BILL READ FRAeS reports on Dubai’s plans to begin operating the world’s first aerial taxi service using autonomous passenger-carrying drones.

Dubai has announced plans to begin operating an aerial taxi service from July using passenger-carrying drones. The announcement was made by Mattar al-Tayer, Director-General of the city's Roads and Transportation Agency at the World Government Summit held in Dubai in February.

Mattar al-Tayer, Chairman of the Dubai RTA announced that Dubai would be introducing a passenger-carrying aerial taxi service from July. (RTA)

The service would be operated using a fleet of Chinese-made eHang 184 eight-rotor autonomous aerial vehicles (AAVs). Fitted with a passenger cabin, these large scale electrically-powered drones can carry one passenger and luggage with a combined weight of up to 100kg and has a 30 minute flight time. A promotional video from the Dubai Roads and Transportation Agency (https://www.youtube.com/watch?v=a5Q2W0r5e-s), shows a customer using their mobile device to summon the drone from a parking area from where it would fly to where they wanted to be collected.

There is space in the AAV to carry a small suitcase. (RTA)

After storing their luggage in a small ‘boot’ at the back of the drone, customers would get into the cabin and use a map touch screen on a tablet console to select their destination from a predetermined menu of take-off and landing sites.

Passengers would enter the AAVthough a gull-wing door. (RTA)

Once their seat belt had been fastened, the air-conditioned drone would take off and fly them to their programmed destination. The flight would be completely automated and would require no further input from the passenger but would be monitored and controlled from a ground-based flight command centre.

The passenger seat in the 184 will include a touch screen panel to input destination details. (eHang)

According to al-Tayler, the introduction of the AAVs in part of a directive from Sheikh Mohammed bin Rashid Al Maktoum, Vice-President and Prime Minister of the UAE and Ruler of Dubai, to transform Dubai into the ‘smartest’ city in the world. The RTA is also working on plans to provide self-driving road transport with the aim of using self-driving vehicles for 25% of total individual trips by 2030. As part of this policy, the RTA is to buy 200 Tesla electric vehicles fitted with autonomous driving technology to be added to the limousine fleet of the Dubai Taxi Corporation (DTC).

Introducing the eHang 184

eHang 184 specifications. (eHang)

The drone manufacturer, eHang, is based in Guangzhou in China with two overseas branches in Dusseldorf and California. In addition to the large scale 184 AAV, eHang specialises in small leisure and commercial quadcopter drones. According to eHang‘s website (http://www.ehang.com/ehang184), the main frame of the 184 AAV is constructed of carbon fibre epoxy composite with other components made of aluminium alloy. Measuring 3.989m x 4.024m x 1.447m (including propellers), the aircraft weighs 240kg and is powered by eight rotors with a maximum output of 152kW. The cabin has a width of 1.018m and a height of 2.074m and is fitted with a moulded seat. Luggage capacity is limited to an ‘18in backpack’.

The AAV flies in an ‘inverted U shape’, flying up vertically to a set height, then flying horizontally and then descending vertically over the landing area. It has a maximum payload of 100kg - which is the same as the version announced for Dubai - but only has a 25min cruising duration which is less than the 30min advertised for the Dubai service but perhaps this refers to the horizontal flight time. The manufacturer claims that the 184 can cruise at 60km/hr at a maximum height of 3,500m - although al-Tayer’s presentation said that speeds for the Dubai AAVs would be limited to 100km/hr down from a maximum speed of 160km/hr at a height of 3,000ft (914m). The AAV can still fly safely with one power system out of action and will automatically land in the event of component malfunction. The command centre could also prevent the AAV from flying if it considered that weather conditions were too dangerous.

Flight tests

Still from an eHang video showing the 184 being flight tested. (eHang)

Matt al-Tayer said that the Agency had ‘experimented with this vehicle flying in Dubai's skies’ in conjunction with the Dubai Civil Aviation Authority (DCAA), although when and where these tests were carried out is not clear. The 184 has been test flown in China and, in May 2016, an agreement was signed between eHang, the Nevada Governor’s Office of Economic Development and the Nevada Institute for Autonomous Systems (NIAS) which gave the go-ahead for NIAS and eHang to collaborate in flight testing, training and development of the passenger-carrying drone at its FAA-designated Nevada UAS test site. However, it is not certain how far these flights tests have gone and how close the 184 is to airworthiness certification.

