When flying a domestic US flight, an alternate airport is not required unless the weather is below specific minimums at the destination.

What are the rules when on an international flight plan and leaving or returning to the US?

In larger airplanes, carrying the extra fuel required to fly to an alternate (which costs money) is a little silly when there isn't a cloud in the sky and there are multiple airports in the vicinity of your destination that can be easily reached with your already required 45 minute IFR reserve. We should always have a plan for when things go wrong, but if it can be done safely, is it legal to file an international flight plan without an alternate?

  • $\begingroup$ To specify it a little: FARs doesn't require you to have an alternate if an instrument approach procedure is available at your destination and the forcasted weather at your destination between one hour prior and one hour after xour estimated time of arrival is 3SM or more visibility and ceiling 2000 feet or higher - VFR (VMC). $\endgroup$ – Falk Jan 9 '14 at 17:56
  • $\begingroup$ @Falk I'm asking about international regulations though, not just FAR's. :) $\endgroup$ – Lnafziger Jan 9 '14 at 18:30
  • $\begingroup$ I just wanted to add this for those who don't know and wonder about FARs - like I did a few weeks ago ;) $\endgroup$ – Falk Jan 9 '14 at 22:10
  • $\begingroup$ There are other reasons why runway might become unavailable, for example an accident. What are you going to do than if you don't have fuel reserve to fly to alternate? $\endgroup$ – Jan Hudec Feb 20 '14 at 19:45
  • $\begingroup$ @JanHudec Fly to one within the 45 minute reserve! As I said in the question: "We should always have a plan for when things go wrong, but if it can be done safely,.." $\endgroup$ – Lnafziger Feb 20 '14 at 20:18

As a simple anwer, no, it is not always required.

ICAO Annex 6 Destination alternate aerodromes

For a flight to be conducted in accordance with the instrument flight rules, at least one destination alternate aerodrome shall be selected and specified in the operational and ATS flight plans, unless:

a) the duration of the flight and the meteorological conditions prevailing are such that there is reasonable certainty that, at the estimated time of arrival at the aerodrome of intended landing, and for a reasonable period before and after such time, the approach and landing may be made under visual meteorological conditions; or

b) the aerodrome of intended landing is isolated and there is no suitable destination alternate aerodrome.

Also, there are similar descriptions for the requirements for take-off and en-route alternates.

EASA adds aditional requirements in OPS 1.295 in the form of maximum flight time of 6 hours and at least two runways at the airport, but it is still allowed. I can only assume FAA does a similar thing

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I think the answer here is "It depends on the rules of the countries whose airspace you will be using" -- For example if I'm going in to Canada from my home base in New York I would need an alternate airport if either the US or Canadian regs required one.

Of course as Lucas pointed out what is legal and what is prudent aren't always the same: you probably want to have an alternate airport in mind for every flight (VFR or IFR), and you may want to list them on your flight plans so ATC has the information (even if it's not visible to controllers it can be used for Search & Rescue purposes and the like if the worst should happen).
Similarly you probably want to have multiple realistic diversion options in mind along your whole route, just to have all your bases covered.

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This isn't very clear, at least based on the published information that I could find. The AIM 5-1-9 says:

Use of FAA Form 7233-4 is recommended for domestic IFR flights and is mandatory for all IFR flights that will depart U.S. domestic airspace.

7233-4 is basically an ICAO flight plan form, and the AIM says this about the alternates:

(b) Alternate and 2nd Alternate Aerodrome (Optional)

But it isn't clear - to me - if the word "optional" applies here to the entire line, or only to the second alternate.

Interestingly, the AIM also says this:

NOTE- Although alternate airport information filed in an FPL will be accepted by air traffic computer systems, it will not be presented to controllers. If diversion to an alternate airport becomes necessary, pilots are expected to notify ATC and request an amended clearance.

That could mean that both the alternate and second alternate are optional, since there would be no point in requiring information that isn't even visible to ATC. However that's a guess and could easily be wrong (the data could be useful in other ways); I couldn't find any guidance on this on ICAO's site either. And airlines probably have their own internal rules on identifying and filing alternates as well.

A flight returning to the US would almost certainly use an ICAO flight plan, so whatever the correct interpretation of "optional" is here, it would apply to those flights too.

Anyway, regardless of what the regulations say, filing alternates does have the significant benefit of 'forcing' you to plan and review your route more carefully.

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You all give some nice explanation but to answer the actual question, no, there are operations, where no alternate is required.

Some really remote airports which are right in the middle of nowhere are referred as isolated airports. If you are going to these fields, no alternate will be required but you are required to take a lot of extra fuel (EASA requires the fuel you would consume while holding for 2 hours in 1500 feet above the destination). I chose this example because I know that this is pretty much the same all around the world, but different authorities also approve some other flights without having an alternate. See the FAA, or even the very strict EASA which doesn't require an alternate if independent runways with instrument approaches and sufficient weather information for the destination, forecasting 'good' weather are available.

It does not depend on the state you are going to, anyway this state has to except your operation first, but on the state of the operator. The exact procedures saying for which kind of operation you need which amount of alternates, where they must be located, what minimum equipment they need to offer and how much fuel you need to take is written in the operations manual, which is at least as restrictive as the rules of the state of the operator.

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  • $\begingroup$ Do you know if ICAO allows flights without an alternate? Also, do you have a reference for the EASA not need one in some cases? $\endgroup$ – Lnafziger Jan 8 '14 at 17:20
  • $\begingroup$ I'll remember the EASA stuff from my flight training. I'm not really familiar with the suggestions of the ICAO regarding this because they don't really affect me directly but for sure EASA rues and FAR are based o these suggestions. $\endgroup$ – Falk Jan 8 '14 at 17:34
  • $\begingroup$ You maybe like to refer to page 23 of this document: easa.europa.eu/agency-measures/docs/opinions/2012/02/… $\endgroup$ – Falk Jan 8 '14 at 17:38
  • $\begingroup$ @Falk: Could you perhaps edit the link into the answer? Though I still don't see the exact requirement you mention (fuel for holding for 2 hours in 1500 AGL) there. $\endgroup$ – Jan Hudec Feb 20 '14 at 20:12
  • $\begingroup$ Sorry, I would appreciate to help you but curently I only have my mobile to go online, which makes things difficult. That's the final reserve fuel required by EASA when flying to an isolated aerodrome. $\endgroup$ – Falk Feb 21 '14 at 2:57

Think about why you have to choose an alternate airport. The most important thing to remember about alternates is that they will only be used when the weather is bad. The destination airport has gone below IFR minimums, and you are now relying on your alternate airport to get safely back on the ground. The planned flight has essentially been aborted, and a back-up plan of action is required.

So even if the rules do not dictate that you should get an alternate airport, it's best to have one or more in case something goes wrong. During an emergency the last thing you want to do is get a chart and start finding an airport.

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  • $\begingroup$ I agree, but do we have to file one for every international flight? $\endgroup$ – Lnafziger Dec 27 '13 at 12:22
  • $\begingroup$ Better have alternates in mind all along your flight path. I've had to divert part way to a destination due to buildups we could not get around/through... $\endgroup$ – Brian Knoblauch Dec 27 '13 at 20:39
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    $\begingroup$ Well, the most important thing to remember about alternates is that they may need to be used even under other circumstances than bad weather. A blown tire is often enough to close a runway for an hour or two and if the aircraft just ahead of you becomes disabled on the only available runway... $\endgroup$ – Jan Hudec Feb 20 '14 at 19:53

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