/o ground support. they are commonly used by sports teams, oil companies, cruise lines, casinos the big business right now is the military.

re: APU
I've been told that 1,000G of fuel is about 15 hours of APU operation. If there is no ability to stretch for let's say a week or two, then it isn't worth the effort to run. Anyway, it produces way more energy than they need at this point. The only feasible long-term method is to use steam power with the APU, and I agree, it would take a huge boiler for that. I don't think anything existing on the plane could be repurposed for that.

re: RAT
Would the RAT deploy if the captain shut down the engines? He does it just before they hit the water. I think the RAT is plausibly the best thing to use for generation once they reach a little more sophisticated stage of development.

re: saltwater immersion
In this scenario, the plane is not immersed/floating in seawater. It's more like it is a powerboat blasting through shallow water/bottom as it rides up onto the shore. It isn't in the shallows for more than 5-10 seconds - so I'm going to pretend that nothing was really damaged by the saltwater except the engines.

re: aircraft gennys
I think there is some confusion. I'm talking about using the 28V AC alternators that are driven by the engine as backup power. I believe these are 300W at 2300 RPM. I'm not talking about the IDG - those are heavy duty 120KVA alternators that spin at 24K.

re: power conversion/inversion
I realize the APU has to also be removed from the plane to get the output to be converted to something that will work with portable electronics and AC tools. I do have an AMT on the airplane (for a good plot reason). She will be able to use her docs on her laptop to figure out the bits and pieces.

re: ditching?
Why is that so far fetched? If Captain Sulley could have ended the flight of his Airbus right onto a gently sloping beach, don't you think he would? Anyway, I do have a pilot who currently flies 777s reviewing the book and he didn't mention anything wrong with this scenario. I think it is because he's reading what I wrote and you're assuming something about what I wrote. Maybe I'll publish those portions on this forum if that will help.

re: charter flight
It would be a big change in the plot/characters to go with a charter flight. I'm hoping that I can use the excuse that there is an AMT on board who is headed to fix a 757 and is bringing along a decent set of tools to make sure they can.

re: hacksaw
Things get a lot more complicated without a way to cut SS/Alum up. One option is to have it in the cargo hold. I'm a sailor, and I know that whenever I travel to my boat, I'm bringing all sorts of tools/replacement parts. All it takes is for some passenger who is scheduled to spend a week on a boat somewhere in the Caribbean to be bringing some badly needed tool to the skipper.

re: Sat phone/406 EPIRB/GPS
These won't work as there are no satellites in the sky. Help is not around the corner. There is no rescue being staged, no one is coming for them. They are on their own.

You must be referring to the BUG's. Instead of explaining I will cut and paste.

Yes, I believe that is correct. Someone else on this forum provided me with the 300W and 2,300 RPM info. Not a lot of power, but it works for a wind-generator that they can fairly easily build - using a bike frame/gearing to get higher RPM from the windmill.

Thanks for contributing.

It would take a lot of skill, and quite a few tools, to extract an APU from a ditched aircraft and get it into a runnable state, with the rest of the aeroplane fully or partly emersed in salt water.

Almost certainly, unless he deliberately disabled it.

Most stuff emersed in saltwater can be resurrected by prompt rinsing through in freshwater.

And the large box of specialist tools to remove then modify the APU?

Why don't you just save your credibility by inventing the carriage of some equipment with an electric motor and basic servicing tools in cargo?

No, I don't think he would - you can't reasonably expect to judge the stop-distance with any accuracy. I think that he'd do again pretty much what he did do - land parallel with the shoreline to create a short distance to shore.

Also remember the fire-axes in the cockpit and galleys.

There are always satellites in the sky.

Have you considered for example not using a 777 and using something basic (a DC3?, Islander?...) run by a small inter-island charter airline? More likely to have accessible tools as less in the way of security checks, more basic equipment relatively easy to canibalise, much less in the way of hi-tech avionics.

