Aviation Weather

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How weather affects
aviation and best
practices to manage it.

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Group Members
USAMA ZULFIQAR (L)
Sheraz Ali
Zian Alamgir
Salat butt

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INTRODUCTION
The aviation industry has long been aware of the challenges posed by
weather. Weather has the potential to cause flight delays, cancellations,
and even accidents. Pilots and other professionals in the aviation industry
must be familiar with weather patterns and how to manage them.
 20 to 30% of worldwide air accidents are due to adverse
weather conditions.
 Because of the different scales, the hazards have not the same
impact if the aircrafts encounter them En-Route (Regional and
Global scales) or in the airport terminal area (Local scale).

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Classifications
Airports Terminal Area Local Airport Weather:
 Wake Vortices
 Thunderstorms (microbursts, hail, wind shear)
 Icing (waiting aircraft stacks)
 Low ceilings and visibility

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Classifications
En-Route: Regional and Global scales Weather
 Thunderstorms (hail, turbulence)
 Clear Air Turbulence(CAT)
 Icing (regional flights at lower altitudes)

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Airports Terminal Area Local Airport Weather
WAKE VORTICES
Small aircraft encountering wake vortices from a much larger
aircraft may find its flight path dramatically disrupted to the point
that control is lost. Larger aircraft may well sustain some sharp and
sudden disturbances but are more likely to be able to maintain safe
flight.
 approximately 1,000 feet below and 10 – 20 nautical miles
behind heavy aircraft types and that a number of injuries to
passengers and crew have been sustained in these encounters.

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Thunderstorms
 A storm accompanied by thunder and lightning.
 A Thunderstorm is local in nature and is always produced by the
growth of a cumulus cloud into a c cloud.
Three stages
1. Cumulus(The developing stage of a thunderstorm is marked by a
cumulus cloud that is being pushed upward by a rising column of air)
2. Mature(The mature stage is the most likely time for hail, heavy rain,
frequent lightning, strong winds, and tornadoes.)
3. Dissipating(large amount of precipitation is produced and the updraft is
overcome by the downdraft beginning the dissipating stage)

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Icing
 Ice is present in the atmosphere at all times-15,000 feet in
summer and as low as 1,000 feet in winter.
 Glaze and Rime ice form on an airplane's windshield, its
propeller, and other aerodynamic surfaces.
 • Glaze ice is formed and builds quickly as an airplane flies
through super-cooled rain droplets.

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Icing
 Rime ice forms when an airplane is flying through super-cooled
cloud condensation.
 Frost disturbs airflow to reduce lift efficiency.
 Larger, more sophisticated aircraft are equipped to break or melt
ice as it is formed.

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CEILING AND LOW VISIBILITY
 Ceiling at your intended destination may be defined as the lowest
broken or overcast cloud layer. If the sky is totally obscured, height of
vertical visibility is used as the ceiling.
 Three miles lateral visibility is acceptable for safe flight under
visual flight rules (VFR).
 Possibility for accidents is greatest when visibility is reduced and
the pilot is not trained to fly according to instrument flight rules
(IFR).
 Clouds, rain, snow, fog, and obstructions.

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Clear Air Turbulence (CAT)
Clear Air Turbulence (CAT) is defined as sudden severe
turbulence occurring in cloudless regions that causes violent
buffeting of aircraft. This term is commonly applied to higher
altitude turbulence associated with wind shear.

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Practice to manage weather conditions
 FORECASTING
 DETECTING
 ICING MANAGEMENT
 AVOIDANCE IN FLIGHT
 RECOGNITION

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FORECASTING
 The forecasting of weather in general and the associated
conditions that are potentially hazardous to aviation in particular
has improved significantly in recent years, with satellite imagery
providing a global view and powerful computers able to feed
vast quantities of data into complex meteorological models.

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AVIATION WEATHER REPORTS
1.) Aviation Routine Weather Reports (METAR) are observations of
current surface weather. METAR reports are typically in a standard
international format and are used around the world, although many
countries have their own version.
2.) Pilot Weather Reports (PIREP) are reports by pilots on weather
conditions they see outside as they are flying. PIREP data includes
visibility, cloud height and size, and locations of turbulence and icy
conditions. These reports allow agencies and service outlets to inform
other pilots who may be on a similar flight path or flying through the same
region.
3.) Radar Weather Reports (SD) come from radar stations and give
information on areas of precipitation, wind speed, weather systems, and
thunderstorms.

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DETECTION
 Airborne weather radar is a type of radar used to provide an indication
to pilots of the intensity of convective weather. Modern weather radars
are mostly doppler radars, capable of detecting the motion of rain
droplets in addition to intensity of the precipitation.

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ICING MANAGEMENT
 Icing on the ground is managed by three critical functions:
inspection; de-icing, and; anti-icing. During cold weather
operations with temperatures close to or below 0 C (32 F),
especially during precipitation and/or high humidity it is vital that
the airframe and engines are inspected for ice and snow
accumulations in accordance with the manufacturer’s guidance.
 In the air pilots must pay heed to the ice detection systems and
be vigilant for accumulations of ice in areas visible to them. If
airframe icing is detected or suspected in flight, the airframe ice
protection systems must be operated in accordance with the
SOP.

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AVOIDANCE IN FLIGHT
 industry guidance has advised pilots to avoid Cumulonimbus
convective cloud by 20 nautical miles laterally, thereby ensuring
separation from most of the threats inside and around the cloud.
 However, experienced pilots know that convective clouds
seldom exist in single, easy to avoid units, instead tending to
appear in group of cells often at differing stages of development
and frequently embedded in more general cloud. In such cases
it may be necessary to deviate significantly from the planned
track by 100 miles or more in order to maintain separation.

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RECOGNITION
 The transition from normal stable flight to a potential LOC-I event may be
gradual or it may be quite sudden but there is a period of transition in all
cases. It is this period that allows pilots the opportunity to recognise that all
is not well and to intervene to prevent further deviation or recover to stable
flight conditions.
Factors:
1. The first of these factors is effective monitoring.
2. The second critical factor is a sound knowledge of what ‘normal’ looks like
for any phase of flight. Pilots must know approximately what thrust setting,
airspeed and attitude to expect throughout climb, cruise, descent and
approach for a variety of aircraft weights and at the full range of altitudes.

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THANK YOU