flight training and the effects of weather presented by patrick murphy director of training comair...

FLIGHT TRAINING AND THE FLIGHT TRAINING AND THE EFFECTS OF WEATHEREFFECTS OF WEATHER

Presented By

PATRICK MURPHY

DIRECTOR OF TRAINING

COMAIR AVIATION ACADEMY

Developed By

RICHARD MORRIS

ASSISTANT CHIEF OF FLIGHT STANDARDS

FLIGHT TRAINING IN FLIGHT TRAINING IN FLORIDAFLORIDA

Sea breezes & coastal thunderstorm development.

Downdrafts, windshear, microburst, hail & Lightning.

How to make the most of the thunderstorm season.

CLOUD DEVELOPMENTCLOUD DEVELOPMENT

Clouds will not form in dry air.Their development is dependent on 3

factors:1. Water Vapor2. Condensation nuclei3. Cooling

THUNDERSTORM THUNDERSTORM DEVELOPMENTDEVELOPMENT

Thunderstorms are an every day part of life in Florida.

On average central Florida receives 90+ days per year of thunderstorm activity.

THUNDERSTORMSTHUNDERSTORMS

THUDERSTORM THUDERSTORM FORMATIONFORMATION

3 basic components are required for the formation of a thunderstorm.

1. Moisture.2. Unstable Air.3. Lifting Action.

MOISTUREMOISTURE

In the case of Florida we have water on both sides of the peninsula, in the form of the Atlantic Ocean and the Gulf of Mexico.

This means that there is an abundance of available moisture that can be utilized for the formation of a thunderstorm.

THE SEA BREEZETHE SEA BREEZE

During the day the sun heats the land and the water.

However it takes far more energy to heat the water, and thus the land warms more quickly.

Due to this unequal heating, a pressure gradient develops with high pressure forming at altitude over the land and low pressure beneath it.

THE SEA BREEZETHE SEA BREEZE The heated air over the land rises and is replaced

by cooler air from over the water. This occurs due to the pressure over the water

being now relatively higher than the pressure at low level over the land.

This forms a circulation pattern, and as it does so forms what is referred to as a sea breeze.

This is most prominent during the time of maximum heating, and in Florida is greatly felt in the mid afternoon.

PRESSURE GRADIENTSPRESSURE GRADIENTS


The fact that sea breezes form on both sides of the Florida peninsula, produces lines of thunderstorms.

These thunderstorms can move inland a significant distance due to the lack of inhibiting topography.


In Florida we have an abundance of water vapor due to the sea breezes bringing moisture in land from the oceans.

The moisture in the air then attaches to the “hygroscopic nuclei” and this allows a surface on which the moisture in the atmosphere can change state and condensation occurs to form water droplets, or deposition occurs to form ice crystals.


In order for clouds to form we know that the air must be saturated.

In order for this to occur there are 2 ways for this to occur.

1. Add more water to allow the Relative Humidity to reach 100 %.

2. Cool the air. This we know is true, as the amount of water vapor necessary for saturation decreases with temperature.

UNSTABLE AIRUNSTABLE AIR

Air is termed as unstable when LR ( Lapse Rate) is greater than DALR (Dry Adiabatic Lapse Rate).

This we know to be true in Florida, as the air at the surface is heated far above that of standard conditions and therefore is immediately above the normal LR scale.

UNSTABLE AIRUNSTABLE AIR

LIFTING ACTIONLIFTING ACTION

As already discussed the lifting action is the heating of the land surface, which produces the necessary vertical motion.

THE FLORIDA THE FLORIDA THUNDERSTORMTHUNDERSTORM

Florida thunderstorms are generally less than 15 miles in diameter.

However they grow vertically to heights in excess of 10 miles into the atmosphere.

This vertical development and concentrated moisture can lead to 4 or more inches of rain in less than an hour, while locations a few miles away may see less than ¼ inch.

FORMATION OF A COASTAL FORMATION OF A COASTAL THUNDERSTORMTHUNDERSTORM

THUNDERSTORMSTHUNDERSTORMS

THERE ARE AN ESTIMATED 100,000 THUNDERSTORMS IN THE UNITED STATES EVERY

YEAR.

