Diverting & Listing an alternate

JC150

Pre-takeoff checklist
Joined
Apr 22, 2013
Messages
491
Display Name

Display name:
JC150
If you're diverting while IFR to an airport besides your alternate, would you need to provide an alternate to ATC if an alternate is required? The way someone explained it to me is ATC treats it as a new flight plan from present position to that airport and if an alternate is required, you're required to state that to ATC. Does anyone know how true this is?

I read somewhere on one of these forums that someone was violated for trying to pick up IFR clearance to an airport that was closed due to an airshow, so he picked another airport nearby but did not give ATC the alternate and was violated for not having an alternate.

Perhaps I mis understood the story, I'll keep searching for it. But I wanted to ask here anyway. Thanks!
 
I've always been told that ATC can't even see filed alternates, and that those are only for SAR purposes through Flight Service. ATC would only know/care about your current destination/clearance fix, and that's it. Just last week, while operating a scheduled airline flight, I diverted to an airport not filed as an alternate and no one cared the slightest, besides that we landed safely.

Perhaps Mark will be along shortly to shed a bit more light on the subject...
 
If you're diverting while IFR to an airport besides your alternate, would you need to provide an alternate to ATC if an alternate is required? The way someone explained it to me is ATC treats it as a new flight plan from present position to that airport and if an alternate is required, you're required to state that to ATC. Does anyone know how true this is?

I read somewhere on one of these forums that someone was violated for trying to pick up IFR clearance to an airport that was closed due to an airshow, so he picked another airport nearby but did not give ATC the alternate and was violated for not having an alternate.

Perhaps I mis understood the story, I'll keep searching for it. But I wanted to ask here anyway. Thanks!

Long story short no

. In your second scenario listed the person never opened a flight plan and essentially filed a new one, in which case you'd be subject to the standard rules for needing an alternate for your destination airport

Logically it wouldn't make sense to file an alternate for your alternate if you divert. Main reason being why would they allow you to file alternate airports well below the requirements for determining if you need an alternate? If so then you would always require a second alternate and so on. If you needed to file an alternate for your alternate they'd make the alternate weather requirement the minimum required to not need an alternate at your destination, which as we know is not the case.

And you never have to go to your filed alternate if somewhere looks better, it's simply for filing and legality purposes to show you definitely have the fuel and weather to get into somewhere just incase.

That was very wordy hope it made sense
 
And you never have to go to your filed alternate if somewhere looks better, it's simply for filing and legality purposes to show you definitely have the fuel and weather to get into somewhere just incase.

BINGO!

ATC doesn't care about your filed alternate. Heck even your destination can be changed no questions asked.
 
I've always been told that ATC can't even see filed alternates, and that those are only for SAR purposes through Flight Service. ATC would only know/care about your current destination/clearance fix, and that's it. Just last week, while operating a scheduled airline flight, I diverted to an airport not filed as an alternate and no one cared the slightest, besides that we landed safely.

Perhaps Mark will be along shortly to shed a bit more light on the subject...

I've been told the same thing; ATC doesn't see the filed alternates. What I include in the Remarks section is "WX ALT APT - KXYZ." This they do see, or so I've been told.
 
I've been told the same thing; ATC doesn't see the filed alternates. What I include in the Remarks section is "WX ALT APT - KXYZ." This they do see, or so I've been told.

Yes, they do see the remark. But what is the point? Plans should always be able to be changed based on circumstances. Diversions can occur at any time. Even with this remark, when you report missed approach, ATC is going to ask you for your intentions.
 
I've always been told that ATC can't even see filed alternates, and that those are only for SAR purposes through Flight Service. ATC would only know/care about your current destination/clearance fix, and that's it. Just last week, while operating a scheduled airline flight, I diverted to an airport not filed as an alternate and no one cared the slightest, besides that we landed safely.

Perhaps Mark will be along shortly to shed a bit more light on the subject...

Filing an alternate is not for SAR purposes. It is solely a flightplan requirement to make sure the pilot has sufficient fuel to conduct the flight to the destination and then on to an alternate airport plus reserves. The forecast is required to be well above minimums at the airport for an approach that the aircraft is equipped to fly. So even if the airport has an ILS with 200 foot DH and 1/2 mile, the alternate requires a forecast no worse than 600 overcast and 2 miles visibility, which is intended to cover the worst case scenario where the GS and approach lights are out of service, permitting the pilot to still fly the localizer approach to a landing.
 
