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As the 747 Begins Its Final Approach, a Pilot Takes a Flight Down Memory Lane

nytimes.com

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Re: As the 747 Begins Its Final Approach, a Pilot Takes a Flight Down Memory Lane

#31

Post by analog31 »

jacquesm wrote: post #26
analog31 wrote: post #17

Earlier quoted context omitted.

I wonder if the increase in turbulence was due to climate change.

I really don't see how that would relate to each other, there was a pretty strong correlation to which aircraft the flight was in and the routes were very similar.

That's fine. I'm curious how aircraft design affects the behavior of a plane when it flies through turbulence. My layperson's expectation would have been that turbulence is caused by localized air currents, and the plane is just getting shoved around. That's why I suspected a change in the behavior of the air itself.

Re: As the 747 Begins Its Final Approach, a Pilot Takes a Flight Down Memory Lane

#32

Post by gsnedders »

DaiPlusPlus wrote: post #22
avar wrote: post #12

For anyone wondering why airlines are retiring the 747 this Wikipedia section summarizes it: https://en.wikipedia.org/wiki/Boeing_747-400#Retirement_and_... Summary: Old, inefficient, less need for jumbo jets. Everyone's either buying smaller or migrating to the modern Airbus A380.

The A380 isn't that popular either. The A380 only makes sense for really popular routes with a guaranteed high passenger count, whereas the 787 is more flexible because it has a similar range and takes less passengers but is almost as efficient per passenger-mile. And in 2016 there were fears Airbus might even cancel the A380 entirely: https://qz.com/782361/airbus-a380-airlines-are-abandoning-th...

> The A380 isn't that popular either. The A380 only makes sense for really popular routes with a guaranteed high passenger count, whereas the 787 is more flexible because it has a similar range and takes less passengers but is almost as efficient per passenger-mile.

Also with airports where you're slot limited, and hence operating a single aircraft is easier.

Re: As the 747 Begins Its Final Approach, a Pilot Takes a Flight Down Memory Lane

#33

Post by HarryHirsch »

analog31 wrote: post #17
jacquesm wrote: post #15

I used to fly these every two weeks, KL691 and KL692 the flights between Schiphol, Netherhands and Toronto, Canada. Then at some point they moved to 777's, and even though it was a nice plane and far more modern the 747 almost never had a turbulent ride whereas the 777 trips were far less comfortable, especially the red-eye return flight rarely was smooth enough that I could get some sleep. Retiring the 747 was one (…

I wonder if the increase in turbulence was due to climate change.

Why is this being downvoted? Turbulence is caused by atmospheric instability, which is driven by the atmospheric temperature gradient, and that has increased in the last few decades thanks to global warming.

https://www.wmo.int/pages/prog/arep/wwrp/new/wwosc/documents...

Re: As the 747 Begins Its Final Approach, a Pilot Takes a Flight Down Memory Lane

#34

Post by astrodust »

analog31 wrote: post #31
jacquesm wrote: post #26

Earlier quoted context omitted.

I really don't see how that would relate to each other, there was a pretty strong correlation to which aircraft the flight was in and the routes were very similar.

That's fine. I'm curious how aircraft design affects the behavior of a plane when it flies through turbulence. My layperson's expectation would have been that turbulence is caused by localized air currents, and the plane is just getting shoved around. That's why I suspected a change in the behavior of the air itself.

It's to do with the aerodynamic design of the planes, the response of the wings to turbulence, and the altitude and speed at which they're flying.

The 747 is a longer plane with more wing surface area. Maybe that gives it better stability. https://www.quora.com/Is-a-Boeing-747-bigger-than-a-777

The new composite materials might also be a factor, where perhaps the plane is designed to flex and distort more, which could make the trip more rough.

