Weather - pilots best friend cum troubler in chief. All
books on Piloting mention about checking the weather at both source and
destination. If we look at many aircraft checklists too, it has a weather
checked - item among a host of pre-flight checks. I was trying to demystify the
above single item check on the checklist and thought about coming up with a
detailed sub checklist for weather to be completed by all pilots. Let me
elaborate my efforts in this direction:
1. Visibility:-
Whether you are in Visual Meteorology Conditions(VMC) or Instrument Meteorology
Conditions(IMC), its essential to know the visibility because without it,
taxying cannot be started. To know visibility, one must check METAR report or
obtain it from ATIS. Future trends can be obtained from TAF. However, old
school method of knowing visibility is to check for a known distant marker
object from a predetermined position to get a fair idea. Having said that, let me narrate an incident that I faced during
my flight training days. We used to have a marker and it was clearly visible,
but our Aerodrome METAR had a lower report(Controlled AD) and we used to go
ballistic about it. However, during one of my pre-dusk arrival from long cross
country flight during hazy weather day, we couldn’t clearly see the end of
downwind marker(we used to have markers on ground in circuits) before joining
the downwind. Upon landing, the fixed visibility marker was clearly visible.
This was ample proof that old school ways, though serving the purpose, are not
to be relied on 100% as they are indicative of straight line visibility whilst
what is needed for Pilot is slant visibility and is accurately obtained from
METAR/TAF/ATIS.
2. Winds:- Winds are essential component as they are the
basis of flight. Wind speed and direction can be obtained by looking at the
windsock at the runway(conventional) or from METAR/ATIS and TAF(future trends).
It helps determine the runway orientation to use and also the drifts one can
expect in flight.
3. Temperatures: Temperatures are a good indicator for
engine performance and flight conditions. Temperature and dew point are
obtained from METAR/ATIS. TAF does not include any temperatures. ARFOR could be
used to determine enroute temperatures at higher flight levels. From
temperature and dewpoint, we can deduce the cloud base height to help us
determine safe cruising altitude to opt for. It also gives clues on icing
conditions that one could encounter.
4. Pressure: Its essential measure to set in our aircrafts
altimeter before start. Pressure can be obtained from METAR/ATIS. All
heights/altitudes/FLs are dependent on the correct setting made by noting the
appropriate pressure(Qfe/Qnh/Qne). Besides, it can also be an indicator of
aircraft performance.
5. Clouds: The height and amount of clouds can be obtained
to understand the climb profile and cruise altitude to opt for and also any
deviations or infact NoGO/NoTakeOff conditions can be determined. During my
training days, I used to wonder if the heights were as per name say AGL or
altitudes or FL - in this regard I used to try to roughly measure the cloud
heights while flying below it and tried to be oversmart or overdumb in the
process. But in reality, the clouds are mathematical deductions based on angle
subtended at the point of observation and instruments used(ceilograph) - hence
are to be treated as heights(AGL).
6. Extra weather phenomenon: Weather is not constant and the
predicted changes can be obtained mainly from TAF with indicators like FM/TEMPO/BECMG/INTER/PROB
etc. These must be carefully assessed and Flight/NoFlight can be determined.
7. Weather Images: Satellite weather images of current and
expected trend images should be checked. These can be obtained from your Local
Weather Services Agency or could be obtained from viewing the images in
Newspapers/News TV channels. These are indicative of strong weather conditions
that are likely to be encountered.
After gathering above data, I have come up with formulating
a checklist which follows a flow that could be followed similar to an airplane
checklist coming up in part-2 of this blog series.
Notes:
1. All the above weather information represented is based on
information I used to gather for my flights during my training days(SE & ME
aircrafts).
2. Airline Pilots/other pilots could have more information
at hand in the briefing documents received - I have no information regarding
those - request readers to pitch in with their views to enhance the above
effort to come up with the checklist or if already any such checklists exist,
please do share if allowed to.
