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Revision as of 09:02, 28 October 2008 by Josy.Verdonkschot (Text replace - 'Skybrary' to 'SKYbrary')
The following have a direct and indirect influence on flight safety:
- 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, can cause structural damage to aircraft.
- In-Flight 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, 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; the influence of wind on directional control cross-wind or aircraft stability during take-off and landing, and generally on en-route performance.
- 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 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 Full Authority Digital Engine Control (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:
- 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: 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.
The study of aviation meteorology can be divided into a number of topics:
- 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 110 year period 1994-2003:http://www.asias.faa.gov/aviation_studies/weather_study/studyindex.html
- Review of US Weather Turbulence Accidents during 10 year period 1992-2001 (FAA 2004)
- Safety Study: Risk Factors Associated with Weather-related General Aviation Accidents (NTSB 2005)