Bjorn’s Corner: The challenges of airliner development. Part 2. Why Certification?

By Bjorn Fehrm, Henry Tam, and Andrew Telesca.

May 7, 2021, ©. Leeham News: The major challenge with developing commercial aircraft is the certification process. You can’t just develop the aircraft based on your unique knowledge and ideas, you must do it according to a detailed rulebook written with the knowledge from thousands of accidents and incidents.

From the beginning of the design process when you’re thinking about how big your engines would need to be or whether you can carry enough passengers to have a competitive advantage the certification rules influence (and sometimes govern) your design decisions.

Beyond just scrutiny of the design of the vehicle and its components, the process by which it is designed, the production site & methods used, and the organization doing the work all go through certification processes.

Figure 1. The FAA certification rules website. Source: FAA.

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Bjorn’s Corner: The Challenges of Airliner Development. Part 1. Introduction

By Bjorn Fehrm, Henry Tam, and Andrew Telesca

April 30, 2021, ©. Leeham News: After our hydrogen series, we now start a series around the Challenges of Airliner Development.

We have more aeronautical projects in development than ever, fueled by the transformation to new, more sustainable technology and new forms of flight, like Urban Air Mobility and Drones based on electrical propulsion.

Many of these projects underestimate what it takes to ready a certified air vehicle. We describe what’s involved in a series of Corners.

Figure 1. A typical aero development CFD graphic. Source: Boeing.

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Bjorn’s Corner: The challenges of hydrogen. Part 33. Wrap-up: The Eco-system

By Bjorn Fehrm

April 16, 2021, ©. Leeham News: Last week, we wrapped up the operational part of sustainable air transport using hydrogen as an energy source.

Now we look at where we are with the all-important Eco-system. It has many moving parts and risks a chicken and egg stalemate.Figure 1. The prospective conversion of the European gas pipeline network to hydrogen. Source: EU.

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Bjorn’s Corner: The challenges of hydrogen. Part 32. Wrap-up: Going forward

By Bjorn Fehrm

April 9, 2021, ©. Leeham News: Last week we made a summary of the history of initiatives for sustainable aviation, now we look at the likely developments over the next 10 years.

What is the likely development for different classes of airliners and what technologies will be popular?

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Bjorn’s Corner: The challenges of hydrogen. Part 31. Wrap-up: Where we stand

By Bjorn Fehrm

April 2, 2021, ©. Leeham News: It’s time to wrap up our series on the hydrogen airliner alternative for Sustainable Commercial Aviation.

We review the status for sustainable aviation as of today, then look at the future next week.

Figure 1. The first certified electric aircraft, the Pipistrel Velis Electro. Source: Pipistrel.

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Bjorn’s Corner: The challenges of hydrogen. Part 30. Integrated nacelles.

By Bjorn Fehrm

March 26, 2021, ©. Leeham News: This week, we look at combining the propulsion and hydrogen tank in an integrated nacelle as Airbus proposes in Figure 1.

Airbus calls it its “pod” solution. What are the advantages, and what challenges does it present?

Figure 1. Airbus concept for a turboprop with integrated nacelles. Source: Airbus.

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Bjorn’s Corner: The challenges of hydrogen. Part 29. Gas turbine heat management.

By Bjorn Fehrm

March 19, 2021, ©. Leeham News: This week we look deeper into the gains we can have for a hydrogen gas turbine-propelled airliner.

The ideas stem from the work of Chalmers Professor T. Grönstedt’s team in different EU research projects.

Figure 1. Gas Turbine heat management as presented in EU ENABLEH2 project. Source: ENABLEH2.

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Bjorn’s Corner: The challenges of hydrogen. Part 28. Airbus priorities

March 12, 2021, ©. Leeham News: I had the chance to talk about Sustainable Air Transport with Airbus VP Zero Emission Aircraft, Glenn Llewellyn, in the week.

The discussion centered around Airbus’ overall direction and the targets with their ZEROe project.

Figure 1. Airbus ZEROe airliner concepts. Source: Airbus.

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Bjorn’s Corner: The challenges of hydrogen. Part 27. Fuel cell APU gains

By Bjorn Fehrm

March 5, 2021, ©. Leeham News: We have discussed different auxiliary power generation principles for a hydrogen aircraft over the last weeks. We found a fuel cell auxiliary power system has many attractions, one being the possibility of making an elegant more-electric aircraft system architecture.

With or without such an architecture, the fuel cell alternative will save hydrogen consumption and cost compared to a hydrogen-converted APU alternative. What’s the value of the saving?

Figure 1. The Ballard/Audi FCgen-HPS fuel cell stack for cars and other mobility applications. Source: Ballard Power Systems Inc.

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Bjorn’s Corner: The challenges of hydrogen. Part 26. Auxiliary power

February 26, 2021, ©. Leeham News: Last week we discussed auxiliary power generation for a hydrogen aircraft and found that a fuel cell system had many attractions.

However, it’s more challenging to develop than a hydrogen-converted APU, and we were asked to work through this case as well.

Figure 1. The principal parts of a single-aisle APU. Source: United Technologies.

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