Thanks rlumley.

have you ever heard the term "seaworthy" applied to ships? It's like that, but because it's airplanes it's for the air and not the sea... so it's just a general description of the condition of the plane

Per Wikipedia:

Airworthiness is a term used to dictate whether an aircraft is worthy of safe flight. It is illegal in most countries to fly an aircraft without first obtaining an airworthiness certificate from the responsible government agency. The airworthiness usually must be maintained by a program of inspections by an authorized Aircraft Maintenance Technician, typically performed annually, or after a fixed elapsed flight time, such as every 100 hours.

It's also a formal title for Michael Jordan.

no, isn't it airwhoriness? the amount by which the air is whorey?

I wonder why some airworthy airplanes crashed. WHat's the safety leverl of today's airplanes? The book tell me taking an airplane is likely the most safe way of long distance travel.

"no, isn't it airwhoriness? the amount by which the air is whorey?"

aerial refueling lol

*Cracks knuckles*

These guys are right on, so I won't bother.

Zhang, modern aircraft are ridiculously safe. You are hundreds as times as likely to be killed or injured on your way to/from the airport than actually flying. I use that statistic on the wife when I have to go fly in bad weather.

Also, I'm glad you're interested in aircraft and would be happy to answer any further questions.

What do you do if there is something on the wing? Some. Thing.

is it also true that more people die from falling coconuts than shark attacks each year? (those insideous coconuts are out to get us!)

Diplofool, while you're here, can you answer some questions on aeronautics that I've had?

Are you suggesting coconuts are migratory?

In order to maintain air speed velocity, a swallow needs to beat its wings forty three times severy second, right?

And what if two swallows carried a coconut together?

Frankly I consider that statistic on car deaths versus airplane deaths as an indicator of how out of control our traffic is. People drive like crazy and everyone thinks they are safe when they are far from safe. It's nuts how many people die or are injured by cars and no one seems to care.

There is a surfeit of caring.

Maybe what people dare is not death but is that they could not control there life.

The_Master_Warrior, thanks for your answer. The book says the chance of an aircraft crash should be no more than 1/1000000. Where does this standard come from? Is 1/1000000 reasonable and acceptable? Why not 1/10000000000 ?

1/1000000 over what time period?

it means for every 1000000 flights, there will be one crash.

@rlumley - <Grin>

@Alderian - to cut the number of car related deaths replace all of the drivers safety systems (seat belt, airbag, collapsible steering column) with a rigid steering column topped by a 9 inch steel spike. The number of car deaths would fall dramatically.

@ZhnangFang - Reducing the chances of a catastrophic failure from 1/1000000 to 1/10000000000 would be prohibitively expensive.

It costs money to keep an aircraft airworthy. Every aircraft has an AF/BF (pronounced "Aff Baff") an After-Flight/Before flight inspection. This is also known as "count the wings and kick the tyres". It's to make sure all of the parts (antennas, pitot-heads, static wicks, wings, tyres, engines, etc.) are there and properly attached.

Every part has a lifetime-to-failure. For fixed wing aircraft, regular servicing is carried out to replace these parts before they become life-expired. For rotary wing aircraft, parts are replaced when half their expected life-time has expired (half-life to failure). This is done at a Minor Service.

Every few years the entire aircraft is stripped down to bare metal and all of the airframe is inspected for cracks and corrosion, then it is rebuilt and repainted (a Major Service).

All these steps make the aircraft as safe as economically viable. If you watch "Aircrash Investigation" you'll know that a significant number of crashes were caused by an airline reducing costs by stretching the intervals between services or even skipping them entirely. The parts failed and people died.

Real-world example: working on a helicopter squadron during a conflict long ago. We couldn't get spares, so the junior engineering officer signed half-life expired items as fit-to-fly (125 hours in this case). Every one had to be inspected and tested after every flight. But we still couldn't get spares so, after more flying hours (170), the senior engineering officer became involved. The part in question (part of the electrical power system) was well past its half-life but not yet at its full-life expectancy. It appeared functional and passed every test, so he signed it fit-to-fly. Eventually it reached its full 250 flying hours and we *still* couldn't get spares. The decision went even higher - but we needed the aircraft and, while a failure would end the mission it would not directly endanger the aircraft, which could fly back to base with its essential electrical systems run from the batteries. Why do I remember this? Because the part failed at 254 hours, just 4 hours past its expected lifetime to failure.

Pilot error, folks. Happy to help!

Just like any other human, pilots can make errors as well. What sets these errors apart is pilot error is very dangerous. Although the entire flight is automated from tarmac to tarmac, pilot error is still a factor.