Guest essay by Eric Worrall
Climate Scientists predict Global Warming will be bad for air travel – but their claims ignore human adaption.
Climate change means longer take-offs and fewer passengers per aeroplane – new study
February 14, 2020 2.23am AEDT
Guy Gratton Associate Professor of Aviation and the Environment, Cranfield University
Paul D Williams Professor of Atmospheric Science, University of Reading
…
As the local climates at airports around the world have changed in the past few decades, the conditions that pilots have relied on in order to take off safely have changed too. Our new research suggests that higher temperatures and weaker winds are making take-off more difficult. In the long run, this means that airlines are delivering fewer passengers and cargo for the same amount of fuel.
“Climate” essentially means the average weather conditions at any given place. Scientists know this is changing, but not uniformly. While global temperatures have risen by about 1°C on average, some places have warmed by much more already – and others may be getting cooler.
But climate change isn’t just about temperature – winds are slowing down and changing direction around the world too. This is a problem for airport runways that were built many years ago to align with the prevailing winds at the time.
Research has predicted that take-off distances will get longer as the climate warms. This is because higher temperatures reduce air density, which the wings and engines need to get airborne. With reduced headwinds, aeroplanes also need to generate more groundspeed just to get into the air. Once they’re up there, they’re subject to in-flight turbulence, which is getting worse due to climate change increasing the energy in jet stream winds.
…
That could mean that airlines must reduce the numbers of passengers they carry on flights, or search for ways to lengthen their runways. In some extreme cases, it could become impossible for some aeroplanes to use some airports altogether. This is another reminder of how rapidly and extensively human actions are transforming the world around us, and how ill equipped we are to deal with the consequences.
Read more: https://theconversation.com/climate-change-means-longer-take-offs-and-fewer-passengers-per-aeroplane-new-study-131613
The abstract of the author’s study;
The impacts of climate change on Greek airports
Guy Gratton, Anil Padhra, Spyridon Rapsomanikis, Paul D. Williams
First Online: 13 February 2020Time series of meteorological parameters at ten Greek airports since 1955 indicated the level of climate change in the Eastern Mediterranean area. Using this data, take-off performance was analysed for the DHC-8-400—a typical short range turboprop airliner, and the A320, a typical medium scale turbofan airliner. For airports with longer runways, a steady but unimportant increase in take-off distances was found. For airports with shorter runways, the results indicate a steady reduction in available payload. At the most extreme case, results show that for an Airbus A320, operating from the, relatively short, 1511m runway at Chios Airport, the required reduction in payload would be equivalent to 38 passengers with their luggage, or fuel for 700 nautical miles (1300 km) per flight, for the period between the A320’s entry to service in 1988 and 2017. These results indicate that for airports where aeroplane maximum take-off mass is a performance limited function of runway length, and where minimum temperatures have increased and/or mean headwind components decreased, climate change has already had a marked impact on the economic activity in the airline industry. Similar analyses could be usefully carried out for other runway-length–limited airports, which may often include island airports. It is also noted that previous research has only considered temperature effects, and not wind effects. Wind effects in this study are less significant than temperature, but nonetheless have an effect on both field performance noise and pollution nuisance around airports.
Read more: https://link.springer.com/article/10.1007%2Fs10584-019-02634-z
Why am I disputing the predictions of a professor of aviation?
For starters, the body of their study expresses a lot less certainty that anthropogenic climate change is responsible for the observed changes than is suggested by the press release. From body of the main study;
In Greece, in particular, the wind speed at 20 measurement sites at a height of 2 m has decreased over the period 1959–2001, consistent with our findings at airports. A possible explanation for these wind trends is that anthropogenic climate change is warming the poles faster than the tropics in the lower atmosphere, weakening the mid-latitude north-south temperature difference and consequently reducing the thermal wind at low altitudes (Lee et al. 2019). Another possible explanation is that anthropogenic climate change is expanding the Hadley cells, pushing the fast winds associated with the storm tracks towards the poles and away from the midlatitude regions. A final possible explanation is an increase in surface roughness, caused by an increase in vegetation or (in our case) development around the airports.
