Standards Development

Scope

This document specifies the measurement methods for noise of large uncrewed vertical take-off and landing (VTOL) aircraft, and is applicable to the noise testing of large uncrewed aircraft with vertical take-off and landing capability (with a Maximum Take-Off Mass (MTOM) greater than 150 kg, level V according to ISO 21895), including multi-rotor, compound wing and tiltrotor aircraft. The methods specified in this documnet include the outdoor environmental measurement of aircraft noise and the aeroacoustic wind tunnel measurement.

Purpose

(Please see ISO/IEC Directives, Part 1, Annex C and additional guidance on justification statements in the brochure Guidance on New Work)

In recent years, the global low-altitude economy has developed rapidly. Large uncrewed vertical takeoff and landing (VTOL) aircraft have been widely used in scenarios such as urban air mobility (UAM), heavy-duty logistics transportation, emergency rescue, and air sightseeing, becoming the core equipment of the low-altitude transportation system. Such aircraft have the advantages of vertical takeoff and landing, flexible deployment, high efficiency and low carbon emissions. They are moving from experimental verification to large-scale commercial application, with accelerated technological iteration, continuously expanding application scenarios, and a rapid growth trend in industrial scale and market demand.

At the same time, large uncrewed VTOL aircraft mostly operate at low altitudes in densely populated areas such as urban core areas, residential areas and business districts. The noise generated by their multiple operating conditions including hovering, take-off and landing, and cruise is likely to have a significant impact on public life, the acoustic environment and the ecology. Noise has become a key bottleneck restricting the compliant development of the industry and public acceptance.

At present, there are significant gaps and inapplicability issues in international noise measurement standards: ISO 5305 only covers small unmanned aerial vehicles (UAVs) under 150 kg, the upper weight limit for application of relevant EU regulations and European Union Aviation Safety Agency (EASA) guidelines is relatively low, and the relevant standards of the International Civil Aviation Organization (ICAO) are for traditional manned aircraft, which fail to take into account the uncrewed VTOL configuration, multi-rotor interference, multi-operating condition noise characteristics and directional radiation characteristics, and cannot meet the noise measurement, evaluation and certification requirements of large uncrewed VTOL aircraft. The inconsistent noise measurement methods, incomparable data and unstandardized evaluation have hindered global technological collaboration, product certification and market interoperability.

The development of a unified, scientific and implementable international standard for noise measurement of large uncrewed VTOL aircraft is of great significance: first, to standardize test conditions, layout of measurement points, data processing and correction methods, and ensure the accuracy and comparability of uncrewed results; second, to support the low-noise design optimization of products and guide the technological upgrading of the industry; third, to provide a unified basis for regulatory authorities of various countries and improve the noise control and management system for low-altitude aircraft; fourth, to promote the safe, green and orderly development of the global lowaltitude economy, and balance industrial innovation and public environmental rights and interests