Redispatching flights

Flagship_dxer

Legacy Airline Dispatcher
If only there was some sort of SCHOOL where you could learn all about this and other topics related to dispatching...oh, wait...
Frankly, I don't think any dispatch school should be teaching B044. The point of dispatch school is to get the license. Keep it simple. Many of the people getting the license may rarely if ever use B044. If the airline that hires you has B044 and wants you to use it, they will have training for that.
 

manniax

Well-met in the Ka-tet
Frankly, I don't think any dispatch school should be teaching B044. The point of dispatch school is to get the license. Keep it simple. Many of the people getting the license may rarely if ever use B044. If the airline that hires you has B044 and wants you to use it, they will have training for that.
I think it was mentioned but not covered in depth - it may have been mentioned in the international flight planning class held after the regular class was over. It's been quite a while for me! With all the current exemptions authorized by the FAA, it's pretty rare for us to use redispatch flight planning any more, even on flag flights, but we do use it occasionally (on a couple routes it's mandated that we do so.)
 

who'swho

Don't hesitate. Penetrate!
I think it was mentioned but not covered in depth - it may have been mentioned in the international flight planning class held after the regular class was over. It's been quite a while for me! With all the current exemptions authorized by the FAA, it's pretty rare for us to use redispatch flight planning any more, even on flag flights, but we do use it occasionally (on a couple routes it's mandated that we do so.)
We redispatch in my shop basically any flight it'll save fuel on. I don't remember it being mentioned when I went to school for my license. Definitely one of those things best left for new hire training.
 

Heliman81

Well-Known Member
We redispatch in my shop basically any flight it'll save fuel on. I don't remember it being mentioned when I went to school for my license. Definitely one of those things best left for new hire training.
Never learned about it in dx school either. Was trained on it once I needed to know it and that was more than enough.

I'd ask why he's worried about knowing about redispatch before even having a license but I already know my answer.
 

A1TAPE

Well-Known Member
Never learned about it in dx school either. Was trained on it once I needed to know it and that was more than enough.

I'd ask why he's worried about knowing about redispatch before even having a license but I already know my answer.
Was studying regs under 121 subpart U ahead of time.
 

johnotd

Well-Known Member
If anyone has a different interpretation, I am open to it. I just think it's important to be clear on the terminology when it can easily become muddled.
I'm on board with that interpretation, but I want to stir the pot. :)

If you change your destination while en route IAW 121.631(f), and the "new destination" is below 2000' and 3SM, do you need to designate an alternate for the new destination?
 

DispatchDan

Well-Known Member
I'm on board with that interpretation, but I want to stir the pot. :)

If you change your destination while en route IAW 121.631(f), and the "new destination" is below 2000' and 3SM, do you need to designate an alternate for the new destination?
Not really stirring the pot... if the WX at your new destination requires an alternate then you are absolutely required to name an alternate and have the required fuel.... it doesn’t necessarily have to be the 2000’ and 3SM, for example, if your company has an exemption where you can lower those then you can apply the exemption and go without an alternate.
 

johnotd

Well-Known Member
Not really stirring the pot... if the WX at your new destination requires an alternate then you are absolutely required to name an alternate and have the required fuel.... it doesn’t necessarily have to be the 2000’ and 3SM, for example, if your company has an exemption where you can lower those then you can apply the exemption and go without an alternate.
The reason I bring it up is there seems to be this notion that “once you’re airborne, only approach mins matter” and people conflate this with changing destination. I think the implication with “once you’re airborne...” is that if you’re proceeding to your alternate, altn mins no longer apply. However, your alternate does not become your destination just because you’re proceeding there. The only case in which your alternate becomes your destination is if you change destination.

For example:
A flight from DFW-ORD with MKE as alternate.
Fuel planning assumes burn to destination, MA, burn to alternate.
So long as MKE is listed as alternate, it must remain above alternate minimums, or you need to change to a new alternate within fuel range.
If your flight diverts while MKE is still listed as the alternate, alternate mins still apply all the way to ON.
If you instead change destination to MKE, fuel planning is predicated on PPOS to MKE, and approach mins apply. If MKE is below 1-2-3, you must designate an alternate for MKE.