Read more: Same link as above
I have personal experience flying an aircraft. “Surface roughness” has a huge impact on low altitude wind speed. “Surface roughness” should have been their first theory, not wild speculation about Hadley Cells or reduced latitudinal temperature differences, especially given recent observational evidence that away from “surface roughness”, global windspeed is actually increasing.
Urban heat island from all that development might also explain much of the observed rise in temperature at the airports in the study.
What about the other points the professors make? Their calculation of the impact of wind speed and temperature on aircraft performance look reasonable, temperature and wind speed do have a significant effect on aircraft.
But the authors of the press release did not explain that their study ignores human adaption to changed circumstances.
If local warming at the airports and reduced wind speed does start to have a significant impact on the ability of aircraft to operate in some regions, aviation companies will not simply abandon profitable routes whose airfields which are causing them operational difficulties. Aircraft manufacturers will respond to new requirements by upgrading the aircraft; by modifying the engines to deliver more thrust on takeoff, or by adjusting aircraft wings to provide greater lift for difficult takeoffs.
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And yet aviation advances steadily, with shorter take offs and increased passengers. Funny how that works!
As the planet is not warming and likely actively cooling, take off distances are not an issue. Their point is that warmer air is thinner air. However, it is known that the atmosphere is contracting so much that the drag of the upper atmosphere on the International Space Station has been decreasing, which indicated a contracting and cooler atmosphere. This is another piece of propaganda based on the assumption that the average reader assumes that the climate is warming, which it is not.
The outer atmosphere is contracting because the sun is in the quite phase of this cycle. It has nothing to do with the temperature of the planet.
And simultaneously aviation related climate research goes backwards as desperate wannabee academics publish increasingly shallow and speculatice ‘research’ that is essentially a vehicle or the term ‘climate change’ and a general narrative that articulates the doom and gloom attributed thereto.
Woke world expands its frontiers.
Methinks the local development affecting surface ‘roughness’ and ‘heat island’ would be the primary drivers to consider regarding any material effect on aircraft take off performance. The latter seems to have a significant effect on the brains of certain academics causing memory loss in some instances and event full blown dementia in others not to mention delusions.
It’s time for another government grant. That new Porsche looks awfully good!
The pity is that practitioners of “Science!™” won’t be able to market their results to the People’s Liberation Army since the Chi-Comm spymasters won’t buy fictional studies.
Bugger! Those damn Chi-Comms.
Get woke, go broke. The only way woke-ism can continue is by stealing tax dollars.
In other words, become a Climate Science academic?
Or politician, both simply exist to lie and steal.
The answer is quite simple: Manufacturers need to develop aircraft that can flap their wings, for that added boost at takeoff….
aircraft wings are already flapped.
The latest iteration of aircraft carriers are using electro-magnetic catapults. We should expect that, maybe as soon as the next 10-20 years, these systems will begin to be used at commercial air fields.
A catapult on a carrier brings a fighter jet up to takeoff speed using only about 300 feet of runway. A jumbo jet, weighting roughly 7 times as much as a fighter jet, would have maybe 3000 feet of runway for the catapult and engines to get the plane up to takeoff speed. Plus, the electro-magnetic catapult would reduce the on board fuel needed during takeoff, saving money and increasing the paid payload capability.
Gibberish by idiots who know a little about aviation. What is that axiom? “A little knowledge is a dangerous thing”. Indeed.
I am a pilot and an essential element of pre-flight rigor – whether a Cessna 150 or a 747 is the weight and balance determination. Which factors in density altitude, wind speed and direction vs active runway heading, empty weight, fuel and passenger and baggage weight, and where the actual CG of the aircraft is. (or rather if the CG is first within the safe operating envelope, and second what it’s position dictates regards trims and critical speeds and flap settings etc) Maximum takeoff and landing weight, and most critical takeoff distance required at the anticipated flight conditions. V1, Vr and V2 etc….
