Achieving the goals of climate neutrality by reducing the impact of aviation is a task that requires a carefully drafted roadmap for the development of disruptive technologies and concepts of operations. With particular attention to the emissions of pollutants and noise in airport local airport areas, a synergetic approach is needed that combines together interventions on the aircraft side and on the airport side. This calls for coordinated efforts in developing technologies that not only provide benefits during cruise conditions but also are capable of improving the local air quality and noise in airport areas where the impact of pollutants and annoyance to local communities has been demonstrated to be quite large in terms of morbidity and mortality.
INDIGO is a collaborative project.

INDIGO is a collaborative project between academia, research centres and airports that aims at identifying the margins of improvement in airport local air quality and noise resulting from the introduction of a new non-conventional mid-range aircraft featuring distributed propulsion based on hybrid electric/sustainable and conventional fuel powertrain and large aspect-ratio wings capable to fly quietly and in zero-to-low-emission mode (i.e. electric and SAF) at low altitudes near airports and resort to conventional aviation fuel only when required, e.g. at higher altitudes or to recharge batteries during cruise.

INDIGO explores a new paradigma of aircraft.

INDIGO will explore a new paradigma for the next-generation of silent and clean mid-range aircraft and for the way such a new aircraft will allow transforming the operations "at and near" airports. It will introduce improved methods for the analysis of future aviation environmental impact that, under the filter of uncertainty, will be able to account for non-conventional aircraft performance and future airport scenarios.


INDIGO project has received funding from the European Climate, Infrastructure and Environment Executive Agency (CINEA) under the Horizon Europe programme under grant agreement No 101096055.

  • HEU funding to EU beneficiaries 3,111 m€

  • Parallel funding to associated partners from UKRI 1,290 m€ 

The topic of the call is  HORIZON-CL5-2022-D5-01-12 – Towards a silent and ultra-low local air pollution aircraft.


Organization and Timeline

  • 7 WPs , 15 Deliverables

  • 36 months

  • Started on 1 February 2023

  • Ending on 31 January 2026



INDIGO’s Objectives and Ambition

The ambition of project INDIGO is to further the progress towards net-zero aviation by innovating the de-sign and the near-airport operations of the mid-range aircraft class. As a leap towards meeting the demand for both silent and ultra-low-emission aircraft near airports, INDIGO’s overarching objective is to explore, develop and perform initial validation of technical solutions for the combination of Distributed Hybrid Electric Propellers (DHEP) and Large Aspect Ratio Wing (LARW) air-frames capable of exploiting the most recent Noise Reduction Technologies (NRT) and fully-electric/SAF operations at low altitudes over airports. With a duration of 36 months and a team of experts in aircraft aerodynamics, aerostructures, propulsion, aeroacoustics, multi-disciplinary design, air traffic management and airport operations, INDIGO is well-positioned to realistically achieve the following specific objectives that address key needs and important research questions:


    1. Develop an innovative mid-range aircraft concept integrating Distributed Hybrid Electric Propellers (DHEP), Large Aspect Ratio Wing (LARW) airframe and Noise Reduction Technologies (NRT) and the corresponding novel methodology for analysis and robust optimal integration.

    2. Assess different concepts of operations for taxi, take-off, loiter and landing exploiting the performance offered by a DHEP-LARW aircraft.

    3. Explore the margins of improvements in Local Air Quality and Noise (LAQN) with respect to the projected (uncertain) TRL escalation of key technologies in DHEP, LARW airframes and Noise Reduction Technologies (NRT).

    4. Enhance current methods to evaluate pollutants and noise mapping over airport areas to provide more accurate assessments of Local Air Quality and Noise (LAQN) and to better inform policy-makers and air navigation services providers.

Project Implementation

Concept: a 3D project

INDIGO is structured around a concept that brings together, in a digital modelling and simulation framework, three elements: the aircraft system, the airport operations and the uncertainty on low-TRL technology performance: