NZ WX Alternates

[palauisland]

Two weather questions for any met gurus out there.

1. If WN has TAF say 8000m and ovc 017 but has a Tempo of 600m and ovc 500 can you still use WN as an alternate but carry 60min gas for the Tempo?

2. If you depart from an airport that has WX below landing minima thus requiring a departure alternate, can you use an airport that has a tempo below altinate minima (assuming you again take 60min xtra gas for the tempo)

Any help would be much appreciated.

[empacher48]

According to our Sops, which must be based on the rules.

1. No

2. No

[Water Wings]

What does your exposition say?


For us, yes, we can "clean out" the tempo elements of a forecast in the scenario you describe by carrying extra hold fuel at altitude (varies slightly depending on exactly the scenario - sometimes 30mins, sometimes 60mins).

[empacher48]

I would refer to the following rule parts, some may apply to you depending on what you are certified under:

NZCAR Part 91.405 for the requirement to hold an alternate. There is no allowance to adding more fuel under NZCAR Part 91.403, or NZCAR Part 121.75 or 121.157. (this may differ if you are certified under Part 125 or Part 135, I haven't read those rules in years).

As for fuel for a departure alternate then read NZCAR Part 121.161, which basically states for a twin engine aeroplane that you must have an appropriate aerodrome within a maximum of one hour flying time in still air. You can't nominate a departure alternate that is an hour away and still plan to possibly hold for an hour. Either choose a better option or don't depart.

[empacher48]

combination of forecasts and reports have to be better then the requirement?

Yes, so if the TAF has no mention of cloud or vis below the requirement, but the METAR or ATIS has reports showing cloud of vis below the requirement, then you are required to nominate an alternate.