Urban Air Mobility:

UAM refers to all aerial mobility options in dense urban areas, which includes traditional helicopters and anticipated electric-propulsion aircraft. Helicopters have existed since the early 20th century but they remain on the fringes of mobility options due to the high cost of operation and the significant noise concerns. Recent advances in battery technology have attracted a wave of innovators, engineers, and investors who are interested in bringing electric-propulsion aircraft to the market. There are over 200 electric-propulsion aircraft currently under development around the world, which are anticipated to have lower operating costs and be quieter than helicopters.

Various UAM services are now within reach because some electric-propulsion aircraft manufacturers have agreed with the FAA on the certification requirements for commercial operations. Due to the significant interest from investors, local governments, and manufacturers, several UAM operators have announced new service launches within the next 3-4 years, using electric Vertical Takeoff and Landing (eVTOL) aircraft. Now is the time for cities and local governments to be proactive in setting policy and planning for potential UAM operations in their jurisdictions. NASA has proposed six UAM maturity levels (UML) differentiated by the volume of operations and levels of automation of aircraft operations and air-traffic management.

This article focuses on UML 1 and 2, which are anticipated in the latter half of this decade and early in the next decade. This initial maturity level will have piloted low-density operations in controlled environments. Of the many components required to get UAM services off the ground, the three principal components are the aircraft, the facilities, and the airspace structure and management.

eVTOL aircraft development is making rapid strides, and the current airspace structure and concept of operations will likely be adequate to support operations in UML 1 and 2. Therefore, the planning and development of facilities needs to mature to the level of the other two principal components.

Vertiports are expected to be a combination of upgraded existing heliports and purpose-built new facilities.

There are many important aspects that cities, local authorities, and existing airport operators should consider as they plan for vertiports in their jurisdictions. Landrum & Brown has a long history of planning heliports for cities, hospitals, and independent operators. Leveraging its technical and global experience, L&B has addressed some of the common questions about vertiport planning and development. Even though many airports, both commercial and general aviation, have helipads, this article draws parallels between standalone heliports in urban environments and vertiports as they are most similar in their planning, development, and operating considerations.

What certification and planning regulations apply?

The FAA and EASA do not have certification requirements for standalone heliports, unlike airports, which go through an intensive certification process before commencing operations. The primary reason for the FAA and EASA to exempt heliports from requiring certification is they serve very few scheduled air transport operations.

Initial UAM operator models are based on point-to-point on-demand service, but scheduled service may be offered in the future that may trigger new certification requirements.

Aviation regulators of ICAO member countries may require compliance with design guidelines specified in ICAO Annex 14, but in the U.S., the FAA only has direct regulatory oversight over heliports that accept FAA grants. Currently, only three of the 6,000 heliports in the U.S. have accepted FAA grants and are required to adhere to the Heliport Design AC. The FAA does not have direct regulatory oversight to enforce the Heliport Design AC, but local and state laws may require heliport operators in their jurisdictions to comply with the FAA AC. In fact, local laws may include additional or more stringent planning and operational criteria that possibly make it inconducive for the development of new vertiports. For example, lawmakers have introduced bill H.R. 4880, Improving Helicopter Safety Act of 2019, that prohibits helicopter flights over any city with a population of eight million people. This bill has not passed the House; however, similar legislation could be introduced by state and local governments. Therefore, vertiport developers should engage extensively with local governments during the planning process to determine the applicability of local laws.

Who will use the facility?

New vertiport development could be sponsored by cities, independent infrastructure operators, or be purpose-built for specific UAM operators. Facilities that are exclusive to specific operators will likely only serve a few aircraft types and could be optimized to take advantage of specific aircraft characteristics. On the other hand, approval of operator-exclusive vertiports could result in concerns such as proliferation of vertiports with competing requirements, inefficient resource utilization due to disaggregation of facilities, and the risk of expensive abandoned facilities Common-use facilities that cater to multiple operators with a variety of aircraft types and should be planned for a critical aircraft type, which can be either one aircraft or a composite of various aircraft types.

The FAA has indicated that the Vertiport Design AC may include performance-based categorization for vertiports, which may help narrow the number of aircraft types to be considered during the planning process.