This has been the norm for a long time. Reduced operational parameters are nothing knew to anyone who has “real” aviation knowledge. But pinheads like the authors of this study are either clueless or deliberately lying to scare people.
Aircraft already operate in a hugely wider envelope of atmospheric conditions than any minuscule “global warming” temperature increase would present. The argument is essentially “lies, damned lies and statistics”.
There are charts, calculators (used to be rotary slide rules, but now there are apps) for pilots of any [aircraft] type to render these essential determinations before takeoff – from way back when CO2 was 350 ppm or less.
As an example, I was on a charter with ~250 other idiots going to India back in 1977 – we were in Srinigar – and only 737’s could use the runway as it was some 5,200 feet ASL, and it is HOT there. (so we needed 2 flights to carry all of us back to Delhi)
As we boarded and awaited leaving the gate in Srinigar on a 737, it was 110 F at 09:00 and it was rising at 1 degree every 2 minutes. My fellow idiots were then complaining as cabin crew started removing passengers – a dozen in fact.
I commented to the whiners – shut up! As the reason for the removal was the plane could not fly with the weight at these high temps and thin air!
Sure enough the takeoff roll was scary as hell – to me anyway… The 737 did a short field run up (hold brakes and bring thrust to 100% before brake release) – and it lumbered along – and along and holy crap batman this is an Extremely long take off roll, I said to myself…. Then just as the plane rotated, the frigging runway end passed under us and plane dropped 50 feet at the cliff edge before it started gaining altitude!
This issue (take off distance vs wind, and density altitude) is part of normal operations and has been for as long as big planes have been around. (well the unprofessional Air India pilot’s behavior is not good – they cut it way too close on their calculations)
https://en.wikipedia.org/wiki/Density_altitude
My point is, this diatribe on takeoff distance is misinformed, or misleading to say the least.
D Boss
Good story!
The reason all long distance flights out of Johannesburg take off after sunset is rather obvious: it is Denver high and pretty darned warm on the runway.
There used to be a Montreal-Moscow Aeroflot direct flight that had to take off about 7:30 AM because after that it couldn’t get into the air, it was so loaded with fuel. And that is at sea level.
A contact of mine who flew short hops from Lubumbashi to Kolwezi said the standard safety limits meant the takeoff weight was less than half what was technically possible. As the Russian planes piloted by Ukrainians in the Congo fall out of the sky far too frequently, he was worried. He was asked to take mining drills and heavy items in the aisle – running about 150% above the safe takeoff payload. He complained because hanging in the props just after takeoff was very risky. One misfiring cylinder and the plane would fall. Simply ridiculous. They fired him and hired someone who wouldn’t complain.
My point is that any prof who thinks the safety margin is zero now needs his head read. If the temperature rises 2 C the effect on air viscosity is what, exactly?? Is he aware that the viscosity of air increases with temperature? Yeah, little subtle things like that are sometimes important when setting limits. The density goes down but the viscosity goes up. Did he know that or is the all-knowing prof factoring in everything relevant, like the great advances in wing design and power to thrust efficiency?
Colour me unimpressed. Flying is amazingly efficient and moreso all the time.
The most drastic changes from these things might be a reduction of 5% at most in the efficiency of takeoff. So only the most marginal of locations is going to be effected and that is simply until the Aircraft mature to be more efficient, as they always do.
As in most safety issues, there is usually a built in safety factor of at least 50%, usually 1 times to 2 times is normal.
Aircraft already do not take off from Johannesburg in the heat of the day.
That’s the other issue. A lot of airports are high and hot already. They have restrictions in the heat of the day on very hot days. It’s as easy to overcome as changing flight times to avoid the hottest part of the day.
The Concord did it’s “hot and high” trials at Johannesburg in 1976. And, as an aviation apprentice in the UK, I copied out altitude/temperature/runway length/takeoff weight tables from graphs. Aviation has ALWAYS had a ‘hot and high’ problem.
In CAGW land (all model-driven), the only thing that may be “warming alarmingly” is AVERAGE daily temperatures.
