Black boxes in autos?

They have been installed in many vehicles for years. Now go adjust your tinfoil hat.

____Reply Separator_____

Oh no! That's set to discombobulate Smokey's radar.

Of couse the converse is true, if YOUR family/firends were the ones hit, would't you like to be able to prove the other poerson was speediing and did not have the brakes on etc etc. ???

BTW, Corvette already has a black box on it.

In some vehicles and they are not mandatory. Maybe you don't have enought tinfoil on your head. :)

-------------- Alex

If I ran a stop sign and killed someone, I think I would deserve some sort of punishment too.

--------------- Alex

For many years I have wondered why there is such a difference between the way automobile accidents are treated and the way aircraft accidents are treated: even the crashes of small planes where the only person killed was the pilot seem to be investigated a lot more thoroughly than multi-vehicle accidents are.

OTOH, why is one supposed (in many places in the US, at least) to call the police for motor-vehicle accidents involving no injuries and trivial property damage? I have lived in places where the police had to be

*notified* (not called to the scene) within a certain time period (24hrs? 48hrs?) only if damage in excess of a certain sizeable amount occurred. Yet our local paper reported recently that someone was in trouble for leaving the scene of an accident when all she did was hit a tree.

MB

On 08/04/04 12:10 pm TOM KAN PA put fingers to keyboard and launched the following message into cyberspace:

Trees are expensive to replace. It could very well be that the damage to the tree exceeded that dollar threshold.

---------------- Alex

Probably the biggest reason is that there are so many more car accidents than airplane accidents. If car crashes were investigated as thoroughly as airplane crashes, you would need a veritable army of investigators.

Matt

But perhaps if motor vehicle accidents were investigated more thoroughly it would lead to better driver training, better design of vehicles, better road design, construction and maintenance, better signage, better . . . -- and therefore fewer accidents.

MB

On 08/05/04 07:50 pm Matt Whiting put fingers to keyboard and launched the following message into cyberspace:

I've no doubt it would have some benefit, but you don't need better accident investigation to know that driver training is a problem as are many other things that are well known. Unfortunately, the issue with most of these is politics, not lack of crash investigations.

Matt

Design flaws and inadequate maintainence schedules for airplanes are realistically more deadly in aircraft hence why aircraft accidents are investigated more. Aircraft also tend to be much older (on average) than cars. Aircraft are MUCH more vulnerable to structural failure than cars (as a cause of accidents). Engines and avionics need to be much more reliable and durable than for a car.

It's critical that pilot error be identified (or ruled out) for aircraft accidents. For car accidents, it's pretty much a given that it was driver error 99.999% of the time (as opposed to equipment failure - ie tire blowing out). For multi-vehicle accidents, the question is which driver was at fault (or how to divide up the fault).

Police are (basically) armed stenographers. Most of what they do is paper-work, and much of that paperwork finds it's way to insurance companies for one reason or another.

Structural failures are VERY rarely the cause of an aircraft accident. I'd like to see your source of information that says aircraft are MUCH more vulnerable to such failures as compared to cars.

Yes, engines need to be more robust in airplanes for two reasons:

1. They are called upon to work much harder than in cars. Most piston engine airplances cruise at 65-75% of their maximum rated power. Most cars seldom see these levels of power and cruise at less than 25% output typically.
2. Engine failure in an airplane has much greater consequences typically.

The downside of this is that new technology is very slow to make it into airplanes, other than in avionics. But most avionics failures are of much less consequence than a powerplant failure.

Why is this critical?

Matt (PP, ASEL, IA)

Actually, I can think of 5 structural failure incidents within the last

10-15 years without even scratching my head, and only considering commercial aircraft: 1) A Lockheed L-1011 rear pressure dome fractured, forcing a return to the takeoff field (in Japan, IIRC) and subsequent scrapping of the aircraft (could have been repaired, but was more costly than the airplane warranted). It was a fatigue failure. 2) 747 pressurization failure (also a rear P-dome I think) that caused a loss of the aircraft and many passengers, also in Japan. Fatigue failure/ 3) The most famous one- the Aloha Airlines Boeing 737 "convertible" that lost the upper half of the fuselage above something like 10 rows of seats. At least 2 deaths, I believe. Fatigue/corrosion failure of the fuselage structure 4) American Airlines Airbus A-310 (or was it an A-300?) over New York. Rudder broke right off. The root cause is now looking like pilot error (excessive rudder input) but it was certainly exacerbated by flaws in both the design and a particular repair performed on the aircraft's composite vertical stablizer. 5) Alaska Airlines MD-80 off Port Hueneme, CA. Elevator control jackscrew shed all its threads resulting in the elevator being un-controllable. All lives lost. The root cause turned out to be that the wrong grease was used on the jackscrew, but the immediate cause was a mechanical failure of the jackscrew.

Going back further, there was the Lockheed Electra engine mount problem that cost a couple of airframes in the 60s, and of course the very first jetliner (DeHavilland Comet) had its career cut short when several airplanes were lost, and it turned out that the fueslage was splitting like a sausage because of fatigue failure at the window frame corners.

