Recently surfaced images and a brief video show Russia's premier stealth fighter, the Su-57 Felon, flying without the canopy enclosure for the aircraft's cockpit. While there isn't a great deal of information available to go along with the footage, it seems very likely that the canopy was not lost due to an accident, but was rather removed intentionally for a specific type of flight testing known as a "cockpit habitability trials."
We first spotted this footage on Reddit, uploaded by user u/st_Paulus, but the event also caught the attention of Scramble Magazine, who posted a screen capture to their Facebook account, credited to a Twitter user they called Hao Goa.
It's obviously pretty unusual to see a pilot at the stick of an airborne, supersonic fighter without the protection of the cockpit canopy, but these somewhat rare tests are vital in the development of an aircraft. Pilots use these flights to test different aspects of the platform's emergency escape procedures in a realistic and dynamic environment. A photo of BAE test Pilot Keith Hartley conducting a similar flight aboard a Tornado XZ630 in the late '80s has made its way around the aviation circles of the internet for years, though it's tough to come by images or video of these tests on other platforms.
"In 1988, our test pilot Keith Hartley flew at 500 knots in a Tornado aircraft with the canopy off, testing the emergency escape procedures of the jet; just one example of the lengths we go to test the safety of the planes we build for the RAF."
-BAE Systems on Twitter
Obviously, flying without your cockpit canopy comes with some significant risk. Not only does the canopy protect the pilot from the incredible winds associated with flying a high speed aircraft, it also exposes the pilot to intense cold, and as anyone who's ever ridden in a convertible will tell you, all that wind noise can be pretty distracting. Other common threats to aircraft (like bird strikes or inclement weather) can also be exacerbated by the loss of a protective layer between the pilot and the outside world. Fighter jet cockpits are pressurized, though not in the same way as most commercial airlines. Instead, the cockpits of most fighters maintain ambient air pressure until they climb above a certain altitude. Without the canopy, flying above that altitude would be extremely dangerous, despite the pilot's mask-fed oxygen supply.
Risk be damned, these tests can help to ensure the procedures you train pilots to execute during emergency situations really work. In other words, the risk is a calculated one meant to save lives.
Russia's Su-57 Felon is the nation's first stealth fighter, and has suffered a number of setbacks along the long road to production. Originally intended as a joint effort shared between Russia and India, India backed out of the agreement in 2018. While public statements remained civil, it has widely been rumored that India's lost interest could be attributed to issues with the new aircraft's stealth capabilities; potentially brought about by Russia's inability to manufacture body panels with the incredibly tight production tolerances required to limit the radar return of an aircraft.
Continuing on their own, Russia built about a dozen Su-57s which have served as a token force of fifth-generation aircraft for the Russian military, while offering little in the way of actual combat capability. Late last year, Russia announced that they would finally begin serial production of the Su-57… only to have the first aircraft to roll off the production line promptly, and embarrassingly, crash during testing.
Su-57 being built (United Aircraft Corporation)
However, recent images of production Su-57s suggest that the aircraft may indeed be better than its prototypical predecessors, with seemingly tighter panel tolerances that just might make Russia's stealth fighter a bit stealthy after all.