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3. HOLDING 

3.1. Holding Speed 

When holding is required, it is generally flown on a “race track pattern”, composed of two straight legs plus two 180 degree turns. As the aircraft is turning around, the distance covered is not the primary objective. On the contrary, the knowledge of the maximum holding time (maximum endurance) is a determining factor for any diversion decision. As a result, it is important, during holding, to try to minimize fuel consumption versus time as much as possible, or to simply minimize fuel flow (kg or lb per hour). 

The minimum fuel consumption speed is somewhere between the minimum drag speed and the maximum lift-to-drag ratio (Green Dot) speed, which are quite close. As a result, in clean configuration, the standard holding speed is selected equal to green dot. 

    Holding patterns may be quite limiting around certain airports due to obstacle proximity. Therefore, green dot is sometimes too high, especially during turn phases where the bank angle can be too significant. As it is not possible to significantly reduce the speed below green dot in clean configuration, slats may be extended and a holding done in CONF1 at “S” speed1. 

Note that green dot and S speeds are easy to fly in selected mode, as they are indicated on the Primary Flight Display (PFD), as a function of aircraft weight and configuration: 

In clean configuration: “Green Dot” 

In configuration 1: “S speed” 

3.2. Holding in Operation 

A holding pattern can be managed by the FMGS at a selected waypoint during flight. For that purpose, it must be entered on the MCDU Flight-Plan page. Holding pattern data may come from the navigation database, or may be defaulted to standard dimensions (which can be changed), when no pattern is available. In this case, the following default data is proposed (Figure H10): 

INB CRS : Inbound course of the holding pattern 

Turn : Direction of the turn (Right or Left). 

Time: Outbound leg of 1 minute below 14,000 feet, 1.5 minutes above. 

DIST: Distance calculated from the predicted TAS which, in turn, depends on the holding speed (speed for max endurance, ICAO speed limit, or constraint speed, whichever is lower). 

1 S speed = Minimum slat retraction speed (from CONF1 to CONF CLEAN) 

I. FUEL PLANNING AND MANAGEMENT 

1. JAR - FUEL PLANNING AND MANAGEMENT 

1.1. Fuel policy 

The fuel quantity required for a safe trip along the planned route is calculated for each flight. Each operator has its own fuel policy. This policy is based on the loading of minimum regulatory fuel requirements (JAR-OPS 1). 

“JAR-OPS 1.255 An operator must establish a fuel policy for the purpose of flight planning and in-flight replanning to ensure that every flight carries sufficient fuel for the planned operation and reserves to cover deviations from the planned operation.” 

1.1.1. Standard Flight Planning 

Although fuel quantity varies in accordance with national regulations, the JAR-OPS requirements and the various national regulations are very similar. 

The minimum fuel quantity (Q) calculated for flight planning is defined as: 

Q = taxifuel + TF + CF + AF + FR + Add + XF 

Where 

 TF = Trip Fuel 

 CF = Contingency Fuel 

 AF = Alternate Fuel 

 FR = Final Reserve Fuel 

 Add = Additional Fuel 

 XF = Extra Fuel 

Figure I1 illustrates the different fuel quantities and associated flight phases of a typical trip. 

The following operating conditions should be taken into account for each flight: 

Realistic airplane fuel consumption data. 

Anticipated weight. 

Expected weather conditions. 

Air traffic services’ procedures and restrictions. 

1.1.1.1. Taxi Fuel 

“AMC OPS 1.255 Taxi fuel, which should not be less than the amount, expected to be used prior to take-off. Local conditions at the departure aerodrome and APU consumption should be taken into account.” 

Taxi fuel is usually a fixed quantity for an average taxi duration. For the A320 for example, it is equal to 140 kg (300 lb). This corresponds to a 12-minute average taxi fuel. Based on statistics or evaluation, the taxi duration and taxi fuel may need to be adjusted. 

1.1.1.2. Trip Fuel 

The required fuel quantity from brake release at the departure airport to the landing touchdown at the destination airport, is referred to as trip fuel. This quantity takes into account the necessary fuel for: