Weather Planning
One of the difficulties I have found with VFR flying has been assessing the weather forecasts, and deciding whether or not I am wise to embark on a journey. "Is the weather good enough to go?" is a very difficult question to answer since it relies on a definition of "good enough". With IMC and now also VFR flying I have instead started to attempt my weather planning based on known limitations, and to ask myself "is the weather bad enough not to go?" This is a much easier question to answer, since there are all sorts of circumstances when this might be the case. If it bad enough, then I do not go - it's as simple as that. If there are no reasons why I should not go then, providing alternates are planned, and fallback options decided, I will go.
It goes like this: assess the known limitations on pilot, current and forecast weather and airframe. Then compare these with conditions likely to be encountered en-route. Imagine a typical flight for me from Newcastle to Fairoaks.
Limitations:
1) Pilot
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Limitation
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Example
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a) Licence Privileges -
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I may not fly IFR or VFR in Class A airspace. In that case what is the minimum in-flight visibility I need when SVFR in Heathrow's CTR? At what heights am I going to need to fly to avoid Airways and the TMAs?
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b) Experience
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Have I flown SVFR in Class A airspace before? Have I been to Fairoaks before, and I am I happy with the visual approach and likely altitude limitation on SVFR transit through the Heathrow CTR.
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c) “Comfort” and confidence level
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If the answer to b) above is "no", am I happy to do this on my own the first time? Would it be better to take a friend?
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2) Weather
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Limitation
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Example
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a) Wind
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How will the wind affect my flight planning? Can I leave before the club is open to get to my meeting on time? How will I manage this? Are there a crosswind, or severe gusts forecast for take off or landing?
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b) Turbulence
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Is Turbulence forecast? If I have no autopilot, do I want to spend 2 hours stuck in bumpy Cumulus? Is my plane equipped with Autopilot to help me in this situation? And what is my maximum manoeuvring speed?
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c) Icing level
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What is the forecast icing level? Do I need to stay below it? How will this affect sector safety altitudes? Can I get into clear air above the cloud without infringing Class A or other airspace, and get down again? If the freezing level is lower than forecast can I get down and stay above Sector Safety Altitude?
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d) Visibility
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Will there be enough visibility to take-off and land safely? Will I be able to get into Heathrow's CTR under an SVFR clearance?
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e) Precipitation
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Is rain, snow or hail forecast? How would this affect the flight?
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f) Frontal Activity
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Where are they, where are they forecast to be, and what effect will they have? Will one be right over my destination when I arrive. How active is that occlusion? If I fly from a cold sector to a warm wet one will it dunpo freezing rain all over me?
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g) Cb activity
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Are thunderstorms forecast? Will they be isolated and avoidable, or embedded and invisible?
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3) Airframe
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Limitation
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Example
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a) Equipment
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Given the availability of radio aids en-route, is my plane equipped with all the necessary radios? Are they working? Does the plane I fly have a 2nd altimeter? Is there an autopilot and does the weather en-route suggest I might be more comfortable with one? Do I have a stormscope to find those embedded Cbs?
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b) Service Ceiling
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How does my preferred cruising altitude match up with aeroplane performance? At what altitude will the plane perform best, and how does this match up with the weather forecast?
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c) De-icing
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Is my plane de-iced in some way? And is it cleared for flight into "known icing?" If not how will this affect my plan? See 2c) above.
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d) Weight, Balance and Fuel
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Does the distance I am planning to fly, with my passengers and baggage allow a proper amount of fuel, allowing for winds en-route, ATC delays and a good reserve? Will the plane be in balance at the beginning and the end of the flight?
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e) Number of engines
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Am I personally comfortable with single engine night-time IFR? What if I am planning to fly over the Channel or to Ireland. Do I want to risk flying in IMC over cloud covered hills? Does this change my risk assessment?
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