Progress Test 12 Flashcards
(14 cards)
What is an associated danger of mountain flying?
Controlled flight into terrain. Caused by pilots being forced lower by descending cloud base. Cause pilots to fly into Cloud and reduced visibility.
What is Cumulus Granit?
Grey in colour when viewed directly ahead through bad weather, have very hard sides.
True or False? When mountain flying winds may not be in the prevailing direction and strong winds can be expected.
True.
What is a mountain wave?
The airflow over a mountain or hill in a wave motion and continues downwind of a range and forces vertically adjacent air to have a wave motion.
What conditions is required for mountain waves occur?
Wind speed is greater than 15kts at the surface
And the wind direction is 30 degrees within right angle of the range.
Hill and mountains provide one half of a Venturi, what does this lead to?
- Airspeed aloft increase
- Pressure is reduced
- Altimeter over-reads
*What are Lenticular clouds?
A form of orographic clouds that form at the peak of the wave pattern, they have a very high icing risk.
When Lenticular clouds appear what occurs downwind of the range?
Turbulence occur at lower altitudes and rotor clouds form, the most turbulent air will be downwind of the range.
What is the Foehn effect in relation to mountain flying?
A hillside will be warmer on the non-winwards side than the windward side, the warm descending air/wind can be effected.
What is Terrain funnelling?
Wind speeds increase to pass through the gap resulting in a local atmospheric pressure decrease. (Bernoulli effect).
Terrain Funnelling can alter the wind flow by 30 degrees, when winds descend from several valleys and merge into one valley what wind is this called?
Mistral winds.
*What are Katabatic winds?
Winds flowing down a slope cause by air being cooled at the surface by radiation, winds can create gale strength.
*What are anabatic winds?
Winds flowing up the slope due to warm air rising, gravity acts against this so the winds are light.
If flying parallel to a range which side should you fly on?
The upwind side, if flying over ridges fly a height that is double the highest terrain.
