On The Radar
Eve Urban Air Mobility, along with partners working on its plans to develop an ecosystem for eVTOL aircraft flights, last week published a concept of operations (Conops) covering the vast and crowded city of Rio de Janeiro. For the offshoot venture from Brazilian aerospace group Embraer, the document gives the Eve-led team a chance to demonstrate how the new mode of transportation could work on home turf. In the introduction to the 82-page publication, Roberto Honorato, head of airworthiness with Brazilian civil aviation regulator ANAC, concluded that “this collaboration helps us reach our common goal of safely developing and launching this new technology.”
A welcoming climate for eVTOL aircraft certification is not enough, as the “UAM ecosystem” encompasses far more than just the new vehicles. Air traffic control (ATC) is one of the biggest demands, given the high anticipated volumes of traffic and the expectation that eventually the aircraft may operate without pilots on board.
Brazilian ATC is operated by the Air Force’s Department of Airspace Control (DECEA), using software developed by Embraer subsidiary Atech. DECEA’s published plans include adding a layer to track drones, which Atech is already working on, and a third layer to control eVTOL flights. The vendor for that development is still undetermined, but smooth integration with the existing layers will be needed.
The Rio Conops document is largely generic and “high concept,” graced with conceptual artwork showing vertiports as far afield as Australia alongside stunning photos of Rio with artfully inserted images of Eve’s proposed four-passenger aircraft. In some cases, realism is suspended as the images show UAM services in places where they are not anticipated and with aircraft flying at altitudes where they’re not expected to fly, such as above the 710-meter (2,329-foot) granite peak of Corcovado with its statue of Christ the Redeemer.
The Conops does have considerable substance. It proposes an initial limited service between Galeão International Airport and three neighborhoods, a plan that was tested late last year with helicopters operated by Helisul standing in for eVTOLs. That trial operated only from the farthest neighborhood, Barra da Tijuca, which the plan judges to have “high” numbers of early and short-term adopters, with the greatest potential time savings, from 30 to 75 minutes, and the largest potential user population, over 380,000. Pages 50-55 of the document are the most specific on the challenging physical and social geography of Rio de Janeiro and the proposed solutions.
While about 13.6 million people live in the Rio de Janeiro metropolitan area, the most likely customers for the envisaged eVTOL air taxi services are squeezed into a narrow strip between the mountains that provide the city’s spectacular backdrop and the sea. This area is marked by an approximate half-circle sweeping clockwise from the northeast Galeão International Airport on Governor’s Island, down past the port area to the city center with Santos Dumont airport extending into the bay, then past the storied beaches of Copacabana and Ipanema/Leblon, around São Conrado where the mountains fall almost directly to the sea, and then to the newer neighborhood of Barra da Tijuca where the 2016 Olympics were installed and where the Jacarepaguá general aviation airport has long resisted encroachment by development. Two military airports inland and to the west also complicate air traffic control arrangements.
The Conops document goes into some detail in listing potential obstacles to secure navigation that result from the terrain, including:
- “Frequent loss of GPS…integrity/continuity while operating at low altitudes in Rio TMA (jamming, ionosphere anomaly, or terrain effect).”
- “Weather peculiarities: frequent haze in the morning at shore and over mountains. Convective weather formations are frequent in the afternoon all year. Due to the topography, weather in low-altitude routes may be significantly different from the observed/forecasted data provided at airports.”
The solutions proposed include better, more detailed terrain mapping and more granular and more frequent weather tracking and forecasting.
Another Rio navigation hazard is couched in euphemisms. Slums on the hills dominated by criminal gangs spread broadly through the city are subject to occasional gunfights. The Conops appears to acknowledge this risk when referring to “[o]verflights below 500 ft [that] may expose the aircraft to a substantial risk of an airstrike.” The same conflicts may explain the GPS jamming referred to above. The document shows the route approved for Helisul’s helicopter trial: a preferred shorter inland route, crossing over and between hills, with a longer alternate route hugging the shore when conditions, atmospheric or human, make the shorter route hazardous.
A concept is not a complete solution. Even so, there are holes in this document. For instance, DECEA’s three-layered control concept assigns higher altitudes to aircraft and the lowermost layer to drones, with eVTOL aircraft between. Rio’s mountains poke into the aircraft layer, spoiling the generalities and requiring specifics. The Conops' idealized diagrams of ascent, descent, and cruising altitude are illustrative, but there’s no diagram of what altitudes will actually be used in Rio, or of the altitudes used in the helicopter trial.
The Conops focuses on the charmed crescent of Rio’s upper-class shore, treating the rest of the city as an obstacle to be flown over, or ignoring it altogether. The sister city of Niterói across Guanabara Bay, linked to Rio by ferryboats and a bridge subject to traffic jams, appears on a map and in a table as a possible future route, and in three uncaptioned photos, but never in the text. Certainly, it too could benefit from urban air mobility. During a May 6 discussion hosted by the Rio Bar Association, Coronel Marcelo Cavalcante, head of CGNA, DECEA’s office for new or difficult situations, described working at the 2014 World Cup soccer tournament in Barra da Tijuca while living in Niterói: “You couldn’t get from there to here.”