This paper presents a summary of test results from an experimental flight campaign conducted as part of the Boeing 777 ecoDemonstrator program that used the Collins Aerospace Dual-Frequency Multi-Constellation (DFMC) enabled multi-mode receiver (MMR), the GLU-2100, as the primary position source. As part of this project the GLU-2100 software baseline that supports GPS and SBAS L1 was updated to support the acquisition and tracking of GPS L1/L5 and Galileo E1/E5a signals. This paper provides an overview of the software defined architecture of the GLU-2100 that enabled the addition of the DFMC capability to the certified baseline through a software update. Further the navigation mode and position integrity algorithms were updated to allow the DFMC navigation outputs to be used as the primary navigation outputs for the Flight Management System and the transponder. The details of the MMR software and firmware changes that were made to support the ecoDemonstrator program experimental use of DFMC positioning are provided. The ecoDemonstrator flight campaign included around 50 flight hours that covered Europe, Asia and North America. The flight test campaign is described in detail and an analysis of the raw GNSS data collected during this campaign is provided. A summary of the multipath error statistics of the DFMC signals is also provided. These statistics are critical in developing the error models that would be used in SBAS augmented and non-augmented DFMC RAIM algorithms such as ARAIM. Finally, the results from an initial test run against the currently available DFMC Minimum Operational Performance Standards (MOPS) is provided. The paper describes the very first use of a DFMC capable multi-mode receiver as the primary position source on a civil air transport aircraft. It is expected that the lessons learned from this flight test campaign will further enable and accelerate the use of DFMC signals in civil aviation.