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737 'Tailstrike' Caused By Typo On a Tablet (arstechnica.com)
An anonymous reader writes: In August of last year, a Boeing 737 operated by Qantas experienced a tailstrike while taking off — the thrust wasn't great enough for the tail to clear the runway, so it clipped the ground. The investigation into the incident (PDF) has finally been completed, and it found the cause of the accident: the co-pilot accidentally entered the wrong plane weight data into the iPad used to make calculations about the takeoff thrust. "First, when working out the plane's takeoff weight on a notepad, the captain forgot to carry the "1," resulting in an erroneous weight of 66,400kg rather than 76,400kg. Second, the co-pilot made a "transposition error" when carrying out the same calculation on the Qantas on-board performance tool (OPT)—an iPad app for calculating takeoff speed, amongst other things. "Transposition error" is an investigatory euphemism for "he accidentally hit 6 on the keyboard rather than 7." This caused the problem: "For a weight of 76,400kg and temperature of 35C, the engine thrust should've been set at 93.1 percent with a takeoff speed of 157 knots; instead, due to the errors, the thrust was set to 88.4 percent and takeoff speed was 146 knots."
In the future, any flight engineer or pilot using that iPad to enter the plane weight data runs the risk of having it auto-corrected to the wrong value used by the crew in this case.
No, not really. I hope.
Welcome to the Panopticon. Used to be a prison, now it's your home.
It still boggles my mind how we live in the Information Age and this data was not automatically uploaded and calculated. I'm not saying it dosent require a human to sign off on, but it's mildly insane it isn't all automatically calculated and simply checked.
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Why can't the source of the data convey the data to the tablet apps automatically? Why involve an error-prone human in the process?
So somebody entered bad data into the Flight Management Controller.
Happens all the time with Qantas, which has been caught out for having extremely lax protocols.
Search the ATSB database, there have been more than a dozen incidents in the past decade which by pure luck didn't result in mass casualties.
Then read the BS excuses Qantas gives. Such as "the ladder wasn't tall enough to check the engine cowling was locked".
Enough for business.
Seems to me 5% should be well within the margin or error. Are they trying to save fuel by cutting it that close?
As if the co-pilot couldn't have made the exact same mistake with a calculator or even paper.
They could have just as easily mistyped the weight using the on-board flight management system's keyboard.
Is *not* an "off by one" error.
"I don't know, therefore Aliens" Wafflebox1
you always have both the pilot and co-pilot make the calculations to make sure that they both come up with the same number. That is if you can't have the plane download and measure the necessary inputs in order to calculate the values for you automatically.
That is an arithmetic error, not a transposition error.
Seven puppies were harmed during the making of this post.
except this is not true.
APPS caused a plane to get apped!
Apps!
I used to be a Ramp Agent at a major international shipping firm. We did weight and balance for the flights. We had several layers of redundancy for our numbers: Every container number and weight was rechecked by another Ramp Agent, and then once again at the gate to match with the load sheets. We realized if we put the numbers in wrong, that could result in loss of life (not to mention aircraft assets and cargo). We took this job very seriously. Once we turned that paperwork (now done via ACARS, supposedly), I would hate to think that the cockpit just fat fingered the numbers in on their end without having a secondary check. "Hey Captain, can we check the numbers real quick?" Probably take them 15-30 seconds at most since they'd be concerned with big picture numbers and not individual positions.
If you were me, you'd be good lookin'. - six string samurai
It seems like the summary writer is going out of their way to insinuate that the fact that it was an iPad had something to do with the Co-Pilot's gross incompetence.
#ipadlivesmatter
Seriously, at this time, it would actually make sense for the manufacturers to design in weight happening automatically.
I prefer the "u" in honour as it seems to be missing these days.
The integrated face system would have analysed the correct value preventing transposition errors.
Christ, even a server for a porn site has more error-checking hardware than an iPad.
"First, when working out the plane's takeoff weight on a notepad, the captain forgot to carry the "1," resulting in an erroneous weight of 66,400kg rather than 76,400kg.
Err, really, we're relying on mental arithmetic? Ok, fair enough as a backup, but then...
Second, the co-pilot made a "transposition error" when carrying out the same calculation on the Qantas on-board performance tool (OPT)—an iPad app for calculating takeoff speed, amongst other things. "Transposition error" is an investigatory euphemism for "he accidentally hit 6 on the keyboard rather than 7."
