Flight tests for the E-4C Survivable Airborne Operations Control (SAOC) are currently being held at the Aviation Innovation and Technology Center in Dayton, Ohio, according to a release by Sierra Nevada Corporation (SNC) on a Wednesday.

The program’s engineering and manufacturing development process saw the SAOC’s first flight conducted on August 7. Flight and ground testing for the project will continue through 2026, primarily conducted in Dayton, Ohio, and Wichita, Kansas.

SAOC is designed to function as an airborne command-and-control center, particularly useful in extreme scenarios, such as a nuclear war or significant disasters that compromise military command centers. It enables the President to direct U.S. forces and relay orders from the air during such catastrophic events.

Sierra Nevada Corporation emphasized that these flight tests are critical for early risk reduction in the SAOC development process by identifying potential problems before they escalate and lead to delays.

The aircraft for SAOC are heavily modified Boeing 747-8s. SNC is upgrading these planes to withstand radiation and electromagnetic pulses, in addition to enhancing them with communication antennas, computers, and various mission systems.

The first 747-8 assigned for the SAOC program arrived at Sierra Nevada’s innovation center at Dayton International Airport in June 2024. This was approximately six weeks after the contract was awarded. Since then, three additional 747-8 aircraft have arrived, with the fourth arriving in April 2025.

Sierra Nevada intends to implement a modular open system approach, incorporating modern and secure communication systems in the development of SAOC.

This SAOC contract represents Sierra Nevada’s largest single contract in its 60-year history, and the company aspires for it to pave the way for further significant projects.

To accommodate this initiative, Sierra Nevada is expanding its facilities. In October 2024, the company opened a second hangar designated for the conversion of a 747 into SAOC at Dayton Airport and has also commenced the construction of two additional hangars. The first of these new hangars is anticipated to be operational by October 2025.

The existing fleet of E-4Bs, formally referred to as the National Airborne Operations Center, is over 50 years old and nearing the end of its operational life.

Stephen Losey is the air warfare reporter for Defense News, previously covering leadership and personnel issues for Air Force Times, as well as special operations and air warfare for Military.com. He has reported on U.S. Air Force operations in the Middle East.