There was clearly a new stealth missile on that pylon...
Anyway, there was this last month.
"Honeywell most recently used the aircraft (N757HW) for tests of the new Jet Wave hardware that supports Inmarsat's GX Aviation high-speed in-flight connectivity, with several sorties performed from Birmingham airport in the UK in the run up to Paris.
Its engineers attempted to use many of the typical applications that airline passengers want to access during a flight says Carl Esposito, vice-president of marketing and product management.
In fact, one of the key evaluations was performed with YouTube, with Honeywell's crew - perhaps with a nod to Inmarsat's SwiftBroadband product - repeatedly streaming the video of US pop star Taylor Swift's hit, Shake it Off.
Other recent testing has included integrating high altitude ice crystal detection capability into its RDR4000 radar."
Testing SATCOM/Avionics.
The pylon is fixed but the test engine on the end is removable; it's not taken on the trip because it is not being tested.
For that matter hang around Geneva and Amsterdam for the next few days and you can catch it coming and going.
JPS on A300-600RF A319/320 B737-400/800 B757-200F B767-300F CRJ-200/900. Looking to add more.
Quoting bluewhale18210 (Reply 5): The pylon is fixed but the test engine on the end is removable; it's not taken on the trip because it is not being tested.
I'd love to see a 'GE90-115B' attached to that pylon
Quoting SLCGuy (Reply 8): Kind of a long take off roll for a lightly loaded 757 but the climb was good.
That was 757 LN 5 - it wouldn't have had the performance of latter build aircraft. I suspect those RB211s are not the pocket rockets in use today either.