Flight planning#Reserve reduction

The Recleareance ( Reclearance method - dtsch re- release method ( uncommon), also Reclearance method Reclearance Procedure, redispatch, rerelease or Decision Point Procedure - DPP) is a common method to reduce the amount of accompany such reserve fuel in weight-critical flights. Thus, the payload (passengers, cargo ) of the aircraft is increased.

Reclearance Airport

Normally the reserve fuel for a flight is calculated to the destination airport. When Reclearance process but the flight is not the destination airport ( engl. Destination Airport ), but is designed with a stopover.

This stopover at the intermediate landing airport (English Reclearance Airport - RAP; well: Re -Dispatch Airport ) but is accepted only for hedging purposes. Only in rare cases, under certain circumstances, this stopover takes place really ( see below).

This stopover is therefore virtually. Only shortly before the possible intermediate landing is checked whether the reserve fuel even extends to the actual destination. This method only works if there is a suitable intermediate landing airport, which was also the predicted weather would not permit a safe landing.

The Decision Point, DP ( engl decision point ) is calculated up to the fuel demand ( plus reserve fuel) for the first section of the route, even Reclearance Point ( engl Reclearance point, even re -Dispatch Fix or Reclear Fix) is called. It lies directly on the route to the destination airport. He must not have the potential stopover airport (English Reclearance Alternate) lie. It is enough if this in actual fuel shortage ( for the onward flight to the destination airport ) is still safe distance.

The Reclearance point must be shown in the flight plan.

Due to the usual safety margins of the reserve fuel is sufficient in most cases, and the intermediate landing may be omitted. Shortly before the eventual stopover, a renewed re- release ( engl. In Flight Recleareance, also In Flight Replanning ) by the pilots - after the pilot has verified that the fuel reserve (English Contingency Fuel) was cracked or not. Air traffic control does not care about the Reclearance process. So there is no clearance (release) by air traffic control.

The pilot has a normal flight schedule to the destination airport, he calls his normal off clearance and route clearance to the destination airport. As such, the stopover is only a reserve planning for security reasons. Only when the redispatch Alternate really needs to be serviced once in rare cases, the pilot asks for a diversion in air traffic control for redispatch alternate airport.

If the fuel consumption up to Point Reclearance corresponded to pre-compute or was even cheaper, then had the low fuel to Reclearance Points not be touched, and the flight may continue to the final destination airport. Should the reserve fuel but have been partially consumed, which is usually the case of unforeseen, unfavorable winds the case, then it must be landed and refueled on the Reclearance Alternate.

The Reclearance Point is not on the half of the distance, but as far as possible towards the destination airport - approximately 90 % of the total distance. For long- haul flights of 14 hours of Reclearance Point is 3 to 4 hours before the destination airport. The position of the Reclearance points also depends on the location of the potential intermediate landing airport ( Reclearance Alternate) from. The Reclearance method is particularly worthwhile for long-haul flights, since the Contingency Fuel accounts for a substantial proportion by weight.

Reserve fuel

For fuel for the original planned route (English Taxifuel plus APU Fuel plus TripFuel ) is the reserve fuel (English reserve fuel), resulting from the calculated composed of reserve fuel for:

• The actual planned route - 5% of TripFuel ( Contingency Fuel)
• Queues at the destination airport (because of weather or "congestion" ) - 30 min at 1500 ft above the Alternate (English Holdingfuel ) - ( USA: Domestic Fuel Reserve - for 45 minutes of flight - fuel consumption as in normal cruise flight )
• Missed approach ( engl. missed approach, and go-arounds Fuel)
• A possible onward flight to the alternate airport (English Alternate Fuel, and Diversion )
• Reserve for the final approach (English Final Reserve Fuel)

Holdingfuel and Alternatefuel are independent of the route of flight, fixed sizes. Only the Contingency Fuel is interesting for the Reclearance process, since it increases with the distance of the flight because of the percentage calculation. Contingency Fuel is a part of the reserve Fuels

When Reclearance process you have to stock up for the entire stretch less, because the 5 % reserve fuel at startup are simply taken for only the first stretch (up to Relearance Point). Or, from another point of view formulated: it is taken only reserve fuel for the first stretch. If the text have remained untouched ( which is almost always the case), then this reserve fuel used is also for the second stretch. Alternatively, one could also say that the first section is planned without reserve fuel, there still sufficient fuel is carried in the tank which is provided in the normal case for the second stretch. The fuel for the second track section thus serves as a reserve fuel for the first stretch.

Up to the "invention" of Reclearance about 20 years before the jet had to make a stop because he lacked the reserve fuel for the onward flight.

With the Reclearance process but now there is a "Share Change" in the air, and the same reserve fuel is used in the second route for the onward flight from Recleareance Point to the destination airport. Therefore, more payload can be taken instead of the Contingency Fuel.

To get to the destination airport, Point must have a minimum amount of fuel on Reclearance be present, otherwise must be dodged and refueled for Reclearance Airport. Reclearance is primarily used for weight- critical long-haul flights. Flight planning, and thus the determination of the Reclearance - point is, by the flight planner (English Dispatcher - flight dispatcher ).

