5 ms·

This is a surprisingly poor article from the BBC. So, padding, according to this article has a negative environmental impact. But that argument isn't justified

This is a surprisingly poor article from the BBC. So, padding, according to this article has a negative environmental impact. But that argument isn't justified and doesn't make sense, most time lost is either unavoidable for the airline (e.g. airport problems/weather) or at a phase of travel without the engines running (boarding delays, waiting for a gate, etc). Flying slower is actually a environmental win since aircraft are more efficient at slower speeds (although costs more to the airline due to staffing/opportunity cost). They seem to want us to believe that if padding was removed, and airlines magically got more efficient, that they'd use less fuel but what is the mechanism? What phase of flight sees the fuel reductions? It is like they don't know that aircraft often use either ground-power or only the generator while waiting. In fact the core premise of the article is clickbait. Oh no, airlines are making sure you can plan your travel times accurately by accounting for common delays within a route! The horror! Sorry, but not biting today.

Klathmon 8y ago
>Flying slower is actually a environmental win since aircraft are more efficient at slower speeds Do you have any more information on this? Obviously slower-speed turboprop planes are much more efficient than jet powered planes, but I've read in the past that flying a jet engine slower can actually increase fuel consumption and increase emissions.
- sokoloff 8y ago
  There is an efficiency curve for jet transports. There is a defined MRC (max range cruise, which varies by weight) and a calculated LRC (long range cruise, typically defined as 1% less fuel efficient [in kg/nm], which gives 99% of efficiency and about 104% of cruise speed vs MRC). Modern flight management systems have economy calculators that can predict not only fuel-at-destination figures, but can incorporate winds and other airline cost indices (crew, maint reserves, etc) to emit an "ECON" speed target. It is only speeds below the MRC that cause a decrease in (still-air) fuel efficiency. Airlines do not typically operate in that speed range in cruise absent an ATC directive to slow down to avoid holding ahead. (Obviously, flying a hold is done below MRC as well.)
- aeroevan 8y ago
  There are two optimal values for speed depending on the objective. There is a max endurance speed (for holding, etc.) and a max range speed, both are a function of altitude. So slowing down under those speeds will decrease efficiency, but typically the airline's cost index (~additional hourly cost to operate, like crew cost) will typically push the speeds higher to minimize the overall cost. http://www.eaa1000.av.org/technicl/perfspds/perfspds.htm http://www.eaa1000.av.org/technicl/perfspds/perfspds.htm is about the best thing I can google right now as a reference.
fyfy18 8y ago
> In fact the core premise of the article is clickbait I feel like basically all the BBC articles I've seen posted here recently are nothing more than clickbait. Does anyone else feel the same?
- johnnycab 8y ago
  They are no more clickbait-y compared to some articles from other red tops, which appear regularly in the Apple News feed, for example.
- GordonS 8y ago
  TBH it feels like all of BBC news has been turning tabloid for the past 5 years or so - many articles feel click- baity and sensationalist. It's not just written media either - I hear Radio 1 news sections from time to time in the car, and they are so basic and devoid of information it's like they're designed for young children.
oeuviz 8y ago
Additionally, airlines might choose a more economic route which might take longer but save fuel due to better weather conditions/jet stream.
jillesvangurp 8y ago
It's not just flying slower. If you've ever flown into London, you are probably familiar with the notion of a holding pattern. When things get busy at the airport, due to poor scheduling, it is quite common for planes to fly in circles for 10-20 minutes or even longer in some cases. Also, planes sitting on taxi lanes burning fuel with six planes in front of them is a common issue. Planes are assigned landing and take off slots and if they miss those, that's a problem. So, if the schedule is unrealistic, planes might be taking off "on time" knowing full well they'll be circling downtown London for some time.
- robjan 8y ago
  It's not poor scheduling, so much as Heathrow being at 99.5% capacity which means queuing is required so they can maintain one landing per minute.
  - CydeWeys 8y ago
    Yeah, the airport is at capacity. I'm not seeing how it has anything to do with schedule padding at all. They're doing take-offs and landings there as quickly as possible.
    - jillesvangurp 8y ago
      Airlines know before they take off their ETA to the other side pretty much down to the minute. Their planning builds in padding so that they are guaranteed to make it on time. Which means they expect to arrive early and end up in a holding pattern because the take off slot and landing slot are deliberately misaligned. This is exactly what the article is implying. That's of course aside from the inevitable issues arising from operating at 99% capacity. Anyone familiar with queuing theory or logistics knows that this just means things pile up at the cost of delays and extra fuel being burnt. So, that too is poor planning. You never operate systems with queues at close to 100% capacity unless you are looking for severe cost overruns and bottlenecks. This poor planning results from misaligned incentives. Airports can just park planes in holding patterns for however long they desire. It's not their fuel being burnt. So they over provision knowing full well they will have planes in holding patterns throughout the day, This maximizes their revenue. So they are actively incentivized to do this. Likewise, airlines buy fuel cheaply and only get penalized for being late. So they are incentivized to implement padding. So, the fix is re-aligning the incentives for airports and airlines to minimize planes in holding patterns and fuel being burnt. There are several ways to do this but the bottom line would be making sure both airlines and airports aim to not have planes in holding patterns because that costs both of them something.
mikekchar 8y ago
> This is a surprisingly poor article from the BBC. It's not a staff writer. I always check these things once I started to realise that some of the biases I saw in news reporting were actually determined actions by a relatively small number of independent writers. Here's her bio on Forbes: https://www.forbes.com/sites/kathryncreedy/#4c0ca61271e2 https://www.forbes.com/sites/kathryncreedy/#4c0ca61271e2 (though she's an independent writer as far as I can tell). In my experience the BBC buys up a fair amount of stuff to just "fill up" the offering. Usually it's pretty poor quality. I don't actually have an opinion on this piece since I know nothing of the subject. I just want to encourage people to understand where their "news" comes from.
csours 8y ago
I agree. The first figure presented out of context is the difference in flight time from the 1960s to today. While some of that is certainly padding, airlines in the 60s actually ran faster. https://www.youtube.com/watch?v=CHw3nRjj5xc https://www.youtube.com/watch?v=CHw3nRjj5xc

