Development
Two of the original 747-200 airframes were originally planned to be commercial airliners. When the airline did not complete the order, Boeing offered the airframes to the USAF as part of a package leading to a replacement for the older EC-135J NEACP (National Emergency Airborne Command Post). Under the 481B NEACP program the Air Force Electronic Systems Division awarded Boeing a contract in February 1973 for two unequipped aircraft, designated E-4A, powered by four P&W JT9D engines, to which a third aircraft was added in July 1973. The first E-4A was completed at the Boeing plant outside Seattle, Washington in 1973. E-Systems won the contract to install interim equipment in these three aircraft, and the first completed E-4A was delivered to Andrews AFB, Maryland in December 1974. The next two were delivered in 1975, the third differed by being powered by the GE F103 engine, which was later made standard and retrofitted to the previous two aircraft. The "A" model effectively housed the same equipment as the EC-135, but offered more space and an ability to remain aloft longer than an EC-135.
Additionally the E-4 was capable of operating the "Looking Glass" missions of the former Strategic Air Command (SAC).
In December 1973 a fourth aircraft was contracted for, which was fitted with more advanced equipment, resulting in the designation E-4B. On 21 December 1979 Boeing delivered the first E-4B (AF Serial Number 75-0125), which was distinguished from the earlier version by the presence of a large "hump" on the dorsal surface directly behind the upper deck. This contains the aircraft's SHF satellite antenna. By January 1985 all three E-4As had been retrofitted to E-4B models. The E-4B offered a vast increase in communications capability over the previous model and was considered to be 'hardened' against the effects of electromagnetic pulse (EMP) from a nuclear blast. Hardening the aircraft meant that all equipment and wiring on board was shielded from EMP. Additional steps were taken to block radiation from the aircraft's cabin air management system and cockpit, including the novel use of the same screens used to cover the windows of microwave ovens placed over the flight deck windows.
Estimates at the time of the production of the first E-4B placed the developmental cost at nearly US$ 1 billion. The roll out cost of the fleet was placed at approximately US$ 250 million each. In 2005 the Air Force awarded Boeing a five year, US$2 billion contract for the continued upgrade of the E-4B fleet.
Read more about this topic: Boeing E-4
Famous quotes containing the word development:
“Men are only as good as their technical development allows them to be.”
—George Orwell (1903–1950)
“The proper aim of education is to promote significant learning. Significant learning entails development. Development means successively asking broader and deeper questions of the relationship between oneself and the world. This is as true for first graders as graduate students, for fledging artists as graying accountants.”
—Laurent A. Daloz (20th century)
“This was the Eastham famous of late years for its camp- meetings, held in a grove near by, to which thousands flock from all parts of the Bay. We conjectured that the reason for the perhaps unusual, if not unhealthful development of the religious sentiment here, was the fact that a large portion of the population are women whose husbands and sons are either abroad on the sea, or else drowned, and there is nobody but they and the ministers left behind.”
—Henry David Thoreau (1817–1862)