If you wish to contribute or participate in the discussions about articles you are invited to join SKYbrary as a registered user

 Actions

Difference between revisions of "Weather"

From SKYbrary Wiki

(Further Reading)
m (Aviation Meteorology)
 
(34 intermediate revisions by 5 users not shown)
Line 1: Line 1:
 
{{Infobox Weather
 
{{Infobox Weather
|source            = Skybrary
+
|source            = SKYbrary
|source_image      = skybrary
+
|source_image      = SKYbrary
|source_caption    = skybrary
+
|source_caption    = About SKYbrary
|control          = Eurocontrol
+
|control          = EUROCONTROL
|control_image    = Eurocontrol
+
|control_image    = EUROCONTROL
|control_caption  = Eurocontrol
+
|control_caption  = EUROCONTROL
 
}}
 
}}
 
'''Wx'''
 
'''Wx'''
 
==Description ==
 
==Description ==
  
Of all things which influence the safety of flight, the [[Weather|weather]], the characteristics and behaviour of the Earth’s [[atmosphere]], is without doubt the most powerful.
+
Of all things which influence the safety of flight, the weather - the characteristics and behaviour of the Earth’s [[atmosphere]] - is the most uncertain and influential (either directly or indirectly).
  
The following have a direct and indirect influence on flight safety:
+
==Aviation Meteorology==
*Turbulence associated with convective activity (for example, [[Thunderstorm|thunderstorm]]s), terrain (for example, the movement of air masses over mountains), [[Jet Stream|jet stream]]s and the interaction between air masses, can cause structural damage to aircraft.
 
*[[Icing]] can alter the aerodynamic characteristics of an aircraft, cause damage to the engines, and seriously affect the performance of an aircraft. Ice crystal engine icing, in particular, is an important and improperly understood phenomenon.
 
*Reduced visibility, associated with [[Cloud|cloud]], mist, [[Fog|fog]], or [[Sand Storm|sand storms]], can make safe flight difficult or even impossible, even with the help of technology ([[ILS]], [[Weather Radar|weather radar]], [[Synthetic Vision Systems|synthetic vision systems]], etc)
 
*Surface contamination; standing water, ice, or snow on take-off, landing and manoeuvre surfaces.
 
*Wind; the influence of wind on directional control [[Cross-Wind|cross-wind]] or aircraft stability during take-off and landing, and generally on en-route performance.
 
*Precipitation; for example rain, [[Hail|hail]], and snow affect aerodynamics and visibility.
 
*Lightning; a lightning strike can be very distressing to passengers (and crew!) but physical damage to an aircraft is not likely to threaten the safety of the aircraft. Of greater concern is the effect a lightning strike can have on avionics, particularly compass systems, and the potential for the transient airflow disturbance associated with lightning to cause engine shutdown on both [[FADEC]] and non-FADEC engines with close-spaced engine pairs.
 
  
Many of the operational safety issues that are addressed within SKYbrary are influenced by weather:
+
The following can have a direct and indirect influence on flight safety (note: this list is not intended to be exhaustive):
 +
*'''[[Turbulence]]''' associated with convective activity (for example, [[Thunderstorm|thunderstorm]]s), terrain (for example, the movement of [[Air Masses|air masses]] over mountains), [[Jet Stream|jet streams]] and the interaction between air masses (for example polar fronts and associated dynamics), can be significant enough to cause structural damage to aircraft.
 +
*'''Icing''': [[Ice Formation on Aircraft]] can alter the aerodynamic characteristics of an aircraft and cause damage to or loss of function of the engines and seriously affect the performance of an aircraft. The article [[Aircraft and In Flight Icing Risks]] discusses the commonly-encountered issues whilst [[High Level Ice Crystal Icing: Effects on Engines|high level ice crystal icing]] of turbine engines is a recently-identified and improperly understood phenomenon which occurs outside the normal icing envelope. Ice may form on aircraft whilst they are on the ground prior to flight and this must be removed and any  further accretion on the airframe prevented by the [[Aircraft Ground De/Anti Icing]] so that any aircraft is free of ice deposits at the point at which it gets airborne.
 +
*'''Reduced visibility''', associated with [[Cloud|cloud]], mist, [[Fog|fog]], or [[Sand Storm|sand storms]], can make safe flight difficult or even impossible, even with the help of technology ([[ILS]], [[Weather Radar|weather radar]], [[Synthetic Vision Systems|synthetic vision systems]], etc)
 +
*'''Surface contamination'''; standing water, ice, or snow on take-off, landing and manoeuvre surfaces.
 +
*'''Wind Velocity'''; near the ground, the influence of wind on directional control and [[Cross Wind Landings]] or take-offs can, if not dealt with effectively, lead to [[Runway Excursion]].
 +
*'''[[Precipitation]]'''; for example rain, [[Hail|hail]], and snow affect aerodynamics and visibility.
 +
*'''[[Lightning]]'''; a lightning strike can be very distressing to passengers (and crew!) but physical damage to an aircraft only very rarely threaten the safety of an aircraft. Of greater concern is the effect a lightning strike can have on avionics, particularly compass and air data systems, and in case of rear mounted jet engines, the potential for the transient airflow disturbance associated with lightning to cause engine shutdown on both [[FADEC]] and non-FADEC engines because of their close spacing and exposure to the same airflow disturbance at the same time.
  
