Leeham News and Analysis
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Leeham News and Analysis
- Boeing wants to remarket China’s airplanes. It’s costly and time consuming. April 28, 2025
- Bjorn’s Corner: Air Transport’s route to 2050. Part 19. April 25, 2025
- How good is the C929? Part 2. April 24, 2025
- Boeing First Quarter Results Update: China is 10% of the backlog, with 500 in “Unidentified” April 24, 2025
- Boeing First Quarter Results: Tariffs, Return flights, $10.55bn asset sale April 23, 2025
Fundamentals of airliner performance, Part 4
By Bjorn Fehrm
Nov. 25, 2014: In our article series around the performance of a modern airliner we have now come to the climb after takeoff. 
We started with cruise as this was simplest because the aircraft is flying in steady state, then we looked at the modern turbofan and how this is affected by both altitude and speed. We then examined how this affects the takeoff and today we continue with the climb after takeoff.
Before we start, let’s sum up a few points we need for today:
- Drag is the one thing we always need to be aware of as this regulates how much excess power we have in different flight situations and therefore if we can stay on our altitude or climb.
- Drag diminishes with altitude as the airs density diminishes and thereby our dominant drag component, air friction against our aircraft’s skin. This is the major component of the aircraft’s dominant drag, parasitic drag.
- Our lift force is generated by forcing air downwards and this causes induced drag as this downwash cost energy to generate and maintain. Induced drag is mitigated by a wing with a large span.
Lufthansa to use A340s in “lower cost” operation; our analysis against the 787
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By Scott Hamilton and Bjorn Fehrm
Introduction
Low cost long haul service is gaining traction, but previous efforts proved difficult to be successful.
Dating all the way back to Laker Airways’ Skytrain and the original PeoplExpress across the Atlantic, airlines found it challenging to make money.
More recently, AirAsiaX retracted some of its long-haul service, withdrawing Airbus A340-300 aircraft when they proved too costly. The airline recast its model around Airbus A330-300s as an interim measure, unable to fly the same distances as the longer-legged A340. AirAsiaX ordered the Airbus A350-900 and now is a launch customer for the A330-900neo.
Cebu Pacific of the Philippines is flying LCC A330-300 service to the Middle East. Norwegian Air Shuttle famously built its entire LCC long haul model around the Boeing 787, initiating service with the 787-8 and planning to move to the 787-9.
Canada’s WestJet is leasing in four used Boeing 767-300ERs to offer LCC service,
Legacy carrier Lufthansa Airlines plans to use fully depreciated A340-300s to begin “lower cost” (as opposed to “low cost”) long haul service. LH says the fully depreciated A340s come within 1%-2% of the cost per available seat mile of the new, high capital-cost 787s.
Summary
- AirAsiaX’s A340 LCC long haul service proved unprofitable. Can Lufthansa’s similar service with fully depreciated A340s work?
- Our analysis shows that it can. It can even support the lease rates that would be charged for a 10 year old A340 if the fuel price remains at the present level.
- When doing the research for this article and going through the results of our proprietary model we started to ask ourselves, is the A340-300 the ugly duckling of the airline market?
Fundamentals of airliner performance, Part 2.
By Bjorn Fehrm
In our first article on how to understand the fundamentals that make up airliner performance we defined the main forces acting on an aircraft flying in steady state cruise. We used the ubiquitous Boeing 737 in its latest form, the 737 MAX 8, to illustrate the size of these forces.
Here a short recap of what we found and then some more fundamentals on aircraft’s performance, this time around the engines:
When flying steady state (Figure 1) we only need to find the aircraft’s drag force to have all important forces defined.
Figure 1. Elementary forces acting on an aircraft at cruise. Source: Leeham Co.
The lift force is given as equal to and opposite to the aircraft’s weight and the tail downforce that we need to add to this was small. We also presented the two classes of drag that we will talk about:
- Drag independent of lift or as we often call it drag due to size as almost all drag components here scale with the aircraft’s size.
