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Some American Airlines planes are grounded because the pilots’ iPads crashed

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Re: Some American Airlines planes are grounded because the pilots’ iPads crashed

#101

Post by kayfox »

coldtea wrote: post #43
joezydeco wrote: post #28

Earlier quoted context omitted.

American once boasted they saved $40,000 in fuel costs a year by deleting an olive from the salads in the passenger meals.

Which sounds like BS / urban legend. $40.000 for (generously) 1 gram x 300 passengers = less than a pound per flight? [UPDATE] not sure for fuel, but might be true in olive prices, given these numbers: Their website says 6,700 flights per day. Let's round it to 6000. 6,000 flights a day -> It's 2,190,000 flights a year x 100 meals per flight x 1 olive saved -> 219,000,000 olives saved. This list http://sizes.com/food…

http://skeptics.stackexchange.com/questions/5935/did-removin...

None of the discussions I found online tried to calculate fuel costs, which is also a major factor in how much that one olive costs.

Re: Some American Airlines planes are grounded because the pilots’ iPads crashed

#102

Post by blktiger »

rpmcb wrote: post #70
k-mcgrady wrote: post #56

Earlier quoted context omitted.

I thought it was the flight plan.

The flight plan is programmed into the airplane's avionics, as well as on a printed hard copy in the cockpit. The app is supplemental. It can not be used as a primary navigation reference, per FAA regulations.

It sounded to me like the pilot's couldn't input the flight plans into the cockpit avionics because they didn't have a paper copy of the flight plan.

Re: Some American Airlines planes are grounded because the pilots’ iPads crashed

#103

Post by innguest »

phdp wrote: post #82
VLM wrote: post #75

Earlier quoted context omitted.

Maps too, from what I hear. The problem is scalability. If no one carried maps, everyone would have to talk verbally and take notes with ATC for five minutes for every landing to make sure nothing had changed. 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 pl…

Charts, not maps ;)

You got me curious. Can you explain?

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

Re: Some American Airlines planes are grounded because the pilots’ iPads crashed

#104

Post by [deleted] »

draugadrotten wrote: post #32
SixSigma wrote: post #22

Earlier quoted context omitted.

> The pilot came on and said that his first mate’s iPad powered down unexpectedly, and his had too, and that the entire 737 fleet on American had experienced the same behavior. user mode programs causing power down is not an app bug

> that the entire 737 fleet on American had experienced the same behavior. That seems to be inaccurate. American Airlines confirms "several dozen flights" which is probably less. http://www.theguardian.com/technology/2015/apr/29/apple-ipad... And the fix was available through nearest Wi-Fi. Leaving cockpit a few minutes. The horror! "In some cases, the flight has had to return to the gate to access a Wi-Fi connection…

[deleted]

Re: Some American Airlines planes are grounded because the pilots’ iPads crashed

#105

Post by mikeash »

kayfox wrote: post #101
coldtea wrote: post #43

Earlier quoted context omitted.

Which sounds like BS / urban legend. $40.000 for (generously) 1 gram x 300 passengers = less than a pound per flight? [UPDATE] not sure for fuel, but might be true in olive prices, given these numbers: Their website says 6,700 flights per day. Let's round it to 6000. 6,000 flights a day -> It's 2,190,000 flights a year x 100 meals per flight x 1 olive saved -> 219,000,000 olives saved. This list http://sizes.com/food…

http://skeptics.stackexchange.com/questions/5935/did-removin... None of the discussions I found online tried to calculate fuel costs, which is also a major factor in how much that one olive costs.

This article claims that it takes one extra gallon of fuel for 100 pounds of weight on a domestic airline flight:

http://www.budgettravel.com/blog/overweight-passengers-cost-...

I don't know how accurate that is, but it passes a basic smell test for me.

An olive is about 6 grams, so the per-olive fuel consumption is about 0.0001 gallons. Jet fuel currently costs about $1.70/gallon, so that's about 0.017 cents per olive in fuel.

To save $40,000 in fuel per year by reducing olives, you'd be flying about 200 million fewer olives.

American flies about 500 million passengers per year, so $40,000 in fuel savings could be achieved with about 0.4 olives saved per passenger.

I have no idea if this actually happened, but the numbers look about right!

Re: Some American Airlines planes are grounded because the pilots’ iPads crashed

#106

Post by danans »

Perhaps they chose too complex a platform, given the use case. Paper, while it has its own failure modes, is pretty failsafe, especially for information that doesn't change during the course of the flight.

I wonder if there is an in-between solution that would provide the benefits of an electronic display without introducing as many failure modes as a device like an iPad which is designed primarily for consumer use.