*[[Runway Excursion]]: The indirect contribution of weather to runway surface state and the direct effect of crosswind component on directional control.
+
Many of the operational safety issues that are addressed within SKYbrary can be affected by weather:
*[[CFIT]]: CFIT accidents often occur when an aircraft is in cloud or in reduced forward visibility, when the crew may be subject to extra workload, be distracted, or have reduced situational awareness associated with the weather conditions.
 
*[[Loss of Control]]: as a result of turbulence or windshear such as might be experienced in a [[Microburst]].
 
  
There are numerous specific mitigation strategies to maintain the safety of flight in certain types of weather. These may be technical, procedural, or navigation related, or all three, and it may be necessary to delay or cancel the flight if no safe mitigation is available. A common requirement is that all those associated with the safety of flight should have an understanding of meteorology.
+
*'''[[Runway Excursion]]''': The indirect contribution of weather to runway surface state and the direct effect of crosswind component on directional control.
 +
*'''[[CFIT|Controlled Flight Into Terrain (CFIT)]]''': CFIT accidents often occur when an aircraft is in cloud or in reduced forward visibility, when the crew may be subject to extra workload, be distracted, or have reduced situational awareness associated with the weather conditions.
 +
*'''[[Loss of Control]]''': Commonly as a direct or indirect result of turbulence or [[Wind Shear|windshear]] such as might be experienced in an unintentional excursion into active [[Cumulonimbus]] clouds, or an encounter with a [[Microburst]] or because of exposure to [[In-Flight Icing]] which exceeds the capacity of the available or selected [[Ice Protection Systems]].
  
==Aviation Meteorology==
+
There are numerous specific mitigation strategies to maintain the safety of flight in certain types of weather. These may be technical, procedural, or navigation based, or all three, and it may be appropriate to re-route, delay or cancel a flight if no satisfactory mitigation is available. A common requirement is that all those associated with the safety of flight should have an understanding of meteorology appropriate to their operational role.
  
The study of aviation meteorology can be divided into a number of topics:
+
==Organisation of Weather Knowledge on SKYbrary==
 +
The growing number of weather and environmental related articles on SKYbrary are organised into the following subject areas:
 +
*[[Icing|In-Flight Icing]]
 +
*[[Turbulence]]
 +
*[[Volcanic Ash]]
 +
*Weather Risk Management
 +
*Weather Phenomena
 +
*[[Cloud|Cloud Formation]]
 +
*[[Climate|Climatic Phenomena]]
 
*[[Atmosphere]]
 
*[[Atmosphere]]
*[[Air Mass]]
 
*[[Cloud]]
 
*[[Thunderstorm]]
 
*[[Lightning]]
 
*[[Icing]]
 
*[[Wind]]
 
*[[Visibility]]
 
*[[Weather Forecast]]
 
  
 
==Further Reading==
 
==Further Reading==
 
+
* The theme of [[Hindsight 7]] (EUROCONTROL's Safety Magazine) was Weather and contains a number of articles discussing hazards to aviation associated with weather phenomena.
*The theme of [[Hindsight 7]] (EUROCONTROL's Safety Magazine) was Weather and contains a number of articles discussing hazards to aviation associated with weather phenomena.
+
* FAA Review of NTSB weather related accidents during the 10 year period [https://www.asias.faa.gov/i/Wake_Weather_Turbulence_Report_2016.pdf (2002 to 2013)]
*FAA Review of NTSB weather related accidents during the 110 year period 1994-2003:[http://www.asias.faa.gov/aviation_studies/weather_study/studyindex.html http://www.asias.faa.gov/aviation_studies/weather_study/studyindex.html]
+
* Review of Aviation Accidents involving Weather Turbulence in the United States 1992-2001 [https://www.asias.faa.gov/i/turbulence_study_new.pdf (FAA 2004)]
*Review of US Weather Turbulence Accidents during 10 year period 1992-2001 (FAA 2004)
+
* see also FAA "Lessons Learned from Transport Airplane Accidents": [https://lessonslearned.faa.gov/ll_main.cfm?TabID=3&CategoryID=3 Inclement Weather / Icing]
*Safety Study: Risk Factors Associated with Weather-related General Aviation Accidents (NTSB 2005)
 
