Weather Minima / Standard Alternate Minima

[Trash 'n' Navs]

I am looking in to the differences that exist between countries in the weather minima requirements. It is variously referred to as Weather Minima, Alternate Minima or Standard Alternate Minima.

I would like to compare the differences that exist in the criteria for determining if the weather at your destination is suitable or whether you need to hold an alternate. If you do require an alternate, then what are the requirements at it.

For example, the US specifies that for a precision approach, the weather minima at the alternate airport is 600FT ceiling and 2 statute miles visibility. On the other hand, New Zealand requires 600FT ceiling and 3000 metres visibility but for non-precision approaches it gets more complex: ceiling of 800FT (or 200FT above MDA, whichever is greater) and visibility of 4000 metres (or 1500m above the prescribed minima, whichever is the greater). Compare that to the US where it's 800FT and 2 statute miles.

Why the differences?

Specifically, what I would like to know is:

1. What is specified in your rules/regs as to the ceiling & visibility requirements at airfields when operating under IFR?
2. Does this minima apply to the destination and/or your alternate?
3. What other requirements do you have (eg NAVAID, lighting, standby power)?

Any help will be gratefully received as I’m sick of ‘Googling’ my way through the Internet. If you also have a reference, that’d be a great help.

Cheers.

[Piltdown Man]

For the standard that JAA countries work from, get the grey Aerad supplement. £8.00 or so, but the real minima are the ones laid down your company's Ops manual. So your question is really "how long is piece of string".

Cheers.:cool:

[slingsby]

I agree with PM, the answer is infinite. Each aerodrome has its own different minima, as has each aircraft type, and each different company SOPs. Crew ratings and experience can also play a factor, ie junior F/Os may not be CAT3 qualified so that will present different flight parameters. Generally the minima is set out by your company and the type of aircraft you are flying. For an example a B767 is CAT3B and can land (in theory) in zero visibilty. However, in Heathrow the airfield minima is 75meters with nil vertical visibilty (Don't quote me on that, it's been a while), the vis limit is set for airfield firefighting equipment access to runways, you don't want them to get lost if you need them.
My company flight plans include suitable alternates for destination with fuel planned. Wx notices are read prior to departure and the flight is planned with wx in mind. If for instance our destination is marginal for wx/vis/ops and our alternative is also marginal, then the answer is you don't go.
Maybe this will help but probably not the answer you are looking for. Good luck hunting.

[Trash 'n' Navs]

Thanks guys - I understand what you're saying but it's not really what I was after.

I'm more looking for the legislative requirements (ie JAA, FAA, CAA) for the weather minima.

The info I mentioned above came from the US FAR Sec 91.169 para 2c, the Kiwi requirement is in IFG (OPS) page 8 and I found the Canadian requirements in their AIP (RAC 3-10).

I am comparing foreign requirements to those I operate under to determine if they are still relevant. No-one I've spoken to knows where my organisations minima standards came from and it appears they don't match any legislative rules so the question begs - are they still appropriate?

PM, Slingsby Are you saying your company nominates your alternates for you based on certain criteria?