5 ms·
I have no knowledge of this particular situation, but... Before I worked in aerospace as a structural engineer, I couldn't understand why airplanes are as expe
by Scramblejams 6y ago
I have no knowledge of this particular situation, but...
Before I worked in aerospace as a structural engineer, I couldn't understand why airplanes are as expensive as they are.
Once I'd worked in aerospace as a structural engineer, I couldn't understand why airplanes aren't more expensive than they are.
I worked in stress analysis, where you'd analyze a part of an airplane to determine whether it fulfilled strength/fatigue life requirements. At this stage, the part's already been designed. So you take the part's material properties, geometry, surface preparation and coatings, machined features, and so on, and check it against anywhere from a few dozen to many thousands of load scenarios. You find the handful of critical load cases, and then you write up the analysis against those. The analysis is intended to be mostly self-contained, readable by any qualified engineer, and serve as a complete treatment of the part's structural sufficiency. It's not much of an exaggeration to say that every single structural component of an airplane is backed up by a stress analysis report running somewhere between 20 and 400 pages, written by one or more degreed engineers making what was, in the U.S. probably an average of $50-60/hr. Airliners are made up of many, many structural parts. The costs of proving the safety of those parts add up quickly.
Now, if I had to guess, instruction manuals are probably a bit cheaper to produce. Tech writers probably aren't as well compensated as engineers. But a lot of engineers' time will be eaten up nonetheless. (I once spent a memorable few weeks (!) proving that a dowel pin on a part that hadn't been machined correctly would not, during installation, shear off, so that existing installation documentation could still be used. Yay. After that I was known as the office dowel pin SME.) Good maintenance documents sweat the details and require input from designers, stress analysts, manufacturing engineers, supply chain representatives, and others. And then as the design evolves -- the design always evolves on the way to delivering a product -- these documents must be tweaked, added to, subtracted from, sometimes entirely rewritten, and those changes must be checked by a variety of folks.
So, $84 million for 100,000 pages might sound like a lot. But for what is in many ways a custom built aircraft, with divergences from the base aircraft that probably run into the millions, to me, it doesn't seem ridiculous.
- starpilot 6y agoPrinting manuals, $1 million. Research by thousands of highly trained engineers, compiled by experienced technical writers and illustrators: $83 million.
- markdown 6y agoPaper: $1M Research by highly trained engineers: $50M Printer ink: $32M
- cmauniada 6y agoThanks for the detailed analysis, I was near ready to take my pitchfork out.
- samstave 6y agoI can tell you in one sentence: MATERIALS engineers are what the fuck is the problem. We need superb materials engineers and materials engineering is HARD, and we need to drop off all the bdsm MIT cowards who get hard because they think they are going to be the bog swinging johnson after they leave, and are truly a bunch of cucks. (This comment is deeper thAn you realize, so dont downvote the depth that you dont understand) Edit: materials engineering is the first thing we should be throwing all things ML&AI at
- sandworm101 6y agoThat's the odd thing. To provide a custom aircraft with custom parts you have to do all the analysis and testing. The person installing each part then needs the manual for that part to installing it. The creation of manuals is organic to the creation of a new aircraft. To see manuals as a separate, very expensive, line item is odd. But we must remember a famous line from a bad movie: "You don't actually think they spend $20,000 on a hammer, $30,000 on a toilet seat, do you?" Given what this aircraft is, what it does, I think it safe to assume a high degree of vagueness and miss-labeling in the non-classified version of the budget.
- Scramblejams 6y agoCouple of notes: You don't necessarily need the full maintenance manual to support initial installation. And the project may have been broken out differently to make the rest of the aircraft's sums seem more palatable -- bureaucratic budgetary games.
- kace91 6y agocosts aside, I wonder how useful it is. The average reading speed is about a page every 1-2 minutes (for non technical texts). 100.000 pages would then be a 800-1600 hour read, which is about half a year for a person spending 8 hours a day just flipping through pages. Obviously such a manual is probably not meant to be read cover to cover, but even compared to a reference work, it's three times the volume of the entire Encyclopaedia Britannica - a giant amount of information to be easily used.
- GuiA 6y agoThe cost of the information not being accessible when it is most urgently needed could easily be billions of dollars or many human lives.
- egd 6y agoYou may never actually need all 100,000 pages, but you don't know in advance which pages you will need, and you'll definitely need that page when you need it.
