Confused by 121 alternate regs...

F

flyingsioux

New Member
Someone jump in here and correct me if I'm interpreting these wrong.

1. Takeoff alternate is required if wx is below mins for the lowest published approach at the departure airport.

2. Arrival alternate required if destination hour before to hour after is forecast lower then 2000 and 3 miles.

3. Arrival alternate must be within 1 hour for 2 engine aircraft in still air and 2 hours for 3 or more engines. Must be at least 2000 feet and 3 miles or 1500 above highest MDA/DH and 2 miles above lowest vis requirement whichever is higher.

4. CA with less then 100 hours PIC in type adds 100 feet to MDA/DH and 1/2 mile to vis requirement

5. RVR is controlling over vis...confused by the 6/6/6 rule etc....anyone shed some light on this in a way that isnt as boring as interpreting regs?
 
At a quick glance, the only prob I see is:

#3 - that applies for the takeoff alternate not your "arrival" or destination alternate.

For all alternates your company derived minimums (one navaid / two navaid rule) apply if the alternate airport uses standard 600-2/800-2 alternate minimums.

#5, RVR is always controlling - but 6/6/6 applies for takeoff minimums, the actual numbers 6/6/6 is company specific. for landing minimums look at your approach plate
 
In the 121 world, you just call up the dispatcher if you have any questions.

I personally like to call Doug Taylor. He is my favorite dispatcher. :)
 
Like woodreau said, it's all right except it's a takeoff alternate for the still air etc stuff, not an arrival alternate.

Wait till ya get to 3585 stuff. That's the real mind bender when it comes to alternates.

Never trust the dispatcher. I've been FO on several aircraft that the dispatcher has tried to push us to go when we weren't legal. Also "Another TAF is coming out soon" is right up there with "The check's in the mail" and "The van is on the way."
 
Do sweat it, man. Your carrier will help you with the specific stuff. You just need to have a basic understanding of 121 regs. I would recommend getting a book that breaks them down for you. Besides, when you go through class, you'll learn weather and alternates specific to your carrier.

The basics of 6/6/6 are that runway rvr trumps anything else when you're arriving or departing a specific runway. The reason being that ATIS viz and tower viz weren't necessarily meaured anywhere near that runway! In part 91 you're allowed to "take a peak", but in part 121 you have to have the rvr mins if the runway uses it.

The new Captains have to add a 1/2 mile and raise their decision height by 100 feet, because, well, they're new! This applies to the destination airport.
 
woodreau said:
At a quick glance, the only prob I see is:

#3 - that applies for the takeoff alternate not your "arrival" or destination alternate.

For all alternates your company derived minimums (one navaid / two navaid rule) apply if the alternate airport uses standard 600-2/800-2 alternate minimums.

#5, RVR is always controlling - but 6/6/6 applies for takeoff minimums, the actual numbers 6/6/6 is company specific. for landing minimums look at your approach plate
Click to expand...

So the 3 miles vis or 2 miles greater then the lowest required approach vis and 2000 feet/or 1500 above lowest DH is whats required for forecast wx to use the airport for a takeoff alternate ? Or an regular alternate? Or both?
 
flyingsioux said:
So the 3 miles vis or 2 miles greater then the lowest required approach vis and 2000 feet/or 1500 above lowest DH is whats required for forecast wx to use the airport for a takeoff alternate ? Or an regular alternate? Or both?
Click to expand...



Except for FAA designated special airports. Then you revert to the 1-2-3 rule.
 
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