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spierpoint jones
12th Jul 2007, 09:51
Looking for some FAA pilots to explain to me please , why there is on some flights a re -dispatch point and the hold point of having a re-dispatch release as per CFR Part 121 rules. Whats the real world application of this procedure.....
As far as I know this concept doesn't appear in the JAA rules.....
Thanks in advance ...
jones:ok:

742
12th Jul 2007, 13:43
Under United States 121 Flag (international) rules the fuel reserve includes, among other things, 10% of the flight time from departure to destination. This can get to be a very large fuel load on long flights. The work around is the “Planned Redispatch”, where the flight is in effect broken into two sections. The first part is from the departure airport to an initial destination, then approaching that point if all is going well the flight is redispatched to the final destination--which starts the fuel reserve calculation over.

An example might be a JFK-FRA flight with AMS as the initial destination. There is no intent to land at AMS, which exists in the planning as only a paperwork exercise. Of course sometimes it does not work out as planned

Much longer explanations are possible, but this is the basics of it.

Broomstick Flier
12th Jul 2007, 14:26
spierpoint jones,

This issue is indeed adressed by JAA, under JAR-OPS 1.255 Fuel policy

"An operator should base the company fuel policy, including calculation of the amount of fuel to be carried, on the following planning criteria:
[...]
1.3. Contingency fuel, which should be the higher of (a) or (b) below:
a. Either:
i. 5% of the planned trip fuel or, in the event of in-flight replanning, trip fuel for the remainder of the flight; or
ii. Not less than 3% of the planned trip fuel or, in the event of in-flight replanning, trip fuel for the remainder of the flight, subject to the approval of the Authority, provided that an en-route alternate is available; or
[...]"

Salz

BelArgUSA
13th Jul 2007, 07:55
Hola Jones -
xxx
Let me give you an example of fuel savings (or available increased payload) with re-dispatch -
According to FAR 121, for a 747-200.
Example, flight from London to New York, with re-dispatch near Gander.
xxx
LHR to JFK - airways distance 3,300 NM, assuming 50 kts headwind.
Trip fuel 75,400 Kg - Time 7:32
Reserve 10% of 7:32 or 46 minutes - 14,000 Kg
Missed approach - 2,000 kg
Fuel to alternate EWR - 4,000 kg
Holding 30 minutes above EWR - 9,000 kg
Fuel required LHR to JFK = 104,400 kg
xxx
LHR to YQX (re-dispatch point at 50º West) distance 2,300 NM, 50 kts headwind.
Trip fuel 55,000 kg...
YQX to JFK - airways distance 1,100 NM, again 50 kts headwind.
Trip fuel 23,600 kg - Time 2:32
Reserve 10% of 2:32 or 16 minutes - 3,500 kg
Missed approach - 2,000 kg
Fuel to alternate EWR - 4,000 kg
Holding 30 minutes above EWR - 9,000 kg
Fuel required LHR to JFK with YQX re-dispatch = 97,100 kg
xxx
Fuel savings shown here - 7,300 kg... nearly 10,000 liters...
You must have 42,100 kg remaining in the tanks to continue beyond YQX.
xxx
You could also red-dispatch more than once if somewhat low on fuel.
I had situation where I got re-dispatched from YQX to BGR (Bangor, Maine) then JFK.
Drain the tanks of a few drops for my Zippo lighter please...
xxx
:)
Happy contrails