The Brazilian air force has started testing aerial refueling capabilities of Embraer’s KC-390 airlifter.
"Since the F-5M and KC-390 have different envelopes, it is necessary to find a third envelope, at the intersection of the between the two aircraft, to carry out refueling," Lt. Col. Fernando Benitez Leal, technical manager of the air force's KC-X program was quoted as saying by UPI Friday.
The first in-flight refueling mission of the aircraft occurred earlier this month, and military and company personnel are working on another test campaign with F-5M fighters again acting as the fuel receiver aircraft, the air force said.
The KC-390 by Embraer is a medium-sized jet transport. Embraer has so far built two prototypes of the aircraft.
In the refueling tests, no fuel was transferred from the KC-390 but other refueling procedures were carried out.
Engineers also evaluated the common parameters for the correct flight profile by the tanker and receiver aircraft in initial tests.
The KC-390 refuel test program is schedule will run until the end of 2018. Currently, there are two prototypes performing in-flight testing in parallel, and a third is in the finalization phase.
In all, there will be more than 2,000 flight hours for the development and certification tests of the aircraft.