- Drag due to lift or drag due to weight as we call it as this drag scales with weight when one flies in steady state conditions.
We could see that the aircraft’s flight through the air created a total drag force of 7900 lbf, Figure 2 ( lb with an f added as we prefer to write it as this is a force and not a measure of mass. Mass we denote with just lb or the metric units kg or tonne = 2205 lb).
Figure 2. Drag of our 737 MAX 8 and how it divides between lift and non lift drag. Source: Leeham Co.
We also learned that if the drag is 7900 lbf then the engine thrust is opposite and equal. It is then 3950 lbf per engine when cruising at our mean cruise weight of 65 tonnes or 143.000 lb on our 1000 nm mission. Drag due to size consumes 63% of our thrust and drag due to weight 37%. Read more
Zhuhai Airshow: China’s aircraft industry is gaining speed
The 10th Chinese airshow at Zhuhai opened today. It was a day with fewer announcements than expected from the usual suspects (Airbus, Boeing…) but the Chinese industry did not disappoint. China is now showing more and more of its coming might as a player on the aeronautics arena.
The most prominent displays at this show were on the military side, where China has two stealth aircraft projects flying (the large Chengdu canard J-20 and the smaller Shenyang J-31) while their canard Chengdu J-10 was flying the display circuits overhead (Figure 1).
Figure 1. Chinas latest fighter developments; the J-31 and J-20 stealth fighters and the canard J-10. Source: China internet.
All aircraft are of latest structural and aerodynamic design if not in engines and systems. This is a big difference to previous shows where the Russian Sukhoi and MIG aircraft and their local copies did the flying display until 2008. Since then everything has changed and now China and USA are the only countries in the world with two different stealth designs flying. USA has one in operation (F-22) and one close to (F-35) whereas China still has many years to go until they have their new aircraft operational. But it is significant that the old aeronautical behemoths Europe and Russia have none respective one (PAK-50) stealth fighter in flight test.
Boeing 737 MAX 8 as a long and thin aircraft and how it fares in general versus Airbus A320neo.
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By Bjorn Fehrm
Introduction
Over the last weeks we have looked at Boeing’s 757 replacement possibilities on its long and thin network niche, including a ground breaking launch interview for the A321neoLR with Airbus Head of Strategy and Marketing, Kiran Rao. In the series we have seen that the A321neo has the potential to replace the 757-200 on long and thin international routes. Boeing’s equivalent single aisle entry, 737 MAX 9, has problems to extend its range over 3,600nm. It is too limited in the weight increase necessary to cover the longer range.
Many have asked how the less- restricted Boeing 737 MAX 8 would fare, suitably equipped with the necessary extra tanks. This is the subject of this week’s sequel on the theme long and thin. At the same time we look at Airbus entry in this segment, the A320neo, to see how it stacks up to the 737 MAX 8, both in their normal 1,000 to 2,000nm operation and then also in a long and thin scenario.
Let’s first summarize what we found so far in our four articles around the Boeing 757 and its alternatives:
- The Boeing 757-200 with winglets can serve international routes with city pairs up to 3,500nm. The rest of its range capability (about an additional 500nm) is needed for unfavorable winds and reserves.
- The A321neo has the capabilities to be extended to cover the range of the 757-200. This was also announced by Airbus during our series. The improvements are an increase in range of 500nm by virtue of three extra center tanks and an increase in max takeoff weight of 3.5 tonnes ( 7,400 lb). The efficiency improvement over 757-200 would be 25% with a small decline in passenger capacity (162 vs. 169 seats) in a typical First, Premium economy and economy cabin.
- Boeings 737 MAX 9 fares less well. While it has the wing to fly the range, the aircraft’s squat stance hinders the aircraft to cant the wing to generate the necessary lift for an increased takeoff weight. MAX 9 can’t rotate to more than 70% of the angle of an A321neo. Subsequently the take off distances get too long with any weight increase.
