Estimated reading time 7 minutes, 35 seconds.
I spoke to Giorgio Clementi, president of the International Test Pilots School (ITPS) Canada Ltd., a European Union Aviation Safety Agency (EASA) authorized training organization (ATO) for flight test training, based in London, Ontario.
The school offers a range of flight test pilot and engineering courses with candidates coming from across the aviation spectrum. More recently, it has also counted German eVTOL developer Lilium and Slovenian cargo drone company Pipistrel among its clients, as eVTOL manufacturers are seeing the need for a more structured approach to flight testing.
We discussed the project where his team are in the final phases of putting together an eVTOL engineering simulator. This device is planned to support flight test courses starting in Q2 2022.
The school’s interest for eVTOL was a natural progression from its unmanned aircraft systems (UAS) program that Giorgio established in 2013. He stated that the school is cognizant of the rapid development in advanced air mobility (AAM). The school was proactive in tailoring the course content, duration, and format to eVTOL test pilots’ and engineers’ needs, which are not necessarily the same for candidates that would go on to work on CS-25 / 14 CFR Part 25 programs.
Nevertheless, it should not be assumed that AAM vehicles are simple aircraft. For the most part, they have complex fly-by-wire flight controls, state-of-the-art sensors, navigation, and flight management systems, all of which must be certified. While these companies are employing young, talented, and highly skilled engineers, Giorgio noted that one risk could be if they do not follow the traditional ethos of flight test. In a nutshell, this is the incremental and systematic approach to flight test planning, risk management, and execution.
The UAS course syllabus was designed around the NATO Standardized Agreement (STANAG) 4671, which standardizes the airworthiness requirements for unmanned aerial vehicles (UAVs) for NATO members. With the advent of EASA’s Special Condition SC-VTOL-01, and associated means of compliance (MoC), which assume a sound understanding of the handling qualities rating, Giorgio needed a representative platform on which to teach these techniques.
The handling qualities assessments are based on Aeronautical Design Standard (ADS) — 33 exercises such as pirouettes, slalom maneuvers, etc. This is where a simulator becomes an invaluable tool to train candidates to competency for the discipline required to set up these pilot-in-the-loop tasks in highly automated aircraft.
EASA has already established a very targeted regulatory framework for eVTOL certification, but Giorgio also believes that the U.S. Federal Aviation Administration (FAA) requirements will be very similar.
The eVTOL engineering simulator
The simulator is based on a Bell 206 with a 317-shaft horsepower (shp) Allison engine. To have a similar figure of merit (FoM) to the Bell 206, the school’s engineers came up with an 18-rotor distributed electrical power system with 340 kilowatts of electric motors. With the current cell technology, this assumes approximately 1,600 pounds (726 kilograms) of batteries, resulting in a vehicle that weighs around 2,800 lb (1,270 kg) — not far off from the Bell 206. Giorgio said that his engineers are still tweaking the design to optimize the flying qualities and should be ready by the first courses in the spring.
Since last November, the school started using mixed reality with Varjo VR headsets with excellent results in the fixed-wing courses, which will now also be used in this simulator. This gives a full immersive experience and allows you to see your hands on the controls and the actual instrument panel.
Specific eVTOL flight test challenges
I asked Giorgio if he saw any challenges when testing and certifying eVTOL aircraft. He pointed out that these aircraft will be using very high voltage systems and will also need good thermal management to dissipate the generated heat. Endurance is another issue, and with the current technology, he only managed to get about 20 minutes of practical endurance. This is a challenge for flight testing as there will only be a very short flight time to set up and carry out the flight test cards.
The operational aspects can also be a challenge. In the SC-VTOL-01 Enhanced Category, you need to demonstrate that the aircraft is capable of continued safe flight and landing after a critical malfunction of thrust/lift — in other words, it needs to land at the destination or alternate vertiport after such a failure. This is no mean feat. In addition, operating in an urban setting with a very specific environment continues to compound the challenge.
According to Giorgio, the success of AAM will very much depend on the flight testing that is being done right now, which must be conducted safely and accurately. He is reassured to see that many projects are employing some “old hand” flight test pilots and engineers, but with all the startups in the ecosystem, training new personnel will be essential to keep up with the demand.