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wings. How much of an increase depends on both the aircraft type and amount of ice. Stall characteristics of an aircraft with ice-contaminated wings will be degraded, and serious roll control problems are not unusual. The ice accretion may be asymmetric between the two wings which requires calibrating. Also, the outer part of a wing, which is ordinarily thinner and thus a better collector of ice, may stall first rather than last.
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392:: High airspeeds lead to heating on the wings or propellers of the aircraft, which can counteract icing to some degree. UAVs fly at lower velocities than manned aircraft and will not benefit from the same heating effect. Therefore, icing on UAVs can occur at a broader range of temperatures than on manned aircraft.
386:: Small aircraft accumulate ice faster, and more ice per unit area, compared to large aircraft. UAVs are typically smaller than manned aircraft and therefore more sensitive to icing. Furthermore, the added mass from ice accretions can have quick negative effects on UAVs with stringent weight restrictions.
404:
for UAVs is approximately an order of magnitude lower than that for manned aircraft. This leads to UAVs operating in flow regimes where laminar flow effects are more prevalent than turbulent flow effects. Because laminar flow is more easily disturbed than turbulent flow, the negative effects of icing
112:
water. They freeze on contact with a potential nucleation site, which in this case is the parts of the aircraft, causing icing. Icing conditions are characterized quantitatively by the average droplet size, the liquid water content and the air temperature. These parameters affect the extent, type and
268:
refers to ice formed in supercooled large droplet (SLD) conditions. It is similar to clear ice, but because droplet size is large, it extends to unprotected parts of the aircraft and forms larger ice shapes, faster than normal icing conditions, which nearly all aircraft aren't sufficiently protected
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A common approach is to route engine "bleed air" into ducting along the leading edges of wings and tailplanes. The air heats the leading edge of the surface and this melts or evaporates ice on contact. On a turbine powered aircraft, air is extracted from the compressor section of the engine. If the
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Icing on UAVs is a global phenomenon, and icing conditions at the operational altitude can occur year round around the world. However, icing risks are particularly big in the sub arctics, Arctic and
Antarctic. In large parts of the Nordics, for example, icing conditions are present from 35% to more
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All of these methods remove existing contamination, but provide no practical protection in icing conditions. If icing conditions exist, or are expected before takeoff, then anti-icing fluids are used. These are thicker than deicing fluids and resist the effects of snow and rain for some time. They
375:
are an emerging technology with a large variety of commercial and military applications. In-flight icing occurs during flight in supercooled clouds or freezing precipitation and is a potential hazard to all aircraft. In-flight icing on UAVs imposes a major limitation on the operational envelope.
363:
The wing will ordinarily stall at a lower angle of attack, and thus a higher airspeed, when contaminated with ice . Even small amounts of ice will have an effect, and if the ice is rough, it can be a large effect nonetheless. Thus an increase in approach speed is advisable if ice remains on the
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contain a definition of icing conditions that some aircraft are certified to fly into. So-called SLD, or supercooled large droplet, conditions are those that exceed that specification and represent a particular hazard to aircraft, which all aircraft must try to avoid.
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indicate icing conditions in terms of their effect upon the aircraft, and will be dependent upon the preexisting capabilities of the aircraft. Different aircraft may report the same quantitative conditions as different levels of icing as a result.
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is the result of water freezing on unprotected surfaces while the aircraft is stationary, before flight even starts. This can be dangerous when flight is attempted because it disrupts an airfoil's boundary layer airflow causing a premature
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Electrical heating is also used to protect aircraft and components (including propellers) against icing. The heating may be applied continuously (usually on small, critical, components, such as
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Positioning aircraft towards the Sun to maximize heating up of snow and ice covered surfaces. In practice this method is limited to thin contamination, by the time and weather conditions.
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There is a difference between deicing and anti-icing. Deicing refers to the removal of ice from the airframe; anti-icing refers to the prevention of ice accumulating on the airframe.