But airplanes don’t take off and land in AVERAGE conditions, they operate in ACTUAL temperatures, wind speeds, altitudes, and loads.
The ACTUAL data show that the only things warming slightly are overnight lows, winter temperatures, and locations surrounded by human construction and activity. The aviation industry has already adapted to all of those minor changes.
They might as well have written that butterflies will evolve larger wings to compensate for thinner air.
Sheesh – Stupid is as Stupid Does.
Unless I’m mistaken airlines and their pilots already know how to fly in and out of Qatar, Abu Dhabi, and all those other hot and humid annexes of Hell when it’s up to 130 Fahrenheit. Also, engineers know how to put larger and more efficient lifting surfaces on aircraft….so even if manmade global warming were happening, (and as an engineer I say it’s entirely unproven at best) it’s effects on aviation are easily overcome.
Slats and Flaps?!!!
Taking off from Joburg in a 747-400, the limitation was often the maximum tyre speed, not runway length.
The occasional problem exists is when locations experience a heat wave and did not account for it. It happened for a few days in the SW USA when loads had to be decreased.
Most aircraft have accounted for this after an aircraft (4 engine) crashed into a cabbage patch near Toronto in the 1950’s or 1960’s. I think it was determined that it lost lift due to density loss in the heat.
As far as “global warming” causing a problem – not likely. There is more seasonal variation in temperatures.
They have to add 6 inches to the length of a runway. So what?
Or just lower the fence and not worry about it!
Perhaps the study is a premonition of the future fictional electric airplanes. Presumably these will need runways longer than most motorways in the UK. Future Heathrow passengers will be sitting in their electric jumbos going round and round the M25 with their arms out of the windows flapping hard in the hope that a sudden gust of wind will finally enable them to take off after a day or so while viewing the vast numbers of abandoned and rusting electric cards along the hard shoulders.
@ur momisugly MCEA you daft bugger,
You owe me a new keyboard
Saveenergy
Sorry, but why?
I just find it increasingly impossible to take any of the eco conjured-up claims and hysterical drivel at face value or worth serious comment anymore.
MCEA
Probably spilt his coffee laughing at your funny comment. This assumes the M25 carpark is empty of course.
@ur momisugly MCEA
Yes, it was the mental picture you conjured up made me snort
saveenergy, aka…. Angry of Anglesey.
I imagine that an electric airplane with high torque motors would have a shorter runway. However, as batteries are low-density energy storage units, the plane would not fly, but rather progress in a leapfrog fashion with periods of rest and renewal. Think layovers with a Green blight distribution.
Amusing as your post is, in fact electric aircraft do not suffer from lack of power.
It is lack of duration.
It’s perfectly possible to flatten a lithium battery in less than 5 minutes to give massive peak power.
Vertical take-off is no problem.
It is flying to London afterwards that is the problem
Much like the cars, fun to dice with a lecky car. Then I drove home and he had to go recharge…..
Did a back of an envelope calculation for electric aircraft .
A 737 is a lot more fuel efficient than earlier types , but uses an average of 750 gals an hour for a transatlantic flight & will carry fuel for 10 hrs .
7500 gals equals about 300,000 KWh of energy .
Ignoring the fact that it would have to be propeller of fan , & therefore a lot less efficient than jet , an electric aircraft would need 3000 100 KW batteries which weight over half a ton each .
So can anybody help with the calculation on how long a runway would be needed when there is 1500 tons of batteries on board
I guess extending the runways is completely out of the question. N’est-ce pas?
Of course they could adapt passenger aircraft to VTOL
Good for my golf game, however.
There’s your headline. Global warming lowering golf scores.
“…A final possible explanation is an increase in surface roughness, caused by an increase in vegetation or (in our case) development around the airports…”
So development and the lack of development cause the same issue. All bases are covered.
“…With reduced headwinds, aeroplanes also need to generate more groundspeed just to get into the air. Once they’re up there, they’re subject to in-flight turbulence, which is getting worse due to climate change increasing the energy in jet stream winds…”
Reduced winds and increased winds. All bases are covered.
