Getting fast and furious: How fast jet pilots practise flying low-level at speed

Almost every day of the year, state-of-the-art aircraft tear down a network of valleys in Snowdonia as pilots hone their skills in some of Britain's most challenging terrain.

It's called the Mach Loop – otherwise known as The Roundabout by US Air Force fighter pilots based in the UK.

The Mach Loop is a 21-mile circular network of valleys that gives both UK and US aircrews an unrivalled opportunity for six to seven minutes of uninterrupted high-speed low-level flying through steep valleys.

• Royal Navy man becomes first Briton to teach USN pilots how to fly the F-35C
• Still fighting at 50: F-16s prove their worth defending Nato's eastern flank
• Nato's largest air exercise sees a massive 150 sorties flown each day

From valleys to canyons

And across the pond in southern California we can visit its geographic cousin – an area known as the Sidewinder Low Level.

This is a 300-mile military low-altitude training route located within what's known as the R-2508 complex.

There's even a Star Wars connection, because not only does it remind pilots of the trenches on the Death Star used by the X-Wing rebel pilots in the movie, but part of the route is even known as the Jedi Transition.

And the Sidewinder has played a pivotal part in developing every fighter pilot's best friend – the Automatic Ground Collision Avoidance System, or Auto GCAS for short.

Developed by the Air Force Research Laboratory, this on-board system prevents an aircraft from hitting the ground when a pilot loses situational awareness, vision or blacks out under extreme G-forces by automatically pulling the aircraft up.

First tested on F-16s, it became part of the F-35 programme in 2019.

Auto GCAS is credited with saving at least 17 lives across US military platforms including the F-16 Fighting Falcon, the F-22 Raptor and the F-35 Lightning II.

Speed second, safety first

The Sidewinder route is regularly surveyed using a C-12 Huron twin-engine turboprop flying out of Edwards Air Force Base.

Flying the low-level routes down to nearly 200 feet, the C-12 crews look for obstacles that could obstruct any aircraft using the route.

The Mach Loop and the Sidewinder Low Level are both crucial for low-flying training.

They're also the best locations in the galaxy for pilots getting to feel like an X-Wing rebel fighter pilot.

:: Filmmaker Louis Skupien is the man behind the amazing Sidewinder cockpit footage in our report.

You can watch his full documentary here.