What John said. The alternate is for your fuel planning requirements and not SAR. ATC cares about your divert since that's where they're getting ready to clear you beyond your current clearance limit. They don't care about the filed alternate.

Had about 5 F-5s go missed before off the GCA. No clue what their filed alternate was because it doesn't show up on the strip. Didn't matter anyway because they verbally requested a divert field. Each one went missed, we amended each flight strip to the new destination (CHS). Flashed them to CHS. Done.
 
What John said. The alternate is for your fuel planning requirements and not SAR. .

True, however, they will look at your flight plan to see where your planned route of flight was (incl alternate) if you disappear or fail to show up. Of course if you're radar identified they'll know about where you went down, but there are nonradar areas too. But again, it's for fuel planning primarily. As mentioned, ATC doesn't know what you filed as an alternate.
 
I'm not sure but I think that while traditionally, the flight strip ATC sees doesn't include the alternate, that may change with the move to ICAO flight plan (which even includes a non-required second alternate). And I'm fairly certain it's available if you disappear with lost comm so SAR has at least a starting point.

But the reality is that the purpose of the listing of an alternate is for planning. Period. Weather changes and what was a sound alternate at the time the flight was planned may not be the best choice once you need to go missed at the destination you planned to get into to begin with.
 
I'm not sure but I think that while traditionally, the flight strip ATC sees doesn't include the alternate, that may change with the move to ICAO flight plan (which even includes a non-required second alternate). And I'm fairly certain it's available if you disappear with lost comm so SAR has at least a starting point.

But the reality is that the purpose of the listing of an alternate is for planning. Period. Weather changes and what was a sound alternate at the time the flight was planned may not be the best choice once you need to go missed at the destination you planned to get into to begin with.

Even in the lost Com situation, I am not going to necessarily go to the alternate, unless it happens to make sense at the time.
 
It's not clear what use it is even for SAR. As pointed out, nothing says you have to go to the alternate. Pretty much you end up overdue, they'll contact the destination and then every other airport you had enough fuel to get to from the last point they knew where you were. SImilarly the search for you off airport follows the same procedure.
 
I always file an alternate even if the field is VFR. Never hurts to do so. A few months ago I was flying to Rochester with scattered thunderstorms and a cold front all along the east coast. On the return trip there was a wall of thunderstorms and cells and i knew I wasn't going to get to my destination or alternate. I decided to divert to another airport and a few vectors and an approach later I was at the airport. You don't always have to divert to your alternate.
 
SImilarly the search for you off airport follows the same procedure.

Not at first.

Searching is VERY labor intensive. The first sorties will follow your expected route of flight. If that comes up blank, the alternate may be next. It will be augmented with whatever other information is available, especially radar, ELT reports, and cell phone forensics. Sometimes none of that works.

There is no saturation searching early in a search. That takes many weeks and is not done while the pilot may still be alive. Searches concentrate on likely locations, not all possible locations at first.

It IS a good bet that every airport you could have made it to will get a phone call, eventually. But that will start with your destination and alternate. Just how many airport managers do you want to wake up in the middle of the night?

So, if ATC doesn't know where you're going for whatever reason, and you have to divert, go to your filed alternate unless there is a reason not to. And make sure you contact FSS afterward if you can. You'll save us some late nights. If ATC does know what you're doing, that's fine.
 
Last edited:
Yes, they do see the remark. But what is the point? Plans should always be able to be changed based on circumstances. Diversions can occur at any time. Even with this remark, when you report missed approach, ATC is going to ask you for your intentions.

Calm down. High Flying A380 said in his post "I've always been told that ATC can't even see filed alternates." ATC can see filed alternates if the alternate is in the Remarks block. That's all.
 
Filing an alternate is nothing more than an exercise in fuel planning. It forces you to carry more gas when the weather is bad. How much more? Enough to get to another place with the same reserves (reserve gas being another exercise in fuel planning.)

If you change your destination in flight then that is a new plan and that new plan may require an alternate. But if you divert to your alternate or another airport after being unable to get into your destination for whatever reason that does not require an alternate.

Slim difference I know, but logically it does make sense.

As pointed out above, there is absolutely no requirement to actually go to your 'filed' alternate with or without comms. Again, it's just you declaring, on paper, that you planed the flight to have enough gas to get somewhere if the destination becomes 'unlandable' for any reason. Once in flight you do what's best.
 
Back
Top