Bjorn’s Corner: The challenges of airliner development. Part 12. The Prelaunch Phase.

By Bjorn Fehrm, Henry Tam, and Andrew Telesca.

July 16, 2021, ©. Leeham News: Last week, we showed the first cut of an overall Program Plan for our 19 seat airliner project.

Now we discuss the Prelaunch Phase activities in more detail, including what type of knowledge, tools and resources we need to get on board for the project.

Figure 1. The Viking Twin-Otter utility-oriented unpressurized 19 seater. Source: Wikipedia.

The Pre-Launch Phase

We continue to discuss the program plan we presented in Part 11 (Figure 2) and describe deeper what we do in each task.

Figure 2. Our overall program plan. Source: Leeham Co. Click to see better.

Market Research and Sales and Marketing

The overall program plan in figure 2 is expanded with Sales and Marketing activities. These span the whole project and start after our preliminary Market Research.

Our Sales and Marketing team then sets out to visit the operators what would be our customers for the market segments we are focusing on. The discussion with the customers gives input to our aircraft configuration (acceptable economics, support expected, the configuration of cabin, size of cargo ports and hold…), but also input to our Business Case, with potential sales to different customers, prices we can expect, the performance and operating costs we must achieve, etc.

Concept development

As we develop Concepts of our product, these are discussed with the customers at the visits. To develop our concepts, we need tools and knowledgeable specialists. We need an aircraft conceptual development tool, a first geometry design package to feed CFD tools for aerodynamic flow and loads analysis, analysis packages for first sizing of systems like air conditioning packs, etc.

It all results in a first version data package that teams can use to analyze structural concepts and weight, engine thrust, bleed air requirements for the Environmental Control Systems (ECS) and de-Ice, loads on hydraulics and electrical supply, etc.

As CFD aerodynamic tools are good at analyzing cruise conditions but struggle with low-speed aero, we make the first small scale windtunnel model that we run in a low-speed tunnel to get takeoff and landing data.

The concept of our aircraft progresses in steps during this phase, where each step expands the data package both for internal and external use.

Supplier Collaboration

An aircraft of this size has close to a million parts. Almost all of these we need to specify and then purchase, from the smallest nuts and bolts/fasteners to stuff like Structural parts/Assemblies, Engines, Environmental Control Systems (ECS), Avionics, Flight Control System, Fuel System, Hydraulic and Electrical Systems, Landing Gear, Bleed-Air System, De-Ice System, etc.

We need to contact the supplier base early. Most critical is the engine supplier, with the engine representing about one-third of the cost of the aircraft. But we need to get a relationship going with all critical suppliers at this stage.

As we hold the first meetings, we sell the program to the suppliers, and suppliers sell their capabilities and services to us. Some will say this program is not for them. They might not have any parts or systems to adapt to our aircraft, and development from scratch is too risky for them.

Typically we can’t pay for the development of new systems for our aircraft. We will have to use a modified version of what the supplier is already developing or producing. This is especially true for the engines. New aircraft of this kind are designed around engines already in use by other projects.

It’s critical we find an engine that is mature and in production. And that we can get it in a version that meets our Green goals for the program. To develop both engine and aircraft new for a program is for the experienced OEMs, and they go through mega problems doing it many times.

Other areas where we can’t develop from scratch are avionics and flight control system (flight control computer for autoflight, actuators, sensors). These contain software of thousands of programmer-years, and we adopt these “as is” to a large degree and design the aircraft around them.

Making a “Green” aircraft

Our ambition is to make a “Green”  19 seater. We have done our homework in the Conceptual Work that our range requirements of 500nm for the aircraft with full passenger load, makes a battery-based aircraft non-feasible. Not with the batteries we can get in the timeframe of this project.

A hybrid can get us the range, but it complicates the aircraft without promising any gains over a classical turboprop in fuel burn and, therefore, emissions. The maturity of hydrogen solutions are not at a stage where we can run a normal project and expect to crack the problems of a hydrogen propulsion system in the project.

This means we have to find a turboprop engine that can run on SAF (Sustainable Aviation Fuel). With a fuel system and engine that can accept 100% SAF, we meet the goal of producing a Green aircraft without taking unnecessary risks in the program.


Our total team gradually expands to around 100 persons during the Pre-launch Phase.

Most of these are Preliminary Design Engineers for different areas of the aircraft, but we also need other Specialists (Project managers, Stress engineers, IT specialists) and Admin personnel.

To this we add Sales and Marketing profiles, Purchase specialists to deal with the suppliers, Economists, and as we will see in next week’s Corner Certification Specialists.

At this stage we hire our first Production Specialist as well, to start the investigations on how we shall produce the aircraft. Shall we set up Final Assembly (FAL) ourselves, or contract an established aircraft company to do the FAL for us?

Next week we continue our drill down and discuss the remaining tasks in the Pre-Launch phase.

1 Comments on “Bjorn’s Corner: The challenges of airliner development. Part 12. The Prelaunch Phase.

  1. At the risk of having lost context, I note that new designs of components are developed.

    The geared fan, albeit probably using knowledge from large turboprops like the T56, Tyne, and newer ones.

    Electric brakes on the 787?

    Constant speed drive was new decades ago.

    New avionics data bus methods as on the A380 and 787 (severely constrained Ethernet).

    Inertial navigation systems. (Rooted of course in military technology including missiles. I suppose the star-tracking system on Blackbirds and C141s could be called a modern version of traditional sextants.) The ‘ring laser gyro’ uses a principle I remember from a physics course in the 1960s, to measure velocity rather than acceleration, one less integration to get to distance.

    Budgets for small aircraft may be limited, but if there is a substantial advantage in performance or price….. Fiber-optic versions of ring-laser gyros perhaps.

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