Then we have military aircraft: the Lockheed C-141 Starlifter main wing spar replacement program (due to cracking), the early retirement of the F-105 Thunderchief due to wing cracking, two fire-tankers lost year-before-last (including one C-130 caught on videotape) because the main wing spar failed and the wings came off during flight.

Even private aviation has had issues- the Beech 1900D (a derivative of the King Air turboprop) had an engine mount failure mode that cost at least 1 airframe and several lives.

And beyond the actual accidents, ALL airframes have a limited structural life beyond which they must either cease flying or be very thorougly inspected and reinforced. In some cases the predicted life has been exceeded and extended (The Douglas DC-8 is still hauling cargo with many good years left, as is the Boeing 727) and in other cases like the Starlifter, the initial lifetime estimate was grossly under-estimated.

in contrast, when was the last time you heard of a car wreck because a part of the chassis failed due to fatigue? it DOES happen (google for BMW Z-3 differential mount failures...) but not to near the extent it does with aircraft. Most cars are STRUCTURALLY over-built by huge margins. Aircraft are not, or else they would be grossly inefficient and impractical.

I disagree. How many automobile engines use advanced ceramic coatings (besides the 5.7 Hemi, of course :-) ), or "single crystal" metal components? It is quite common in aircraft engines, and has been for at least 10 years.

I don't know why the OP said it was critical, but from my perspective it is critical to determine (to the best possible degree) the cause of EVERY aircraft accident because every aircraft is subject to unexpected mechanical failure through a common mechanism. Ruling mechanical failure ensures the safety of the remaining fleet of that type aircraft.

Five isn't exactly a huge number given the number of airplanes flying and the number of miles they cover. And I don't consider the failures due to improper maintenance to be a structural failuer, but rather human error. I don't consider it a structural failure when a pilot gets into a dive and then pulls up too abruptly and sheds the wings. That is no more a structural failure than is a car driven into a tree.

Yes, pressurizes airplanes tend to have a higher incidence of structural failure. However, since the topic was cars, a much better comparison is to small private airplanes and for them structural failures (other than those that are pilot induced) are very rare.

No, all airframes don't have a specified structural life. Life limits on airframes is a fairly new certification requirement.

I've been to several car wrecks caused by ball joints that came apart, tie rod ends that came apart, spindles that broke, even a couple of frames that failed due to rust. Structural failures on cars happen all the time, you just don't hear about it as with airplanes.

Which aircraft engines? Turbines? Most piston engines, at least from the big two, aren't much different than they were 50 years ago. They still use two valves per cylinder, run at low RPM, have low compression ratios, use magnetos, have manual primers, have manual mixture controls, no engine control computers, etc. There are a few systems in the works and a couple aftermarket sytems available, but they are a good 20 years behind the auto makers.

But why is this more critical for airplanes than for cars?

Matt

I think he was talking about severity vs. likelihood of such a failure, Matt - a distinction that you yourself allude to later in your post. In that sense, I think he is right to say that aircrfat are more vulnerable to such failures.

Of course severity of a critical part failure is much more sudden and unrecoverable in a helicopter. When I was a captian's driver for a captain over several Navy flight training bases in the early 70's, I personally witnessed the results of the failure of a blade coupling on a small Bell trainer helicopter (can't recall the model - much smaller than a Huey). That's the single piece of metal with concentric diameters that the individual blade attaches to and rotates about in its cyclic and collective adjustments. When it suddenly failed about 300 feet off the ground as the student was practicing an autorotation, of course the blade flew off, and the imbalance of the rotor with the remaining blades resulted in immediate disentigration of the chopper with the result that both instructor (a decorated Viet Nam pilot) and student were lost. I also drove the father and widow of the instructor in the funeral procession.

Anyway, as a result of that single accident, the whole fleet of that model was downed while they investigated. They found cracks forming in the same part on several of them. Obvious solution (20/20 hindsight) was replacing all of the couplings, and increasing frequency of inspection and replacement of those parts. One could argue the thin line between a design flaw and a maintenance issue on that one - after all even a good design with conflicting contraints (i.e., weight, strength, performance, etc.) requires some finite maintenance schedule. A "bad" design with a given maintenance schedule becomes a good design with a better maintenance schedule. A maintenance procedure and schedule could (should?) be considered part of the whole design package (as in FMEA), so, in that sense, one could consider that a design failure even though you might calssify it as a maintenance issue - the difference is academic in this case.

[several examples given by Steve]

And don't forget the DC-10 engine pylon bulkhead-to-wing attachment failure, which was a maintenance induced failure (American and other airlines took a shortcut not recommended by the manufacturer in R&R'ing the engines). 273 persons died on takeoff out of O'Hare in '79, plus there are other DC-10 crashes suspected to be from the same problem that occurred before the O'Hare one.

Partly because one plane crash can kill hundreds of people and wipe out an entire airline and/or manufacturer from liability and traveling public perception?