HOW A THUNDERSTORM IS HOW A THUNDERSTORM IS FORMEDFORMED

There are 3 basic stages in the life cycle of a thunderstorm.

1. Cumulus Stage.2. Mature Stage.3. Dissipating Stage.

CUMULUS STAGECUMULUS STAGE

During this stage the atmospheric moisture and instability are sufficient to produce airmass thunderstorms.

In Florida, specifically, the surface heating leads to rapid development resulting in towering cumulus (TCU) clouds.

This stage can happen as rapidly as 15 minutes and can grow in that time to a height in excess of 20,000 feet.

CUMULUS STAGECUMULUS STAGE

MATURE STAGEMATURE STAGE

The mature stage of the thunderstorm begins when “precipitation-induced downdrafts” reach the ground.

Lightning and thunder develop as the storm grows to about 5-10 miles in diameter.


Thunderstorms reach their greatest intensity during this stage of development, and can form to heights that take the tops of the clouds into the lower stratosphere.

“Precipitation-induced downdrafts”, if exceptionally strong and small my be classified as a “Microburst”.

DOWNDRAFTSDOWNDRAFTS

Downdrafts occur when the altitude of a cumulus cloud exceeds the freezing level, leading to rapid growth of the cloud

However, at some point the updraft is no longer strong enough to support the weight of the larger particles in the cloud, and they begin to fall.


These falling particles literally drag the air downwards.

This is the beginning of the “precipitation induced downdraft”.

The downdrafts are strengthened where unsaturated air outside the cloud is mixed across the boundaries of the cloud.


Evaporation then further cools the downdraft, increasing its negative buoyancy.

It is vital to remember that the “precipitation-induced downdraft” is a major component of the life cycle of a thunderstorm.

MICROBURSTSMICROBURSTS

As discussed earlier, microbursts are exceptionally strong downdrafts that are exceptionally dangerous.

For a pilot downdrafts and microbursts create a serious danger.

MICROBURSTSMICROBURSTS

DISSIPATING STAGEDISSIPATING STAGE

In Florida, usually 30 or so minutes after it has started the thunderstorm reaches the dissipating stage.

During this stage the downdrafts and precipitation spread throughout the lower levels of the thunderstorm cutting off the updrafts.


Since the source of energy for thunderstorm growth is the supply of heat and moisture from the surface layer, the cutting off of the updrafts spells the end of the storm.

With no form of moisture, the precipitation decreases and the entire thunderstorm takes on a stratiform appearance, gradually dissipating.


Because the anvil top is an ice cloud, it often lasts longer than the rest of the cell.

It is important to remember that just because the thunderstorm is dissipating it is still to be given a wide berth.

HAILHAIL

Another product of the strong updrafts produced by thunderstorms is the formation of hail.

With strong updrafts, small water and ice particles have a longer time to grow in a favorable cloud environment before they fall.

HAILHAIL

We know that accretion may produce a large particle which becomes the nucleus of the hailstone.

The hailstone then continues to grow if the updrafts are strong enough, until a point when they become so big that the updrafts can no longer support them and they fall to the ground, often with devastating consequences.

HAILHAIL

LIGHTNINGLIGHTNING

Lightning is a visible electric discharge produced by a thunderstorm.

There are several types, such as in-cloud, cloud-cloud, cloud-ground and occasionally cloud-clear air.

LIGHTNINGLIGHTNING

Whatever the form of lightning , all lightning discharges involve voltage differences of about 300,000 volts per foot or more.

Air along the discharge channel is heated to more than 50,000 degrees Fahrenheit, causing a rapid expansion of the air and a shock wave that moves away from its source, which finally reaches our ears as thunder.

LIGHTNINGLIGHTNING

Lightning in general is formed by negatively charged particles forming in the lower part of the cloud.

This can occur by many means, for example the transfer of ions when a warm hailstone comes in contact with colder ice crystals.

Other methods include freezing and splintering.

