Peter wrote:
I wonder how many people (a) knew this and (b) actually do it?
First of all, I have problem to understand it because I always have problem understanding law related stuff. It’s not about understanding English but it’s about understanding the language laws and rules are written with. Simply, it doesn’t have anything with spoken language of language our minds are primed with. It’s usually bunch of nonsense that you need algorithmic approach to analyse and understand.
ATO used to make PPL+IR people read Part-CAT (or whatever the legacy national version for their training manual as approved by the NAA back), but I think for a private flyer it’s worth reading Part-NCO once in a lifetime in some airport lounge, then you are free to make your own damn mind, I am sure I can understand the law better than some instructors who have not read a legal text since they got the BCPL pre-JAR in 1990 let alone NCO/SERA, if I have a doubt I will ask in EuroGA 
Maybe some ATOs now has evolved a bit but only those where some senior instructors do fly GA under Part-NCO, the majority of CAT FI-types would be the least up to date on NCO/SERA and would never have flown from airport without ILS or reported RVR, let alone file it as alternate 
Ibra wrote:
I think for a private flyer it’s worth reading Part-NCO once in a lifetime in some airport lounge
I wholeheartedly agree. Everyone flying noncommercialy should have read part-NCO – and SERA – at least once.
Emir wrote:
First of all, I have problem to understand it because I always have problem understanding law related stuff. It’s not about understanding English but it’s about understanding the language laws and rules are written with. Simply, it doesn’t have anything with spoken language of language our minds are primed with. It’s usually bunch of nonsense that you need algorithmic approach to analyse and understand.
I believe, the “gotcha” here is that the weather at the alternate at the time or arrival (+/- 2h) must not be only at minima or better for the available instrument approach, BUT the ceiling must be 1000 ft ABOVE the DA/MDA and visibility of at least 5.5 km MORE than the minimum vis for the approach.
No, it’s not like that at all. Some posts in the other thread mixed up the actual rules with helicopter rules and rules for isolated airports.
Forecasts and observations must show that at the time you would use the alternate, the wx will be above minima.
Thanks once again to AA for getting us rid of the BS factor here.
For those who can‘t read legal texts, I still recommend the summary to Part-NCO by bookworm even though this now almost 5 years old. Have there been any significant changes in Part-NCO since its inception?
I always assumed the obvious which is that for a flight to be legally planned you need to be in possession of a TAF showing at least one of the destination and the alternate to be forecast above the IAP minima.
So I print out the metars and tafs on a bit of paper and shove that in my pocket, before every flight
It would also be somewhat idiotic to embark on a flight otherwise!
In practice, in the real world as the thread title says, if the wx is forecast to be anywhere near minima, I would want some other solid alternate as well. Also, in the real world, with an ADL150 one can get wx as one goes along so the alternates can be under a constant review.
In the US, a forecast is needed. A TAF is a forecast, but not the only forecast product available that one can determine if the destination and or alternate forecast criteria is met. There are hundreds of airports with a TAF, but there are thousands of airports in the US that may be used as a destination or for the filing of an alternate. The NWS used to produce an area forecast, but now uses graphical products for this purpose which are graphical cloud coverage forecast and graphical surface visibility and winds. Interestingly in the US, unless the approach facility is monitored, the approach may not be used for alternate planning purposes. So at my airport, we have an ILS to Rwy 2 and an RNAV to Rwy 2 and 20. The ILS is not monitored so does not qualify to be used for the purposes of an alternate, but the two RNAV approaches are monitored at the national level, so they qualify.
I think it’s important that people are able to locate the documents required and find the regulations for themselves. As can be seen in this (and the other) thread, it is all too easy to mix up various regulations. Keeping in mind that I think forum members here are likely to me slightly more ‘au fait’ with regulations than the average GA pilot who takes no extra interest, and there has been a mix up of regulations for Part-CAT, Part-NCO, Rotary and isolated aerodrome ops.
Assuming fixed wing, non isolated ops, then the current rules for alternate planning are:
NCO.OP.140 Destination alternate aerodromes – aeroplanes
For IFR flights, the pilot-in-command shall specify at least one weather-permissible destination alternate aerodrome in the flight plan, unless:
(a) the available current meteorological information indicates that, for the period from 1 hour before until 1 hour after the estimated time of arrival, or from the actual time of departure to 1 hour after the estimated time of arrival, whichever is the shorter period, the approach and landing may be made under visual meteorological conditions (VMC)
Also, to clear up the RNAV approach stuff:
GM1 NCO.OP.142 Destination aerodromes — instrument approach operations
PBN OPERATIONS
The pilot-in-command may only select an aerodrome as a destination alternate aerodrome if an instrument approach procedure that does not rely on GNSS is available either at that aerodrome or at the destination aerodrome.
The regulation that has been mentioned about the alternate needing wx for the next worse approach is only applicable to part-CAT ops.
If the weather either at destination or alternate is not suitable, or if a forecast isn’t available then you need a second alternate in order to meet the regulation.
The rules for part-NCO are subject to change as per NPA 2020-02 (here)
