Landing gear, ATA Chapter 32.
Wheels, Brakes, shock absorbers, lock braces, side stays all terms that are familiar to the aviation industry. But ever heard about ACLS?
ACLS is an abbreviation for Air-Cushion Landing System.
A Royal Canadian Air Force de Havilland CC-115 (DMC-5 Buffalo) heavily modified and renamed to a XC8A ACLS made its first flight on this day with an Air-Cushion Landing System while on loan to the USAF Flight Dynamics Laboratory. Instead of a conventional landing gear, it had a "hovercraft like skirt" under the fuselage which could be inflated by a PT6F-70 engine powered two-stage axial flow fan under each wing. To provide stability on the ground a skid/float was installed under each wing.
On the 11th of April 1975 the first landing was made using the ACLS. the 4950th Test Wing, Aeronautical System Division of the USAF carried out the flight testing at Wright Patterson Air Force Base.
On the 30th of April 1979 the aircraft was returned to the Canadian Air Force and converted back to a standard CC-115 (DHC-5A Buffalo) and is used for SAR operations with the 442 Squadron in British Columbia
Sources: - http://www.va3kgb.com/milac/cc115/115451.htm - https://archive.org/details/NASA_NTRS_Archive_19790017874/page/n9/mode/2up?q=april