Getting a 787 back in the air after a diversion • Hacker News Board

Re: Getting a 787 back in the air after a diversion

#11

Post by newnewpdro » Sat, Jan 04, 2020, 5:36 AM UTC

dehrmann wrote: post #5

t34543 wrote: post #3

Earlier quoted context omitted.

Anecdote: My dad did this in the 70s. I believe you’re correct. He was working overseas and was frequently dispatched to countries without modern repair facilities such as Saudi Arabia. One story that stands out is he asked a local worker to warm up the APU. The worker proceeded to build a fire under the APU, destroying it. What he meant was start it up and let it run until it reaches operating temperature.

I might get some of the backstory halfway off, but my grandfather was in Alaska during WWII for the construction of the Alaska Highway. They tried to never turn off truck and equipment engines because if you did, you had to build a fire under them to get them warm enough to start again.

Sounds right, they describe this method in Alaska Crude, an interesting old book photo-documenting the development of Prudhoe Bay Oil Field.

The engine and gear oil would freeze solid. Required fires under differentials, oil pans, etc. just to get the oil liquid again.

Re: Getting a 787 back in the air after a diversion

#12

Post by fnbr » Sat, Jan 04, 2020, 5:36 AM UTC

acomjean wrote: post #7

dehrmann wrote: post #5

Earlier quoted context omitted.

I might get some of the backstory halfway off, but my grandfather was in Alaska during WWII for the construction of the Alaska Highway. They tried to never turn off truck and equipment engines because if you did, you had to build a fire under them to get them warm enough to start again.

Cars in northern Canada sometime have block heaters installed for cold starting. How cold should it be before you use it? Ask the internet: https://www.theglobeandmail.com/amp/globe-drive/culture/comm...

In my experience, it's all cars in Canada- I've never seen one that doesn't have it (other than imports). I guess you could probably get away without it on the west coast.

Most cars do start though. It’s really a maintenance issue, where it’s bad for your car to start it at -30 (as the linked article says). In my experience, a newer car in decent shape will start consistently.

Re: Getting a 787 back in the air after a diversion

#13

Post by WalterBright » Sat, Jan 04, 2020, 5:37 AM UTC

Back when I worked at Boeing they had the AOG (Airplane On Ground) crew to do this sort of thing. Their job was to be on call 24/7 and do whatever it took to get that airplane back in the air, and they pretty much had a blank check to do it.

Naturally, they were the best mechanics Boeing had.

An airplane makes money only when it is flying. When it is sitting on the ground, it loses money at a prodigious rate. A large focus of the engineering on the 757 I worked on was to keep that airplane flying as much as possible.

I understand that Microsoft has a similar crew they can dispatch to any customer to get their business software working again. This is how Microsoft is able to successfully compete against free software.

Re: Getting a 787 back in the air after a diversion

#14

Post by WalterBright » Sat, Jan 04, 2020, 5:41 AM UTC

dehrmann wrote: post #5

t34543 wrote: post #3

Earlier quoted context omitted.

Anecdote: My dad did this in the 70s. I believe you’re correct. He was working overseas and was frequently dispatched to countries without modern repair facilities such as Saudi Arabia. One story that stands out is he asked a local worker to warm up the APU. The worker proceeded to build a fire under the APU, destroying it. What he meant was start it up and let it run until it reaches operating temperature.

I might get some of the backstory halfway off, but my grandfather was in Alaska during WWII for the construction of the Alaska Highway. They tried to never turn off truck and equipment engines because if you did, you had to build a fire under them to get them warm enough to start again.

My family was stationed near London for a time. My father told me later that once an airline pilot mistook a WW2 strip for the Heathrow runway (!) and landed there, using every inch of it to get it to stop. The strip was too short to take off from, so what to do?

They stripped everything off the airplane they could. Seats, interiors, galleys, everything. They put in just enough fuel to hop over the trees to Heathrow. He said they did it, but barely.

Re: Getting a 787 back in the air after a diversion

#15

Post by WalterBright » Sat, Jan 04, 2020, 5:42 AM UTC

jandrese wrote: post #9

dehrmann wrote: post #5

Earlier quoted context omitted.

