SAMRA Flashcards
How does drizzle form?
With the condensation in stratus clouds
Which lifting process is involved in the formation of TCU in the centre of a low-pressure system?
In the centre of a low-pressure system, several airflows arrive from high-pressure areas and converge.
Over mountain ranges, where wind shear and CAT are the most intense?
Above and to the lee of mountain ranges
Weather at a frontal system is determined by?
Speed of the cold air mass
Stability and moisture of warm air mass
What is the effect of wind on PNR (Point of No Return) and CP (Critical Point)?
Either tail- or headwind, it will shorten the distance to the PNR.
Tailwind : CP closer to departure
Headwind : CP closer to arrival
What is the accuracy of GPS position?
6m horizontal
8m vertical
95% of the time
At which speed does aerodynamic heating eliminates the risk of ice formation?
Above 500 kts
When will TS-associated icing will be the most serious?
During the beginning of the mature stage of the TS
Definitions of bursts?
- Macroburst : diameter > 2 NM, winds for 5 to 20 minutes. Can cause tornadoes.
- Microburst : diameter < 2 NM, wind for 5 minutes or less
- Wet : when precipitation reaches the ground
- Dry : when precipitation doesn’t reach the ground. The descending air column contains virga, increasing the burst strength.
What does SFC WND SPD mean in an AIRMET?
Surface winds will blow at 30 kts or more
What are the 3 types of fixed RNAV routes?
- Q : High Level RNAV route, controlled
- T : Low Level RNAV route, controlled
- L : Low Level RNAV route, uncontrolled
On which technology(ies) is ADS-B based?
On aircraft avionics, satellites and/or ground infrastructure, to relay a range of aircraft parameters to the ATC.
What can cause attenuation on a Wx radar?
The accumulation of ice on the radome
What are the 3 levels of rain on a Wx radar screen?
- Level 1 : light rain
- Level 2 : medium rain
- Level 3 : heavy rain
Time to station formula? (VOR)
Time in min = Time in sec / diff. radials
On a 250hPa chart, how do you recognize sufficient horizontal shear for CAT?
30kts isotachs are closer than 90NM from each other (generally on the low-pressure side of the jet stream)
What is the expected accuracy to be expected for RNAV?
95%
How does steam fog form?
Cold air moving over warm water
In HF frequency, what is the difference between single-side band (SSB) and dual-side band (DSB) ?
SSB signal is stronger and covers greater distances than DSB
When can an ELT 406 be tested?
At the time indicated by manufacturer’s instructions
What accuracy should unpublished VOR radials meet?
None, unpublished radials are not required to meet a particular standard of accuracy
If turbulence is to be met near a sloping tropopause, where will the turbulences be most pronounced?
On the temperature-change zone, in the stratospheric side of the sloping tropopause
What is the formula to calculate the critical point?
Total trip distance x GS to go back
/
GS to go back + GS to go to destination
The vertical distance between any two specific pressure levels is…
Less in cold air than in warm air
What instrument can be used to measure humidity in the air?
Psychrometer
It consists of a wet-bulb T°-meter and a dry-bulb T°-meter. Also called hygrometer.
What is implied by the presence of snow grains precipitations on the ground?
Snow grains imply that FZDZ is present aloft.
Air masses over Great Lakes and their consequences…
cA moving southbound during winter : snow showers immediately to the south of southern shorelines
cA moving southbound during early autumn : steam fog over northern portions of the GL
mT moving northbound during spring and early summer : low stratus clouds, drizzle and fog over north shores.
Which meteorological process reduces the relative humidity and causes water to evaporate?
Subsidence
What causes ADF night effect?
Sky waves directed to the earth interfere with ground waves.
On which range of frequencies ACARS and SELCAL work?
HF and VHF.
ACARS is supported by SATCOM over oceanic areas.
SELCAL works mostly on HF.
What is mainly determining the intensity of radar echo on an airborne Wx radar?
Size of the drops (at a greater extent than number of them)
Minimum speed for a wind to qualify as a jet stream?
60 kts
On a Wx radar image, what a hook shape and a finger shape indicate?
Hook = severe turbulence or tornado activity
Finger = hail
Where is MLAT (Multilateration) used?
On the ground, to provide full surveillance coverage of RWYs, TWYs and aprons areas.
What is the typical area covered along a planned flight path for visual research in SAR?
15 NM.
What are the codes to put in Item 10 of flight plan to indicate that RVSM or MNPS is approved?
RVSM = W
MNPS = X
