Leeham News and Analysis
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Bjorn’s Corner: Faster aircraft development. Part 21. Certification Implementation.
By Bjorn Fehrm and Henry Tam
December 19, 2025, ©. Leeham News: We do a series about ideas on how the long development times for large airliners can be shortened. New projects talk about cutting development time and reaching certification and production faster than previous projects.
The series will discuss the typical development cycles for an FAA Part 25 aircraft, called a transport category aircraft, and what different ideas there are to reduce the development times.
We will use the Gantt plan in Figure 1 as a base for our discussions. We have concluded the articles about flight tests with the aircraft. Now we revisit the Certification subject and look at how we can show compliance with requirements and work our way to a Type Certificate. We are at the end part of the Testing and Certification phase in our Program Plan in Figure 1.
Figure 1. A generic new Part 25 airliner development plan. Source: Leeham Co. Click to see better.
** Special thanks to Andrew Telesca for helping with this article **
The state of alternative propulsion aircraft? Part 5.
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By Bjorn Fehrm
December 18, 2025, © Leeham News: In our series about alternative propulsion aircraft, last week we looked at the energy consumption and range of a typical nine-seater battery-electric commuter aircraft using our Aircraft Performance and Cost Model (APCM).
We could see that the useful range for this aircraft was short, even when using the full 19,000lb Maximum TakeOff Weight (MTOW) to give the battery the maximum size and using VFR flight rules. Under IFR flight rules, the commuter was not usable with available batteries this side of 2030.
Figure 1. Our battery-electric commuter was similar in design to the Tecnam P2012 nine-seater commuter. Source: Tecnam.
When a project discovers these constraints (which often happen several years into the project, as upstarts don’t have competent aircraft performance models that handle energy consumption for different phases of flight), they start looking at Hybrid architectures.
We do the same. Once again, our model will help us to predict performance, range, operational economics, and also production costs (as a hybrid is a more complex aircraft than a battery electric one).
Bjorn’s Corner: Faster aircraft development. Part 20. Flight Testing.
by Bjorn Fehrm and Henry Tam
December 12, 2025, ©. Leeham News: We do a series about ideas on how the long development times for large airliners can be shortened. New projects talk about cutting development time and reaching certification and production faster than previous projects.
The series will discuss the typical development cycles for an FAA Part 25 aircraft, called a transport category aircraft, and what different ideas there are to reduce the development times.
We will use the Gantt plan in Figure 1 as a base for our discussions. We have completed the articles on Prototype Manufacturing and Ground Vibration Tests (GVT). We now conduct the program’s flight tests with the manufactured test aircraft.
Figure 1. A generic new Part 25 airliner development plan. Source: Leeham Co. Click to see better.
Bjorn’s Corner: Faster aircraft development. Part 19. Flight Test Aircraft Assembly.
December 5, 2025, ©. Leeham News: We do a series on ways to shorten the long development times for large airliners. New projects aim to cut development time and achieve certification and production faster than previous projects.
The series will discuss the typical development cycles for an FAA Part 25 aircraft, called a transport category aircraft, and the different approaches to reducing development time.
We will use the Gantt plan in Figure 1 as a base for our discussions. We have exited the Detailed Design phase after conducting Critical Design Reviews, CDRs, and now enter into Prototype Manufacturing. After reviewing the acceptance and testing of the first parts and systems from suppliers, we now discuss putting together the first flight-test aircraft.
Figure 1. A generic new Part 25 airliner development plan. Source: Leeham Co. Click to see better.
** Special thanks to Ron Everlove for helping with this article **
The state of alternative propulsion aircraft? Part 4.
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By Bjorn Fehrm
December 4, 2025, © Leeham News: In our series about alternative propulsion aircraft, last week we looked at the aircraft batteries. These are heavy components with very low energy capacity per unit weight.
To illustrate the kind of aircraft-level challenges the batteries pose, we are using our Aircraft Performance and Cost Model (APCM) to design a typical alternative-propulsion battery-electric aircraft and then fly it on typical missions.
The aircraft is similar in size to a 9-seat Tecnam P2012 commuter (Figure 1) but optimised for Battery-Electric propulsion.
Figure 1. The Tecnam P2012 nine-seater commuter. Source: Tecnam.
The APCM will give us the airframe-level energy consumption for each phase of the flight. Subsequently, we can add the different losses in the propulsion system to determine the energy consumed from the battery and the endurance/range it offers, dependent on VFR or IFR mission reserves.
Airbus rolls out prototype A350F in march toward 2026 certification
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By Scott Hamilton and Bjorn Fehrm
Dec. 1, 2025, © Leeham News: Airbus rolled its first A350F out of the factory last week. It now moves to another building for the installation of systems and engines. The first flight is planned for the third quarter next year, as a second freighter is completed to begin regimented flight testing.
Airbus hopes to deliver the first freighter in the second half of 2027.
Figure 1. The first Airbus A350F rolled out of the factory this month. Source: Airbus.