If the captain's working is being checked on the iPad, i.e. "same calculation", surely 76,400kg is an OUTPUT, not an INPUT. Was the co-pilot's "transposition error" such as to very coincidentally produce a 66,400kg output? Otherwise, the pilot and co-pilot's answers would be different, and they should have both started again.
"For a weight of 76,400kg and temperature of 35C, the engine thrust should've been set at 93.1 percent with a takeoff speed of 157 knots; instead, due to the errors, the thrust was set to 88.4 percent and takeoff speed was 146 knots."
11 knots and 4.9% thrust the difference between a safe take-off and a tailstrike? Christ, that's a narrow margin.
Get up there in a hurry! And keep the wheels down in case you have to bring it down in a hurry! It's the simple things that makes this work!
It's back to slide rules for everyone now.
Honestly flooring it is always the best option.
Do not look at laser with remaining good eye.
"Okay. I found 5 restaurants like 'calculate takeoff thrust' near you"
It's almost like ipads are a stupid, portable toy for rich morons and they don't belong in the real world like for example a workplace. My merchant services vendor massively screwed up my application a few years ago because that dumbass was using an ipad as well. It's almost like tablets are an inferior way to typing data into a computer system or something.
The tablet didn't miscalculate. The human did. In fact, tablets (or any technology) are great at math. To solve issue, automate the calculation and entering of the weight (or any other known information). People in the world all full of "I can't" or "it's not possible". But believe me, "it can happen" and "it is possible" to automate.
At least they didn't run out of fuel like they did on the Gimli Glider.
On a recent flight from SYD to MEL our Qantas pilot ranted on the PA about how evil the ATSB was because they wouldn't let the plane take off, because Qantas engineering accidentally put an incorrect black box into our plane. He said that Qantas maintenance made mistakes like that all the time, and that, since it wasn't a safety issue to fly without a black box, the ATSB were just being pricks.
I will never set foot on a Qantas plane ever agin.
A transposition error's what you get when you mistakenly transpose 2 digits when typing a number, ie 5712 instead of 5172. If there's an error in the expected total of a set of numbers and the difference is divisible by 9, chances are good one of the numbers has a transposition error.
I'm a fan of and real big advocate of teaching people about Quantum Physics, and the observer effect.
Now as a programmer and executive in Information Technology for 30 years, there's a base assumption that Information Stored in databases is flawlessly stored. A bit's a bit's a bit and there's no altering that information when it's committed, right?
Enter Quantum Physics. And as you investigate the smallest particles of matter, there has been consistently demonstrated 'observer effects'.
Put specifically: Sometimes it's difficult to tell if a particle is changing because this is how it behaves or this is how it behaves under observation.
In this case here. You have investigators which first look for pilot error.
Biased observers are looking for information which might lead the attention away from this being a system design flaw, and point to pilot error. Other 'observers', such as Boeing, and the Engineers. Are creating quantum bias as well which also shapes the findings.
This shapes reality itself. And somewhere, a bit flips from a zero to a one through sheer collective observer pressure which creates a butterfly effect of making it appear like one person is responsible.
And in the end.
You have the Observer Flaw argument of the greater good. the collective finds their proverbial villain.
And one person takes the hit while the collective survives.
When the truth, firmly missed, is somewhere in between.
I wish you people would brush up on recent findings in Quantum Mechanics.
You would understand this better.
So human makes calculation on paper. The result is 66,400kg. Human then enters the same number onto a tablet.
Sure the human involved sucked at math and got the wrong result in the first place, but he copied the (wrong) result into the tablet perfectly fine.
How does this have anything to do with the tablet?
(yes, all this stuff should probably be automatically generated in this day and age, but that is a different discussion to have)
Why is this not an automatically entered value with the ability to be manually changed, instead of having to be typed in all the time.
Imagine dying because someone fat fingered some figures on an iPad? I think most of us can testify that we are more likely to make a typo when typing on a touchscreen. Oof! Now the part with forgetting to carry the one is a whole 'nother issue. heh
"Never give up, for that is just the time and place when the tide will change." -Harriet Beecher Stowe ^_^
Can't the plane weigh itself?
This was not a tablet error. It was a math error.
The real question is not really why this data has to be entered manually (instead of automatically), but why it is needed at all. You'd think that with all the sensors on an airplane, this sort of thing should be handled via automated control systems, based on actual measurements of how the plane is doing.
It might still be useful to enter the data, but only as a sanity check; that is, to identify when the plane isn't handling the way it should based on the weight that the crew things it actually has.
