As the aviation industry evolves, an emerging sector that aims to introduce electrically powered Vertical Takeoff and Landing (VTOL) aircraft into our airspace, Advanced Air Mobility (AAM), promises to offer new transportation options. However, the success of this vision hinges on a critical yet often overlooked component: the enabling policies for the infrastructure to support these aircraft.
With classifications from airports and heliports to vertiports and back again, the vertical flight infrastructure policy landscape continues to undergo significant changes. This article addresses where we’ve been, where we stand, where I think we may be going, and what needs to happen in the ever-changing policy arena relating to vertical flight infrastructure.
Historically Speaking: The Evolution of Vertical Flight Standards
A Vertiport By Another Name (Heliport)
The journey of vertical flight infrastructure standards in the United States began in December 1959 when the Federal Aviation Administration (FAA) released its first Heliport Design Guide. Since then, these standards have undergone nine revisions, with the most recent update, Advisory Circular (AC) 150/5390-2D, published on January 5, 2023.
The Short-Lived Original Vertiport Standard
In 1991, industry developed tiltrotor aircraft, the FAA introduced its first standards for vertiports through the Vertiport Design AC 150/5390-3. Unfortunately, the ambitious vision for widespread vertiport adoption failed to materialize, largely due to the extensive clear space required for compliance. As a result, the FAA withdrew this standard in 2010.
Engineering Briefs Galore
Recent advancements in electrically distributed lift technology have breathed new life into the VTOL transportation concept. As a result, the FAA has worked diligently since late 2020 to establish new standards for vertical flight infrastructure that can support this innovative new sector. Using a phased approach, the FAA issued Engineering Briefs (EBs) as interim guidance, with the end goal of codifying these standards in an AC.
The FAA published the first EB that introduced initial vertiport standards, EB-105, in June 2022. On December 27, 2024, they issued a Congressionally-mandated follow-up, EB-105A. This latest EB introduces key updates in infrastructure classification, marking, geometry, parking and downwash and outwash caution areas.
A Vertiport is a Heliport Now?
In an interesting turn of events, instead of developing a standalone Vertiport AC similar to its original 1991 publication, the FAA has decided to incorporate the information from EB-105A into the existing Heliport AC 150/5390-2D. This document now redefines vertiports as a specialized category of heliports with distinct requirements.
On the upside, this classification change simplifies the approval process for local municipalities, as most already have ordinances that address heliports. On the downside, FAA and industry stakeholders have more work to do to finalize vertiport design guidance in the next revision of the Heliport Design AC. A Congressional mandate slates that updated publication for no later than the end of this year. What will it say? Only time will tell but I’ve summarized some of the hot topics and how I think the FAA may – or should – address them.
Top 3 Ongoing Issues and Deep Thoughts
The Prescriptive vs. Performance-Based Dilemma
Historically, vertical flight infrastructure standards have been primarily prescriptive and have outlined specific design requirements. Since 2013, due to the International Civil Aviation Organization’s (ICAO’s) advocacy, there’s been a growing push towards performance-based standards, informed by the capabilities of individual aircraft.
The FAA explored the performance-based concept for heliports as early as the 1980s, suggesting that heliport design could vary based on the performance classifications of different helicopters. However, progress stalled due to insufficient data in helicopter flight manuals to inform and support such standards. This drove the need for extensive and expensive flight testing which the industry pushed back on.
Rex’s Deep Thoughts: A hybrid approach combining prescriptive and performance-based criteria seems likely to emerge. This would balance traditional design standards with the flexibility needed for evolving aircraft capabilities.
Addressing Safety Concerns: Downwash and Outwash
A notable addition to recent standards is the FAA’s inclusion of Downwash and Outwash (DWOW) considerations. The FAA has defined DWOW as “the downward and outward movement of air caused by the action of rotating rotor blades, propellers, or ducted fans. When this air strikes the ground or another surface, it causes a turbulent outflow of air from the aircraft.”
Although this phenomenon is well-documented in the helicopter industry, EB-105A marks the first time the FAA has assigned a specific velocity to DWOW to plan Downwash/Outwash Caution Areas (DCA) (now defined as any area where downwash and/or outwash velocities may meet or exceed 34.5 mph).
This change gains importance in light of recent DWOW incidents. The Australian Transport Safety Bureau identified 18 helicopter downwash incidents over five years, nine of which occurred at hospitals, resulting in six injuries. In one such incident from October 2021, a DWOW event involving an AW139 helicopter in Australia caused serious injury to a pedestrian. Similarly, the UK’s Air Accidents Investigation Branch has conducted an investigation that highlighted systemic safety issues in the design and operation of hospital helicopter landing sites, following the March 2022 DWOW incident involving an S92 helicopter that resulted in a fatality.
Rex’s Deep Thoughts: The introduction of Downwash/Outwash Caution Areas (DCAs) at vertiports and heliports, while a positive development for safety, may require reevaluation of existing heliports, risk assessments and the implementation of mitigation strategies. Addressing these issues will require a coordinated national effort.
The Oversight Conundrum
While the FAA develops and publishes standards for aviation infrastructure, its authority to enforce compliance with these standards remains limited. The FAA has oversight authority only for public-use heliports, and even then, its enforcement capability is limited unless federal funding has been used for the facility’s development.
According to the Code of Federal Regulations (CFR) Title 14 Part 157, a public-use facility is defined as being “available for use by the general public without a requirement for prior approval of the owner or operator.” In contrast, private-use facilities are described as “available for use by the owner only or by the owner and other persons authorized by the owner.”
This distinction creates complications for AAM operations. Public-use facilities, by definition, must be open to the general public, including private pilots. This inclusion is problematic for AAM, which relies on high-volume, commercial transportation models that typically exclude general aviation. At large airports, general aviation is segregated to separate areas to avoid conflicts with commercial Part-121 air transport operations. However, heliports and vertiports often lack the space for such segregation. This raises concerns about air traffic conflicts, flight delays and the potential for high-risk situations to develop.
Further complicating the issue is the fact that private-use airspace is not protected by the FAA, and private-use facilities are ineligible for federal funding through the Airport Improvement Program (AIP). This funding and oversight gap could limit the development and operational integration of AAM facilities at private locations.
According to the FAA’s online airport master record database ADIP, there are 6,253 heliports in the U.S., of which only 56 are designated as public-use; the remaining 6,197 are private-use, which the FAA has said falls under state jurisdiction. This gets even more interesting when states, such as Texas, explicitly choose not to regulate heliports.
Rex’s Deep Thoughts: A new category, such as “Commercial Use,” could be introduced to define facilities intended for structured, high-volume operations like AAM. This category could enable private-use locations serving commercial operations to receive federal grant funding, benefit from FAA oversight, and implement safeguards to manage airspace and operational risks effectively. This would require legislative and policy change. However, to ensure that General Aviation is allowed to prosper in parallel to commercial operations in AAM, “Personal Use” must also be defined.
Conclusion: Advanced Air Mobility Requires Flying Right
While recent course corrections by Congress and the FAA are steps in the right direction, they are insufficient to address the deficiencies of our current mediocre vertical flight infrastructure system that has been neglected for far too long.
I remain optimistic that meaningful changes can be implemented, but success will require a collaborative effort involving industry and regulatory bodies at the federal, state, and local levels.
To achieve this, open and transparent dialogue throughout the development process is essential. The days of drafting standards in isolation and sending them to industry for comment after the fact must end. True progress depends on active and inclusive participation from all stakeholders. So let’s fly right…together.
By: Rex Alexander