Planes are actually surprisingly fuel efficient. The short haul flights in Europe are often served by Airbus A320 or A321 Neo, with fuel consumption per seat at 2.19 L/100 km. A mid-sized petrol-powered car consumes three times as much. And that figure ignores that planes take a straight route - taking that into account, the emissions are close to a single-occupant electric car
> A mid-sized petrol-powered car consumes three times as much.
Average ICE bus consumes order of magnitude less per seat than planes. The only reason planes win vs cars is that cars aren't public transport and planes are. So you divide by many more seats.
You know, I've actually done a few multi day trips by bus, around Croatia and its many places to visit (all the way from Plitvička Jezera to Baska, Krk and Vrbnik, then over to Venice), as well as Egypt (Hurghada to Luxor and later to Cairo). Oh and also a bit around Norway (though i only have Flåm tagged on my map, don't remember the route).
I would say that longer trips by bus are not as unpleasant as you might suggest - as long as you don't attempt to do them in one go, but rather make stops along the way and get some fresh air, walk around and stretch, get something to eat, or maybe do some shopping if needed.
There's probably something to be said about travelling more slowly and enjoying the locales along the way and maybe using motels for the longer trips, as opposed to viewing travel as purely getting from point A to point B as fast as possible. Of course, to be honest, that might not always be possible either in our fast paced culture.
Now, there can be certain drawbacks in practice:
- certain places will only have old buses, so no Wi-Fi
- for some reason many buses don't have USB outlets for charging
- many buses also disallow you to recline your seat, what's up with that?
- some of the older buses also have pretty poor AC, then again, the weather in Egypt was pretty hot to begin with
- for some reason the head rests are always smaller when compared to those in planes, making sleeping less comfortable
- some of the drivers really love to drive in ways that appear unsafe to the passenger (perhaps due to the long wheelbase and suspension)
- this feels especially uncomfortable mountainous roads
In short, try to take the newer buses whenever that's possible but otherwise just hope that the old ones will get replaced eventually.
Though personally I'd still say that trains feel like the safest mode of travel, followed by buses and then planes feeling the least safe of all, regardless of what engineering excellence goes into making them. That's enough to sway my personal choice.
And if that's somehow better for the environment, then why not? Plus, the food in roadside eateries seems better than airplane food.
No need to use bus amenities outside of emergencies, just go to them at your nearest rest stop, far more comfortable than any plane!
> Is the seat same size as Ryanair?
I'd say that depends on the bus - many of the older ones or cheaper ones can be cramped, but most are fine. Plus, the chances of having two seats to yourself are higher.
Where planes are better: premium seating options, akin to getting a ride in a car.
> Vibration so bad that $500 noise cancelling headphones don't cope?
That's never been an issue for me headphones or no headphones. Depending on the roads, motion sickness could be a bigger problem for some folks, especially depending on the suspension, much like how some folks also get sick in planes.
I'd say that good buses or trains are amongst the most comfortable in regards to vibrations, followed by planes like Airbus cruising in clear skies, followed by most other buses. Whereas most planes would be less comfortable than those during takeoff, landing, climbing, or whenever there's turbulence or the planes are just older. Older trains would also take one of the latter positions, but they're probably not as bad as planes that are gaining altitude.
Actually, should probably mention boats while we're at it, those can be better in regards to sleeping, but otherwise the experience varies based on the conditions in the sea and size. Of course, the environmental impact is debatable, especially cruise ships.
> Try taking 1000km trip on a diesel bus once and tell me if that metric matters to anyone.
I did some such trips. Never bothered asking if it was diesel or petrol but whatever. Don't see much difference from a car (in fact it's more convenient than a car cause there's more space).
I'm using electric buses every week but they are driving inside my city, never seen them used between cities nevermind countries - it wouldn't make sense cause of small range. Also inside they were exactly the same as normal buses so I don't understand what you wanted to say.
> I’m tall so I prefer to be squeezed for 1 hour instead of 14 hours.
Add 2 hours of standing in queues without your shoes, but yes, planes are faster. I was talking bus vs car though.
> fuel consumption per seat at 2.19 L/100 km. A mid-sized petrol-powered car consumes three times as much.
It seems like you are comparing fuel per seat for planes with fuel per vehicle for cars. At five seats, that would be equivalent to 11 l/100km, which almost all modern cars should beat. Even if you only count four seats for the car, it would still be 8.8 l/100km, which many cars can beat.