Klathmon 8y ago

>Flying slower is actually a environmental win since aircraft are more efficient at slower speeds Do you have any more information on this? Obviously slower-speed turboprop planes are much more efficient than jet powered planes, but I've read in the past that flying a jet engine slower can actually increase fuel consumption and increase emissions.

sokoloff 8y ago
There is an efficiency curve for jet transports. There is a defined MRC (max range cruise, which varies by weight) and a calculated LRC (long range cruise, typically defined as 1% less fuel efficient [in kg/nm], which gives 99% of efficiency and about 104% of cruise speed vs MRC). Modern flight management systems have economy calculators that can predict not only fuel-at-destination figures, but can incorporate winds and other airline cost indices (crew, maint reserves, etc) to emit an "ECON" speed target. It is only speeds below the MRC that cause a decrease in (still-air) fuel efficiency. Airlines do not typically operate in that speed range in cruise absent an ATC directive to slow down to avoid holding ahead. (Obviously, flying a hold is done below MRC as well.)
aeroevan 8y ago
There are two optimal values for speed depending on the objective. There is a max endurance speed (for holding, etc.) and a max range speed, both are a function of altitude. So slowing down under those speeds will decrease efficiency, but typically the airline's cost index (~additional hourly cost to operate, like crew cost) will typically push the speeds higher to minimize the overall cost. http://www.eaa1000.av.org/technicl/perfspds/perfspds.htm http://www.eaa1000.av.org/technicl/perfspds/perfspds.htm is about the best thing I can google right now as a reference.

fyfy18 8y ago

> In fact the core premise of the article is clickbait I feel like basically all the BBC articles I've seen posted here recently are nothing more than clickbait. Does anyone else feel the same?

johnnycab 8y ago
They are no more clickbait-y compared to some articles from other red tops, which appear regularly in the Apple News feed, for example.
GordonS 8y ago
TBH it feels like all of BBC news has been turning tabloid for the past 5 years or so - many articles feel click- baity and sensationalist. It's not just written media either - I hear Radio 1 news sections from time to time in the car, and they are so basic and devoid of information it's like they're designed for young children.

oeuviz 8y ago

Additionally, airlines might choose a more economic route which might take longer but save fuel due to better weather conditions/jet stream.

jillesvangurp 8y ago

It's not just flying slower. If you've ever flown into London, you are probably familiar with the notion of a holding pattern. When things get busy at the airport, due to poor scheduling, it is quite common for planes to fly in circles for 10-20 minutes or even longer in some cases. Also, planes sitting on taxi lanes burning fuel with six planes in front of them is a common issue. Planes are assigned landing and take off slots and if they miss those, that's a problem. So, if the schedule is unrealistic, planes might be taking off "on time" knowing full well they'll be circling downtown London for some time.

robjan 8y ago
It's not poor scheduling, so much as Heathrow being at 99.5% capacity which means queuing is required so they can maintain one landing per minute.
- CydeWeys 8y ago
  Yeah, the airport is at capacity. I'm not seeing how it has anything to do with schedule padding at all. They're doing take-offs and landings there as quickly as possible.
  - jillesvangurp 8y ago
    Airlines know before they take off their ETA to the other side pretty much down to the minute. Their planning builds in padding so that they are guaranteed to make it on time. Which means they expect to arrive early and end up in a holding pattern because the take off slot and landing slot are deliberately misaligned. This is exactly what the article is implying. That's of course aside from the inevitable issues arising from operating at 99% capacity. Anyone familiar with queuing theory or logistics knows that this just means things pile up at the cost of delays and extra fuel being burnt. So, that too is poor planning. You never operate systems with queues at close to 100% capacity unless you are looking for severe cost overruns and bottlenecks. This poor planning results from misaligned incentives. Airports can just park planes in holding patterns for however long they desire. It's not their fuel being burnt. So they over provision knowing full well they will have planes in holding patterns throughout the day, This maximizes their revenue. So they are actively incentivized to do this. Likewise, airlines buy fuel cheaply and only get penalized for being late. So they are incentivized to implement padding. So, the fix is re-aligning the incentives for airports and airlines to minimize planes in holding patterns and fuel being burnt. There are several ways to do this but the bottom line would be making sure both airlines and airports aim to not have planes in holding patterns because that costs both of them something.

mikekchar 8y ago

> This is a surprisingly poor article from the BBC. It's not a staff writer. I always check these things once I started to realise that some of the biases I saw in news reporting were actually determined actions by a relatively small number of independent writers. Here's her bio on Forbes: https://www.forbes.com/sites/kathryncreedy/#4c0ca61271e2 https://www.forbes.com/sites/kathryncreedy/#4c0ca61271e2 (though she's an independent writer as far as I can tell). In my experience the BBC buys up a fair amount of stuff to just "fill up" the offering. Usually it's pretty poor quality. I don't actually have an opinion on this piece since I know nothing of the subject. I just want to encourage people to understand where their "news" comes from.

csours 8y ago

I agree. The first figure presented out of context is the difference in flight time from the 1960s to today. While some of that is certainly padding, airlines in the 60s actually ran faster. https://www.youtube.com/watch?v=CHw3nRjj5xc https://www.youtube.com/watch?v=CHw3nRjj5xc