The US Air Force has awarded a contract to Sierra Nevada Corp to develop a successor to the E-4B, known as the Doomsday plane. The Survivable Airborne Operations Center (SAOC) project aims to replace the aging 1970s-era aircraft, which is approaching the end of its service life. The E-4B fleet, which currently operates four highly-modified Boeing 747-200 jumbo jets, is becoming increasingly difficult and expensive to maintain as parts become obsolete. The E-4B is expected to reach the end of its service life in the early 2030s.
In a recent development, Korean Air has announced that it will sell five of its planes to U.S. aerospace firm Sierra Nevada Corporation, which recently won a $13 billion U.S. Air Force contract to develop the successor to the E-4B Nightwatch. The planes being sold are four-engined Boeing 747-8s. The sale is valued at 918 billion Korean won ($674 million) and is scheduled to take place in September 2025 [92b289c8].