Reclearance
The Reclearance ( Reclearance procedure - German: re-release procedure (uncommon), also Reclearance Method , Reclearance Procedure , Redispatch , Rerelease or Decision Point Procedure - DPP) is a common procedure to reduce the amount of reserve fuel to be carried on flights with critical weight . This increases the payload (passengers, cargo) of the aircraft.
Reclearance Airport
The reserve fuel for a flight to the destination airport is usually calculated. When Reclearance process, however, the flight is not the destination airport (Engl. Destination Airport ), but planned a two-segment.
This stopover at the intermediate landing airport ( Reclearance Airport - RAP; also: Re-Dispatch Airport ) is only accepted for security purposes. Only in rare cases, under unfavorable circumstances, does this stopover actually take place (see below).
So this stopover is virtual. Only shortly before the possible stopover is it checked whether the reserve fuel is sufficient to reach the actual destination airport. However, the procedure only works if there is a suitable stopover airport at which the forecast weather would still allow a safe landing .
The Decision Point , DP (dtsch. Decision point ), to which the fuel demand (plus reserve fuel) is calculated for the first portion of the route is also Reclearance Point (dtsch. Reclearance point , also Re-Dispatch Fix or Reclear Fix called). It is located directly on the route to the destination airport. It does not have to be above the potential intermediate airport ( Reclearance Alternate ). It is sufficient if it can still be reached safely if there is an actual lack of fuel (for the onward flight to the destination airport).
The clearance point must be shown in the flight plan.
Due to the usual safety margins, the reserve fuel is sufficient in most cases and the stopover can be omitted. Shortly before the possible stopover, the pilots re-release the fuel ( in flight reclearance , also in flight replanning ) - after the pilot has checked whether the fuel reserve ( contingency fuel ) has been opened or not. The air traffic control does not care about the Reclearance process. So there is no clearance by air traffic control .
The pilot has a completely normal flight plan to the destination airport, he requests his normal take-off clearance and route clearance to the destination airport. In this respect, the stopover is only a reserve plan for safety reasons. Only when the redispatch alternate really has to be flown to in rare cases does the pilot request a diversion from air traffic control to the redispatch alternate airport.
If the fuel consumption up to the recovery point corresponded to the forecasts or was even cheaper, then the fuel reserve did not have to be touched up to the recovery point and the flight can continue to the actual destination airport. However, if the reserve fuel has been partially consumed, which is usually the case with unforeseen, unfavorable winds, then you have to land on the Reclearance Alternate and refuel.
The Reclearance Point is not halfway through the route, but as far as possible towards the destination airport - after around 90% of the total route. For long-haul flights of 14 hours, the Reclearance Point is 3 to 4 hours before the destination airport. The position of the Reclearance Point also depends on the location of the potential intermediate landing airport (Reclearance Alternate). The reclearance procedure is particularly worthwhile for long-haul flights, as the contingency fuel makes up a considerable proportion of the weight.
Reserve fuel
In addition to the fuel for the actually planned route (trip, contingency & alternate), there is reserve fuel , which is arithmetically made up of reserve fuel for:
- Waiting patterns at the destination airport (due to weather or "traffic jams") - 30 minutes at 1500 ft above the alternate ( holding fuel ) - (only applies to jet engines)
- 45 min at cruising altitude or 2 hours, for fan guns (detailed description under Final Reserve Reciprocating Aircrafts)
- Missed approach (Engl. Missed approach , and go-arounds Fuel )
- a possible onward flight to the alternate airport ( alternate fuel , also diversion )
- Reserve for the final approach (English Final Reserve Fuel ).
Holding fuel and alternate fuel are fixed quantities that are independent of the route. Only the contingency fuel is of interest for the reclearance procedure, as it increases with the length of the flight route due to the percentage calculation. Contingency fuel is part of the reserve fuel.
With the clearance procedure, you have to refuel less for the entire route because the 5% reserve fuel is only taken with you for the first section of the route (up to the relearance point) at the start. Or formulated from a different point of view: only reserve fuel is taken with you for the first section of the route. Should this then remain untouched (which is almost always the case), then this reserve fuel is also used for the second section of the route. Alternatively, one could also say that the first section of the route is planned without reserve fuel, since there is still enough fuel in the tank that is normally provided for the second section of the route. The fuel for the second route section thus serves as reserve fuel for the first route section.
Up until the "invention" of clearance around 20 years ago, the plane had to make a stopover because it lacked the reserve fuel for the onward flight.
With the clearance procedure, however, there is now a "release change" in the air, and the same reserve fuel is used in the second section of the route for the onward flight from the clearance point to the destination airport. Therefore, more payload can be carried instead of the contingency fuel.
In order to get to the destination airport, a minimum amount of fuel must be available at the Reclearance Point, otherwise you have to go to the Reclearance Airport and refuel. Reclearance is primarily used for weight-critical long-haul flights. The flight planning, and thus the determination of the Reclearance-point is carried out by the flight directions (engl. Dispatcher - flight dispatcher ).