Re: As the 747 Begins Its Final Approach, a Pilot Takes a Flight Down Memory Lane

#35

Post by agumonkey »

jacquesm wrote: post #15

I used to fly these every two weeks, KL691 and KL692 the flights between Schiphol, Netherhands and Toronto, Canada. Then at some point they moved to 777's, and even though it was a nice plane and far more modern the 747 almost never had a turbulent ride whereas the 777 trips were far less comfortable, especially the red-eye return flight rarely was smooth enough that I could get some sleep. Retiring the 747 was one (…

Now that's a making of I'd like to see.

Re: As the 747 Begins Its Final Approach, a Pilot Takes a Flight Down Memory Lane

#37

Post by pirocks »

inferiorhuman wrote: post #23
avar wrote: post #12

For anyone wondering why airlines are retiring the 747 this Wikipedia section summarizes it: https://en.wikipedia.org/wiki/Boeing_747-400#Retirement_and_... Summary: Old, inefficient, less need for jumbo jets. Everyone's either buying smaller or migrating to the modern Airbus A380.

That and the fact that to be legal to fly in the US (possibly elsewhere) as of 2018, they'll need an expensive fuel tank inerting system retrofitted.

Why is this necessary. I take it 747s have been safe up til now?

Re: As the 747 Begins Its Final Approach, a Pilot Takes a Flight Down Memory Lane

#38

Post by gist »

joezydeco wrote: post #19
avar wrote: post #12

For anyone wondering why airlines are retiring the 747 this Wikipedia section summarizes it: https://en.wikipedia.org/wiki/Boeing_747-400#Retirement_and_... Summary: Old, inefficient, less need for jumbo jets. Everyone's either buying smaller or migrating to the modern Airbus A380.

Remember that Boeing's original plan was to use the 747 as a freighter. Passengers would fly on supersonic jets like their prototype 2707 SST. This is why the 747's cockpit is on top, it provided a continuous open tube for cargo underneath. http://www.nycaviation.com/newspage/wp-content/uploads/2015/...

> Remember that Boeing's original plan was to use the 747 as a freighter.

You have to wonder actually if that is even true (I've heard it as well obviously). Reason being Boeing may have been thinking SST wouldn't work or be practical (after all it wasn't) but it was easier to sell a 747 based on saying it could be used as a freighter primarily. If they had said it was just another long range high capacity plane the project might have never gotten approval because of the 'bet the company' risk.

Re: As the 747 Begins Its Final Approach, a Pilot Takes a Flight Down Memory Lane

#39

Post by avar »

pirocks wrote: post #37
inferiorhuman wrote: post #23

Earlier quoted context omitted.

That and the fact that to be legal to fly in the US (possibly elsewhere) as of 2018, they'll need an expensive fuel tank inerting system retrofitted.

Why is this necessary. I take it 747s have been safe up til now?

The reason the FAA considered fuel tank inerting in the first place is because of a 1996 crash of a 747 that killed 230 people[1], and which is thought to have been avoided had the tanks been inert[2]. Other 747s were lost to the same issue, such as the ULF48 that crashed in 1976 killing all aboard[3].

To answer your question, no, the 747 is not "safe". No aircraft ever made is "safe". They will all crash and kill people given sufficient flight hours. The question is what we consider acceptable risk, those standards change over time as technology improves, and as regulators phase out older models by sunsetting certain exceptions.

As that's done older aircraft either need to be retrofitted, or sold to jurisdictions with laxer rules.

1. https://en.wikipedia.org/wiki/TWA_Flight_800

2. https://en.wikipedia.org/wiki/Inerting_system#Aircraft

3. https://en.wikipedia.org/wiki/Boeing_747_hull_losses#1970s

Re: As the 747 Begins Its Final Approach, a Pilot Takes a Flight Down Memory Lane

#40

Post by [deleted] »

pirocks wrote: post #37
inferiorhuman wrote: post #23

Earlier quoted context omitted.

That and the fact that to be legal to fly in the US (possibly elsewhere) as of 2018, they'll need an expensive fuel tank inerting system retrofitted.

Why is this necessary. I take it 747s have been safe up til now?

[deleted]
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