HAATS Flashcards
What are the three greatest challenges mountains present to flying?
A) Increasing density altitude (decreasing power)
B) Difficult wind issues
C) Visual illusions affecting aircraft control
What are the 3 main areas of focus of the HAATS course?
A) Power Management Training
B) Wind & Terrain Analysis
C) Cockpit Indicators
Every flight is an exercise in habit formation…
Either you are creating “good” habits or you are creating “bad” habits, habits that are extremely difficult to break in the stressful environment of max gross weight, combat operations. It is a medical fact that under periods of great stress, our perceptual field narrows or collapses. In these moments, it is our training, our habit formation coming to the fore to see us through safely. Crews that continue to “pull” any amount of power to accomplish approaches and departures are developing poor habits of awareness and execution that may very likely cause them and their aircraft to be lost in the early stages of a deployment.
What is the basis for all air movement?
Temperature is the basis for all air movement locally or system wide. It creates the differential pressures that stirs motion, creates highs and lows, initiates thermals and downdrafts, land and sea breezes as well as mountain valley winds.
In mountainous terrain the winds are categorized in three types…
A) Prevailing (winds aloft)
B) Local or valley (convective)
C) Surface winds
What are prevailing winds and what are some of their defining characteristics?
As a rule, prevailing winds (winds aloft) move west to east in the Northern Hemisphere. Above 2000′ AGL to 3000′ AGL, air flows parallel to the isobars and direction.
What are local or valley (convective) winds and what are some of their defining characteristics?
During warmer, high-pressure days, particularly in the summer season, surface conditions are dominated by local or valley (convective) winds. These winds are the result of convective heating and cooling. They generally flow parallel to valleys and drainages.
What causes local or valley (convective) winds?
Those molecules in contact with the surface of hillsides warm more quickly than counterpart molecules at the same altitude above the valley floor. Consequently, they begin to rise and are replaced by molecules below them in a chain reaction. This movement is laminar in nature, the highest velocities closest to the hillside surface, the lowest velocities away from drainage walls, higher above the valley floor, reflecting the differences in temperature. Aviators desiring the assistance of these daytime updrafts should fly as close to the rising drainage surfaces as safety permits.
What terrain attributes most affect the velocity of valley flow?
The shape and elevation of the terrain profoundly affects the velocity of both the day and nighttime valley flows. Deep and narrow valleys and steep walled canyons create a natural venturi and can greatly accelerate the airflow. Twisting drainages slow the airflow whereas straight valleys allow the maximum momentum to be achieved. Vegetation provides drag and dampens movement, the denser the trees, the greater the impact. Where valleys turn, the air flows up and out, creating local updrafts on the outside of the turns and decreasing the velocity further upstream by allowing air flow to escape. As the air moves up a valley it fans out in all the tributaries draining into a valley.
What causes turbulent zones in convective winds?
The collision of currents rising around and over obstacles
When presented with convective winds from both sides of a ridge, what is the best practice?
The best practice is to land as close to the drainage he believes to be dominating the precise landing point. In any event, when such a situation is believed to exist, an excellent escape route should be established and maintained.
When do local or valley (convective) winds most often occur?
On warmer days when higher DA reduces power availability and control, hence the velocity of adverse winds the aircraft can accept is reduced.
Concerning the great majority of aircraft accidents involving high DA and LTE, what was found to be a significant contributing factor?
Undetected adverse winds were a significant contributing factor
What are two techniques a crew can use to determine convective activity?
1) See if there is a higher thanks standard (-2/1000ft) temperature laps rate from lower elevations to that of the LZ.
2) Search for updrafts where the particular drainage offers a sharp increase in elevation. In some situations, the crew may have to explore these regions some distance from the LZ. If convective activity exists in a nearby drainage, it exists in all drainages affected by the same air mass.
Surface winds are the….
Surface winds are the result of either prevailing or local winds, or the interplay of both.