Assuming similar regulations as helicopters, it will be the Prior-Permission-Required vertiport owner/operator’s responsibility that pilots of all authorized operations are thoroughly familiar with the facility, its operational procedures, and any other facility limitations. Therefore, common-use vertiport owner/operator’s should balance flexibility with practicality during the planning process, so the operational or aircraft type restrictions are factored into the flight approval process. In addition to flexibility for the proposed use case, local governments must ensure continued long-term viability of facilities by balancing immediate requirements with future adaptability. Vertiport planners may also want to consider emergency situations beyond the proposed use case, such as the National Guard, Fire, or Law Enforcement. For example, L&B typically considers the Sikorsky UH-60 Black Hawk helicopter as a potential user when planning heliports, even if it is only intended for passenger or medical use.

What are the airside components of a vertiport?

The primary airside components of any vertiport will be the Final Approach and Take-Off Area (FATO), the Touchdown and Lift-Off Area (TLOF), the parking positions, and taxiways.

• The FATO is the area on which the pilot completes the final phase of approach transitioning to hover or landing, and the area on which the pilot transitions from stationary or hover to take-off.
• The TLOF is the load-bearing paved area on which the aircraft performs a touchdown or lift-off. The TLOF is typically centered in the middle of the FATO but could be located outside it.
• The Parking Position is an area where an aircraft is temporarily parked to avoid blocking the FATO and TLOF. Passenger operations and charging will be completed at the Parking Position.
• Aircraft need to taxi between the FATO and the parking position using taxiways. Vertiports need to plan for hover-taxi because most eVTOL aircraft do not have wheels for ground-taxi.
• These elements are planned based on the physical characteristics of the aircraft to be served. For helicopters, typical parameters considered are the maximum weight, the overall length, the rotor diameter, the tail rotor arc radius, and the undercarriage dimensions.

These elements are planned based on the physical characteristics of the aircraft to be served. For helicopters, typical parameters considered are the maximum weight, the overall length, the rotor diameter, the tail rotor arc radius, and the undercarriage dimensions.

The Design Helicopter for a facility is a single or composite helicopter that reflects the most demanding values for each critical parameter. eVTOL aircraft not only vary in design, but also in the underlying mechanism to generate vertical and forward flight.

Identifying the critical dimensions for these various designs and adapting planning can be challenging and is a source of significant risk for infrastructure developers following the Heliport AC.

What is the typical layout?

Several possible layout configurations are possible, yet most vertiports are likely to resemble high-volume transport heliports that have one or more FATOs with co-located TLOFs, and a separate parking area with multiple parking positions as shown in the diagram below. Transport heliports are only allowed to use “turn-around’” parking positions and not ”back-out” parking positions. This one-size-fits-all approach may not be suitable for vertiports. One of the primary safety concerns with rotorcraft is passengers walking into the main or tail rotor. Due to the different underlying technologies, each eVTOL aircraft type may require a separate passenger safety risk assessment before determining an appropriate stand layout.

If initial operational volume is managed with a single FATO, new vertiports should plan for expansion to multiple FATOs to accommodate future demand growth.

Current heliport regulations require FATOs with simultaneous operations to be planned with at least 200 ft (60 m) of lateral separation. These requirements could vary for vertiports depending on the aircraft dimensions, procedures, and layout. The capacity of a FATO, without passenger loading/unloading or charging, is anticipated to be around 20 operations an hour. It is recommended that new vertiports be planned with separate arrival and departure FATOs to maximize capacity.

Each component of the vertiport, such as the FATO, the taxiways, the number of parking positions, and the charging points, will have its own respective capacity. The capacity of the vertiport will depend on the layout and the concept of operations and will be equal to the capacity of the component with the lowest capacity. For example, even if the vertiport has space for multiple FATOs, the airspace may not be able to support a higher volume of operation. Therefore, L&B recommends a holistic planning approach to avoid incongruous facility development.

What airspace procedures are needed?

The FATO only refers to the area over which the pilot completes the final phase of approach or the initial phase of departure.
The approach or departure path, which extends well beyond the FATO, connects the vertiport to the wider airspace. Vertiports should be planned, like heliports, with two approach/departure paths that are clear of obstructions. Ideally, one path is aligned with the primary wind direction and the secondary path will provide adequate wind coverage to avoid operating with strong crosswinds.

Today, the majority of civilian helicopter operations are conducted under visual conditions in good weather. It is anticipated that initial UAM services will have similar limitations, and it is envisioned that pilots will likely fly GPS-based instrument procedures under visual flight rules.