Boeing 747 ‘Doomsday’ plane: First E-4C SAOC begins flight testing
September 4, 2025
Work is now well underway with the US Air Force’s next-generation E-4C Survivable Airborne Operation Centre (SAOC) aircraft in the early stages of flight testing. Based on the Boeing 747-8, when complete, the E-4Cs will be some of the most heavily modified Jumbos flying.
First E-4C ‘Doomsday’ aircraft takes flight
According to FlightGlobal, Sierra Nevada Corporation (SNC) has already launched the first test campaign for the new Doomsday aircraft. The inaugural flight took place on 7 August.
This is not the first flight for the airframe, as these are ex-passenger aircraft formerly operated by Korean Air. SNC has purchased five Boeing 747-8i passenger aircraft from Korean Air, and received the fourth aircraft in April 2025.
We’re excited to announce arrival of the 4th SAOC 747-8i aircraft at our Aviation Innovation and Technology Center in Dayton, Ohio – as we celebrate one year since this historic contract award. #TeamSNC #TeamSAOC
— Sierra Nevada Corporation (@SierraNevCorp) April 30, 2025
Learn more: https://t.co/vRyGUobNGx. pic.twitter.com/aqAFB8CrLi
The initial test flights are intended to reduce engineering risks and to help them be delivered on time. Flight and ground testing are set to continue with the first E-4C aircraft into 2026.
The contract for these aircraft is worth $13 billion, making these aircraft some of the most expensive platforms ever produced. They will be several times more expensive than the upcoming B-21 Raider strategic bomber on a per-unit basis.
It is not known how many E-4Cs the Air Force is procuring, although it has four legacy E-4Bs, and SNC has purchased five airframes for the task.
The E-4C’s ‘doomsday’ role
The E-4C is a strategic command-and-control aircraft designed to be a survivable mobile command post for the National Command Authority in an emergency, such as in the event of a nuclear attack.
They provide a command centre even if ground-based command centres have been destroyed. The aircraft are part of the US nuclear deterrent and are seen as critical to its defence strategy.
They are designed to ensure that the highest level of the US Government can survive an attack and coordinate a response, including a nuclear response. They can also coordinate with civil authorities.
SNC selected to replace ‘Doomsday’ aircraft
The prime contractor for replacing the Air Force’s fleet of E-4B Nightwatch is SNC, although there are various other notable subcontractors like Rolls-Royce.
GE Aerospace has also received a contract under the program to overhaul and upgrade the aircraft’s GEnx-2B engines. Other contractors in the program include Collins Aerospace, Greenpoint Technologies, NIAR, and Lockheed Martin Skunk Works.
SNC won the contract in 2024 after Boeing bowed out of bidding after the DoD insisted on a fixed price contract. Boeing has lost billions of dollars accepting fixed price contracts on developing the next-generation VC-25B Air Force One aircraft and the Boeing Starliner space capsule.
The current E-4 aircraft were built in the 1970s and, like the current Air Force One aircraft, are approaching the end of their operational lives.
There had been a move in 2006 to retire the aircraft starting in 2009 due to their age. However, there was no capable replacement, and it was decided to keep the aircraft in service. The effort to replace them only commenced in 2019.
The first E-4C SAOC is expected to enter service around 2028, and the contract is scheduled to be completed by 2036.
