21 國家應急空中指揮所(doc)
21. National Emergency Airborne Command Post The E-4B is designed to provide National Command Authorities (NCA) with a survivable capability to direct and control military forces in all levels of conflict, including nuclear war. Unlike ground-based command sites that are vulnerable to attack, the E- 4B has the mobility to escape direct assault. Its communications system is hardened to withstand the massive electromagnetic pulse of a nuclear burst, so that the communication network will function following an enemy attack and enable the NCA to direct a retaliatory1 strike2. As aircraft operations and maintenance are self-contained, operation are possible from a large number of civilian, abandoned or damaged airfields whose number and distribution further increase the E-4B’s survivability. Four General Electric CF6-50E engines give the modified 747-200B a certified maximum take-off gross weight of 362,874 kg. This provides sufficient fuel for the E-4B to remain airborne3 for 12 hours without refueling or 72 hours with in-flight refueling. A 1500 meters runway enables the E-4B to take off with an 8-hour endurance; take-off from shorter runways is possible by further reducing fuel load. Worldwide communication over many links is possible because of the E- 4B’s advanced command and control electronics. These are powered by a 1200 Kilowatt4 generator 5 system and include 13 external communication systems operating through 50 antennas6. The ability to access satellite systems reduces ground station dependence and protects against jamming7 and direct tracking attempts. A long range link, established with the high power Very Low Frequency8 (VLF) system, resists atmospheric nuclear effects and is very difficult to jam. 　　The E-4B system is capable of tying with commercial telephone and radio networks and could potentially be used for radio broadcast to the general population. When it is on the ground, it can also be connected to a ground communication network, which can be quickly disconnected. The E-4B accommodates9 up to 94 crew members on three decks with 510m2 of deck space. The upper deck contains the cockpit10 and flight crew rest area for long missions. 國家應急空中指揮所 設計E- 4B的目的，是在各種規(guī)模的沖突中（包括核戰(zhàn)爭），為國家指揮當局提供指揮和控制部 隊的生存能力。 　　不像易受攻擊的地面指揮所，E-4B具有躲避直接攻擊的機動能力。它的通信系統(tǒng)經(jīng) 過強化，可抵抗核爆炸產(chǎn)生的大量電磁脈沖，因此通信網(wǎng)在遭到敵人核攻擊后仍繼續(xù)運 行，使得國家指揮當局能夠指揮反擊。由于飛機集操作與維修于一體，從大量民用的、 廢棄或損壞的機場起飛都成為可能，這些機場的數(shù)量和分布進一步增強了E
21 國家應急空中指揮所(doc)