利用者:林さん/sandbox

木々の梢をカバーのために用いるヘリコプター

地形追随飛行またはNOE（Nap-of-the-earth）とは、軍用機によって用いられる極めて低い高度を飛ぶやり方である。これは敵の探知や多大な脅威を生む状況での攻撃を避ける。他、以前には「ground-hugging」、 「terrain masking」、「flying under the radar」、「hedgehopping」と呼ばれていた。

NOE飛行中、地理的な特徴ある場所が遮蔽のために用いられる。利用されるのは地形の中の谷、丘陵地の小さいくぼみであり、飛び越えるよりはこれらの中に進入する。これで敵の防空レーダーの探知範囲よりも機の高度を低く保ち、空中にシルエットが浮かび上がるのを避ける。

用途

NOEは敵の航空機、AWACSの監視・管理システム、地上に配置されたレーダー、また攻撃目標による探知を最低限化するため使われる。

A high-flying aircraft can be detected by defense systems at long range, giving an air defense system time to react, alerting SAM and AAA missile systems and fighter aircraft. Using NOE flight, the approach may be undetected; the aircraft "pops up" to attack the target and then turns to escape before the enemy can respond. Doppler radar has the potential to detect NOE flight, but the incoming aircraft has to be within radar range in the first place, and low flight minimizes this possibility by using hills and mountains to break the line of sight (terrain masking), defeating terrestrial air defense radar and in rough enough terrain also airborne early warning.

NOEのためのセンサー類

Most NOE flying is done during the day using visual reference by pilots who are experienced in low flying. Data from a radar altimeter or terrain-following radar system is also used, the latter enabling low flying in adverse weather where it would not be possible by visual reference and manual pilot control. At night, a night-vision device may be used.

ヘリコプターのNOE飛行

Helicopter following a river to enable low level flight

AH-64 Apache at the Oirschotse Heide Low Flying Area

The lowest NOE flying is by helicopters because they have lower speeds and more maneuverability than fixed-wing aircraft, particularly fast-jets. Helicopters can fly at treetop levels or even below the height of surrounding trees where there are clear areas (such as in river gullies), flying under wires (such as electricity cables) rather than over them. Attack helicopters can hide behind trees or buildings, "popping up" just enough to use their (rotor mast-mounted) radar or other sensors and then minimally exposing themselves to launch weapons. The required altitude depends on the type of terrain, such as low vegetation or low buildings, tree canopy layer of less than 45 m (148 ft), presence of tall buildings or concrete pylons with heights of up to 25 m (82 ft) international standard, or emergent tree layer canopy and lattice steel electricity pylons to 100 m (330 ft) being present. Over populated areas with tall radio transmission towers, an altitude of 150 m (490 ft) AGL applies.

地表面のやや上の高さを飛ぶ

Height above ground level (AGL) in NOE and low flying generally vary with the aircraft speed, aircraft maneuverability and the ruggedness of the terrain. Helicopters are capable of flying with no more than a few feet of clearance below the helicopter's skids or wheels. Fast jets are more constrained and at a typical low-flying speed of 450 knots (800 km/h), 200 feet (60 m) is not unusual and 50 feet (15 m) is possible in relatively flat terrain. Power wires are a danger to all aircraft flying at low level and "wire strikes" are common, such as the Cavalese cable car disaster. Special maps are produced that plot the routes of these wires but these are difficult to keep up-to-date, especially for foreign/enemy countries. Pilots are trained to scan for the pylons or power-poles that support these wires, because they can be seen at a distance where the wires themselves cannot.

関連項目

• Low flying military training
• Low-altitude parachute-extraction system
• Radar altimeter
• Radar horizon
• Sea skimming (missiles)
• Terrain-following radar

参考文献

[[Category:航空機　操縦]]