A question of airspace

Dubai RPAS no-fly zones. (DCAA)

The announcement of the introduction of large scale passenger-carrying drones in the skies over Dubai has come at the same time that the emirate is busy trying to restrict the risks posed by UAVs. As far as smaller UAVs are concerned, the DCAA regulations say that drones can only be operated in line of sight and it is illegal to fly them over congested areas or within 50m pf people, vehicles and structures (https://www.dcaa.gov.ae/Files/UAV%20Safety%20Rules%20Flier2%20with%20arabic.pdf). In addition to introducing regulations in April 2015 requiring drone registration, the emirate also has no-fly zones for drones over both its commercial airports, Al Minhad Air Base and the Palm Jumeirah. Prior permission is also required for nine other areas, including downtown Dubai around the Burj Khalifa (currently the highest building in the world).

Despite these restrictions, there were three incidents in June, September and October last year in which flights at Dubai International Airport were suspended due to drone incursions. As a result of these incursions, Dubai Airports is conducting trials of a tracking system to detect drones in the vicinity of its airports and the radio frequency on which they are being operated. Those caught infringing the no drone fly zone over the aircraft face up to three years imprisonment and a fine of up to 100,000 dirhams ($27,228).

This raises the questions - the first of which is where could the AAV actually fly? Assuming that the larger AAV has to comply with the same regulations, its area of operation must be somewhat limited, as much of Dubai is built up with many high-rise buildings. Its most obvious use would be to fly people to and from the city’s airports and the business district - both of which may be out of bounds.

According to the promotional material, the fleet of AAVs would operate on pre-programmed routes to a pre-determined set of destinations where, presumably, there would be space for them to land. Where these routes and landing sites will be is not yet clear - presumably they would be in open areas away from people and tall buildings with sufficient space for several AAVs to land at once. How convenient would the locations of these pick-up and landing sites be for a business traveller, compared to a door-to-door service offered by a conventional taxi? 

Are 30mins enough?

The RTA video shows an empty AAV taking off to fly to a customer. (RTA)

Another question is the range over which the AAVs could operate. The RTA’s promotional video showed the empty AAV taking off to fly to the customer and then immediately flying on to his destination. Assuming that this take-off site is a central ‘parking area’ where the AAVs are stored, serviced and recharged, the AAV would need to fly to the customer pick-up point, then fly to its destination and then return to the central area. All these three journeys would need to be completed within the maximum flight time of 30mins. If the AAV did not have enough battery charge to return to its base, would it then need to be recharged at one of the landing sites? The RTT has said that battery recharging could take between one to two hours.

Safety issues

The eHang 184 may have potential safety issues with eight unshrouded propellers close to the ground and the passenger doors. (RTA)

Although the eHang 184 is fitted with safety systems which will keep the AAV flying and enable it to land safely in the event of mechanical problems, there must be safety concerns about the risk of battery or such a large aircraft over a built-up area, as they would be unable to autorotate like a helicopter.

An additional safety concern is that the AAV design features eight unshrouded propellers located at ground level and close to the passenger door. It would therefore be very important that the propellers are not in motion when passengers are entering or exiting the aircraft. Revolving propellers could also be a potential safety issue if the passenger needed to exit the AAV in a hurry in the event of an accident.

The AAV also has the limitation that it can only carry one passenger and a very limited amount of luggage. It would not therefore be a suitable option for a group of business people wishing to travel somewhere together. It is also not yet known what would be the likely cost of using an AAV compared to a car or a taxi.

Ready by July?

Are the regulations and infrastructure in place to introduce the AAVs from July? (RTA)

There is also the question of timing. The RTA has said that the service is to commence in July, yet there is no indication that the eHang 184 has yet received flight safety certification from either the US or China. It is also not known whether the RTA has placed an order from eHang for a fleet of AAVs or what progress has been made on setting up the ground-based control station.

However, Dubai is renowned as a city of progress where miracles can happen and happen fast, so the future vision of unmanned aerial taxis may yet come true.

Bill Read
21 February 2017

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