2. Ch 15 – Additional Weather Hazards

3. Introduction Introduction –There are a number of aviation weather hazards that do not fall clearly into any categories of the previous chapters. –The purpose of this chapter is to describe these hazards and to examine their causes and effects

4. Ch 15 – Additional Weather Hazards –Additionally, information is presented to help you anticipate their occurrence and avoid their negative effects –After you complete this chapter, you will understand such diverse phenomena as atmospheric electricity, stratospheric ozone, volcanic ash, condensation trails and whiteouts

5. Ch 15 – Additional Weather Hazards Section A – Atmospheric Electricity Section A – Atmospheric Electricity –Lightning Lightning Effects Lightning Effects –Static Electricity Section B – Stratospheric Ozone Section B – Stratospheric Ozone

6. Ch 15 – Additional Weather Hazards Section C – Volcanic Ash Section C – Volcanic Ash –Volcanic Ash Hazards –Ash Cloud Behavior –Reports and Warnings Section D – Condensation Trails Section D – Condensation Trails Section E – Miscellaneous Hazards Section E – Miscellaneous Hazards –Whiteout –Low-Level Inversions –Runway Conditions

7. Ch 15 – Additional Weather Hazards Section A: Atmospheric Electricity Section A: Atmospheric Electricity –Lightning – defined as any or all of the various forms of visible electric discharge produced by thunderstorms –Lightning Effects – lightning strikes on aircraft result in a variety of adverse effects. Although most of them are minor, in some cases, the damage can be severe enough to result in an accident or incident. Although most of them are minor, in some cases, the damage can be severe enough to result in an accident or incident. A lightning flash can be extremely bright; A lightning flash can be extremely bright; –temporary blindness is not an unusual occurrence

8. Ch 15 – Additional Weather Hazards –Static Electricity – refers to the spark or point discharges that occur when the electric charge difference between the aircraft and its surroundings become large enough –St. Elmo’s fire – a corona discharge that appears as a bushy halo around some prominent edges or points on the aircraft structure and around windscreens

9. Ch 15 – Additional Weather Hazards Section B: Stratospheric Ozone Section B: Stratospheric Ozone –Ozone (O3) – A prominent feature in the lower stratosphere; has both good and bad qualities; good qualities include its absorption of damaging UV radiation from the sun; has both good and bad qualities; good qualities include its absorption of damaging UV radiation from the sun; bad qualities include it not being good in an environment where animals, people and plants are present because it is toxic; bad qualities include it not being good in an environment where animals, people and plants are present because it is toxic; large quantities have an acrid smell which irritates the eyes and can cause respiratory difficulties large quantities have an acrid smell which irritates the eyes and can cause respiratory difficulties

10. Ch 15 – Additional Weather Hazards Section C: Volcanic Ash – consists of gases, dust and ash from a volcanic eruption and can spread around the world and remain in the stratosphere for months or longer Section C: Volcanic Ash – consists of gases, dust and ash from a volcanic eruption and can spread around the world and remain in the stratosphere for months or longer –Volcanic Ash Hazards – when an aircraft approaches an ash cloud some distance from a volcano, the cloud is not always easy to distinguish from ordinary water or ice clouds –Ash Cloud Behavior – volcanic ash clouds are most dangerous close to the volcano when an eruption has just occurred because the ash particles are large

11. Ch 15 – Additional Weather Hazards Reports and Warnings Reports and Warnings –Volcanic Ash Advisory Centers (VAAC) – These 9 centers have the responsibility for the preparation and worldwide dissemination of a Volcanic Ash Advisory Statement in a timely manner so that appropriate Meteorological Watch Offices (MWO) may issue SIGMETs; VAAC in the U.S. also prepare Volcanic Ash Forecast Transport and Dispersion (VAFTAD) charts VAAC in the U.S. also prepare Volcanic Ash Forecast Transport and Dispersion (VAFTAD) charts

12. Ch 15 – Additional Weather Hazards Summary Summary –This chapter alerted you to a variety of additional aviation weather hazards, some of which are rare and others that are more often nuisances –However, all have the potential of contributing to serious difficulties when they occur with other flight problems

13. Ch 15 – Additional Weather Hazards Summary Summary –Also, a few of them by themselves can create critical flight conditions (for example, lightning, volcanic ash, whiteout, and hydroplaning). –As with all weather hazards, your newly gained knowledge of their causes and of the conditions under which they occur should help you anticipate and avoid the hazards