If you want to compare a large passenger plane to a land based vehicle you should pick a train. Both the train and the plane can only go certain routes and are mass transit vehicles.
I agree, we should switch to trains where feasible. I'd like to see more long-haul trains set up with affordable sleeper cars. But most land transportation over long distance is still by car.
At a slowing speed and typically at near-idle thrust. The aircraft exchanges gravitational potential energy for velocity through most of the descent.
The only high-trust portions are when reverse thrusters are engaged, typically for a few seconds following landing, or if TOGO power is invoked for an aborted approach.
Which is effectively level flight / continued cruise, a low-power flight segment, not a high-powered one. That last would only apply if the aircraft had aborted an approach, which typically gives priority.
Again: the original claim was that both take-off and landing were high-fuel-consumption flight segments. That's untrue. Under normal conditions only take-off is, and even most deviations from a nominal approach have a fairly minor impact.
You're going to extreme lengths to avoid admitting this, and are making the issue personal to boot. Any particular reason for that?
> 1.1.4.6 With the need to ensure that CDO does not compromise safety and capacity, it may not always be possible to fly fully optimized CDO. As well, it may be necessary to stop a descent and maintain level flight for separation or
sequencing purposes. The aim should be, though, to maximize CDO to the extent possible, whilst not adversely affecting safety and/or capacity.
Obviously level flight near sea level is less fuel efficient than at cruising altitude.
Likewise, descending into a significant headwind, or avoiding adverse weather will require more fuel than the optimal.
I'm not saying that a continuous descent is actually guzzling gas like crazy. There's very many smart people that have been optimising fuel usage in planes for decades.
I just want to emphasise that while the ideal descent is very fuel efficient, not every descent is ideal.
And of course, it varies significantly based on the plane.
This paper shows that interestingly, some A330 models used equivalent, or even more, fuel on approach than takeoff. Although I speculate that's more due to very efficient takeoffs rather than inefficient approaches.
I'm trying to correct the implied claim repeated in this thread that the ideal descent can be used to model every descent.
Oddly enough, nobody asked that question.
I'm not saying that a continuous descent is actually guzzling gas like crazy.
Well, at least you're admitting as much.
For a trip segment, takeoff and climbout are the initial high-fuel-flow phase. Note that LTO (landing and take-off) data are based on flight segments at and below 3,000 ft. AGL, which is 1/10 or less of cruise height of FL30 -- FL40. See Fig. 1 of your reference. The LTO data (limiting climbout / descent phases to <= 3000ft) are relevant to local emissions concerns near airports, the focus of the paper, but not to total fuel / emissions of an entire aircraft flight profile as we're discussing here, and omit 90%+ of the relevant climb/descent characteristics. As discussed in the paper.
Figure 2. also provides a strong clue as to why the LTO data show lower total fuel use in the approach vs. climbout phases, again, <=3000 ft: the aircraft monitored are spending 2-5x longer in the approach phase. That is, they're climbing out steeply, with very high fuel-flow rates, whilst they're descending slowly (and hence, spending more total time <=3000 ft) at a much lower fuel-flow rate.
Again: you're wrong, given your own cited reference.
The slowing isn't using gas - its not like they put the plane in reverse to slow it down. They're descending and trading potential energy for energy to maneuver at low altitudes. The thrust is near idle.
True, but not every approach to an airport is a nice constant vector.
Continuous descent operations are the optimal, but there's plenty of suboptimal airport approaches that require level flight at a height where fuel efficiency is far less than at cruising altitude.
Do you have any statistics to say it happens so often that airplane landings are so suboptimal that they use anywhere near climbing fuel rates and times that it matters to the overall discussion? It seems unlikely to me.
The thing is that the chemical effects involved at the altitude airline planes fly is way more greenhouse impactful that the same consumption for a car, so you can’t compare that way. Also, trains are way better than this. French trains drive you around on nuclear energy.
But that increased impact is a short term difference, right? The changes to air composition we cause by digging up in a few decades what had been sequestered off in millions of years are forever changes.
Good questions, I don’t know enough details. CO2 stays in the air for a long time, but not forever either. For sure though, it’s absorbed way too slowly than what we’re outputting now.
I think they mean the emissions from generating all that electricity, which isn't always clean. You'll get a lot of hydro and renewables in some countries at some times but then also coal and gas at other times.
Kerosene must be taxed because it emits a lot of CO2 per flight.