G

re: RAT
OK, it got partially deployed and it's a tangled mess. Might be something salvageable, but not initially.

re: tools
Yes, I have to accept there will be some tools in cargo. I had hoped not to use the "magic box" of cargo to solve problems, but seems this might be required.

re: BUG
I think I can use this still, at least initially. I'm not hearing any good reasons why that can't be removed from the plane and used for power generation. I agree it isn't trivial as it means the BUG Converter must also be pulled from the plane to convert the power. I'm not sure if it delivers 115v 60Hz or if it delivers 115v 400hz.

re: ditch scenario
I think it will make sense if you read it. At least I hope so. It's important that the plane winds up mostly salvageable. This seems as gentle as I can do it.

re: world
You misunderstand me. I didn't say there are no satellites in sight, I mean there are NO satellites. Neither are there any reinforced concrete runways where they are...

re: fire axes
Thanks! Those are going to be very handy. Do you know how many? Those are going to be major players!

re: not a 777
I've made the 777 a major actor in the story and it'd mean a lot of rework/research. I also need a lot of people to come to this new world (hundreds). Less than 100 won't support the long-term goals of the story.

The BUGs are still large 20kva gens, frequency wild machines that are directly driven by the engine gearbox that can provide power in tbe event of a main gen failure. The FADEC alternators are tiny units designed only to provided power to the FADEC EECs, very easy to drive by a small wind turbine, also designed to give a useable output at low rpm for windmilling air starts etc. Yes the output would have to be rectified but that only requires a few diodes.

Leatherman
 

Any AMT or LAME worth their salt will have a Leatherman in their toolbox. If they are not flying as a flying spanner, then they are very likely to have it clipped onto their belt. The Leatherman Wave or Supertool has an excellent hacksaw. Modern day security busybodies get very nervous letting engineers fly on planes with tools these days.

If on flying duties he or she might have a lightweight toolbox stowed in the cockpit, or a larger metal line tool box loaded into the bulk cargo.

Flying spanner - Colloquial term for an aircraft engineer employed on flying duties.

I'm a flying spanner currently on B767s but I also have B777 type rating.

re: BUGS
Thanks for the clarification on BUGs, I should be saying FADEC EECs. They don't seem to be well documented in my research, thanks for steering me straight.

re: Flying Spanner
Thanks for those kinds of inside terminology. I'll definitely use them.

If you have a crashed, stranded aircraft, and one pax is found to possess useful tools - then you'd better include the war between the survivors over possession of those tools. :) I trust you've read Lord of the Flies. :(

One axe in the cockpit, a second in the most rearward galley.

Also if you're interested, 2 megaphones, 4 hand fire extinguishers: probably 2 halon, 2 water. There should be a well equipped first aid kit, and *possibly* an emergency medical kit somewhere.

G

re: second axe
Great to know. I didn't see it on my Boeing Flight Crew Op manual. I guess some airlines might have it and others don't. Or, my document is out of date. Seems a security risk to have an axe where the public can access it...

re: LOTF
Yes, read it, I'm hoping to keep things from degenerating that far, but there will certainly be differences in opinions about how to survive and what to do with their future.

re: fire fighting
My Boeing doc says there are (777-200):

o Axe
• 1 cockpit
o Flashlights
• 2 cockpit
• 12 cabin (1 per attendant seat)
o Oxygen
• 15 small portable ones in cabin
o Oxygen mask with smoke goggles
• 2 cockpit
o Portable breathing equipment (PSE)
• 1 cockpit
• 6 cabin
o Fire extinguishers
• 1 Halon in cockpit
• 3 H2O
• 3 Halon

It's quite feasible to have a toolkit on board, you often get contract engineers flying between jobs and their tools go as freight, you might also find tools as cargo etc..

Have you thought of driving your generator by water power, if there is a waterfall or stream a wooden paddle wheel could be built to turn it.

Have you thought about how your engineer is going to do the fabrication of turning your apu into a steam engine?

You may have a box of hand tools on board that belongs to your engineer. But to fabricate and connect things like pulleys and gears onto axles you're going to need to be able to weld. I've come up with an idea for this. You could use the aircraft main battery as a supply and the steel spring rods inside the passenger seats as the welding rods. Aircraft battery is a Nicad 24V with lots of juice, but you're going to have to watch the temperature during welding or it will explode! Then you will need to recharge it again.

