Leeham News and Analysis
There's more to real news than a news release.
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.
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 8. Conceptual System design.
September 19, 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.
*** Special thanks to Ron Everlove for helping with this article***
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.
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 5. Market research.
By Bjorn Fehrm and Henry Tam
August 29, 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 4. Feasibility studies.
By Bjorn Fehrm and Henry Tam
August 22, 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 3.
By Bjorn Fehrm
August 15, 2025, ©. Leeham News: We do a series about recent 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. Before we start the discussions, we outline the process to certify a transport category aircraft under the US FAA 14 CFR Part 25 regulations and how it relates to the Figure 1 plan.
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.