March 3, 2023, ©. Leeham News: We started a series last week that will look at what environmental and air traffic economy improvements we can get with traditional aeronautical technology developments.
Before we look at technology, we must define what air transport market has the highest impact from changes. Useful technology developments are not necessarily the same for Regional, Narrowbody, or Widebody aircraft.
When analyzing what new technology can bring in fuel consumption reduction, and thus Green-House-Gas (GHG) reduction, we must understand what market and type of aircraft brings the best return from investments.
In Figure 1, we look at the situation in 2019. How many flights were done at different range buckets, and what aircraft types flew these? The data is Available-Seat-Kilometers, ASK, i.e., how many flight seats were flying a specific range interval during a year.
We use the data from the well-respected JADC (Japan Aircraft Development Corporation) market surveys. We like to use these as they are of high quality and unaffiliated with any aircraft OEM. The OEMs also do and publicize this type of market research, but if independent research is available, we prefer it over OEM data.
We see that narrowbody ASK in the 1,000 to 2,000km (550 to 1100nm) range is up to six times higher in ASK than wideboy buckets where the distribution is around 200bn ASK from 6,000km and up to 10,000km (3,200 to 5,400nm).
We also see that regional and turboprop traffic is virtually nowhere regarding ASKs compared with the other types.
This is a yearly glimpse just before the Pandemic. How does it look going forward?
Figure 2 shows the expected new deliveries of different aircraft types during the next 20 years, from 2022 to 2041.
The dominant sector is Narrowbodies 171 to 230 seats, i.e., the market where Airbus A321 and Boeing MAX 10 represent the major share. The Narrowbodies deliveries outnumber the Wideboy deliveries by 3.5 times in this period.
Though Widebodies have more seats, their seating is not proportional to the aircraft’s increased size. The Widebody long-range seating takes more space, so fewer passengers are housed per square foot or meter in the plane. The differences are significant.
A typical A321neo that flies up to six-hour flights has around 200 seats for new deliveries. The Boeing 787-9 or Airbus A330-900 have about 290 seats, an increase of 45%. But should we equip these with the typical domestic seating of the A321/MAX 10, they would have 350 seats or 175% more.
We will focus our technology discussions on the segment described as Narrowbodies, and there, aircraft with 170 seats and up. It’s where technology changes will bring the most, both in term of GHG reductions and improvement in operating costs and, therefore, airfares. It doesn’t mean we will not look at twin-aisle aircraft for this segment. Is a single-aisle plane still the best choice when we pass 200 seats or is a small Widebody then a better plane? We will see.
Would be nice to see the difference like SWA changes from a full 737-700 to a full 737MAX8 for their route mix how it changes the CO2/pax or for fully seated AA A319-100 to a A321neo. For freighters a FedEx 757F to an A321F
With the data in Fig 1 you can see an opportunity for a huge fuel saving, namely banning narrowbody jets on short routes that could be served by turbo-props.
This couldn’t be done overnight, but an agreement to restrict routes of less than say 500 Km to turbo-prop aircraft (or eHybrids thereof, if any come about) in five years time would give sufficient notice to operators and OEMS, and the distance could be increased in increments at later dates.
A significant and effective near term measure using low risk existing technology but requiring a good dose of short-supply political will.
mandating a specific technology (turboprops) is a bad solution. it just begs for the lowest common denominator solution and provides an artificial and unrelated constraint which actually prevents innovation.
it is like saying “all cars within city limits must have 4 cylinder engines”.. that does not in any way guarantee lower emissions, greater efficiency or anything. it just guarantees companies will make 4 cylinder engines capable of powering behemoth pickup trucks.
it also does not account for flights that require more capacity than existing or planned turboprops can support.
mandating an efficiency standard is the appropriate way to go (as in X kg CO2 per ASK on routes under Y km (emissions), or X km/l per ASK (fuel))
Turbo-props are inherently more efficient than jets at lower speeds and short ranges. Wording a requirement differently won’t change that. The point is you need to move pax from jets to turbo-props where you can, and so reduce fuel consumption. Five years is enough time for airlines to order turbo-props and longer is needed to build bigger turboprops. This is a policy of engineering the market (dirigism) and not leaving it to the market to find the best solution, to be sure, but markets don’t always find the best solution for the environment, they find the best solution for the market and the current biggest stakeholders.
An alternative example is to ban all air routes that are served by existing train services, as is done in France. Is that a bad solution? No, it makes a difference at once.
For a great many more instances where train services are not available, substituting turbo-props for jets would achieve the desired results. At once.
today’s turboprops are no where near as efficient as they could be. the engine designs all predate 3d aero, 3d printing, high efficiency low emission combustors etc. they may be more fuel efficient than an RJ per ASK, but they may not be “cleaner” in terms of pollution per ASK.
the way to go is to mandate efficiency and environmental metrics per ASK and make them stricter on a predictable schedule. that way we get better turbofans _and_ better turboprops. not just more of today’s antiquated turboprops.
GE has come out with a brand new turboprop, the Catalyst, in the most popular thrust range. They have all the buzz words you mention Do you think say Pratt will doing nothing to equal their gains ?
