Nap-of-the-earth (NOE) is a type of very low-altitude flight course used by military aircraft to avoid enemy detection and attack in a high-threat environment.[1] Other, mostly older terms include "contour flying",[2] "ground-hugging", "terrain masking", "flying under the radar" and "hedgehopping".
Helicopter using treetops as cover
During NOE flight, geographical features are used as cover, exploiting valleys and folds in the terrain by flying in, rather than over, them. This keeps the aircraft below enemy air defenceradar coverage, avoiding being silhouetted against the sky.
NOE is used to minimize detection by hostile aircraft, airborne early warning and control surveillance and control systems, ground-based radar, or attack targets.[1]
A high-flying aircraft can be detected by defense systems at long range, giving an air defense system time to react, alerting surface-to-air missile and anti-aircraft 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.[3]
Sensors for NOEedit
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.
Helicopter NOE flyingedit
Helicopter following a river to enable low level flightAH-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),[1] flying under wires (such as electricity cables) rather than over them. Attack helicopters can hide behind trees or buildings, "popping up" with minimum exposure, just enough to use their (rotor mast-mounted) radar or other sensors and launch weapons.[4] 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. In populated areas with tall radio transmission towers, an altitude of 150 m (490 ft) above ground level applies.
Height above ground leveledit
Height above ground level 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 (830 km/h), 200 feet (61 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 1998 Cavalese cable car crash.[5] 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.
^ abcHelicopters at War - Blitz Editions, Bookmart Limited, 1996, ISBN1-85605-345-8
^Wragg, David W. (1973). A Dictionary of Aviation (first ed.). Osprey. p. 98. ISBN9780850451634.
^Nelson, Dean; Pearlman, Jonathan (17 March 2014). "Missing Malaysia plane flew at 5,000ft and used 'terrain masking' to avoid radar detection". The Telegraph. from the original on 7 March 2017. Retrieved 7 March 2017.
^Cacutt, Len (1989). Combat. Aerospace Publishing Ltd. p. 185. ISBN1-55521-240-9.
^Tagliabue, John (4 February 1998). "20 Die in Italy As U.S. Jet Cuts A Ski Lift Cable". The New York Times. from the original on 13 May 2017. Retrieved 7 March 2017.
January 01, 1970
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This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Nap of the earth news newspapers books scholar JSTOR July 2008 Learn how and when to remove this message Nap of the earth NOE is a type of very low altitude flight course used by military aircraft to avoid enemy detection and attack in a high threat environment 1 Other mostly older terms include contour flying 2 ground hugging terrain masking flying under the radar and hedgehopping Helicopter using treetops as cover During NOE flight geographical features are used as cover exploiting valleys and folds in the terrain by flying in rather than over them This keeps the aircraft below enemy air defence radar coverage avoiding being silhouetted against the sky Contents 1 Purpose 2 Sensors for NOE 3 Helicopter NOE flying 4 Height above ground level 5 See also 6 ReferencesPurpose edit nbsp Terrain masking NOE is used to minimize detection by hostile aircraft airborne early warning and control surveillance and control systems ground based radar or attack targets 1 A high flying aircraft can be detected by defense systems at long range giving an air defense system time to react alerting surface to air missile and anti aircraft 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 3 Sensors for NOE editMost 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 Helicopter NOE flying edit nbsp Helicopter following a river to enable low level flight nbsp 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 1 flying under wires such as electricity cables rather than over them Attack helicopters can hide behind trees or buildings popping up with minimum exposure just enough to use their rotor mast mounted radar or other sensors and launch weapons 4 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 In populated areas with tall radio transmission towers an altitude of 150 m 490 ft above ground level applies Height above ground level editHeight above ground level 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 830 km h 200 feet 61 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 1998 Cavalese cable car crash 5 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 See also editLow flying military training Low altitude parachute extraction system Radar altimeter Radar horizon Sea skimming missiles Terrain following radar Wire strike protection systemReferences edit a b c Helicopters at War Blitz Editions Bookmart Limited 1996 ISBN 1 85605 345 8 Wragg David W 1973 A Dictionary of Aviation first ed Osprey p 98 ISBN 9780850451634 Nelson Dean Pearlman Jonathan 17 March 2014 Missing Malaysia plane flew at 5 000ft and used terrain masking to avoid radar detection The Telegraph Archived from the original on 7 March 2017 Retrieved 7 March 2017 Cacutt Len 1989 Combat Aerospace Publishing Ltd p 185 ISBN 1 55521 240 9 Tagliabue John 4 February 1998 20 Die in Italy As U S Jet Cuts A Ski Lift Cable The New York Times Archived from the original on 13 May 2017 Retrieved 7 March 2017 Retrieved from https en wikipedia org w index php title Nap of the earth amp oldid 1194663013, wikipedia, wiki, book, books, library,