- swsh 6y agoWell it also covers all of the sub-systems on the aircraft as well, from countermeasures to communications down to how to evacuate the aircraft toilet waste. The information in that manual is probably spread over the domain of 100's of people all performing different roles. I don't think their is any expectation that one single human would read the entirety. Kinda like your car manual or university textbook. I've never read mine from cover to cover, but it is a useful reference sometimes. Particularly in the case of Air Force One where I doubt an internet search covers most troubleshooting requirements.
- killjoywashere 6y agoComes out to 14 hours at $60/hour per page. Does it take about 2 days to produce a page of balls-on-dead-accurate guidance for one of the most complex flying machines on earth? I can believe that.
- SlowRobotAhead 6y agoWell... yea, but there are some pictures in there and maybe it’s double spaced! /s
- WalterBright 6y agoFormer Boeing flight controls engineer here. Nice to see a stress guy! I'm always amazed that for a few hundred bucks I can fly halfway around the world in a jetliner. Anyhow, you might be amused by this incident between me and the stress guy, when I was called over to visit them: SG: We're concerned about the parts you're designing. WB: Um, yes? SG: Your parts are coming in at barely 1% stronger than the Ultimate Load. WB: So they meet the requirement. What's the problem? SG: How did you design them? WB: I started with the load requirement, worked backwards to size the part, and rounded up the tolerances. SG: We don't like that. We like to see 10% over. WB: So, you want the parts to be overweight? SG: No, we just feel better about stronger parts. WB: But my parts meet the requirements at minimum weight. If you'd like stronger, heavier parts, you guys need to change the requirements. SG: !@#$%^&*( Hope you guys aren't still mad at me :-)
- NikolaeVarius 6y agoThat's surprising from the Stress Guy. The ultimate load by definition should already have the safety factor + everything else factored in. Having a requirement go over the ultimate load, means its not really the ultimate load.
- WalterBright 6y agoThere's always some concern that the math models correctly reflect reality. That's why there's a 50% safety factor, and it's backed up by the engineers' experience that things "look right", bench testing, and flight testing. (In early flight test, they'll tape strain gauges all over the place to see if the math predictions of the stress matches reality.)
- voldacar 6y agoDid you ever experience any times when a part passed the math model, but didn't "look right"?
- WalterBright 6y ago
- atdt 6y agoI understand why it costs this much. I don't understand why we think it is worth doing. Rather than fabricate a flying White House, why not deputize the vice president to carry out presidential duties while the president is in the air? There is a well-defined presidential line of succession that exists expressly to ensure continuity of government in case the president is incapacitated. Why reserve its use for emergencies? We can use it routinely. Use the $5 billion to build housing for homeless people.
- pm321 6y ago"Use the $5 billion to build housing for homeless people." Homeless people are outside the circle of social distance and, therefore, social sympathy. Just sayin' the way to lower the cost is to produce more and sell more reprints of the manual at scale.
- kgin 6y agoFinding housing for homeless people isn't a money problem. We just don't want to do it. We find/print money for things we want to do.
- dragonwriter 6y ago> I understand why it costs this much. I don't understand why we think it is worth doing. Rather than fabricate a flying White House, why not deputize the vice president to carry out presidential duties while the president is in the air? We have a national airborne command post, ultimately, in case the ground based command (the White House) is destroyed or under imminent threat requiring it to be (temporarily or permanently) abandoned. It's used for routine transport, and command and control while being used for routine transport, since it is desirable for it to be near the C-in-C at all times, and it doesn't make much sense not to use it.
- NikolaeVarius 6y agoAfter working in Aero, I'm still amazed airplanes fly at all. Every single line of that document would have been double checked multiple times, and literally have 3x more documentation tracking why that piece of top level documentation exists and tracking any changes to it.
- WalterBright 6y agoThese days git handles the tracking changes thing very nicely and almost effortlessly.
- NikolaeVarius 6y agoGood for git? Gotcha comment is not useful when the industry (as far as I've seen) isn't using git to write manuals.
- kinkrtyavimoodh 6y agoI can understand why a B737 can cost about a 100 million dollars, but I can't understand why a 4-seater Cessna costs as much as 300000 dollars... Can someone shed some light on it?
- Scramblejams 6y agoVery few units over which to amortize everything. I can't recall the exact numbers, but there were years in which (I believe it was) Continental shipped 80,000 small aircraft engines, and a decade or two later, they were down to shipping ~3,000/year.
- NikolaeVarius 6y agoI've always liked the detail that the space shuttle maximum thrust is rated at 104% because after some flights, they learned that the RS-25 could be run harder than the specs required, and it was simpler/less chance for error to just set max at 104% of rated thrust, rather than recalculating everything and changing all the documentation.