It’s an aluminized tape called “SPEED TAPE”.
It’s been around for decades. It IS NOT “Duct Tape”, and mechanics have used it without incident forever. They use it for quick fixes, like a whistling window. NASCAR uses it to patch crashes.
I remember flying on a United 727 simply covered in the stuff, (And Red Tags), just a couple of days before they were officially retired.
Ground Crew 1: "Ah! Grand job, Mick. Grand job."
Ground Crew 2: "Do ya tink it'll hold, Pat. I mean, dese tings go 600 miles per hour."
Ground Crew 1: "Do they, now? Well . . . still 'tis a fine job ya done, Mick. A fine job."
Ground Crew 1: "Ah! Grand job, Mick. Grand job."
Ground Crew 2: "Do ya tink it'll hold, Pat. I mean, dese tings go 600 miles per hour."
Ground Crew 1: "Do they, now? Well . . . still 'tis a fine job ya done, Mick. A fine job."