SETTING UP EDTO

Threshold Circle Calculation - used to determine the maximum allowed distance for the aircraft from a designated ERA without EDTO being required

Minutes

Enter the maximum time limit for the aircraft to reach an ERA during a flight.

Use Max. Fuel, MTOW

Select this option to use the maximum take-off weight (MTOW) and fuel flow from the advanced performance data for the aircraft in EDTO calculations.

Zero Fuel Weight

You can manually insert the weight of the aircraft when empty of fuel and the weight of fuel to be used in the EDTO calculations if you do not want to use the advanced performance data.

Fuel

Flight Level

Enter a flight level for the threshold circle calculation (in the range 050-999).

Power Settings

Select the aircraft power setting to be used in the calculation from the options in the advanced performance data.

Calculated Radius

This value of the threshold circle radius is calculated based on the settings above.

Radius Override

Enter a preferred value for the threshold circle radius to override the calculated value from the previous settings.

Equal Time Point Calculation

Use Flight Level from current FPL

Choose whether to use the flight level and cruise profile from the current flight plan in calculating the EDTO equal time points on the route, or to select default settings to use in all cases.

Use Cruise profile from current FPL

Flight Level

Power Profile

Approval Area Calculation - used to determine the maximum distance that the aircraft can travel under EDTO planning rules

EDTO Maximum Minutes Approval

Select the maximum flying time from each ERA to use in the EDTO diversion fuel calculations.

Drift Down (manual) Allowance Method

Select the method that best suits your operating authority's guidelines to calculate the approval area (the distance flown under EDTO conditions in the number of minutes selected above).

Each option affects the settings displayed.

Constant FL only - calculate distance based on cruising at a constant altitude

Use Max Cruise Flight Level from FPL

Select this option to use the maximum cruise flight level from the current flight plan in the distance calculation.

If you don't select this option, then you need to enter a flight level in the Cruise Flight Level to ERA option that is displayed lower down in the menu.

Use Aircraft Mass at TOC

Select this option to use the calculated aircraft mass (weight) at the top of the climb in the flight.

If you don't select this option, then you need to:

EITHER - choose to use the maximum take-off weight (MTOW) and fuel flow from the advanced performance data for the aircraft by selecting Use Max. Fuel, MTOW;

OR - manually insert the weight of the aircraft when empty of fuel (Zero Fuel Weight) and the weight of Fuel to be used in the distance calculations.

Level Off Cruise Profile

Select the cruise profile at the end of the flight to the ERA before the normal descent to land commences.

Driftdown Allowance (data) - calculate distance based on driftdown profile from aircraft advanced performance data

Use Max Cruise Flight Level from FPL

Select this option to use the maximum cruise flight level from the current flight plan in the distance calculation.

If you don't select this option, then you need to enter a flight level in the Drift down from option that is displayed lower down in the menu.

Use Aircraft Mass at TOC

Select this option to use the calculated aircraft mass (weight) at the top of the climb in the flight.

If you don't select this option, then you need to:

EITHER - choose to use the maximum take-off weight (MTOW) and fuel flow from the advanced performance data for the aircraft by selecting Use Max. Fuel, MTOW;

OR - manually insert the weight of the aircraft when empty of fuel (Zero Fuel Weight) and the weight of Fuel to be used in the distance calculations.

Level Off Cruise Profile

Select the cruise profile at the end of the flight to the ERA before the normal descent to land commences.

Driftdown Allowance (manual) - define the driftdown profile for your aircraft (overruling the advanced performance data)

Use Aircraft Mass at TOC

Select this option to use the calculated aircraft mass (weight) at the top of the climb in the flight.

If you don't select this option, then you need to:

EITHER - choose to use the maximum take-off weight (MTOW) and fuel flow from the advanced performance data for the aircraft by selecting Use Max. Fuel, MTOW;

OR - manually insert the weight of the aircraft when empty of fuel (Zero Fuel Weight) and the weight of Fuel to be used in the distance calculations.

Level Off Cruise Profile

Select the cruise profile at the end of the flight to the ERA before the normal descent to land commences.

Drift Down to FL

Enter the flight level at which the driftdown stage ends, before the normal descent to land commences.

Distance Covered

Enter distance, fuel and time parameters to define the driftdown profile used in the EDTO approval area calculations.

Fuel Used

Time Elapsed

NM Override - set the approval area distances directly

75 Mins, 90 Mins, etc.

Enter distances in nautical miles for one or more time options.

You do not need to define every option; any that are undefined will not be available in the EDTO Selected Range drop-down list in Step 1 of the flight planning menu.

Scenario Parameters - applied to all the EDTO emergency fuel scenario options

Calculate Scenarios at EEP & EXP

Select this option to add fuel calculations at both the EDTO Entry and Exit Points as well as the Equal Time Points. This is recommended for shorter flights when there are only 2 or 3 ERAs along the route, and the distances to and from the EEP and EXP become significant.

Wind Correction

Select a bias factor to apply to the forecast wind for the fuel calculations for the diversion routes to the ERAs. The correction is added for a headwind and subtracted for a tailwind.

ERA Holding Altitude

These two values allow extra fuel to be allowed for in case of holding at an ERA.

Enter an altitude in feet above ground level (AGL) and a duration in minutes.

ERA Holding Duration

ERA Missed Approach Fuel

If required, enter an additional weight of fuel to allow for a second attempt to land at an ERA.

Medical Emergency, Aircraft OK

Include as EDTO Scenario

As this is an optional scenario, select this option to include it in the calculations to determine the most penalising scenario for diversion fuel requirements.

Use planned FL, Cruise & Descent profiles

Select this option to use the flight level and profiles from the current flight plan in the fuel diversion calculations.

If you do not select this option, you need to select a Cruise Profile from the options available for your aircraft and enter an initial Flight Level.

1 ENG Inoperative (Driftdown)

Calculation Method

Select Data or Manual.

Data - uses the aircraft's advanced performance data for the EDTO calculations in this scenario. Select the Driftdown Profile, Cruise Profile at Level Off, Descent Power Profile and Holding Profile from the options in the drop-down lists.

Manual - specify the distance covered, fuel used, time elapsed and the Level Off flight level for the driftdown descent to the ERA (the final descent to land is taken from default aircraft data).

Apply APU Inflight Burn

Include the fuel consumed by the APU in the calculations (defined in the APU Burn Rate section below).

Level off at lower of calculated Level and fixed FL

Select this option to set a maximum altitude at which to level off after the descent. The software will then amend the EDTO scenario to use either this value or the calculated final level after driftdown, whichever is lower.

Depressurization (All ENG Ok)

See instructions for Driftdown scenario, except that an Emergency Descent Profile needs to be selected or defined instead of a Driftdown Profile.

Depressurization with 1 ENG Inoperative

See instructions for Driftdown scenario, except that an Emergency Descent Profile needs to be selected or defined instead of a Driftdown Profile.

APU Burn Rate/hour

Ground APU Burn

Define the weight of fuel burnt by the aircraft's APU per hour when on the ground and in the air. These figures can then be used to improve the accuracy of the EDTO fuel calculations in the scenarios above.

Inflight APU Burn