The US Air Force is on the hunt for new engines to power its upcoming fleet of aerial refueling tankers, according to a request for information (RFI) issued on Monday, March 18.

The Next-Generation Air Refueling System (NGAS) aircraft is designed to replace the current aerial tankers in the service.

Phasing Out Aging Workhorses

The NGAS program aims to replace the Air Force’s current workhorses, the Boeing KC-46 Pegasus and the KC-135 Stratotanker.

The KC-135, a derivative of the Boeing 707 airliner, has been a mainstay of aerial refueling operations since the 1950s.