Load clearance, fuel clearance
Reasons for the Reclearance are
- Enabling long-haul flights, which would otherwise be impossible because the legally required fuel reserves are not reached without the reclearance - i.e. the increase in range ( maximum range )
- the increase in the payload, as with the reserve fuel Reclearance less in favor of payload (engl. Payload ) must be taken (engl. Load Reclearance ) - t will be achieved during long-haul flights of magnitude of 10
- Cost savings through less reserve fuel, even if there are no restrictions due to route length or payload (fuel reclearance)
- Performance issues (eg relatively short runway, strong climb after takeoff required small defects on the flyer -. A failed hydraulic pump, etc.), which increase the prescribed required takeoff distance or the maximum take-off weight (dt. Maximum authorized takeoff weight reduced) so that only less fuel can be carried.
History of Reclearance
The airlines were stimulated by the increased world market price for crude oil and the consequent increase in fuel costs to "invent" and introduce the clearance procedure. The price war between airlines since the deregulation of the aviation market ( Airline Deregulation Act , USA, 1978) also made the reclearance procedure interesting.
The idea for a reclearance flight was first published in 1977 by David Arthur and Gary Rose under the title "REDISPATCH for fuel savings and increased payload" in Boeing Airliner . In the article, many calculations were made to determine the optimal location of the Reclearance Point. These calculations were only applicable to the type of aircraft discussed and only for a certain percentage of the reserve fuel. The weather was not taken into account. The fuel savings from Arthur and Rose's published clearance process depended on three factors:
- The maximum achievable savings depended on the location of the Reclearance Point. The location could not be determined theoretically because there were no exact equations for trip fuel and reserve fuel. Although this point would just be calculated, so maybe there was still no waypoint ( waypoint ) at the corresponding position.
- As a further factor for the maximum possible fuel savings, Arthur and Rose stated that a Reclearance Airport must be available, which is located in such a way that the descent to the Reclearance Airport can begin immediately after passing the Reclearance Point. This reduces the need for reserve fuel between the Reclearance Point and the Reclearance Airport, which increases the amount of reserve fuel available at the Reclearance Point.
- Another helpful factor depends on the location of the Reclearance Airport.
Initially, the clearance procedure was highly controversial and was criticized as a deterioration in flight safety and as a subtle exploitation of a loophole in the law. Proponents point out that theoretically you can use your contingency fuel while taking a taxi and that the start would still meet the legal requirements.
A flight that plans a stopover after the first flight segment from the outset also only flies with reserve fuel for this first segment. More does not have to be on board for this. In practice, however, refueling is saved at the different airports due to time constraints or price differences for fuel. The aircraft that covers the same first flight segment according to the relocation procedure is, however, even more on the safe side in terms of the amount of reserve fuel, since it already has the fuel for the second flight segment on board and, if necessary, as a reserve for could miss the first flight segment. Even in the second leg of the route, the aircraft with the clearance procedure does not do any worse than the flight with a stopover, as both have the required 5% fuel reserve on board.
Even so, flights with a reclearance procedure have fewer fuel reserves on board than before this procedure was introduced. However, flight safety has not really deteriorated with this. Before the procedure was introduced, the fuel reserve at the destination airport was unnecessarily high, almost twice as high as on flights that had started from a potential stopover airport. This idea that it would be better to have more reserve fuel on board than the already strict safety regulations in aviation prescribe, however, would have no upper limit, because then one would be even safer if only fuel was on board and no passengers / none Freight. The safety regulations for reserve fuel are fulfilled with the reclearance procedure. If the reclearance procedure were to be prohibited, a larger amount of reserve fuel would have to be stipulated in order to provide fair compensation for shorter routes in order to equate this with longer routes in terms of flight safety.
Commitment to stay
The commitment to stay (dtsch. Stay requirement ) is another method to save fuel reserve. But it has nothing to do with the clearance procedure. While the reclearance procedure saves on contingency fuel, the commitment to stay saves on alternate fuel.
The use of the "commitment to stay procedure" is only possible under certain conditions and after prior application to the LBA . If this happens occasionally, then under certain conditions (good weather, condition and number of runways) the alternate fuel can also be flown, which is actually reserved for the onward flight to the alternate airport. The aircraft must then land at the destination airport (commitment to stay). In good weather there is no reason why you have to fly on to the alternate. In the event of a suddenly blocked runway or failure of the ILS transmitter, further lanes are available at the destination.
If, in extreme cases, the entire alternate fuel has flown, then (in rare cases) only the final reserve fuel is left in the tank after landing. The consumption of the alternate fuel is notifiable to the LBA, but not a malfunction. Only the breaking of the final reserve fuel for normal flight is (in any case) an administrative offense, which is subject to heavy fines.
The (partial or complete) consumption of the alternate fuel despite landing at the destination airport must be reported to the LBA. With a previous application (for the commit to stay procedure) it does not constitute a disruption according to §5 LuftVO . Without approval, this would be an administrative offense according to §57 LuftBO , for which the pilot in charge can be fined up to 5,000 euros. Further details are specified in the JAR-OPS instruction.
United States
In the USA, the Reclearance procedure is specified in FAR 121, where it runs under the name Re-Release Operation. US airlines are required to carry reserve fuel for 10% of the total flight time.