I might get some of the backstory halfway off, but my grandfather was in Alaska during WWII for the construction of the Alaska Highway. They tried to never turn off truck and equipment engines because if you did, you had to build a fire under them to get them warm enough to start again.

Old farm tractors used what was called "farm oil" in the old days. Basically the cheapest form of fuel you could buy since it was effectively a byproduct of the refining process. It was closer to paraffin wax than diesel, solid at room temperature. In order to start the tractor there was a second tank with diesel that was used until the engine warmed up enough to melt the primary fuel. If your tractor stalled out and…

The Germans in Russia in WW2 would use fires to warm their tanks and airplanes to get them to start.

Re: Getting a 787 back in the air after a diversion

#16

Post by molecule » Sat, Jan 04, 2020, 5:44 AM UTC

(2016)

Re: Getting a 787 back in the air after a diversion

#17

Post by __sy__ » Sat, Jan 04, 2020, 5:50 AM UTC

WalterBright wrote: post #13

Back when I worked at Boeing they had the AOG (Airplane On Ground) crew to do this sort of thing. Their job was to be on call 24/7 and do whatever it took to get that airplane back in the air, and they pretty much had a blank check to do it. Naturally, they were the best mechanics Boeing had. An airplane makes money only when it is flying. When it is sitting on the ground, it loses money at a prodigious rate. A large…

"Prodigious Rate" -- To put this in context, the latest numbers I saw is about $125 per min of unscheduled delay. It also doesn't take that many delays to wipe profitability to zero.

Re: Getting a 787 back in the air after a diversion

#18

Post by sajomojo » Sat, Jan 04, 2020, 5:51 AM UTC

It just seems like a very bad idea that twin-engine planes can fly so far from an air strip. If the #1 engine had failed as well it would have been game over. There's no possibility of gliding a 787 for 2+ hours and hundreds of miles.

If the FAA wanted to prioritize safety, it would still require the use of four-engined planes, as it used to for most long ocean routes. The desire to fly twin-engine planes over the ocean is entirely driven by a desire to maximize airline profits.

Admittedly, it does appear that modern twin-engine planes are reliable enough that it's not entirely crazy. But it would only take a couple of fatal engine failures to make it seem really dumb in retrospect.

People are weirdly dogmatic around this ETOPs rule change by the FAA. There is almost no one questioning it and yet the entire motivation is purely monetary. The FAA and airlines continue to push the limits further and further.

https://en.wikipedia.org/wiki/ETOPS

Re: Getting a 787 back in the air after a diversion

#19

Post by jacquesm » Sat, Jan 04, 2020, 5:59 AM UTC

WalterBright wrote: post #15

jandrese wrote: post #9

Earlier quoted context omitted.

Old farm tractors used what was called "farm oil" in the old days. Basically the cheapest form of fuel you could buy since it was effectively a byproduct of the refining process. It was closer to paraffin wax than diesel, solid at room temperature. In order to start the tractor there was a second tank with diesel that was used until the engine warmed up enough to melt the primary fuel. If your tractor stalled out and…

The Germans in Russia in WW2 would use fires to warm their tanks and airplanes to get them to start.

They still do this in some places in Russia.

Re: Getting a 787 back in the air after a diversion

#20

Post by jacquesm » Sat, Jan 04, 2020, 6:00 AM UTC

fnbr wrote: post #12

acomjean wrote: post #7

Earlier quoted context omitted.

Cars in northern Canada sometime have block heaters installed for cold starting. How cold should it be before you use it? Ask the internet: https://www.theglobeandmail.com/amp/globe-drive/culture/comm...

In my experience, it's all cars in Canada- I've never seen one that doesn't have it (other than imports). I guess you could probably get away without it on the west coast. Most cars do start though. It’s really a maintenance issue, where it’s bad for your car to start it at -30 (as the linked article says). In my experience, a newer car in decent shape will start consistently.

You'd have a very hard time starting a diesel without a block heater. When I lived in Canada I kept an older Ford (a 1949 one!) around for winter use because the diesel tractor was that much harder to start. You can make things a bit better by mixing about 5% gasoline in with the diesel to avoid the diesel becoming flaky but that has limits too and the Canadian winters can throw -40 Celsius at you with some regularity.

Block heaters are a must in that environment.