Cooling… warming… change. Undeniable. Unfalsifiable.
Jet streams – another false claim.
If the poles are warming the jet stream will decrease. However some Brits wrote a model speculation a few years ago claiming the jets will increase and cause more turbulence. So the media ate it up as usual.
Question about slower headwinds extending takeoff distance – Aren’t runways designed with the worst case scenario in mind – no wind at all? Any headwind would would cancel out a slight increase in temperature.
Note that the DHC-8 and A320 were both introduced in 1984, and that the -400 version of the dash 8 was brought out in the 1990s. The meterological data was selected from 1955 for one region. Not mentioned were the many and various business, economic, technological, and social-political factors that changed over the same periods (either 36 or 65 years, depending on which baseline is used). At minimum, such a study should at least also normalize for passenger air/distance, payload air/distance, and costs of fuel before development of an hypothesis for future research. A simpler explanation could easily be established by review of the need to carry less fuel, the means of expanding aircraft life and maintenance cycles, the increase in cargo transport, and the improvements in weather prediction and communications. In this case, it is difficult for me to imagine how the conclusion was not determined before the data was gathered. Beyond the idea of cherry-picking, this study seems to be yet another justification for an update of the GIGO law for Green ideologues: Climate change in -> climate change out.
It’s all good, AOC is canceling all forms of transportation anyway in her Green New Dumb.
Modern aircraft have better flight controls, better engines, and are more efficient. I can’t imagine that the next generation same-size aircraft are going to have ANY trouble taking off from existing runways – likely able to carry heavier cargo at the same time.
And since when were the Greenies claiming that Global Warming causes less wind? How does this tie into their narrative of all storms, tornadoes, hurricanes and cyclones are becoming worse?
The windmills ate up all their wind…
And their minds.
Robert, it will get so hot that rain will become drier. Oh sure, flooding will increase, but they will be drier floods.
More storms, tornadoes, hurricanes and cyclones, and worse still air.
More of everything worse and less of everything else.
Local, perhaps regional, transitory (“weather”) effects.
“. . . weaker winds are making take-off more difficult”
I wonder if the author has taken off or landed in a gusty crosswind? Most would welcome weaker winds. A 1C temp increase would be equivalent to adding about 500 feet to the airport elevation. Each new aircraft seems to be more powerful, lighter (graphite composite), and more fuel efficient.
Here are some big jets landing at Heathrow on February 9th. These pilots could definitely use weaker winds.
https://youtu.be/Ubb–kauZE8
Not so. Global Whamming theory teaches that the winds will be weaker unless they are stronger. That too, however, is an effect of Aggravated Klimate Change propaganda.
“A 1C temp increase would be equivalent to adding about 500 feet to the airport elevation.”
I took another look and used the ideal gas law to calculate the air density change resulting from a 1C temp increase. The 1C temp increase at sea level, 1 atm, and 273 K would be equivalent to adding about 30m or <100ft to the airport elevation. Pretty insignificant. You are welcome to check my math.
An Airbus A320 couldn’t come even close to legally or safely operating on a 1300 meter runway. (LGHI airport in Greece). A320 balanced field length is about 2100 meters. It’s somewhat silly to talk about future limitations on something not done currently. A professor of aviation? Good grief.
Ongoing increases in aircraft power to weight ratios are far exceeding even the worst of the alarmist projections.
Not quite a professor of aviation. “Associate Professor of Aviation and the Environment” So, almost guaranteed, incapable of actually designing an aircraft.
A bit OT I know, but in his autobiography ( A hostage to fortune ? ) Ernest K Gann describes his time flying “The Hump” from India in a DC3, and the problems of having to take off in the early morning before the air became warmer and thinner. He also describes how he almost wrote off the Taj Mahal. Well worth readibg if you can find a copy.
…. reading …
Stupid computer still can’t spell.
We knew whatcha meant.
