HELP 121 Alts and navaid rule 1 and 2

[DXchick]

I need clarification....when establishing that your flight to be dispatched needs a DEST ALT.....is it require to add in the 200 and 1/2 or the 400 and 1 ( navaid rules)TO ALL DEST ALTS???? or just thos that have standard 600/2 and 800/2 approach mins? or is this something from the company Op specs? I can't find anything in FAR121 that clears this up.

 

[dasleben]

This would be spelled out in the company's ops specs (C055). Most 121 operators use the 200-1/2 and 400-1 rule when determining alternate suitability for dispatch (and yes, all alternates would have to meet that requirement unless something like Exemption 3585 is used). Of course, after the flight departs the alternate weather can drop below those requirements and use operational (charted) landing minimums. The above rule is simply for dispatch.

 

[DXchick]

great thanks!

 

[jdlilfan]

Exactly what Dasleben said. BTW, With derived ALT mins, the lowest possible is 400-1. The book "Air Carrier Operations" by Holt/Poynor does a great job of explaining derived min, 3585, and nearly everything else part 121.