That does not mean it can handle 10,000 lbs, it means it can handle MORE than 10,000 lbs - the excess is called a margin of safety. It can be expressed as a "factor of safety". If your factor of Safety is 2, then the engineer believes the bridge can handle twice the stated load.
For aircraft and spacecraft, the US government generally requires Factor of Safety of at least 1.2, but as high as 3 is common. That means that if the tire is expect to hold 10 tons, it was built to actually hold at least 12 tons. (All above info from Wikipedia)
Apparently the idiots that write these programs thought, hey, we don't need to use a reasonable Factor of Safety. They calculated they needed 93.1 units of thrust, but failed only 88.4. That means their Safety Factor was less than 1.12
If the morons had put in the expected margin of safety of 1.2, then the plane should have been able to take off even if they had only applied 77.67 units of thrust.
Clear failure of the programmer to build a sufficient margin of safety into their calculations
excitingthingstodo.blogspot.com
Why is everybody missing the true problem, which is that typing on pieces of smooth glass are incredibly more prone to typing errors than typing on some sort of keyboard or button device???!!!! When I heard that at least some airlines are using iPads for certain in plane tasks, I nearly spit out my teeth. Who the hell thought this was a good idea?
The tablet didn't make the error, the humans did.
And if you think you have to be rich to afford an iPad, well, then I guess you've had a tough, tough life.
Who needs a calculator? Just put the pedal to the metal and scream like a girl.
https://en.wikipedia.org/wiki/...
In aviation, a tailstrike is an event in which the rear end of an aircraft strikes the runway. This can happen during takeoff of a fixed-wing aircraft if the pilot pulls up too rapidly, leading to the rear end of the fuselage touching the runway. It can also occur during landing if the pilot raises the nose too aggressively. This is often the result of an attempt to land nearer to the runway threshold.
Anons need not reply. Questions end with a question mark.
What they described would be a transcription error. However, I submit that it was probably a CYA error. In other words, the pilot did the calculation wrong and the copilot did not check the pilots work, but saying that you did and just typed it in wrong is merely incompetence and carries less penalty than not doing your job, which is insubordination.
If you are not allowed to question your government then the government has answered your question.
Are they trying to save money on takeoff wtf.
Frankly, in 2015, it is a shame the pilots even have to do this...
You can have the airplane weigh itself, using sensors on the landing gear. Then it can take readings from the air (temp, pressure, etc.)
Then it can figure all this out with far less error than the humans can.
That was bugging the hell out of me...
How about double and triple checking before pushing enter?
The proximal cause was the weight of the train was filled in by a clerk, who made an assumption regarding the weight of the cargo. He was wrong. There were other factors.
I can't find the book or author, but circa 1990's an author wrote some books on failures of human inventions. One of his concepts is that more complicated systems become harder to understand. Another was that for failure/disasters to happen often require a confluence of several things going wrong simultaneously, or within the period of time of an emerging situation.
Both of these, for example, are involved in many nuclear power accidents. And most nuclear power accidents until they happen were "not supposed to happen," in the sense that the combination of factors that allowed it to happen were not considered by those estimating risks. Example: Three Mile Island had 3 valves for auxilliary feedwater pumps shutdown for maintenance when the accident occurred, and the reactor should have been shut down. Then a valve to release excess pressure opened as it should, but due to mechanical failure failed to close, allowing too much water to escape...
This is enough to make Wilford Bramley start cussing.
When I used to play flight simulators, I always gave full throttle to take off.
Why did they bother to calculate the optimum? And what is optimized? Fuel consumption? Acceleration (i.e. passenger comfort)?
Don't we still have to turn off our iPads on takeoff?
Too many tail strikes, and they are 99% avoidable, maybe 100%.
Most likely, in the next generation aircraft, the computer will override the pilot when too much pitch is requested too low.
The plane knows it is taking off, and it knows where the runway is (or a small radar can be added to the tail). "Stick back" will stop meaning "nose up" when the tail gets too close to the ground, and will instead start to mean "moar power". As the ground falls away, it will transition back.
Might not even need to wait for the next generation of planes. This could easily become a mandate shortly after the next tail strike that results in loss of life.
See that "Preview" button?
He was trying to calculate using Common Core methodology.
Funny how they're "Captain and First Officer" when they're flying but only "pilot and co-pilot" when something bad happens.
1. Everyone learn their MATHS.
2. Touch screens suck for mission critical applications... including driving a car.
First error in calculation. Second error in not flying the airplane. If it doesn't look right, either add power or abort takeoff. These are basics, even for a 70 year old Cessna 140 tailwheel airplane.