Re: Some American Airlines planes are grounded because the pilots’ iPads crashed

#107

Post by coldtea »

mikeash wrote: post #105
kayfox wrote: post #101

Earlier quoted context omitted.

http://skeptics.stackexchange.com/questions/5935/did-removin... None of the discussions I found online tried to calculate fuel costs, which is also a major factor in how much that one olive costs.

This article claims that it takes one extra gallon of fuel for 100 pounds of weight on a domestic airline flight: http://www.budgettravel.com/blog/overweight-passengers-cost-... I don't know how accurate that is, but it passes a basic smell test for me. An olive is about 6 grams, so the per-olive fuel consumption is about 0.0001 gallons. Jet fuel currently costs about $1.70/gallon, so that's about 0.017 cents per oli…

I'll use yours: 1 gallon for 100 pounds of weight.

If an olive is 6 grams (0.013 pounds), then 100 pounds need: 7,692 olives.

For $1.7/gallon, this gives: .00022 dollars fuel cost per olive (or 77 times less than your estimation).

For 500 million passengers with one olive less, we got: 500 million less olives x 0.00022 = $110,000 in savings.

Taken from another angle, 300 passengers * 0.00022 savings per olive/passenger is: 0.066 savings per flight.

From the 6000 flights/day they have on their site, this gives: 6000 * 365 * 0.066, or a saving of $144,540, so same ballpark.

They seem to save at least $80-$100,000 per year in both fuel and olive costs by removing just one olive.

Of course while it sounds amazing to us, it involves 6000*365 flights / 500 million passengers a year.

Which means that this seemingly "large" number (when compared to say, our salary) is actually peanuts compared to their operating costs. Like, by removing one olive per passenger, they reduce their operating costs per flight by less than .000025%.

Re: Some American Airlines planes are grounded because the pilots’ iPads crashed

#108

Post by mikeash »

coldtea wrote: post #107
mikeash wrote: post #105

Earlier quoted context omitted.

This article claims that it takes one extra gallon of fuel for 100 pounds of weight on a domestic airline flight: http://www.budgettravel.com/blog/overweight-passengers-cost-... I don't know how accurate that is, but it passes a basic smell test for me. An olive is about 6 grams, so the per-olive fuel consumption is about 0.0001 gallons. Jet fuel currently costs about $1.70/gallon, so that's about 0.017 cents per oli…

I'll use yours: 1 gallon for 100 pounds of weight. If an olive is 6 grams (0.013 pounds), then 100 pounds need: 7,692 olives. For $1.7/gallon, this gives: .00022 dollars fuel cost per olive (or 77 times less than your estimation). For 500 million passengers with one olive less, we got: 500 million less olives x 0.00022 = $110,000 in savings. Taken from another angle, 300 passengers * 0.00022 savings per olive/passeng…

"or 77 times less than your estimation"

Your estimate and mine are almost the same. 0.017 cents is $0.00017 is close to $0.00022. The difference is because I did some heavy intermediate rounding, what with olive weight being highly approximate to begin with.

You're right that in relative terms, the savings is tiny. But absolute numbers count as well. If it saves $40,000/year then that means one full-time employee can spend something like 25-50% of his time working on this problem and they still come out ahead.

Re: Some American Airlines planes are grounded because the pilots’ iPads crashed

#109

Post by rpmcb »

blktiger wrote: post #102
rpmcb wrote: post #70

Earlier quoted context omitted.

The flight plan is programmed into the airplane's avionics, as well as on a printed hard copy in the cockpit. The app is supplemental. It can not be used as a primary navigation reference, per FAA regulations.

It sounded to me like the pilot's couldn't input the flight plans into the cockpit avionics because they didn't have a paper copy of the flight plan.

A flight plan and a procedure are very different things. Every commercial flight in America has a hard copy of their flight plan in the cockpit.

Re: Some American Airlines planes are grounded because the pilots’ iPads crashed

#110

Post by capnrefsmmat »

notahacker wrote: post #35
capnrefsmmat wrote: post #20

Earlier quoted context omitted.

The DOT actually has estimates of the value of time lost by passengers, used for economic analyses of delays. See this PDF, page 19: http://www.dot.gov/sites/dot.dev/files/docs/vot_guidance_092... Your time is worth $45-57 an hour, depending on if your travel is personal or business-related.

Seems a tad generous considering a back-of-the-envelope calculation puts the average amount contributed to GDP per US citizen per hour at around $6. From an airline point of view, if their schedule is sufficiently flexible to accommodate the delays without flight cancellations and the delays are insufficiently long to require passengers to be compensated, the biggest costs will be additional fuel if the delays involv…

The DOT numbers are based on median hourly income of airline travelers, rather than their contribution to the economy. You can read the report I linked for their detailed methods.
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