Load Reclearance, fuel Reclearance

The reasons for the Reclearance

• The enabling of long-haul flights that would otherwise because of falling below the statutory fuel reserves without the Reclearance would be impossible - so extending the reach (English Maximum Range )
• Achieved it will be on long-haul orders of magnitude of 10 t - increasing the payload, there must be taken with the Reclearance less reserve fuel in favor of payload (English Payload) ( engl. Load Reclearance )
• Cost savings due to less fuel onboard spare, even if no restrictions by route length or load capacity are available ( fuel Reclearance )
• Performance problems (eg, relatively short runway, strong climb required after the start, small defects on the flyer - a failed hydraulic pump, etc., which increase the required take-off distance or the Maximum Take Off Weight ( dt maximum permissible take-off weight ) is reduced, so that only less fuel can be taken.

History of Reclearance

The airlines have been stimulated by the increased Weltmarktpeis for petroleum and the resulting increase in fuel costs for the "invention" and introduction of Reclearance process. Also, the price war among airlines since deregulation of the aviation market ( Airline Deregulation Act, USA, 1978) made ​​the Reclearance process 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 airliners. In the article, many calculations were made to determine the optimum position of Reclearance Points. These calculations were only discussed on the type of aircraft and applicable only for a certain percentage of reserve fuel. The weather was not considered. The fuel savings by Arthur and Rose Reclearance method depended on three factors:

• The maximum achievable reduction was dependent on the location of the Reclearance points. The location could not be determined theoretically, since there were no exact equations for trip fuel and reserve fuel. Even though this point exactly could be calculated, there was perhaps still no waypoint ( waypoin ) at the corresponding position.
• Another factor for maximum fuel savings was reported by Arthur and Rose, that one must have a a Reclearance Airport available, which is such that the descent to Reclearance Airport can begin immediately after passing the Reclearance Points. Thus, the need for reserve fuel between Reclearance Point and Reclearance Airport is reduced, thereby increasing the amount of available fuel reserve on Reclearance Point.
• Another helpful factor depends on the position of the Reclearance airports.

Initially, the Reclearance process was highly controversial and was criticized as deterioration of air safety and as subtle exploitation of a legal loophole. Proponents point out that you should already be theoretically Contingency Fuel consume the taxi and the start would still meet the legal requirements.

A flight who schedules a foregone conclusion a stopover after ersen flight section, also flies only with reserve fuel for this first stretch. That's all he does not have to have them on board. In practice, however, it is the refueling save for reasons of time or price differences for the fuel at the various airports, however. However, the airplane that after Relearanceverfahren travels this same first flight segment is considered even more on the safe side on the amount of reserve fuel, since it already has the fuel for the second flight segment on board and, if necessary first even as a reserve for the flight segment could fly. In the second stretch the plane with Reclearance method does not cut off worse than the flight with stopover, because both contain the prescribed 5% fuel reserve on board.

And yet flights Reclearance processes have less fuel reserves on board, as before the introduction of this procedure. But this flight safety has not really deteriorated. Prior to the procedure, the fuel reserve at the destination airport unnecessarily high, almost double as high as when flying, which had taken off from a potential stopover airport. This idea that you would rather have more reserve fuel on board, as the already tight security in the aviation dictate, but would up no end, because then you would be even safer if only fuel on board and only one passenger. With the Reclearance method, the safety regulations for reserve fuel are met. If you would prohibit the Reclearance process, then one would have to fair compensation for shorter distances even greater amount of reserve fuel require, to assimilate the longer routes them to flight safety.

Commitment to stay

( To stay dtsch obligation) The commitment to stay is another method for saving fuel reserve. It has nothing to do with the Reclearance method. While it is saved on Reclearance process on Contingency Fuel is saved while commitment to stay on Alternate Fuel.

The use of the "Commitment to stay " procedure is only possible under certain conditions and upon prior application to the LBA. If it arises occasionally, it can be dissipated and the Alternate Fuel under certain conditions ( good weather, condition and number of start and runways ), which is reserved for the onward flight to actually alternate airport. The aircraft must then necessarily at the destination airport land ( commitment to stay - commitment to stay ). In good weather, there is no reason why you have to fly further to the Alternate. In a suddenly blocked airstrip or failure of the ILS transmitter further tracks are at the destination.

Should be gone in an extreme case, the entire Alternate Fuel, then ( in rare cases ), only the holding fuel after landing in the tank. The consumption of the Alternate Fuels is notifiable to the LBA, but no malfunction. Only the consumption of the Holding Fuels for normal flight (in any case ) an offense which is occupied with substantial fines.

The ( partial or complete ) consumption of the Alternate Fuels despite landing at the destination airport is notifiable to the LBA. In prior application ( for the commit to stay proceedings ) but he is not a malfunction according to § 5 LuftVO Without qualifying approval would be an offense pursuant to § 57 LuftBO for which the pilot in command of up to 5,000 euro fine can be occupied. For details, is set statement in the JAR -OPS.

USA

In the U.S., Reclearance process in the FAR is 121 set, where it runs under the name re-release operation. U.S. airlines have to carry spare fuel for 10% of the total flight time.

• Aeronautical engineering