I think you are referring to “Fate is the Hunter”. Still easily available. A must read for any budding pilot.
Somewhere in my old VHS collection is one entitled “The Last African Flying Boat” – documentary about one man’s attempt to recreate the Imperial Airways route from the UK to Africa. He was using a PBY Catalina which was, admittedly, not in the best of condition. After landing on a lake at some 5000ft altitude they then had considerable difficulty getting out. Numerous take-off runs during the heat of the day failed to gain sufficient speed, and eventually they gave up, waiting till dawn the next day. Even then, and having left all the passengers behind, the old girl only just made it into the air.
My own experiences of operating an ultralight aren’t quite so bad, but I do remember the difference in rate of climb: On a hot, muggy summers afternoon I used to get 600ft per minute, but on a crisp winters morning this could be nearly 900ft per minute.
Given the Prof seems unaware of the invention of the Turbine Engine, and the massive increase in power they offer over IC aero engines, students studying under him have my commiserations. 🙂
More seriously, is there any subject that cannot claim to be negatively affected by CC ? Apart from Climate Studies, obviously. 🙂
“Is there any subject that cannot claim to be negatively affected by climate change?”
I was going to say Betelgeuse goes supernova, but I now realize it too will be blamed on climate change.
I’ve been flying for over 40 years. Density altitude is what you have to know to figure out your aircraft performance on takeoff. It is the altitude the aircraft actually feels as to compared to the altitude it feels on a normal day (standard pressure and temperature). For a non turbocharged aircraft (like a Cessna 172) typically the takeoff roll goes up about 25% for every 1000′ of altitude due to less engine power and lower propeller efficiency. Piston aircraft with turbochargers don’t lose the engine power so much so they have less of a performance loss. Jets and turboprops also are less effected than the little old Cessnas.
All aircraft have charts in their operating handbooks that give take off rolls based on weight, density altitude and runway conditions. Airports like Salt Lake City and Phoenix have extra long runways to compensate for their base altitudes and the density altitudes of very hot days. Phoenix actually shuts down when the temperature reaches a certain threshold. But today’s aircraft engines are very powerful and the aircraft they go on typically don’t have an issue with density altitude.
I can only remember two times I had to wait on the temperature to drop to depart, and even then I was legal to depart but didn’t want to chance an engine failure at marginal conditions. I really find it hard to believe aircraft will have to restrict operations on what is stated in the article. I wonder if any of the authors even looked at how much margin is built into the aircraft. I can remember leaving SLC on a fully loaded L-1011 in July on a really hot day and getting out. (The L-1011 was notoriously underpowered compared to today’s aircraft). It took all 12,000′ and we circled the airport 3 times to get enough altitude to clear Park City to head east, but if we made it with the L-1011, today’s aircraft will easily make it.
In the past, if there was a commercial advantage, the authorities would just extend the runway. I can’t see that reasoning changing, unless there are planning consideration (aren’t there always of course).
I think the only time I have had to wait for the temperature to drop, was due to brake temperatures which were over the limit, due to the couple of short hops we did in Africa. That was a DC10. From a performance point of view the worst occasions I have come across are when there was snow & icing conditions. That really knocks the performance.
At our local airport there is a move afoot to ensure aircraft take off and land in each direction 50% of the time, to share the noise around, despite the fact that the prevailing wind is westerly. Taking off in a tailwind has a tendency to reduce performance!
With that sort of thinking who needs global warming.
Well, according to the article, winds are slowing down and changing direction, so you have that going for you!
My suggestion is putting some the more vocal proponents of the asinine suggestion in your right seat on a very windy day, taxi out to the runway with the tailwind and tell them there is a 30-70 chance you will get off the ground before the end of the runway due to the tailwind so buckle up tight.
Splendid Idea.
“The L-1011 was notoriously underpowered compared to today’s aircraft”
But probably still better than the B707:
https://www.youtube.com/watch?v=_RKa0_Qr1s4
And this (now legendary) clip from DownUnder: “The Vodka Burner is Rolling”
From the article: “Once they’re up there, they’re subject to in-flight turbulence, which is getting worse due to climate change increasing the energy in jet stream winds.”