I’ve seen a number of different interpretations for how to apply these regs, and I know I’ve made a number of people upset when I told them “you need to designate an alternate for that new destination you’re diverting to”. Curious if anyone here has a different perspective.
 

Heliman81

Well-Known Member
The reason I bring it up is there seems to be this notion that “once you’re airborne, only approach mins matter” and people conflate this with changing destination. I think the implication with “once you’re airborne...” is that if you’re proceeding to your alternate, altn mins no longer apply. However, your alternate does not become your destination just because you’re proceeding there. The only case in which your alternate becomes your destination is if you change destination.

For example:
A flight from DFW-ORD with MKE as alternate.
Fuel planning assumes burn to destination, MA, burn to alternate.
So long as MKE is listed as alternate, it must remain above alternate minimums, or you need to change to a new alternate within fuel range.
If your flight diverts while MKE is still listed as the alternate, alternate mins still apply all the way to ON.
If you instead change destination to MKE, fuel planning is predicated on PPOS to MKE, and approach mins apply. If MKE is below 1-2-3, you must designate an alternate for MKE.

I’ve seen a number of different interpretations for how to apply these regs, and I know I’ve made a number of people upset when I told them “you need to designate an alternate for that new destination you’re diverting to”. Curious if anyone here has a different perspective.
If you are diverting to the alternate you're going to use destination minimums because that's where you're going.
 

Burrito

I'll ask the stupid questions
I love threads like these. Where's that popcorn gif...

If you are diverting to the alternate you're going to use destination minimums because that's where you're going.

Gotta remember too, once the declaration is made to divert, you're not using alternate minimums anymore. Few folks at my former shop had trouble understanding this.
 

johnotd

Well-Known Member
If you are diverting to the alternate you're going to use destination minimums because that's where you're going.
Gotta remember too, once the declaration is made to divert, you're not using alternate minimums anymore. Few folks at my former shop had trouble understanding this.
The crew will use destination minimums for the approach, but so long as the airport is listed as the alternate, it must remain above alternate minimums.

121.625:
Except as provided in §121.624 for ETOPS Alternate Airports, no person may list an airport as an alternate in the dispatch or flight release unless the appropriate weather reports or forecasts, or any combination thereof, indicate that the weather conditions will be at or above the alternate weather minima specified in the certificate holder's operations specifications for that airport when the flight arrives.

121.631(b):
No person may allow a flight to continue to an airport to which it has been dispatched or released unless the weather conditions at an alternate airport that was specified in the dispatch or flight release are forecast to be at or above the alternate minimums specified in the operations specifications for that airport at the time the aircraft would arrive at the alternate airport. However, the dispatch or flight release may be amended en route to include any alternate airport that is within the fuel range of the aircraft as specified in §§121.639 through 121.647.

Legal interpretations don't provide much guidance on the topic as they simply point to "if weather at the alternate falls below alternate minimums for the ETA at that airport, the alternate may be amended IAW 12.631(b)."

The 8900.1 doesn't go much further than that. Review 8900.1 Vol. 3 Ch. 25 Sec. 3 3-1977. Specifically B. Alternate Weather Requirements While En Route. This section stipulates that a flight may not continue to destination while weather at the alternate is below C055 mins.

Additionally, 8900.1 Vol. 3 Ch. 25 Sec. 4 3-1988(F) indicates that weather at the alternate must be at or above C055 mins at the ETA to the alternate.

There is no provision allowing for weather at the alternate to fall below alternate minimums simply because the flight is diverting to the alternate.

An airport is not a destination or alternate based on where it is proceeding to. Destination and Alternate are designations on a flight release that have implications for fuel planning. Listing an alternate is authorization for a flight to proceed to and land at that airport without an amendment, as it is part of the original plan.

It all boils down to how the diversion is processed.

If you are diverting to the alternate without recalculating anything, it is still your alternate, and must be above alternate minimums for the purposes of the flight release.

