N747GF: GE's 747-400 flying testbed
A former Japan Airlines jumbo that has flown the biggest jet engine in the world on one pylon.
Where it is right now
Loading live data…- N747GF…
Positions come from volunteer ADS-B receivers, so an aircraft over the ocean or away from receivers can be flying and still show as not heard.
When GE wants to find out how a new engine behaves in the air, it bolts the engine onto the number-two position of a Boeing 747 and goes flying. N747GF, a 747-400 that spent its first career with Japan Airlines, has done that job since 2010 from GE's flight test center at Victorville, California, flying the GE9X, the largest jet engine ever built, the GEnx, the LEAP and the Passport business-jet engine, and it is slated to carry the open-fan engine GE and Safran are developing for the next generation of airliners. It replaced an older 747-100 that is now in a museum. When it flies, it is usually on long test loops over the Mojave Desert and the Pacific.
At a glance
- What it is
- Boeing 747-446, formerly a Japan Airlines passenger aircraft
- With GE since
- 2010, replacing the 747-100 testbed N747GE (retired 2017)
- Engines tested
- GE9X, GEnx, LEAP, Passport and others; CFM RISE open fan planned
- Base
- GE Aerospace Flight Test Operations, Victorville (Southern California Logistics Airport)
- Seen at
- Farnborough Airshow, July 2026
- Transponder address
- AA0D27
Fifty years of flying testbeds
GE has used a 747 to test engines since 1992, when it bought a 1970 Pan Am 747-100, N747GE, and flew the first GE90 under its wing. That aircraft tested eleven engine models and 39 different builds over 25 years, from the GE90 to the GEnx and the CF34, moving from Mojave to a new hangar at Victorville in 2003. By 2017 it was too old and too expensive to keep flying, and it was retired to the Pima Air & Space Museum in Tucson.
N747GF arrived in 2010 as its replacement: a 747-400 from Japan Airlines with a modern cockpit, more range and a stronger wing, which matters when the engine on the test pylon weighs more than the one it replaces. GE modified the number-two pylon to take engines far larger than the 747's own CF6s and filled the cabin with data racks and seats for test engineers.
What hangs under the wing
The headline was the GE9X, the 777X's engine, which first flew on N747GF in March 2018 with a fan more than eleven feet across; the engine is so large that the pylon had to be extended to keep the nacelle clear of the ground. The aircraft has also flown the GEnx for the 787 and 747-8, the LEAP for the A320neo and 737 MAX, and the Passport for the Global 7500. GE and Safran have said the CFM RISE open-fan demonstrator, an engine with no nacelle around its fan, will fly on the 747 later in the decade.
Test sorties typically last several hours and run patterns over the high desert, out to the Pacific and up to the limits of the engine's envelope, which is why the aircraft appears on the tracker climbing to 43,000 feet and circling where airliners never go. It also travels: it flew to the Farnborough Airshow in England in July 2026, a rare chance to see it on the ground outside California.
How to recognize it
A 747-400 in GE's white-and-blue scheme with "GE Aerospace" titles and, on the left wing, an inboard engine that is obviously the wrong size, sometimes with its nacelle unpainted or a different shape. The 747-400 has the stretched upper deck and winglets. On the tracker it is N747GF, usually with a GE callsign, flying out of Victorville (VCV) or Mojave.
Questions
Why does GE test engines on a 747?
A four-engine aircraft can lose the test engine entirely and still fly safely on the other three, and the 747 is strong enough to carry an engine far larger and heavier than its own. GE has used 747s as flying testbeds since 1992.
Which engines has N747GF flown?
The GE9X for the 777X, the GEnx, the CFM LEAP and the Passport business-jet engine, among others. The open-fan CFM RISE demonstrator is planned to fly on it.
Where is GE's 747 based?
At GE Aerospace's flight test operation in Victorville, California, in the Mojave Desert, where the weather allows year-round testing.
Sources
- Wikipedia: N747GE (GE's 747 testbeds)
- GE Aerospace: flight test operations and GE9X first flight, March 2018
- CFM International: RISE program announcements