Defense Secretary Robert Gates likes to take his office with him and stay connected when he flies overseas. His “Flying Pentagon” is a huge, white aircraft with a blue cheatline running along the fuselage from nose to tail and an American flag on the fin. From a distance it could be mistaken for an ordinary jumbo jetliner.

“The E-4B serves as the National Airborne Operations Center,” said pilot Lt. Col. Mike Howe. “In a national emergency or if ground command control centers were destroyed, the E-4B would provide a survivable, command control and communications center to direct U.S. forces, execute emergency war orders and coordinate actions by civil authorities.” Howe said E-4B airmen don’t like it when the press calls the E-4B the “Doomsday aircraft,” but “they take it in stride.” In a way they encourage end-of-the-world banter by using the radio callsign Nightwatch.

Except for one significant bulge and an air refueling receptacle, the E-4B it looks very much like the Boeing 747-100 that made its maiden flight on Feb. 9, 1969, and revolutionized air travel with its carrying capacity and wide-body configuration. In fact, the E-4B is a version of the 747-200, which hasn’t been manufactured for a quarter of a century. Like its cousin Air Force One – the C-25A used to carry the president – the E-4B is fully a generation behind today’s glass-cockpit, all digital, two-pilot 747-400s. “Ours are older airplanes from a design standpoint,” said Col. Martin Doebel, NAOC commander.

“The E-4B has seen a steady stream of modernization efforts, principally focused on integration of new Air Force or DoD communications systems, such as the Extremely High Frequency Milstar system and sustainment of existing C3 systems,” Doebel said. “The most significant E-4B modernization effort was delivered in 2006 with aircraft 73-1677, transitioning [from] an analog communications backbone to a digital fiber-optic system and providing robust broadband access supporting myriad voice, data and video information systems, applications and tools across all classification levels.”

Never having performed its primary mission of assuring U.S. survival in a nuclear war, the E-4B is kept busy with secondary missions, including Federal Emergency Management Agency support, which provides communications to relief efforts following natural disasters such as hurricanes and earthquakes. Little noticed by the public is its role in VIP travel: the E-4B has become the preferred method of travel for two successive secretaries of defense, Donald Rumsfeld and Robert Gates. Many trips made by the Pentagon’s civilian chief could be handled by a less expensive aircraft – say, a C-37A Gulfstream V – but in the post-9/11 environment Gates says he needs the communications suite that comes with Nightwatch.

BIG RESPONSIBILITY

The Air Force’s Air Combat Command is responsible for the E-4B. The command’s 55th Wing at Offutt Air Force Base, Neb., commanded by Brig. Gen. John N. T. Shanahan, provides aircrew, maintenance, security, and communications support. The Joint Chiefs of Staff control E-4B operations and provide personnel for the airborne operations center.

The 1st Airborne Command & Control Squadron, a part of the 55th Wing, flies the four E-4Bs – but their mission falls under Doebel’s NAOC center, a part of U. S. Strategic Command. Long ago, crews began wearing “Nightwatch” shoulder patches: The term is now a callsign and a nickname for the plane and its mission.

The unremarkable aspects of the E-4B include four 52,500-pound thrust General Electric F103-PW-100 turbofan engines, military versions of the proven CF6-50-E2. The aircraft has a wingspan of 195 feet 8 inches and a maximum takeoff weight of about 800,000 pounds. “We have 60 external antennas that attract interest and an extra hump with SATCOM [satellite communications],” said Doebel. The original hump atop the aircraft, also distinctive, houses a super high frequency radio system.

The first E-4A Advanced Airborne Command Post, or AABNCP as it was then called, made its initial flight in “green” condition without operational systems aboard on June 13, 1973. After being fitted out by E-Systems in Greenville, Texas, it was delivered to Andrews Air Force Base, Md., in December 1974 and was soon joined by the second and third aircraft. The first three aircraft were in test status and became operational shortly after being joined in 1980 by the fourth and final aircraft, the only one built from the outset with minor improvements that upgraded it to E-4B status. All four aircraft had been modernized to E-4B status by 1985. Strategic Air Command, or SAC, operated the aircraft until replaced by today’s Air Combat Command in 1992. Aircraft serial numbers are 73-1676/1677, 74-0787, and 75-0125.

The four-plane fleet has logged a remarkable safety record, including tens of thousands of hours without mishap – but stuff happens. During a May 12, 2010 landing at Offutt, an E-4B’s rear fuselage struck the runway, a seemingly innocent mishap that cost the U.S. taxpayer $ 3.1 million in repairs. No one aboard was injured. The accident report blamed “increased pitch angle by the pilot.” The Air Force reported: “The tail of the aircraft impacted the runway between two to three feet right past the centerline. The pilot and crew brought the aircraft to a stop when they saw a bright flash at the second touchdown. The tail of the aircraft and the lower fuselage sustained damages.”