  
 
[[Category:Weather]]
 
[[Category:Weather]]
 
[[Category:Operational Issues]]
 
[[Category:Operational Issues]]

Latest revision as of 07:38, 31 March 2019

Article Information
Category: Weather Weather
Content source: SKYbrary About SKYbrary
Content control: EUROCONTROL EUROCONTROL

Wx

Description

Of all things which influence the safety of flight, the weather - the characteristics and behaviour of the Earth’s atmosphere - is the most uncertain and influential (either directly or indirectly).

Aviation Meteorology

The following can have a direct and indirect influence on flight safety (note: this list is not intended to be exhaustive):

  • Turbulence associated with convective activity (for example, thunderstorms), terrain (for example, the movement of air masses over mountains), jet streams and the interaction between air masses (for example polar fronts and associated dynamics), can be significant enough to cause structural damage to aircraft.
  • Icing: Ice Formation on Aircraft can alter the aerodynamic characteristics of an aircraft and cause damage to or loss of function of the engines and seriously affect the performance of an aircraft. The article Aircraft and In Flight Icing Risks discusses the commonly-encountered issues whilst high level ice crystal icing of turbine engines is a recently-identified and improperly understood phenomenon which occurs outside the normal icing envelope. Ice may form on aircraft whilst they are on the ground prior to flight and this must be removed and any further accretion on the airframe prevented by the Aircraft Ground De/Anti-Icing so that any aircraft is free of ice deposits at the point at which it gets airborne.
  • Reduced visibility, associated with cloud, mist, fog, or sand storms, can make safe flight difficult or even impossible, even with the help of technology (Instrument Landing System (ILS), weather radar, synthetic vision systems, etc)
  • Surface contamination; standing water, ice, or snow on take-off, landing and manoeuvre surfaces.
  • Wind Velocity; near the ground, the influence of wind on directional control and Cross Wind Landings or take-offs can, if not dealt with effectively, lead to Runway Excursion.
  • Precipitation; for example rain, hail, and snow affect aerodynamics and visibility.
  • Lightning; a lightning strike can be very distressing to passengers (and crew!) but physical damage to an aircraft only very rarely threaten the safety of an aircraft. Of greater concern is the effect a lightning strike can have on avionics, particularly compass and air data systems, and in case of rear mounted jet engines, the potential for the transient airflow disturbance associated with lightning to cause engine shutdown on both Full Authority Digital Engine Control (FADEC) and non-FADEC engines because of their close spacing and exposure to the same airflow disturbance at the same time.

Many of the operational safety issues that are addressed within SKYbrary can be affected by weather:

  • Runway Excursion: The indirect contribution of weather to runway surface state and the direct effect of crosswind component on directional control.
  • Controlled Flight Into Terrain (CFIT): CFIT accidents often occur when an aircraft is in cloud or in reduced forward visibility, when the crew may be subject to extra workload, be distracted, or have reduced situational awareness associated with the weather conditions.
  • Loss of Control: Commonly as a direct or indirect result of turbulence or windshear such as might be experienced in an unintentional excursion into active Cumulonimbus (Cb) clouds, or an encounter with a Microburst or because of exposure to In-Flight Icing which exceeds the capacity of the available or selected Aircraft Ice Protection Systems.

There are numerous specific mitigation strategies to maintain the safety of flight in certain types of weather. These may be technical, procedural, or navigation based, or all three, and it may be appropriate to re-route, delay or cancel a flight if no satisfactory mitigation is available. A common requirement is that all those associated with the safety of flight should have an understanding of meteorology appropriate to their operational role.

Organisation of Weather Knowledge on SKYbrary

The growing number of weather and environmental related articles on SKYbrary are organised into the following subject areas:

Further Reading

  • The theme of Hindsight 7 (EUROCONTROL's Safety Magazine) was Weather and contains a number of articles discussing hazards to aviation associated with weather phenomena.
  • FAA Review of NTSB weather related accidents during the 10 year period (2002 to 2013)
  • Review of Aviation Accidents involving Weather Turbulence in the United States 1992-2001 (FAA 2004)
  • see also FAA "Lessons Learned from Transport Airplane Accidents": Inclement Weather / Icing