WEATHER Flashcards
What does QFE720/0954 mean in a METAR?
720 mm/hg 954 hPa
On a weather chart, if two lines are crossing a jetstream, what does that mean?
Means a wind change of more than 20 kts 3000 ft
There is a Red Lightning warning in HK What are the rules associated with that?
- Headset comms stops
- No pushback, except for pushback that has already started
- May taxi onto frontal bays at the Pax Terminal
- All maintenace activity stops
- Ground guy will disconnect
There is an Amber Lightning warning in HK What are the rules associated with that?
Nothing, it’s only advisory
What is the formula for aquaplanning speed calculation on the B777? What are the actual calculated speeds?
Take-off: 9 x square root of the tire pressure 127 kts
Landing: 7.7 x square root of the tire pressure 109 kts
When is a METAR issued?
Half hourly or hourly.
When is a SPECI issued?
When weather improves or deteriorates through certain criteria
How long is a “Long TAF” valid for, and when are they updated?
Valid for 24-30h
Updated 0000z, 0600z, 1200z and 1800z
How long is a “Short TAF” valid for, and how often are they updated?
Valid for 9h
Updated every 3h
What is a “TREND” when attached to a METAR?
Indicates significant changes in the next 2h
When do we apply cold weather corrections to altitudes?
When temp is ISA -15 deg C
Is a METAR/TAF/ATIS wind info in magnetic or true direction?
METAR/TAF is true
ATIS is magnetic. Except in USA for D-ATIS, because the info is coming from an ASOS station which reports winds in true directions
METAR CODES:
SG
GR
GS
PL
PR
MI
UP
SG = Snow Grains
GR = Hail
GS = Small hail/Snow Pellets
PL = Ice Pellets
PR = Partial
MI = Shallow
UP = Unknown percipitaion
Why do we use full reverse thrust on a wet runway?
- Because it gives the most braking efficiency at high speed. Is related to V speed squared
- To reduce risk of hydroplanning
How long is a METAR valid for?
2h
