Leeham News and Analysis
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Bjorn’s Corner: Faster aircraft development. Part 13. Preliminary Design Review, PDR.
By Bjorn Fehrm and Henry Tam
October 24, 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. Today’s topic, the Preliminary Design Reviews, PDRs, are marked in the chart.
Figure 1. A generic new Part 25 airliner development plan with PDR marked in time. Source: Leeham Co. Click to see better.
Airbus’ A321neo, A321LR or A321XLR?
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By Bjorn Fehrm
October 23, 2025, © Leeham News: Airbus’s A321 was launched in November 1988, around the time the original A320 entered service. Delivery to the first A321 customer, Lufthansa, was in January 1994.
The initial sales of the A321 were modest, with deliveries of the variant languishing between one and three aircraft per month for the first ten years. It wasn’t until after the launch of the A320neo/A321neo in 2010 that sales climbed to 10 per month, 20 years after the first delivery. This shall be compared to the 30 per month after another 10 years in 2024.
The smaller A320 was at 24 per month by 2010 and then touched 35 per month in 2019 before it started to cede the market to the A321neo after COVID. Deliveries in 2024 were at 19 per month.
With the A321 dominating Airbus deliveries from 2022, the question is: which variant of the A321 is suitable for what routes? Does a “misuse” of an A321LR or XLR on short to medium routes mean an operational cost loss compared to a standard A321neo?
We look into the different A321neo variants and compare their capacities and operational costs in this series.
Summary:
- The Airbus A321 started life with low sales, the market preferring the smaller A319 and A320. One of the reasons was the large jump in capacity between the A320 and A321, more than 40 seats.
- By the introduction of the A320neo series, the market had developed to higher capacities. After COVID, the A321neo took over as the dominant A320 range variant.
Bjorn’s Corner: Faster aircraft development. Part 12. Preliminary Design; Requirements Definition.
By Bjorn Fehrm and Henry Tam
October 17, 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 added two milestones to our Program Plan, which we will refer to in the articles: Preliminary Design Review and Critical Design Review. Here is their definition according to NASA:
The Preliminary Design Review (PDR) demonstrates that the preliminary design meets all system requirements with acceptable risk and within the cost and schedule constraints, and establishes the basis for proceeding with detailed design. It shows that the correct design options have been selected, interfaces have been identified, and verification methods have been described. The PDR should address and resolve critical, system-wide issues and show that work can begin on detailed design.
The Critical Design Review (CDR) demonstrates that the maturity of the design is appropriate to support proceeding with full-scale fabrication, assembly, integration, and test. CDR determines if the technical effort is on track to complete the system development, meeting mission performance requirements within the identified cost and schedule constraints.
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***
Bjorn’s Corner: Faster aircraft development. Part 11. Interior Preliminary Design.
By Bjorn Fehrm and Henry Tam
October 10, 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.
Figure 1. A generic new Part 25 airliner development plan. Source: Leeham Co. Click to see better.
Bjorn’s Corner: Faster aircraft development. Part 10. Preliminary design.
By Bjorn Fehrm and Henry Tam
October 3, 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.
Figure 1. A generic new Part 25 airliner development plan. Source: Leeham Co. Click to see better.
Bjorn’s Corner: Faster aircraft development. Part 7. Conceptual Design.
By Bjorn Fehrm and Henry Tam
September 12, 2025, ©. Leeham News: We do a series about ideas on how the long development times for large airliners can be shortened. New project talks 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.
Figure 1. A generic new Part 25 airliner development plan. Source: Leeham Co. Click to see better.
Airbus CEO Guillaume Faury on Supply Chain, Tariffs, and the Next Generation of Aircraft at US Chamber of Commerce Global Aerospace Summit
By Chris Sloan
Sept. 9, 2025, © Leeham News: At the U.S. Chamber of Commerce Global Aerospace Summit in Washington, D.C., Airbus CEO Guillaume Faury shared an optimistic outlook for Airbus operations speaking on supply chain recovery, production goals, tariffs, sustainability, and next generation aircraft programs.
Supply Chain Challenges and Recovery
Faury claimed that the supply chain picture has changed dramatically for the better compared to 2023. Deliveries from most suppliers are now arriving on time, though he admitted that “The one that is impacting the on-time delivery most is the two engine manufacturers.” For the first half of the year, Airbus is averaging as many as 60 “gliders” per end of momth — aircraft completed but waiting for engines. He said the situation has been improving and that “We hear from our engine colleagues that they expect to be back to what we need to deliver our planning goals. That’s why we are maintaining what we believe we are going to deliver to our customers.”
Engine makers remain in recovery mode, working through shortages of both new engines and spare parts. Airlines’ strong demand ahead of the summer peak adds to the pressure, but Faury noted that manufacturers have been transparent about their timelines. “You can’t be speculating on the fact that everything will go well. You have to factor in crises and recover today,” he said. When asked about Airbus’ target of 820 deliveries in 2025, Faury’s response was confident: “The answer is yes because we see that the supply chain is there, slightly better than we planned. I’m really worried about the engines, but what we hear from our engine colleagues is that they’ll be back before the end of the year.” He explained that many of the delayed aircraft would ultimately be delivered in the second half, once engines are available.
Bjorn’s Corner: Faster aircraft development. Part 6. IT support.
By Bjorn Fehrm and Henry Tam.
September 5, 2025, ©. Leeham News: We do a series about ideas on how the long development times for large airliners can be shortened. New project talks 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.
Figure 1. A generic new Part 25 airliner development plan. Source: Leeham Co. Click to see better.
Bjorn’s Corner: Faster aircraft development. Part 2.
By Bjorn Fehrm
August 8, 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.
Figure 1. A generic Part 25 airliner development plan. Source: Leeham Co. Click to see better.
Bjorn’s Corner: Faster aircraft development. Part 1.
By Bjorn Fehrm
August 1, 2025, ©. Leeham News: Four years ago I did a series about aircraft development together with Henry Tam and Andrew Telesca. Both worked on the Mitsubishi Spacejet program. You can find the series here.
It was about the arduous task of developing and producing a certified aircraft for the FAA Part 23 standard and its EASA equivalent. The idea was to better describe what’s ahead for the many upstarts that wanted to develop 9-seat and 19-seat alternative propulsion aircraft.
Now we do a series about recent ideas on how the long development times for large airliners can be shortened. New projects talk about cutting development calendar time by one-third or more. Is this realistic?
Figure 1. The A350 development schedule from December 2011. Source: Airbus.