Boeing’s new freighter, the 777-8F, is still a “paper” airplane. With 59 orders from six customers, entry into service (EIS) is now estimated for 2029 (some say 2030). Airbus has more than 80 orders from 13 customers. Airbus claims a 58% market share of new freighter orders.
A350F sales fall short of the 120 sales for new-build A300-600Fs, Airbus’ best-selling freighter, most of which went to package operators FedEx and UPS. However, neither has chosen between the A350F or the 777-8F for their next airplanes to replace the decades-old Boeing (McDonnell Douglas) MD-11Fs. The future of these aircraft is uncertain following the Nov. 4 crash of a UPS jet in Louisville (KY).
Within days of the accident, which killed three pilots and 11 people on the ground, Boeing recommended grounding the nearly 60 MD-11 freighters on the US registry for inspections. The Federal Aviation Administration (FAA) made the grounding mandatory shortly after.
Related Stories
- UPS crash presents potential opportunities for Airbus’ A350F
- Airbus sticks to 2027 EIS for A350F (Briefing pre-Dubai Air Show)
Bjorn’s Corner: Faster aircraft development. Part 18. Prototype Parts and Systems.
By Bjorn Fehrm and Henry Tam.
November 28, 2025, ©. Leeham News: We do a series about ideas on how the long development times for large airliners can be shortened. New projects talk about cutting development time and reaching certification and production faster than previous projects.
The series will discuss the typical development cycles for an FAA Part 25 aircraft, called a transport category aircraft, and what different ideas there are to reduce the development times.
We will use the Gantt plan in Figure 1 as a base for our discussions. We have exited the Detailed Design phase after conducting Critical Design Reviews, CDRs, and now enter into Prototype Manufacturing.
Figure 1. A generic new Part 25 airliner development plan. Source: Leeham Co. Click to see better.
** Special thanks to Ron Everlove for helping with this article **
The state of alternative propulsion aircraft? Part 3.
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By Bjorn Fehrm
November 27, 2025, © Leeham News: In our series about alternative propulsion aircraft, last week we looked at the electric motor of an electric aircraft, which drives propellers or fans. It’s a component that is straightforward to develop, but the certification requirements for the aircraft and VTOL industry have slowed progress.
Now we look at the component that causes trouble for all alternative propulsion aircraft, except those that burn hydrogen in gas turbine engines: the batteries. Batteries work well in cars, where the requirement for energy capacity relative to weight is much lower and where energy recovery during braking reduces the energy required from the battery.
Figure 1. The battery-electric aircraft that flies operational trials as we speak, the Beta Technologies Alia CX300. Source: Leeham Co.
Aircraft batteries are a heavy component with very low energy storage capacity. Today’s aircraft battery system has about 60 times lower energy density per kg or lb than aircraft fuel.
The hope over the last decade has been that this relationship should improve. It has, it’s gone from about 70 times to 60 times in the last 10 years. This will improve further, the question is if it will continue at the slow pace of the last 10 years or not?
Bjorn’s Corner: Faster aircraft development. Part 17. Critical Design Review, CDR.
By Bjorn Fehrm and Henry Tam
November 21, 2025, ©. Leeham News: We do a series about ideas on how the long development times for large airliners can be shortened. New projects talk about cutting development time and reaching certification and production faster than previous projects.
The series will discuss the typical development cycles for an FAA Part 25 aircraft, called a transport category aircraft, and what different ideas there are to reduce the development times.
We will use the Gantt plan in Figure 1 as a base for our discussions. We are in the Detailed Design phase, and it’s time to conduct the Critical Design Reviews, CDRs.
Figure 1. A generic new Part 25 airliner development plan. Observe the CDRs. Source: Leeham Co. Click to see better.
The state of alternative propulsion aircraft? Part 2.
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By Bjorn Fehrm
November 20, 2025, © Leeham News: In our series about alternative propulsion aircraft, we started last week by discussing what happened after the trigger by the Airbus E-fan flight in 2014 and the introduction of the Tesla Model S car two years before. The alternative propulsion aircraft projects that followed had a rocky path. They followed the Gartner Hype-curve, Figure 1.
There were hundreds of projects announced, more or less serious. A few of these came to producing hardware, and flew test flights, then stopped. Most stayed as PowerPoint presentations and fancy renderings, promising capabilities that were not possible to realize. The result was that we passed the Peak of Inflated Expectations and entered the Trough of Disillusionment. Investors fled to AI, and projects froze or stopped.
Figure 1. The Gartner Hype-curve. Source: Gartner Inc.
By 2025, we are in the Disillusionment phase. As there are signs we can now enter a phase of real, sustainable progress, it’s timely to take stock of where we are and what progress we can expect over the next decade.
To understand why progress has been so difficult, after explaining that learnings from Cars are not transferable last week, we start by focusing on two components that we find in every alternative propulsion concept, the Electric Motor and the Battery system. Of the two components, the motor is the most straightforward to develop and certify for an aircraft. Still, we have only limited progress so far, and we detail why in today’s article.
The Battery System is the most challenging component for alternative propulsion aircraft, both in development and in use. We will spend next week’s article detailing why and how it has slowed down progress so far, and how this can change going forward.