Well, there’s no evidence for this. These scientists just pulled this claim out of thin air.
Turbulence in jet streams is mainly due to the shear caused by the rapid change of windspeed within the core of the jet. Generally, if it was severe, we would just change altitude by 2000 ft or so. Negotiating a change of altitude mid Atlantic could be a slow process though, especially when the only method of communication was HF radio!
Correct.
Is that why on feb. 8 a flight New York – London finished after 4:56 h instead of somewhat over 6 hs ?
Not a problem for DIA or Aspen even on hot days
Bees are also subjected to reduced air densities.
Honey production may also slow if bees are subjected to reduced air densities. It would then be blindingly clear that therefore the added ‘in-flight turbulence’ would also contribute to slowing honey production.
From the article……”Research has predicted that take-off distances will get longer as the climate warms. This is because higher temperatures reduce air density, which the wings and engines need to get airborne. With reduced headwinds, aeroplanes also need to generate more groundspeed just to get into the air. Once they’re up there, they’re subject to in-flight turbulence, which is getting worse due to climate change increasing the energy in jet stream winds.”
If you are from Alabama you could face more cuts than just your air miles.
(2x palmface)
Penny pinching and noise abatement keep us on ground further than climate few degrees shift ever could for whatever ground temperatures accuracy means to airports. Which in practice for summer operations resumes punching 25C for the southbound and 30C for the northbound legs while trying to figure how understated the “cabin weight” will be.
A piece of cake when compared to winter icing voodoo algebra.
Earlier companies school was to get up like homesick angels. Never mind old Capt’s grunting, evil fuel flows and EGT’s, quicker up, quicker in thin air savings, faster at destination, more speed, more prestige, more better.
Then the word was to keep noise down and guess, less revs mean less noise as long as there’s runway to spare.
Some noise abatement gurus even tried to outlaw flaps but I guess were quickly brought to more appropriate for their mental state medications.
High and higher bypass super fuel saving turbofans brought asymmetric take-off thrust anxiety to new levels.
Finally alien civilizations were hired to establish flight crew operating manuals and implement the corresponding algorithms in the thrust management computers.
Surprise, take-off’s turned longer when all was taken into account, fuel saving, noise abatment, engine and airframe wear and tear, safety and somewhere deep sown the list, passenger comfort.
Which is BTW what old grumpy steam-gauges Capts (with a capital “C” please) used to yell, as long as there’s runway, use it !
So yes, globally we take our time at take-off and our distances have comparatively increased with respect to the golden age.
However this has nothing to do with global warming, so, for cryin out loud Mr. Professor, mind your own business, whatever this might be and stay clear from serious topics.
Funny, but so true!
After reading the article I thought: What have the professors been smoking.
I remember a flight with a 747 from Copenhagen to New York, where the captain said we were a bit late. I have flown a few times with 747, but this time it felt like he was only using a few hundred meter of the runway. I must note that it were some decades ago.
So from above mentioned acceleration, I assume the professors were fantasizing.
For confirmation I searched the page for Flight Level and got my suspicion confirmed.
I think it is tragic that CC politics and Green money spinning has sunken to a level where professors writes stories so stupid and ignorant, that it could have been a dictate from a Swedish teen.
CFH, reputable companies would (should ?) consider the cost of missed connections with respect to extra fuel and according to the weather (not climate !) mood and “uh-uh” fuel reserve of the day, dictate us to punch a higher cost index.
Which, because in such case, cost of time massively prevails cost of fuel, results in guzzling take-off, gunned initial then slower climb and overall a greater average ground speed profile.
Affordable mass travel is a very complex system of equations, far above the comprehension altitude of politicians and wannabe green economy experts, let alone indoctrinated brainwashed voters.
How do new reactor designs make the asymmetric power risk more serious?
NiceGuy, officially, on all jet engines, particularly on high bypass burners, the acceleration profile is not linear. Control law is defined to optimize the acceleration in a way that the risk of engine stall is reduced.
