Originally Posted by
kenpimentel
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.
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.
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.
Almost certainly, unless he deliberately disabled it.
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.
Most stuff emersed in saltwater can be resurrected by prompt rinsing through in freshwater.
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.
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?
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.
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.
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.
Also remember the fire-axes in the cockpit and galleys.
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.
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