First of all the regulations require that both actual and forecast weather be taken into acount.
Secondly, any well trained instrument flier will select an alternate where the weather was not only actually but also forecasted to be a sensible margin above the applicable minima i.e. if you use 500ft ceiling and 1800m as a minima for the destination (precision approach) then perhaps 1000ft ceiling and 3Km for the alternate would be appropriate. If the destination forecast / actual is below minima then make sure that two alternates are available.
Thirdly, if all else fails then declare an emergency and not only is that 45 minutes final reserve fuel going to be put to better use but also one will find that one can legally fly to lower minima if it is essential (report required).
When it comes to not understanding the limits of aviation forecasts etc etc IMCrating holders on average are no worse than IR holders. The met forecasting and reporting system is set-up to let us know when certain critical ceilings and visibilities are passed (up or down) because these are of interest to either VFR or IFR flights. Unfortunately if one looks up these critical figures in the lower regions of ceiling and visibility they are very much tailored towards the IR holder. In fact one could argue that the way the met system is set up puts the IMC rated pilot at what could best be described as a distinct disadvantage.
As a non-specific example xyz airport has an ILS with 200ft minima. The ceiling is 500ft, if that lowers to 400ft, the met office will not issue a special report to tell everyone because as they see it there is no problem it is still well above the minima which is fine if you are an IR holder using those minima but not for the IMC rated pilot who was expecting to get in with a 500ft ceiling and is wondering why he had to do a missed approach after not seeing anything.
I would encourage every IMC holder to practice flying to lower minima (note I said practice) and more accurately than is required simply to scrape a pass in the skill test. In VMC with a safety pilot you can try flying the ILS to a 50ft DH under the hood if you want to get right into the sensitive parts!! You could even fly in IMC to a 200ft DH provided that the PIC has an IR.
Perhaps it may surprise some that the CAA's biggest problem with the IMC rating useage is not with minima (very few actually bust minima in the UK) it is actually the fact that the IMC rating does not prepare pilots for extended enroute flight in IMC and as below radar has highlighted, it does not provide much operational knowledge / skills required to operate in the IFR system. New IR holders are a bit better but they have the advantage of being able to get more assistance from the ATS system.
Regards,
DFC
Last edited by DFC; 26th May 2009 at 18:34.