There are about 30,000 tilt-wings certified, today. Look around.

Convertible VTOL aircraft are revolutionizing aviation, and tilt-wings are by far the most safe and efficient convertible VTOL aircraft. However, sometimes we come across the misperception that "tilt-wing aircraft are uncertifiable." So we would like to take a moment to show that not only are tilt-wing aircraft fully certifiable, but indeed you may be surprised to learn that you, dear reader, have already flown on a certified tilt-wing aircraft.

Trimmable stabilizers
‍Aircraft designers have long had to deal with the fact that the ideal angle of incidence for the horizontal stabilizer depends on the aircraft's speed. The ability to change this angle in flight, known as variable incidence or trim, offers significant control and efficiency advantages.

The concept has existed for almost a century, and was an important part of the design of the Bell X-1, the first crewed supersonic aircraft.

In the 1970s, trimmable stabilizers arrived in commercial aviation with the Airbus A300, and have been used in almost every commercial aircraft since. These stabilizers are effectively tilting wings with a limited range of motion, typically around 20 degrees. Next time you are waiting to board a flight, have a look at the tail - you will see the calibration markings.

Commercial aviation has the best safety record of any mode of transport. As an industry, we have achieved this through careful quality control and certification of all aircraft systems, and trimmable stabilizers are no exception.

They are built with multi-load-path, damage-tolerant hinges that can demonstrate continued performance post any single failure, and also that any secondary failure would not become critical within the inspection interval of the aircraft. The stabilizer is driven by a screw jack mechanism with mechanical and power redundancy.

These design techniques have a decades-long safety record, and we draw directly from them for the tilting wings in Aero2 and Aero3.

Safety
We all agree that a hinge is critical for safety and therefore redundancy of the hinge is key.  Even if you have many of them, you do not want to lose a propulsion system, or for structure to detach from the aircraft. So every hinge has to be designed multi load path and damage tolerant. 

Redundancy is a key advantage of distributed propulsion systems. If one propeller unit fails, the others can take over the load and you can continue safe flight. But what if one hinge fails, releasing structure that could then impact other parts of the aircraft and lead to a cascading failure? This obviously would negate the advantages of redundancy, resulting in complexity rather than safety.

In most convertible eVTOL aircraft, you have at least 6 tilting mechanisms. You have to maintain 6 tilting mechanisms and you have the chance that one is failing 6x higher than if you only have 1.

‍Efficiency
"Everything should be made as simple as possible but not simpler." - Albert Einstein

Fewer parts mean fewer inspections, less maintenance, and less cost. Every additional hinge adds complexity and ultimately costs. Having to maintain 1 hinge is by far less costly than having to maintain 6 hinges. Every one of these hinges needs careful maintenance, spare parts, and refurbishment. It needs to be built such that it cannot fail and create a cascading failure. This is the key to building an aircraft that is safe and cost-efficient, which is what operators are looking for.

Conclusion
The technology behind tilt-wing aircraft is safe, efficient and already certified in airliners in the form of trimmable horizontal stabilizers. But with this technology, we are building extremely versatile and efficient VTOL aircraft like Aero2 and Aero3, which will revolutionize critical transport operations, and accelerate sustainable aviation.

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