Commercial aviation is the fastest and most commonly used mode of transport for long distance travel. Faster, cheaper, safer and quieter innovations remain as significant drivers of aviation technology.
On 21 October, The International Road Federation in support of the Southern African Transport Conference, hosted its fourth and final webinar for 2020 and touched on aviation technology developments and the evolving state of the Africa’s flight industry.
Chris Burger, senior researcher at the Centre for Scientific and Industrial Research (CSIR), got the webinar wheels up with a discussion on aviation technology and innovation. Burger began by evaluating the effectiveness of the ‘hub and spoke’ system of travel, where passengers travel to a hub and from that hub to possibly another hub and/or travel to their final destination. This system of travel allows for centralised infrastructure, however, it can make for an uncomfortable travel experience. It is not the ideal way to travel from the passenger’s perspective.
There is a trend away from ‘hub and spoke’ travel with passengers opting for direct, smaller flights that are still profitable for airlines. Burger stated, “The trend has manifested in several interesting ways; one of them is that the major Middle Eastern airlines have seen declining revenues since 2016 and even before the flu [COVID-19] started, passenger numbers declined significantly in the last year or so.” Another way this trend is manifesting, according to Burger, was with the termination of Airbus’s A380 production and more international and long-distance flights going to Cape Town and Durban in recent years.
Burger also notes the increasing consciousness of the environmental impact of aviation. “The stated objective is to halve emissions by 2050 and keep carbon dioxide at current levels despite expansion,” added Burger. There have been amendments to global civil aviation regulations (Part 91), relating to curtailing aviation emissions. Burger stated there is an element of voluntary compliance but large operators are compelled to abide by certain restrictions. This emission regulation pertains to large aircraft and airlines with a fleet producing carbon dioxide emissions of over 20 000 tons per annum.
Avgas, the only fuel containing tetraethyl lead as an anti-knocking agent, has been commonly used as aviation fuel. However, Burger said it is being largely superseded by Kerosene-based fuels and unleaded petrol. Biofuels are undeveloped with only four large airports making it reliably available. Burger stated it is contributing around five percent of aviation fuel used and is expected to constitute the majority of aviation fuel by 2050. The United States Air Force has reported fungal growth in fuel tanks, burger added, noting there has also been evidence of resin in fuel tanks and engines, the point being bio fuel is not without its challenges but Burger maintains these issues are being resolved.
“Around perhaps 20% of operating costs is associated with the unionised members in the front seats [pilots], so a lot of airlines may be very happy towards a solution with no pilots,” said Burger regarding the increasing trend towards unmanned aircraft, which has compelling advantages. For small aircraft, the 80 – 100 kg payload of a pilot is significant. There are also possible safety benefits as tiredness and other human qualities get factored out in unmanned aircraft. Burger does see customer acceptance as a major hurdle for automated flight.
The Aviation 2050 goal to halve the aviation sector’s net CO2 emissions, in line with the Paris Agreement goal to limit global temperature rise to below 2ºC above pre-industrial levels, will take a significant effort from the entire industry. The development of electric propulsion systems could be fundamental in creating cleaner, greener and cheaper aircraft. Many aircraft manufacturers are currently working on developing electric aircraft, including NASA and Uber. The NASA X-57 Maxwell aircraft uses 12 small, 10.5 kilowatt motors for lift and two 60 kilowatt motors for cruising. Airbus has been experimenting with electric propulsion with several aircraft, notably the E-Fan X (now cancelled), the CityAirbus and the Vahana.
Burger also mentioned Uber Elevate, which aims to have an aircraft operational by 2023 – this will use four lifting motors and four tilt motors. These aircraft have zero emissions. The development of the electric aircraft power sources and propulsion systems still has challenges. Power sources such as lithium-ion batteries, while rechargeable, are unable to provide the long flight time of a piston engine. The safety of other power sources such as hydrogen and even lithium-ion batteries also remain relatively uncertain. Propulsion systems are underpowered compared to piston engines, requiring more motors.