- Boeing’s New Small Airplane study covers from 130 to 240 seats and evaluates both single and dual aisle alternatives. The big question mark is when an entry into service (EIS) is necessary and therefore when a launch decision has to be taken. We think after the 777X has entered flight test in 2018/19 for EIS 2025. Boeing’s CEO, Jim McNerney, says he sees EIS as 2030 for a new small airplane. We argue this risks missing the boat.
Summary
- The 737 MAX 8 is 1.5m (5 feet) longer than A320 with a 2.5m (8.2 feet) longer cabin. This brings a 12 seat higher capacity, everything else being equal. The result is that the MAX 8 beats the A320neo on per seat efficiency while being worse on trip efficiency.
- The MAX 8 has a range on internal fuel of 3,700nm. This makes it suitable for extending the range up to 4,000nm with smaller changes. It thereby is probably Boeing’s best bet of offering a long and thin aircraft before the New Small Aircraft (NSA) comes to market. Its major drawback is a 33 seats reduction in capacity compared to 757-200 when both are configured for long and thin.
- A320neo is less ideal to extend to long and thin. It requires several extra fuel tanks to get to 4,000nm nominal range and then there is too little space left for luggage.
Figure 1. Boeing 737 MAX 8 overlaid with Airbus A320neo. Source: Leeham Co.
Boeing considers single, twin aisle, co-development 757/767 style for next new airplane
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Now open to all Readers.
Introduction
Boeing is looking at a number of scenarios for its New Airplane Study (NAS) that would replace the 757 and 737, have ranges from 4,000nm-5,000nm, and carry as few passengers as 130 or as many as 240.
To cover this broad range of demands could require reverting back to the 1980s when Boeing simultaneously developed two airplanes serving very different missions, the 757 and 767, that shared cockpits and some other common elements.
Boeing faces some hard decisions in the coming years, as Airbus outflanks Boeing in the single-aisle sector with the A320neo family and its latest offering, the A321neoLR. Our analysis and sales figures show the 737 MAX falling further and further behind in market share as MAX 9 lags vis-à-vis the A321neo.
We spoke with Kourosh Hadi, director of product development at Boeing, during a break at a conference last week organized by the British American Business Council-Pacific Northwest, and covered this and a number of other topics.
Summary
- Boeing is studying a New Light Twin (NLT) and New Single Aisle (NSA) to replace the 757 and 737 airplanes.
- The tipping point between an efficient NSA and the NLT is around the passenger size of the 757-200.
- Boeing is evaluating materials, including metals and composites, for the NAS and the manufacturing process, which will also be a determining factor in the materials for the new airplane.
- Engine advances for the 777X’s GE9X are beyond the GEnx and CFM LEAP of today and could help drive the next new small engine technology.
- Although having a miniscule portion of the 100-150 seat market, Boeing today plans to continue participation in at least the 130 or 150 seat sector even as airplane size moves up every year.
Part 3: Boeing 757 replacement: 757 and Airbus A321neoLR versus clean sheet designs.
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By Bjorn Fehrm
Part 3 of 3
Introduction
In Part 2 of our three-part 757 Replacement analysis, we took a close look at Airbus’ new 97 tonne take-off weight A321neo, revealed in a world exclusive by Leeham News and Comment October 21. We analyzed the A321neoLR’s capabilities and limitations when compared to Boeing 757-200W and we saw that it could do the international flights that the 757-200 does with about 25% better efficiency. In this final Part 3, we will now compare the 757 and A321neoLR against what can be Boeing’s reaction, a clean sheet New Single Aisle, NSA, or New Light Twin Aisle, (NLT). First the conclusions from Part 2:
- When using the United Airlines-configured 757-200W international as benchmark, we came within seven seats of the 757 capacity for an A321neoLR. It covered the same range and had trip fuel costs that were 25% lower.
- The per seat fuel costs gave a 22% higher efficiency, which was within 2% of Airbus own figures.
- 737 MAX9 is not suitable for stretch to an international version, not because the wing is not good enough but because the MAX9 cannot bring the wing to an angle at take-off where it can work efficiently; the landing gear is too short.