I note they still use a centrifugal compressor
I dont think your claims about ASK add up
“Our standard figure for fuel consumption is 2.8l per seat per 100km. ” says ATR
Only the low cost carriers with all economy class and very high load factors can equal that
The Alaska/US West Coast airline Horizon is a case study of moving away from turboprops to jets
‘Fuel burn per revenue passenger mile for Alaska’s affiliates increased by 11%, and fuel burn per departure increased by 35% from 2016 to 2018.”
Even better if the manufacturers move ( back) into the 100+ seater TP market they left in the 1960s
Turboprop has some disadvantages in cost of operation as you have an expensvive chain of components: prop, power gbx, prop control and accessories like prop anti-ice, gas turbine and noice cancelling equipment. A gas tubine flying at higher speeds and altitudes use intake ramm pressure and less rough air better. The UDF can use the benefit of both if done right. The Q400 is no wonder of reliability hence the CRJ900 is better and Canadair did not have money to do a -600 of the DHC DASH-8-Q400. Today one could design a fly by wire 125-150 seat turboprop with 0nly 63% fuel/seat of an ATR72 with a fuselage taking LD3’s. Still airlines like their jets and it would be FedEx buying it to save money. Then maybe Allegiant and Breeze to beat SWA on set mile cost on short routes and feed its stock owners.
A tu ally the best and most economically efficient way to do this would be a tax on either carbon or jet fuel. Doing emissions per ASM is just going to make everyone buy more MAX10/321. Taxing the inputs will unlock all options possible
Thanks for those good links. Pretty cool what GE is doing, P&W has had the lock on the market forever with awesome PT6.
Claes , the TP gearbox and propeller are very low maintenance items, both types have accessory gearboxes. Geared turbofans indroduce a
fan gearbox as well which some smaller TF have long included.
The GT part like that of jets is also fairly low maintenance but pretty steep cost/time when it comes to major overhaul. The jets also have the large ‘fan’ which TP dont have – the propeller plays that part- and of course much much more rows of compressor and turbine blades
@Duke. The prop system maintenance cost of spinner, prop assy and bearing, anti-ice, beta tubes, hub-actuator and backplate, feather pump, pitch control unit and overspeed governor, brush blocks, prop electronic control and time monitoring unit all adds up. The variable pitch is the main difference to a geared turbojet. If all of this stays on wing for 30 000hrs it is no problem. The simpler turbofan still holds on with present fuel prices, the turboprops are now slowly increasing blade count to 8 to gain more efficiency. We will see if the UDF will supersede both commercial turbofans and tuboprops. Embraer threw in the towel on its turboprop version of the ERJ’s mainly because of engines price and guaranteed maintenance costs were not competitive right now.
Wideboys? Do me a favour!
Of relevance is also the frequency of flights as well as daily flying time which was quoted for a Wideboy (love it) but not the single aisles.
For the same time of flight a single aisle will do 2-3 times the departures and it will be used 10-15 hours a day (tough one due to all the various types of ops flown around the world.
So there are more narrowbody flights, flying more passengers, more miles. But this doesn’t then mean that that they cause the most GHG emissions. When you look at other research its actually the widebody sector that has most emissions because you need to burn more fuel to cover the greater distances involved (burn extra fuel to enable you to carry the extra fuel).
Its the widebody sector that can see most improvement from new tech, both on total GHG emissions, and airfares (because fuel is a bigger % of widebody DOC)
At the same time we’re likely to see more near term impact on the narrowbody sector because of reduced capital costs for R&D and fleet replacement…
I would need to see that data as Widebody spends a lot more time at cruise and single aisle are going up and down more often which is done at max or higher thrust levels.
When forced to by cost , Europe has significantly reduced its domestic use of fossil fuels and in particular gas.Electric cars have just become huge and so have negated any reduction in damage to the planet because the tax system only rewarded the fact that they were battery powered.
Only the market can sort out the airline industries CO2 emissions, and it can do it remarkably quickly if the correct tax structure is put in place.
„A typical A321neo that flies up to six-hour flights has around 200 seats for new deliveries. The Boeing 787-9 or Airbus A330-900 have about 290 seats, an increase of 45%. But should we equip these with the typical domestic seating of the A321/MAX 10, they would have 350 seats or 175% more.“
That should read 75% iso 175%. Still a significant difference.
Thats for long haul too.
ANA in Japan has B777-300s with almost 500 seats for domestic flights.
That is an unusual market of pretty dense population on 4 or 5 main Islands making up a single nation.
The JCDA forecast seems a bit misleading to me. Only jets are taken into account. However, for modules smaller than 100-120 seats, it is reasonable to think that hybrid solutions (ATR Evo) or hydrogen (Universal hydrogen) using propellers will be available before 2040. How are these new developments taken into account in the JADC “jet” forecasts?
2.8 l/Seat per 100 km can be lowered with a New engine type but engine manufacturer want to keep their economical profit mode through high overhaul cosy. As long as GE/PW/RR ” oligopol” will remain it will difficult to change the current situation where PW has the leadership.
I remember having great discussions on this topic with Jim Krebs. https://leehamnews.com/2016/05/31/airbus-aircraft-programs-review/
Jim Krebs passed away last summer at home in Marblehead, Massachusetts, at the blessed age of 98. https://www.ge.com/news/reports/a-strategist-with-insight-remembering-jim-krebs-aerospace-visionary-who-helped-launch-ge
It’s a privilege to be able to occasionally discuss one on one with real skilled people that were pulling & pushing in different aerospace times / ages.