Alternate airfield
An alternate aerodrome (ger .: alternate airport , often only for short alternate ) is an airfield , which is a land of possibility if you are landing at the destination airport as is unsure estimated. The most common reason for landing on an alternate airport is bad weather ( flying weather ) at the destination airport. Other reasons could be traffic congestion or an unforeseen closure of the destination airport. As a general rule, every flight plan that is carried out according to Instrument Flight Rules ( IFR ) must name an alternate airport and include it in the fuel planningto include. Exceptions to this rule can be made if the destination airport has two separate runways, each with an instrument approach procedure and the weather forecast one hour before and one hour after the planned landing promises visibility of at least five kilometers and a cloud base of at least 600 meters, or if the destination airport is geographically so remote (technical term: isolated destination ) that a flight time of two hours or more would be necessary to reach the nearest alternate airport.
Airlines and charter airlines are due to the governorship of an Air Operator's Certificates obliged (AOC) to create guidelines for the selection of an airport as an alternate airfield. The legal basis for this is the JAR-OPS , which has been administered by EASA since 2003 . In addition to the weather, the availability of instrument approach procedures , the operational readiness of search and rescue services ( SAR ), the condition and length of the runways and their lighting are decisive for whether an airfield can be used as an alternate airfield .
In Germany, commercial airports are mainly used as alternative airports. The term alternate airport is also used very often instead of alternate airport, but this is incorrect. However, an alternative landing does not necessarily have to take place at an airport, but can also be carried out at a commercial airfield.
Differentiation from alternate airports
Destination Alternate
If a landing at the destination airport (ger .: destination airport , often only for short destination ) because of inadequate weather conditions or other circumstances appear to be unsafe, so a landing is carried out on a nearby the destination airport airfield. For the fuel calculation, a landing approach and a go - around maneuver are taken into account, as well as a cruise at an altitude that is free of obstacles and leads directly to the alternate airport. A minimum amount of fuel ( final reserve ) should be available there for the implementation of an instrument landing approach .
In the flight planning phase, i.e. before departure, the weather forecast for the alternate airport must be significantly better than the instrument approach procedure on site actually requires. During the flight, a deterioration in the weather down to the minimum level of the actual instrument approach procedure is acceptable. If the weather continues to deteriorate, another alternate airport must be selected during the flight.
En-Route Alternate
During the entire duration of the flight, there must always be a landing possibility at a certain distance from the current position, depending on the type of flight and aircraft type. Normally, this distance corresponds to the distance an aircraft can travel at the speed it can still fly with one remaining engine - commercial aircraft must have at least two engines. Holder of AOC are therefore required for the aircraft they operate a single-engine cruise speed (ger .: single engine cruise speed set). In special cases, that is, if the aircraft manufacturer can demonstrate that its equipment is particularly immune to interference, this time can be extended to two to three hours until the enroute alternate is reached. The exact modalities are specified in the ETOPS rules. For ETOPS alternate airports, stricter selection criteria apply than for normal enroute alternates. The weather conditions for the planning phase and during the flight are the same for the Enroute Alternate as for the Destination Alternate . With ETOPS Alternate , the requirements may be higher.
"3% En-Route Alternate"
When planning the fuel up to the destination alternate , it is assumed that the destination airport is flown to first, before the onward flight to the destination alternate takes place. In contrast, a tightly dimensioned fuel planning can also require the alternate aerodrome starting from a predetermined point (ger .: pre-determined point ) directly to fly without trying first a landing at the destination airport. For this type of planning, JAR-OPS uses the technical term “Pre-determined Point Procedure”, or PDP for short.
Planning with a “pre-determined point” enables the calculation of the fuel reserves for additional fuel consumption during the cruise to go back from the normally 5% fuel reserves to 3% for the entire flight. In some airline operating manuals, this alternate airport is also referred to as Fuel En-Route Alternate . In the event of an alternate landing on the "3% En-Route Alternate", no attempt to land at the destination airport is made beforehand; a go - around maneuver with correspondingly high fuel consumption is therefore not required for fuel planning.
If the decision is made to fly to the "3% En-Route Alternate", there is no longer any additional alternative landing option. This distinguishes this type of planning from “ decision point planning based on reclearance” , in which an alternate airport is to be included for both the reclearance airfield and the destination airfield. There is no need for an alternate airfield if the clearance airfield or the destination airfield can be planned without an alternate airfield (i.e. with two separate runways, two instrument landing procedures, five kilometers of visibility, cloud base 600 meters or higher).
In the current terminology of JAR-OPS, this type of planning is referred to as “Reduced Contingency Fuel” planning, since the requirements for fuel reserves for additional consumption during cruise are negligible until the decision point is reached.
The "3% En-Route Alternate" must be such that the entire flight route from the departure airport to the alternate airport is shorter than from the departure airport to the destination airport. The weather forecast must meet the criteria for Destination Alternate .
Take-Off Alternate
In certain cases it may be necessary to select an alternate aerodrome for take-off. Particularly for the rare but always possible case that during the start an engine fails, the start must be continued, however, as he after exceeding the aborted take-off speed v 1 may no longer be canceled.
The visibility conditions at the take-off aerodrome can be sufficient for take-off, but too poor for a landing, since more stringent requirements are placed on the weather for an instrument landing approach with a failed engine than during regular operation. In this case, the aircraft needs a nearby alternate airport ( take-off alternate , alternate departure airport or departure alternate ) after take-off . In this case, too, the distance is determined by the aircraft-typical single-engine cruising speed. It must be possible to reach the take-off alternate at this speed in one hour. ETOPS-certified flights can extend the distance to their take-off alternate to one to two hours of flight time at single-engine cruising speed.
Additional costs due to alternative landings
In the event of an actual landing at an alternate airport, the airline or the operator of the aircraft incur additional costs in the form of landing and handling fees .
Passengers whose ticket constitutes a contract of carriage must be brought to their destination at the expense of the contractual partner. If the delay is caused by the behavior of the airline or one of its agents, there may be a right to compensation, provided the damage caused by the delay can be clearly shown. In the event of a delay due to an alternative landing due to bad weather, the contract of carriage still exists, but there is no entitlement to compensation.
Late arrivals and the resulting missed connecting flights sometimes mean that the airline that operated the flight has to pay the costs for the overnight stay with breakfast in a hotel assigned by the airline. In most cases, the transport of the passengers of the diverted flight by bus or train, or, if possible, by plane to the intended destination, is part of the service, which is to be provided at the expense of the airline or the tour operator at no extra charge.
The extent to which travel price reductions are entitled (e.g. according to the Frankfurt table for package tours ) depends on the reasons. If the airline is to blame for the delay, then travel price reductions may be considered. Otherwise, exclusion due to force majeure is justified in the event of a weather-related diversion . If the planned destination airport is closed due to a bomb threat or other security risks, the airport will initiate the diversion and must also bear the costs. The airport operator will try to reclaim these costs from the person who caused the safety risk.