226:, strike a surface but do not freeze instantly. Often "horns" or protrusions are formed and project into the airflow, which smoothens it out. This form of ice is also called glaze.
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Unmanned aircraft are more sensitive and susceptible to icing compared to manned aircraft. The main differences between UAVs and manned aircraft when it comes to icing are:
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Several methods exist to reduce the dangers of icing. The first, and simplest, is to avoid icing conditions altogether, but for many flights this is not practical.
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In all these cases, usually only critical aircraft surfaces and components are protected. In particular, only the leading edge of a wing is usually protected.
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If ice (or other contaminants) are present on an aircraft prior to takeoff, they must be removed from critical surfaces. Removal can take many forms:
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that disperse ice build-up on the surface. These systems require less engine bleed air but are usually less effective than a heated surface.
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are not susceptible to carburetor icing, but can suffer from blocked inlets. In these engines, an alternate air source is often available.
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in aviation history. Ice accretion and accumulation can affect the external surfaces of an aircraft – in which case it is referred to as
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The parts of the UAV most exposed to icing are the airspeed sensor, the leading edge of aerodynamic surfaces, rotors, and propellers.
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system, which has hundreds of small holes in the leading edges and releases anti-icing fluid on demand to prevent the buildup of ice.
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and, in some cases, dramatically increased drag making takeoff dangerous or impossible, which could lead to accidents prematurely.
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Atmospheric Ice
Accretions, Aerodynamic Icing Penalties, and Ice Protection Systems on Unmanned Aerial Vehicles
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aircraft. The ridges are the result of the boot being inflated with air to crack and remove accumulated ice.
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1029:"Unsettled Topics in Unmanned Aerial Vehicle Icing (EPR2020008 Research Report) - SAE Mobilus"
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84:(FIKI) – that is flying into areas with icing conditions certain or likely to exist, based on
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sensors and angle of attack vanes) or intermittently, giving an effect similar to the use of
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aircraft is turbocharged piston powered, bleed air can be scavenged from the turbocharger.
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are intended to shear off the aircraft during takeoff and provide no inflight protection.
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14 CFR 25 Appendix C – Atmospheric Icing
Conditions for Aircraft Certification
411:: Rotary-wing UAVs are typically more sensitive to icing than fixed-wing UAVs.
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was created from a revision of this article dated 9 December 2017
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Putting the aircraft into a heated hangar until snow and ice have melted
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is a combination of clear and rime ice, having both properties.
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is applied to carbureted engines to prevent and clear icing.
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are often used to indicate the presence of icing conditions.
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speed that characterize the formation of ice on an aircraft.
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is often clear and smooth. Supercooled water droplets, or
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Icing conditions exist when the air contains droplets of
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To protect an aircraft against icing in-flight, various
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Use of infrared heating to melt and remove contaminants
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Ice accumulated and partially removed on the wing of a
242:, it generally conforms to the shape of the airfoil.
1003:"Federal Aviation Regulations, Part 25, Appendix C"
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De-icing an
Embraer Legacy 450 prior to the flight.
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419:than 80% of the time from September through May.
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53:on an aircraft. Icing has resulted in numerous
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352:Ice protrusions on a rotor blade obtained in a
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208:Supercooled large droplet (SLD) ice on a NASA
934:National Aeronautics and Space Administration
904:National Aeronautics and Space Administration
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454:or even hot water to remove ice, snow, etc.
316:. Unsourced material may be challenged and
172:. Unsourced material may be challenged and
27:Formation of water ice on aircraft surfaces
510:Some aircraft are equipped with pneumatic
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336:Learn how and when to remove this message
192:Learn how and when to remove this message
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269:from. This was a factor in the crash of
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701:Scandinavian Airlines System Flight 751
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691:Ryan International Airlines Flight 590
69:, air inlet icing or more generically
1027:Hann, Richard; Johansen, Tor (2020).
