Windshear And Contaminated R/ys Flashcards
Windshear definition
Abrupt variations in wind along the a/c flight path - sufficient intensity - duration which can displace the a/c abruptly from its intended path requiring substantial control action
LLWAS and when is it activated and possible limitations
Low level windshear alert system
Alert is generated whenever a difference in excess of 15kt is detected
May not detect downbursts with a diameter of 2nm or less
TDWR
Terminal Doppler radar
Enables to detect approaching windshear areas
When to file a PIREP about windshear
Winshear in excess of 20kts or down/updraft in excess of 500ft/min below 1000ft agl
LIDAR
Uses beams of light to detect windshear
Methods to recognise wind shear
IAS variations in excess of 15kts
Gs variations
Wind direction and speed variations
Unexpected vertical speed variations in excess of 500ft/min
Unexcepted pitch variations of 5* or more
G/slope variations of 1 dot
Unusual auto throttle activity
Actions to take if encountering windshear
Immediately set and maintain t/o thrust
Follow f/d and fly close to the stick shaker/stall warning AoA
Do not change the flap/ landing config
Level the wings to maximise climb gradient
Keep a/p engaged
A r/y is contaminated when
More than 25% is covered by
More than 3mm of water/snow/slush
Compacted snow, inc ice
Damp r/y definition
When the surface is not dry, but when the moisture on it does not give a shiny appearance
Wet r/y definition
R/y surface is covered by less than the contaminated value and the sufficient moisture to make the r/y appear reflective
Can you land on a contaminated r/y without a unserviceable anti skid
NO
2 different dynamic hydroplaning speeds and how to calc
Spin down speed - in kts = 9 x square root of the tyre pressure in PSI
Spin up speed = 7.7 x square root of the tyre pressure in PSI
Dynamic occurs when the water is greater than the tyre tread
Viscous hydroplaning
The r/y is contaminated with a film of oil,dust,grease or rubber
Can occur at speeds lower than dynamic
Little bit of a friction coefficient
Reverted rubber is caused by
When the wheel locks and becomes superheated - reverted back to its liquid state
A snowtam is valid for
24hours - new snowtam if sig changes occur
During the winter - issued each day in the morning before flying starts
Item D and item T in the snowtam
D = cleared r/y length is less than published
T = plain language operational information
Vortex are biggest when
The a/c is low and slow
The a/c is heavy
In a clean config
Between a helicopter which produces the biggest vortices
A helicopter
You should avoid larger a/c by
1000 ft below and behind
ICAO publishes wake turbulence separation minima based on MTOM
A bird strike is most likely to occur at
A critical stage of flight
How to avoid a bird strike
Use l/d lights and gently pitch up if possible
What sources of information are available regarding the migration and prescience of birds
Pilot reports
Local ATC
ATIS
Birdtam
Pilots should report bird activity to
ATC
Pilots should report a bird strike to
The local authority within 72hours
% of bird strikes that occur below 200ft
70%
Bird disposal methods
Using birds of prey
Firing pyrotechnic bird scattering cartridges
Playing recorded bird distress calls
