3A51 - Gulfstream MC-55A Peregrine

RAAF A51 Gulfstream MC-55A Peregrine

Four MC-55A Airborne Intelligence, Surveillance, Reconnaissance and Electronic Warfare (AISREW) aircraft are being added to the RAAF fleet as part of a $2.46AU billion acquisition under Project AIR 555 Phase 1. Originally planned as 5 units, the total was subsequently revised to 4 airframes/systems. Procurement of the the MC-55A capability is intended to bolster electronic warfare support to naval, air and land forces for operations in complex electromagnetic environments. According to the Defence Portfolio Budget Statements 2018-19:

AIR 555 Phase 1 – Airborne Intelligence, Surveillance, Reconnaissance, Electronic Warfare (ISREW). This proposed project will replace the Airborne ISREW capability currently provided by the Air Force’s Orion to support intelligence, surveillance, reconnaissance, kinetic and non-kinetic joint effects across all levels of conflict and all operating environments. Subject to Parliamentary approvals, construction is planned to commence in late 2019 and be completed by early 2023.

In June 2018, the US DoD awarded L3 Technologies (Greenville, TX) a US$83m (A$112m) contract for the upgrade of four Gulfstream G550 business jets to the MC-55A standard for the RAAF and this contract is set to run through to until August 2021. Work on the MC-55A Peregrine programme is being carried out at L3’s Greenville, Texas facility and at Gulfstream in Savannah, Georgia. The program has been managed through the USAF 645th Aeronautical Systems Group who specialise in the acquisition, modification and support of special purpose aircraft. Apart from airframe modifications to accommodate mission systems and secure communications equipment, the work also includes installation of a self-protection suite, and ground-based data processing systems.

The four aircraft are being acquired in two tranches (2+2) and will be incrementally upgraded to maintain commonality with US-developed systems. The first two ‘green’ Gulfstream G550 airframes were ordered in January 2016 and were registered in the US as N540GA and N542GD and were followed by N584GA in late 2018. The fourth airframe is yet to be identified.

Incidentally, the aircraft have inherited the name ‘Peregrine’ – a falcon bird of prey – which is a name originally used by Gulfstream in the 1980s for a single-engine business jet (and later a military training aircraft).

8 August 2025, Australian requested to upgrade the still undelivered MC-55A Peregrine fleet to MC-55A Baseline 2 configuration in a Defence Security Cooperation Agency notification (DSCA Transmittal 25-50) to Congress.

At this stage, it is planned that the aircraft will be based at RAAF Edinburgh.

Aircraft Serial	Const No.	Line #	Aircraft History
A51-????	5540	AU1	16/03/2016 Airworthy as Gulfstream G550,28/03/2016 Ferried from Gulfstream (Savannah, Georgia) to L3 (Greenville, Texas), Stored L3,09/05/2019 Registered N540GA with FAA (Expiration date 30/11/2019), Undergoing modification to MC-55A specifications. Flown and registered since 2019 with 645th Aeronautical Systems Group, USAF for tests.
A51-????	5542	AU2	20/06/2016 Registered N542GD with FAA (Expiration date 31/03/2020),21/04/2016 Airworthy as Gulfstream G550,29/04/2016, Ferried from Gulfstream (Savannah, Georgia) to L3 (Greenville, Texas), Stored L3, Undergoing modification to MC-55A specifications. Flown and registered since 2019 with 645th Aeronautical Systems Group, USAF for tests.
A51-????	5584	AU3	Airworthy as Gulfstream G550 N584GA with FAA. Registered (Oct 2018) since 30/06/25 flown with 645th Aeronautical Systems Group, USAF for tests. Call sign GLF09.
A51-????	5607	AU4	Airworthy as Gulfstream G550 N567G with FAA. Registered (Dec 2019) since 26/11/25 flown at Greenville with 645th Aeronautical Systems Group, USAF for tests.

The authors of this page are Brendan Cowan & Gordon Birkett

Sources:

https://australianaviation.com.au/2017/06/us-approves-sale-of-modified-g550-for-raaf/
https://australianaviation.com.au/2019/03/raaf-to-get-four-modified-gulfstream-g550s-for-electronic-warfare-support/ ,
http://adf-serials.com.au/newsletter/ADF%20Telegraph%202019%20Autumn%20.pdf ,
https://airforce-technology.com/news/l3-to-supply-four-mc-55a-peregrine-aircraft-to-raaf/ ,
https://australiandefence.com.au/defence/air/g550-ew-aircraft-buy-clarified-for-raaf ,
https://contactairlandandsea.com/2019/03/18/raaf-buys-mc-55a-peregrine-for-2-46billion/ ,
https://minister.defence.gov.au/minister/cpyne/media-releases/new-peregrine-electronic-warfare-aircraft-air-force ,
https://defence.gov.au/Budget/18-19/2018-19_Defence_PBS_03_Appendices.pdf