The engine FADEC control alternators are your best bet. However they are bolted on to the front face of the engine gearbox at the bottom of the engine, which I imagine will be embedded in the beach! These little alternators produce quite a lot of power for their size and can power the entire engine at only 7% N2 (don't ask me what RPM the alternator is running at, I have no idea) They have two output windings, one for each FADEC channel. The output from these alternators is AC, so you're going to have to run it through a rectifier to be able to charge your battery. Like the standby TRU.

Well you did say you wanted McGyver!

re: tools
Yes, they must be on the plane. You need the basic tools that will allow you to fabricate more tools. I have researched forging of stainless steel and casting of aluminum. AFAIK, those are the only two metals on the plane. I wish there were some brass/bronze or copper. I guess their must be copper in the "300 miles" of electrical cabling claimed by Boeing. I'll have to calculate what that might work out to be...

re: water power
This island is a real island and they don't have those elevations unfortunately.

re: welding
Awesome! I should have thought of that. I mean even with regular lead-acid batteries you can sort of do the same thing. The problem is that they don't like that kind of discharge. I think/hope NiCADs will handle it better. I thought the big batteries on the plane were lead/acid, so it's good to know they're not.

re: FADEC control alternators
Are these the same as the FADEC EECs? Just want to make sure. If so, I'm told they produce 300W at 2300 RPM (by a forum member). Yes, they need to be pushed through one of the TRUs to get DC.

I didn't realize where they were located. I'll have to talk about how hard they were to retrieve. Perhaps an engine is torn off the plane and more accessible...

When I go down route I take my normal line engineer toolbox, that has pretty much everything I need including a hacksaw, files, my own multimeter, gas soldering iron, etc.
With hand tools I think you can be pretty generous with what an engineer would have, especially for a story, also if the aircraft is a charter operation they carry a fair bit of spares. The 777's I work on have a fairly big spares pack up onboard. Don't forget the big aircraft also carry a whole load of cargo, not just passenger bags. You could have anything in there.

Re generators; without wanting to dig out my training notes, am I not correct in thinking that if a motor is driven, it becomes a generator? First class and business class seats are full of electrical motors, could one of these be jury rigged into being a generator? As I said, my little gas soldering kit goes with me on flights!
For some sort of steam shenanigans, the main engines and APU also have air starters, little air turbine motors. One of these connected to a generator on one end and a spanking big kettle on the other might give you a working rotating thing of some sorts!

re: tools
Thats what I wanted to hear. A reasonably well-equipped tool bag. Spares aren't probably useful unless they can be easily repurposed to do other useful things.

re: motors
From my research, it seems that a brushless DC motor may produce DC or AC depending on it's design. I think that is what I learned. For use in power generating, you need a design that produces power at low RPM (500 or so). A high RPM DC motor isn't useful unless you can gear it to get the proper RPMs.

re: turbine starters
That's great news! Theoretically, that could be removed from the APU and put on something smaller. It's probably well setup to drive with steam (once I figure out how to get a decent sized boiler together). I think I could theoretically use the carbon-fiber waste tank as long as I don't heat it with a direct flame. If I protected it with an aluminum plate from the plane, the radiant heat from the plate would heat the tank. After all, it shouldn't have to get more than 150 degrees C to produce plenty of steam. Need to work out all the math and look at the pressures it would require...

Although making your own steam boiler is an easy way to blow yourself up. There's a lot of energy in pressurised steam and making a strong enough boiler is very difficult. That may be a plot device in itself for you of-course. ..

G

Can't help you with where to find the parts on a 777, but you should consider a Sterling cycle steam engine. Low pressure, very efficient, much safer. High pressure steam would be insane without purpose built pressure vessels.

re: steam power
Sterling is great, maybe a little more complex to make than a simple steam turbine mounted on the shaft of an alternator that doesn't try to be very efficient - it dumps heated steam that could do more work. Until I spend some time researching, I don't really know if high pressure was required. I'm sure there is a formula that will tell me what pressure and volume is required to drive a certain horsepower motor. The little research I've done suggests it might work - without high pressures or high temps.

You also have the O2 bottles that'll take a couple of thousand psi and the hydraulic accumulators that'll take over 3000psi