The more airfoils become fuel-optimal, the less tolerant they are to stall. Compressor & hot section blades inclusive. Mixed with unavoidable tolerance discrepancies and wear & tear, thrust management becomes quite a deal.
Specifically when only 2 engines with huge rotational inertia are in charge of the operation.
Single engine taxiing, late starts, cross-gusts add their cumulative effects to the mix.
Once well primed, veering oscillations on acceleration roll will increase unless split second take-off reject.
It feels like if you’re gunning a Winnebago uphill on an iced road.
Maybe a good idea anyhow to reduce the seating. Would give everyone a little extra room. And this shows there are benefits to climate change
Winds slowing, yet……….
https://www.bbc.co.uk/news/uk-england-london-51433720
Not to worry, the UK will get more and more of its energy needs from the wind. Wonder what the overall engineering assumptions are for wind turbines? Declining? Sure hope those don’t contradict the cited aviation study.
Salute!
Thanks, rbabcock.
Many posts by many with little actual knowledge of the problem, much less experience. But I can forgive a certain amount of ignorance.
With about 4,000 hours of fighter time that included several hundred operating at max gross weight and in a hot, humid climate to go blow up things and hurt people, I feel qualified in this matter and agree with rbabcock. A few degrees is like a thousand feet of altitude, and the turbine engines feel it as much as the motors with propellors, maybe a bit more.
While the alarmists have a sliver of real science and engineering to support their conclusions/findings, or whatnot, it is like the model predictions they disagree with – all the emission reduction possible might only lower temp by a fraction of one steenkeeng degree, and result in 8 inches of seal level rise in 100 years or longer from now. Our roll might be another few hundred feet, maybe a thousand feet longer at higher temperatures, so big deal.
Make no mistake, however, about the proven facts and performance of aircraft and engines. Density altitude and gross weight are huge players for we pilots trying to get off the ground in the available runway. And basic weight still obeys one of Newton’s laws concerning foce and mass and acceleration. That means you better check the charts at high altitude, high temperature with a very heavy plane.
Gums sends….
Assumption here,
If the Prof is waving the scare flag in relation to Civil Aviation, then over the time frame of change (not 12 years), aircraft designs would evolve to have larger wing area or diminished carrying capacity, or even bigger engines ? Its not inconceivable that the time could come when the A380 is shown to have been ahead of its time, rather than being a disappointing speculation.
Airport expansion is something of a hot topic here in the UK at this time, so whilst the facts concerning air density and lift potential are very real, I’d have to think that the Prof is trying to get on the bandwagon that portrays peasants houses being demolished to extend runways and thus pander to those who are supposedly destroying Mother Gaia.
As ever the advice regarding Bandwagons applies, to wit, once you can see it, its too late to jump on. 🙂
Was the goal to hurt some people, blow up their things, or to defend other people, and conserve their things?
All of the above.
Density altitude problems were a part of basic flight instruction when I took it in the Sixties .
Density altutude is just one of msny factors that have to be kept in mind when flying. It is hardly a novel issue. You adjust to changing conditions. If you land a light plane at a short, high altitude airport on a day that gets hot you are wise to wait for late afternoon cooling before trying to take off. Been true forever.
Meanwhile, places like Phoenix and Tucson fly regularly with temperaturrs well over 100 degrees though at aroud 120 they check their air density tables more carefully I suspect.
As a young troop, US Army, I was taught methods and necessity for gauging atmospheric conditions for calling in helicopters for resupply, extractions, insertions, dustoffs and close air support. Almost as if these sorts of conditions and issues were already well known to the aviation industry and those who utilize its components! Guess the schmucks pushing this “study” could use some remedial training under the harsh and unrelenting direction of some senior NCOs.
Gums, “Many posts by many with little actual knowledge of the problem, much less experience.”
You assume world population doesn’t consist solely of Airline- and Bush Pilots.
There still must be Resistance Nests of pedestrians.