Summary
For Part 3 we can summarize:
- A New Single Aisle (NSA) or New Light Twin (NLT) which would enter the market in 2025 would be sized at around 200 passengers with subsequent variants covering the 175-225 seat market, all numbers with OEM standard two-class seating. Figure 1 shows the fuselage cross sections we have used in our modelling of NSA and NLT to cover this market segment.
Figure 1. Fuselage cross sections of our models of NSA and NLT. Source: Leeham Co.
- In order to cover the market segment of the 737, A320 and 757 it would have a range in excess of 4,100nm. We will use 4100nm for our modeling to maximize the comparative efficiency information.
- Its efficiency would be higher than an A321neoLR, primarily due to better engines and a more modern wing.
- The New Light Twin (NLT) wins on comfort and ground turn-around time but pays with a larger fuselage cross section due to the extra aisle. This causes more drag and structural weight, net effect is a reduction in efficiency of around 2.5%.
CASM Paradigm: Lower Seat Mile Cost or Higher Yield; Evaluating the GOL competition
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Introduction
As Brazil’s budget airline GOL reportedly evaluates whether to acquire 20 Boeing 737-7s or Embraer E-195 E2s, the principal of the “CASM Paradigm” is a concept worth examining.
This head-to-head evaluation of the E-195 E2 and the 737-7 MAX is a rarity. Typically the head-to-head involves the Bombardier CS300 and the Airbus A319neo. All three have the same seating capacities. The E-195 E2 has slightly fewer passengers than the 737-7 with similar seat pitch.
The competition is also what might be seen as a contrary competition. Airframers agree: the airline industry is upgauging. Capacity discipline, long elusive until after the global financial collapse of 2008, has been driving load factors higher. But lowering unit costs, or the Cost per Available Seat Miles (CASM) has long been the principal measure by which airlines, OEMs and aerospace analysts measure efficiency.
Although Trip Costs of aircraft operating over a route is important, the trend toward upgauging at all levels clearly is the driving force.
Figure 1. It’s an age-old debate: the cost per available seat mile (CASM) vs trip cost. CASM typically wins, and the airline industry is migrating toward larger aircraft. Embraer, not surprisingly, thinks this has gone too far. Graphic: Embraer, reprinted with permission. Click on image to enlarge.
Embraer takes a different view, arguing that trip costs and a smaller airplane should trump the CASM obsession. A smaller airplane will mean higher yields, EMB says. A larger airplane provides lower trip costs but drives yield lower.
We visited Embraer’s headquarters earlier this month and received a full briefing on what EMB calls the CASM Paradigm. In our report today, we detail the presentation and discuss other considerations beside CASM vs Trip Costs that drive the size of the aircraft acquired.
Summary
- The CASM Paradigm becomes a vicious, circular cycle, driving airlines to larger aircraft but lower yields.
- Extra seats on larger aircraft mean lower unit costs but at the cost of profits.
- Scope Clauses remain an issue in the US.
- Connecting traffic, pay scales also are issues.
- We analyze the operating costs of the E-195 E2 vs the 737-7.
- We discuss the GOL competition.
Fundamentals of airliner performance, Part 3
By Bjorn Fehrm
In our first article about how to understand the performance of a modern airliner we defined the main forces that are acting on an aircraft flying in steady state cruise. In our clinic we use the ubiquitous Boeing 737 in its latest form, the 737 MAX 8, to illustrate our case.
In the second article we introduced the aircraft’s engines and understood how they function by pumping air backwards faster than the aircraft’s speed and therefore generating thrust as air is in fact quite heavy. We also looked at the influence of flight altitude on the performance of the aircraft.
In short we can conclude our findings so far:
Having covered the most important aspects of cruise we will today look at takeoff, a subject with a lot of aspects. Read more
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Posted on November 19, 2014 by Bjorn Fehrm
Boeing, CFM, Leeham News and Comment, Uncategorized
737 MAX, Boeing, CFM, CFM Leap-1B