Imagine if the speedometer in your car failed. You shouldn't drive it until you get it fixed, but it won't kill you if it happens while you're on the highway.

For (made up example, I don't know anything in particular about aviation, but know the general approach from working with controls for nuclear powerplants) navigation one might conclude that GPS and old-fashioned UHF radio navigation is technologically different enough that an event taking down one means of navigation (say, jamming of GPS at 1.5 GHz, spread spectrum, digital, ...) will not affect UHF radio (at analog modulation on a few hundred MHz). So one decides that you have GPS and UHF, displayed on different monitors/indicators, powered by separate power-busses in the airplane.

For paper documentation, they'll probably claim: Bring two binders with the procedures to the plane, store at different sides of the cockpit.

For iPads one might have decided that they must not be connected to any network while on the plane, so that data cannot be deleted from the pilot's and first officer's devices. But have they considered the "common cause failure" of two iPads, not being connected to any network, not communicating with each other, with full batteries, probably with passed selfchecks (checksums for stored data on the flash)... to really fail at the same time because of an expired certificate?

Yes, it would be non-optimal if an aircraft had an issue without a handbook, but assuming that communications haven't been lost, someone on the ground can easily read out items.

[0] http://www.boeing.com/news/frontiers/archive/2006/april/i_ca...

If only a couple planes pester ATC then the system will keep up. It would be safe enough. What are the odds of an inflight emergency requiring a diversion at any instant? Pretty low. So if it happened to one plane they'd figure it out verbally. However requiring all ATC and all pilots to talk over all maps at all landings isn't scalable.

Something similar happens with manuals. One plane loses a system and its ipad, you call home on the radio or satphone or contact a fellow pilot on 123.45 MHz or call ATC for help. This doesn't scale to every plane in the air at the same time for every mostly minor maintenance writeup. Maybe you can ignore error messages this flight, after all most measurable things are not important, just like in business. Or maybe engine code 3141Z.kjdf.subsection2 means the engine is about to explode on the wing, but you've got no manuals...

Something often overlooked is megacorp analysis paralysis. You'll be formally written up if you don't file an engine operation temperature profile thingy form or some meaningless catering receipts or whatever according to boring corporate policy, and it will be brought up at your annual performance review, affect your promotion chances, etc. This scales pretty well when one ipad breaks and you use the copilots ipad or call your boss and argue and he issues you an indulgence or the boss takes dictation of the form for you or you refuse to fly (its only one flight after all). This doesn't scale well when every ipad in a company stops working.

Personally, if I were in a plane over water and I lost all my papers out the window, no fuel estimates, no weight and balance, no maps, no flight plan, no list of obstacles, no nav plan, no notes, nothing at all, I'd probably panic and head for the closest coastal airport (and where is that, without any docs?) If one plane does this, it scales VERY well. ATC calms you down, vectors you in, gives you some geographical advice, and you land. If every plane in the air does this simultaneously, you'll overload ATC and probably get someone killed.

This applies everywhere to all industries not just planes.

We've already had a test run for this, and it worked fine. 9/11 involved exactly that scenario - every flight in or heading to the US had to make for the nearest airport and land immediately.

Etymologically there's no good word for map (mappa meant napkin, charta meant a sheet of paper) but 'tabula' was used in Classical times.

Aeronautical charts extrapolate from this because being in command of an aircraft is really just commanding a different kind of vessel. Port, starboard, manifest, fix, captain, first officer, and hull are all valid aviation terms, for example, with roots in the sea. A chart is not a map.