When I buy or rent a car, I can pretty much choose between available models. Yet if I have to fly a certain route as a memebr of the traveling public, my choice of aircraft may be limited or non-existent. When you're in a plane as a commercial passenger, if something goes wrong, you have very little to do with the final outcome. That is not nearly the case in a car that you're driving - even if there is a known safety flaw, you can either compensate for it (say in a vehicle that is known to flip over relatively easily), or easily choose another vehicle. Granted, you still can't protect yourself from such a vehicle that loses control and hits yours. But to me, there is a huge psychological difference in flying in airplane with unexplained previous crashes than in a car with a known safety problem - and I think most people are the same way in that regard. For one thing, right or wrong, most of us feel we can usually compensate for such situations (avoidance & prevention practices, etc.). In a plane, we are - quite literally - along for the ride and have close to zero control once the doors are closed and the engines are started - very scary with less than 100% confidence in the machine - not nearly so in a car.

As a result of the Delta DC-10 crash, Delta had to be sold off even though they were 100% innocent on the cause of the problem (their maintenance procedures were not followed).

Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")

OK, but to me the phrase "vulnerable to" implies a probability of occurence, not the consequences of the event. No doubt that the consequences of most airplane structural failures are far more severe than most auto structural failures, unless the failed tie rod end swerves you into an oncoming semi.

I don't recall a Delta DC-10 crash? When and where? Delta only operated DC-10s for a short time in the early 70s and then again for a short time when they inherited Westerns fleet in the late 80s.

Matt

I don't know about that. In my mind, "vulnerable" is too general a term to say whether it implies probability/liklihood of occurrence or severity/consequences. At minimum, it is ambiquous. Taken at face value, without him saying which he meant, I would have to agree (or at least would not disagree) with MoPar Man's statement "Aircraft are MUCH more vulnerable to structural failure than cars (as a cause of accidents)".

Heh! Not that this has much to do with this discussion, but I have vivid memories as a teenager when on a comping trip with my family, when seatbelts were just being required on new cars, I was standing in the parking lot of a gas station on a rural mountain road while our car was being gased up. Suddenly I heard the screeching of tires and looked up the road to see a telphone company van coming down the road with both front tires splayed out (obviously a tie rod had broken and the driver had instinctively turned the other wheel full out in an effort to travel as close to straight as he could). Everything was in slow motion. The van drifted over to the right (towards where I was standing) and hit a concrete curb and flipped over and traveled another 15 feet or so on its roof. The funny thing was, both the driver and his fellow telephone company worker had their seatbelts on, no doubt as newly mandated by the phone company, and were hanging upside down suspended by their seatbelts. Can't help but wonder if one or both would have been ejected or otherwise seriously injured w/o their seatbelts. Like I say - nothing to do with anything - I just thought it a funny story.

Oops - I meant the McDonnell Douglas DC-10 - I intended to state that McDonnell Douglas, the manufacturer of the DC-10, had to be sold off as a result of the lost sales from the publicity of the problem even though they did nothing wrong. (The airline that owned the one that crashed at O'Hare in 1979 that resulted in the cause of the problem being pinpointed was American.)

Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")

Well, vulnerable has nothing to do with severity, but only with susceptibility. Check your dictionary.

I'm not aware of any structural failures of a DC-10 proper (not counting engines). However, it did have at least one major design flaw that showed up in the Sioux City accident, but that was a systems failure, not a structural failure of the airframe. It was a structural failure of the engine that got it all started though.

Matt

Now it's coming down to semantics.

Webster's New World Dictionary: "that can be wounded or physically injured".

I think about the helicopter blade coupling situation. If you were to ask if that particular helicopter model was vulnerable to the coupling breaking, the answer is yes - both in susceptibility and severity.

But, lets say that the incidence of the coupling actually breaking had never occurred and that if one were to look for cracks in the field, none would be found. What if the question were "Is that helicopter vulnerable to a blade coupling breaking?", you might (or might not) agree with me that the answer would be yes - meaning that dire consequences would result if that were to happen *even* *though* there were no reason to expect that to happen - IOW, the severity would be high even though the liklihood of occurrence was low - yet I think we both would say it was vulnerable to a blade flying off.

If you wanted to know if it was likely to occur, you might not use the word "vulnerable", but instead use the word "susceptible". In the universe where it was known to be a common failure: "That helicopter is susceptible to the blade coupling breaking and the blade flying off. It is also vulnerable when that happens - it disintgrates." In the parallel universe in which no such failures are known, you would say "It was not susceptible, it is vulnerable to such a failure."

A counter example: Lets say the paint peels on that helicopter. One might say "That helicopter is susceptible to the paint peeling. However, it is not vulnerable from the paint peeling" (i.e., does not disintegrate or crash when it does).

The most I will agree to is that it is double-meaning'ed/ambiguous enough that the person making the statement should make it clear which meaning (susceptibility or severity) is meant unless it is clear from the context.

Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")