Urban Air Mobility Noise: 2025 Update on Current Practice, Gaps, and Recommendations

Abstract

Advanced air mobility (AAM) is an aviation concept that involves leveraging emerging technologies, business models, and other capabilities to bring aviation into the regular life experiences of the general public. There is no universally agreed-upon definition of AAM, but it has been described by NASA as “safe, sustainable, affordable, and accessible aviation for transformational local and intraregional missions.” Urban air mobility (UAM) is the sector of AAM that focuses on short-range, local missions around metropolitan areas.

UAM is generally envisioned to leverage heliports or novel vertiports located throughout metropolitan areas as airspace access points to provide rapid transportation capabilities, even in locations with extreme road congestion. Along with the many anticipated benefits of UAM, there will be potential noise issues that must be addressed. In 2018, NASA formed an Urban Air Mobility Noise Working Group (UNWG) to assemble noise experts from industry, universities, and government agencies to identify, discuss, and address UAM noise issues.

This paper presents an update to the 2020 UNWG white paper entitled, “Urban Air Mobility Noise: Current Practice, Gaps, and Recommendations [1],” in which a set of high-level goals was developed to address barriers associated with UAM noise that may hamper their entry into service. The purpose of this paper is to i) develop an updated set of high-level goals, ii) reassess the current practice in four areas of interest (Tools Development and Experimental Validation, Ground and Flight Testing, Human Response and Metrics, and Regulation and Policy), iii) identify gaps between current practice and the updated high-level goals, and iv) assess progress on prior recommendations and make new recommendations to close those gaps.

Unless otherwise noted, the content herein represents a consensus view of the UNWG participants. Any opinions, findings, conclusions, or recommendations expressed in this report are those of the contributors and do not necessarily reflect the views of their companies, organizations, or government agencies.

The 2025 high-level goals replace the 2020 goals and are directed at the community at large. These goals are:

HLG-2025-1. Develop noise and performance tools suitable for application to perceptually low-noise (relative to existing ambient levels) vehicle designs and operations that are validated using laboratory and flight test data.

HLG-2025-2. Develop and assess noise-reduction technologies that are validated using laboratory and flight test data.

HLG-2025-3. Develop vehicle noise and operations databases and tools to support the establishment of standards for UAM aircraft type certification and community noise assessment.

HLG-2025-4. Develop noise-abatement landing and takeoff (LTO) procedures for piloted and automated operations in coordination with UAM vehicle manufacturers and operators.

HLG-2025-5. Develop long-term exposure-response relationships by evaluating multiple metrics, including, but not limited to, day-night average sound level (Ldn) and percentage highly annoyed (%HA), to help inform policy at national, regional, and local levels.

HLG-2025-6. Encourage effective communication of noise effects, along with proactive engagement with the public.

HLG-2025-7. Establish and execute a systematic plan for capturing and sharing lessons learned across all areas related to UAM noise.