LIGHTNINGLIGHTNING

When this occurs a positive charge forms above the negative layer at the base of the cloud.

There is also a positive charge on the ground.

When this charge differential becomes great enough, lightning occurs.

LIGHTNINGLIGHTNING

Lightning is actually a stage of events, starting with the “stepped leader” that carries electrons from the base of the cloud to the ground, creating an ionized channel for the subsequent discharge.

Close to the earth the stepped leader is met by an upward-moving positive charge.

LIGHTNINGLIGHTNING

A bright “return stroke” occurs, marking the route of the positive charge along the original path of the stepped leader back up into the cloud.

In general a thunderstorm will produce 3–4 lightning strokes per minute.

LIGHTNINGLIGHTNING

RULE OF THUMBRULE OF THUMB

The approximate distance (in feet) form your location relative to a thunderstorm is determined by counting the seconds between the lightning flash and the thunderclap and multiplying that number by 1,100.

For example a 4 second lag would indicate that the storm is 4,400 feet away.

COMPANY POLICYCOMPANY POLICY

One of the most important factors in deciding whether a flight should be flown is SAFETY.

The next table will show you how we use our company policies to increase safety and at the same time allow flights that may safely proceed to be launched.

The following slide shows the minimum ceiling heights in Feet AGL.

SAFETY PROCEDURES SAFETY PROCEDURES AND PRACTICESAND PRACTICES

CROSS COUNTRY ROUTESCROSS COUNTRY ROUTES

At Comair Aviation Academy we are very conscious about the fact that delays in training must be balanced by the concerns for safety of our pilots.

Saying this we have developed sets of cross country routes specifically for all our ratings.

These routes allow for both North and South flights, as well as reserve routes that allow for the most severe weather conditions.

CROSS COUNTRY ROUTESCROSS COUNTRY ROUTES

This allows for us to keep flying and keep the progression of our students at a maximum.

One of the major factors that helps to keep this tempo going is the implementation of a “Flight Supervisor Program”.

FLIGHT SUPERVISORFLIGHT SUPERVISOR

The role of the flight supervisor is to help both the instructors and students make safe, intelligent decisions.

They are also there to keep a close watch over developing weather systems during daily flight operations.

Their role is also to motivate students.

FLIGHT SUPERVISORFLIGHT SUPERVISOR

The flight supervisor is as much a psychologist as an instructor in the respect that they are there to help students enlarge their comfort zone whilst still having the backup of an instructor on board the aircraft.

This again helps to make a safer more experienced pilot, and one that will be more confident in their own ability, as well as knowing what to expect from the weather.

UP TO DATE WEATHER UP TO DATE WEATHER INFORMATIONINFORMATION

There is also the importance of having up to date and accurate information.

Many systems now exist, and are relatively inexpensive, that help to aid in the “Go/No Go” decision making process.

We as instructors are charged with ensuring that our students are armed with all the necessary information when it comes to weather.

UP TO DATE WEATHER UP TO DATE WEATHER INFORMATIONINFORMATION

Both of the next slides show the ability the most up to date systems have of producing actual real time weather.

The first slide shows thunderstorm activity, the second rain.

Students must be able to differentiate between the two.

HOW TO MAKE THE MOST HOW TO MAKE THE MOST OF THE THUNDERSTORM OF THE THUNDERSTORM

SEASONSEASON The FAA publishes a great deal of information

relating to weather and weather avoidance. AC-00-6A(Aviation Weather)

AC-00-45D(Aviation Weather Services) AC-00-24B(Thunderstorms)

AC-00-54(Pilot Windshear Guide) FAA-P-8740-30(How To Obtain A Good Weather

Briefing) FAA-P-8740-12(“Thunderstorms – Don’t Flirt’em…

Skirt’em”)

REMEMBER IT IS BETTER TO BE ON THE GROUND WISHING YOU

WERE IN THE AIR, THAN IT IS TO BE IN THE AIR WISHING YOU

WERE ON THE GROUND!

flight training and the effects of weather presented by patrick murphy director of training comair...

Documents