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631:Northwest Orient Airlines Flight 6231
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314:adding citations to reliable sources
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170:adding citations to reliable sources
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1109:"UAV Atmospheric Icing Limitations"
621:Sólheimasandur US Navy C-117D crash
24:
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771:China Eastern Airlines Flight 5210
25:
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954:Yodice, John S. (1 August 2005).
861:Voepass Linhas Aéreas Flight 2283
781:West Caribbean Airways Flight 708
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661:Continental Airlines Flight 1713
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553:Related accidents and incidents
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100:to prevent accidents by icing.
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894:Wadel, Mary (3 August 2017).
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831:Sol Líneas Aéreas Flight 5428
607:American Airlines Flight 63 (
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76:Not all aircraft, especially
924:Wadel, Mary (31 July 2017).
761:TransAsia Airways Flight 791
472:In-flight protection systems
115:Federal Aviation Regulations
80:aircraft, are certified for
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1224:Weather hazards to aircraft
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851:Saratov Airlines Flight 703
368:Effect on unmanned aircraft
10:
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1204:Aircraft Icing – NASA Page
956:"The law on 'known icing'"
930:NASA Glenn Research Center
900:NASA Glenn Research Center
731:American Eagle Flight 4184
681:United Express Flight 2415
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358:NASA Glenn Research Center
271:American Eagle Flight 4184
811:Aero Caribbean Flight 883
721:Alan Kulwicki plane crash
277:
983:Cite magazine requires
875:Accretion (meteorology)
841:Air Algérie Flight 5017
671:Air Ontario Flight 1363
134:Types of structural ice
82:flight into known icing
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1145:Listen to this article
1078:Hann, Richard (2020).
791:Colgan Air Flight 3407
651:Arrow Air Flight 1285R
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478:Ice protection systems
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423:Prevention and removal
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98:ice protection systems
51:formation of water ice
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1229:Ice in transportation
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1140:at Wikimedia Commons
801:Air France Flight 447
641:Air Florida Flight 90
544:Fuel-injected engines
517:A few aircraft use a
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439:Pre-flight protection
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1196:More spoken articles
574:adding missing items
310:improve this section
166:improve this section
821:Iran Air Flight 277
751:Loganair Flight 670
36:Beechcraft King Air
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1041:10.4271/epr2020008
1033:saemobilus.sae.org
741:Comair Flight 3272
572:; you can help by
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1138:Icing in aviation
1136:Media related to
1091:978-82-326-4749-1
962:on 1 January 2015
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847:11 February 2018
787:12 February 2009
767:21 November 2004
757:21 December 2002
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647:12 December 1985
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609:Flagship Missouri
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128:Ice detectors
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123:pilot reports
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18:Ice accretion
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1113:. Retrieved
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1011:. Retrieved
1007:the original
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960:the original
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827:18 May 2011
797:1 June 2009
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526:pitot static
519:weeping wing
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397:Laminar flow
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308:Please help
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164:Please help
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90:observations
81:
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71:engine icing
70:
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40:
405:are bigger.
354:wind tunnel
110:supercooled
43:aeronautics
1218:Categories
1192:Audio help
1183:2017-12-09
1115:2021-12-08
1111:. May 2021
1064:2021-02-12
1013:2008-09-20
881:References
570:incomplete
502:are used:
210:Twin Otter
104:Definition
1059:226200723
598:Accident
297:does not
246:Mixed ice
219:Clear ice
153:does not
94:forecasts
61:– or the
1194: ·
1084:. NTNU.
966:25 April
869:See also
231:Rime ice
1181: (
1152:minutes
318:removed
303:sources
266:SLD ice
236:airfoil
174:removed
159:sources
49:is the
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939:8 June
909:8 June
492:Dash 8
400:: The
278:Effect
92:, and
63:engine
1055:S2CID
595:Date
253:Frost
47:icing
1086:ISBN
989:help
968:2013
941:2019
911:2019
409:Type
301:any
299:cite
157:any
155:cite
1045:hdl
1037:doi
576:.
356:at
312:by
255:ice
238:'s
168:by
41:In
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1100:^
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162:.
20:)
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