Destination As alternate

[MD83FO]

hello, where in FAR 121 can i find the requirements to use the alternate fuel, enroute to destination, or nominating the destination as the alternate.

thanks a lot.

[Intruder]

121.621.

While you can eliminate an alternate under certain circumstances, you cannot "nominate the destination as the alternate".

Once you are airborne, you can use reserve fuel as needed, but must meet the minimum fuel requirements of your dispatch release. If your planned fuel at destination will be less than that to get to your alternate with minimum company reserves, you will need a redispatch.

[+TSRA]

You're not possibly referring to an in-flight re-clearance are you?

I know of a couple of times coming across the Atlantic an operator had filed to Montreal or Boston with Toronto or New York as their alternate. When airborne and crossing the coast of Newfoundland they would state they were proceeding to their alternate. Their original destination was always Toronto or New York, but it saved them the fuel as they were going to pass those cities anyways. I'm sure this still happens as it does save a lot of fuel.

The other possibility is you're referring to the "No alternate IFR" allowance, although I'm not sure of the specifics in the US. Here in Canada you can do it when approved by Transport Canada, the weather is VFR for a couple hours either side of your planned ETA and certain weather conditions, even if VFR, don't preclude its use.

[Intruder]

While in-flight re-clearances are commonly done for diversions, the more common method for the situation you describe is to use a planned redispatch (PRD). With a PRD, the flight plan with ATC is to the intended destination, but the initial dispatch release to the crew is to an airport short of the destination. If the destination weather is acceptable and remaining fuel is above the prescribed minimum at the PRD fix enroute, a new Dispatch Release is sent to the crew, allowing them to continue to the final destination. ATC is not involved.

The PRD is like a brand-new flight plan (even though the actual flight plan with ATC never changes), so it also allows the use of no-alternate situations when the PRD fix is less than 6 hours from the destination.

[MarkerInbound]

121.639 to 121.647 cover fuel. There are no rules on usage, just planning. The redispatch or rerelease works for flag operations because the regs require you leave with enough fuel to get to your destination plus 10% of your enroute time plus to the alternate plus 30 minutes. If you have a 10 hour flight that means you're leaving with an hour and a half of extra fuel. If you can find a redispatch airport at the 7 hour point you can cut the planned fuel by 20 minutes. It could work on a flight from London to New York that the paperwork says you are flying from London to Bangor, Maine with JFK as your alternate and when you coast in the company sends new paperwork that says if you have x amount of fuel you are now released to JFK with Newark as the alternate. Now your 10% many only be 15 minutes and some of the alternate fuel from Bangor to JFK becomes part of the 10% reserve fuel.

[HEATHROW DIRECTOR]

TWA used to do this, many moons ago. Flying from the UK to somewhere on the west coast they would file to some obscure airfield - Great Falls rings a bell - with the west coast airfield as the alternate. When the fuel looked OK they would "divert" to the west coast.

[MarkerInbound]

Under the redispatch program ATC just sees a flight plan to the intended destination. Usually there's a bit of extra fuel in the original load. Twice I've come close to not making it. Once I pointed out we were way above econ speed and once we missed by 200 kg. Called the company and said, "Do you really want us to go to EBF?" They re-re-ran the flight plan and were able to drop the alternate (FAA flag rules allow no alternate if the flight is less than 6 hours and the destination is forecast VFR.)