If you are diverting to the alternate, but you have recalculated to show the alternate as "destination", then you have changed destination and will need to list a new alternate if that new destination is below 1-2-3.
 

Heliman81

Well-Known Member
ETOPS alternates have to meet alternate mins during planning but as soon as your flight blocks out, you use destination minimums for the ETOPS alternates.

That's a bit different than a destination or redispatch alternate.

Never ever have I added an alternate for any diversions. How do you do that if you are diverting and you don't have the fuel to add one?

Also if your crew gets to their diversion airport and weather is not at alt mins they can't land. What sense does that make?
 
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johnotd

Well-Known Member
If you don’t have the fuel to designate a required alternate while en route, you are proceeding in a condition not in compliance with regs.

If you have made the decision to divert to a listed alternate, and the weather at the alternate drops below C055 mins, you are proceeding in a condition not in compliance with the regs.

In both cases, the safest course of action is (likely) to continue, even though you’re out of compliance. Technically, this would be “emergency authority”.
 

who'swho

Don't hesitate. Penetrate!
If your flight diverts while MKE is still listed as the alternate, alternate mins still apply all the way to ON.
If you instead change destination to MKE, fuel planning is predicated on PPOS to MKE, and approach mins apply. If MKE is below 1-2-3, you must designate an alternate for MKE.
Agree 100% with you except for this portion. Don't confuse a diversion with a change of destination. A change of destination is technically a redispatch in which case you need to abide by 1-2-3 rule. You don't need an alternate for a diversion airport there's a reason alt min buffers are built in.
 

johnotd

Well-Known Member
Agree 100% with you except for this portion. Don't confuse a diversion with a change of destination. A change of destination is technically a redispatch in which case you need to abide by 1-2-3 rule. You don't need an alternate for a diversion airport there's a reason alt min buffers are built in.
Right, diversion occurs to a listed destination alternate. For it to remain listed as the alternate, it must remain above alternate mins IAW 121.631(b).
 

Heliman81

Well-Known Member
Right, diversion occurs to a listed destination alternate. For it to remain listed as the alternate, it must remain above alternate mins IAW 121.631(b).
You're describing the planning phase along with the flight itself as long as the flight goes to its destination. If the alternate drops below c055 you give them a new alternate that meets c055 mins.
However, that does not apply if you divert to said alternate.
 

McCrosky

Well-Known Member
Right, diversion occurs to a listed destination alternate. For it to remain listed as the alternate, it must remain above alternate mins IAW 121.631(b).
I think the intent is that once you divert to your listed alternate the crew does not require C055 mins to start the approach when they get there. It’s still an alternate airport. If your giving here something has gone wrong already.

It’s kinda like saying, if you divert to an airport listed in C070 as an “A” you’re in violation cause that is now a destination and it needs to be a R, F, or P.
 

johnotd

Well-Known Member
You're describing the planning phase along with the flight itself as long as the flight goes to its destination. If the alternate drops below c055 you give them a new alternate that meets c055 mins.
However, that does not apply if you divert to said alternate.
Until you decide to divert, yes. Anytime after the diversion point you just need landing mins. And no alternate.
I think the intent is that once you divert to your listed alternate the crew does not require C055 mins to start the approach when they get there. It’s still an alternate airport. If your giving here something has gone wrong already.

It’s kinda like saying, if you divert to an airport listed in C070 as an “A” you’re in violation cause that is now a destination and it needs to be a R, F, or P.

Please point to a regulation, legal interpretation, section of the 8900.1, or the federal register to support the idea that alternate minimums are only applicable during the "planning phase" and not after you are diverting to the destination alternate designated on the release.
 

who'swho

Don't hesitate. Penetrate!
Please point to a regulation, legal interpretation, section of the 8900.1, or the federal register to support the idea that alternate minimums are only applicable during the "planning phase" and not after you are diverting to the destination alternate designated on the release.
Once you start diverting (not change of destination) is it still your alternate? No. We have alt mins to give us a better chance of the alternate maintaining landing mins at the time we divert there.
 
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