ETP Scenarios Fields

Field

Description

ALC

Enter the appropriate airline code.

ETP SCENARIO NUMBER

Enter the desired scenario number (1 - 999).

DESC

Enter a brief description of the ETP scenario for the flight plan printout, e.g. 1EO Depress, etc.

NUMBER OF ENGINES

Enter the number of engines for the scenario, <ALL>, <-1>, or <50%>. 

This field defaults to <?> Search mode; use the up and down arrow keys to select the desired entry. 

Note: An entry of <50%> implies the loss of half of the normal complement of engines. Example: For a 3-engined aircraft this is equivalent to the loss of two engines.

UNITS

Enter weight units of measure for all fixed burn entries, lbs <L> or kgs <K>. 

If this scenario is used for an aircraft calibrated in the alternative units, all fixed fuel burn values will be converted automatically.

TLS/CFSS Check

Used to perform the ETOPS Beyond 180 Minute diversion time calculations, leveraging our current ETP functionality. 

• Designate an ETP scenario to be used for determining compliance with the TLS or CFSS time limits. 

• The ETP Policy used during flight plan calculation must include at least one scenario designated for TLS or CFSS. 

• You can modify an existing scenario or create a new one to be used for TLS or CFSS check.

MAIN / INITIAL DESCENT PROFILE

Indicate how the Initial Descent from cruising altitude is to be calculated. The options are: Driftdown <D>, Instantaneous <I>, Fixed <F> or Level Off <L>. 

• The Level Off option is used as an emergency initial descent profile instead of instantaneous descent for decompression scenarios. This allows the system to actually determine how much fuel, time, and lateral distance is associated when descending to the desired fixed altitude. This produces reduced ETP fuel requirements. 

  • If you select the Level Off option you can enter a Normal and Icing Profile (below the Main field). 

• If these fields are left blank, the default values are used. You may be required to generate new performance data to use the Level Off option.

ALTERNATIVE

If you select driftdown in the Initial Descent Profile field, you will be asked for an alternate method to be used in the case that driftdown performance data is unavailable for the aircraft in use. The options are: Instantaneous <I> or Fixed <F>.

NORMAL PROFILE

Enter a driftdown profile name for normal conditions, if blank use STD.

ICE PROFILE

Enter a driftdown profile name for icing conditions. This field allows icing penalties to be applied to the ETP calculation (driftdown performance) based on specific speeds and flight levels when icing conditions exist.

• Only profiles created by N-FP’s Performance Team can be entered here. This means that you need to provide specific performance data under icing conditions for the aircraft you use before this feature will work. The standard naming convention for these profiles should be “ICE”.

Ice protection ON/OFF

N-FP needs to know when to use the icing profile. If the ETP stations are highlighted in blue, the ETP burn calculation includes penalties for airframe and engine anti-icing. Refer to the drift down performance table for the icing profile, to calculate the burn.

INITIAL DESCENT PROFILE TIME/BURN/DISTANCE

If you have selected Fixed initial descent, then you will be required to provide values for Time (number of minutes), Burn (fixed burn value) and Distance (still-air, in NM) for the initial descent burn, otherwise these fields will be skipped.

LEVEL-OFF

Enter the method to be used to determine level-off altitude: 

• driftdown (determined automatically from the driftdown performance data), 

• Maximum (level-off will be at the maximum altitude for which there is performance data considering the weight of the aircraft at ETP, and the level-off cruise profile), 

• or Fixed (user specified).

FL

If you select Fixed level-off in the previous field, you must specify the desired level-off altitude. The default entry is ACX (aircraft), which implies that the value will be read from the ETP F/L entry in the Aircraft Characteristics record.

INCREMENT / MFL Incr Limit

Enter the level-off increment to be used.

• This entry only applies to scenarios using “I” (instantaneous” descent) as the initial descent profile as well as FIXED LEVEL-OFF – decompression only. For instance, if additional fuel is required for this scenario, NFP will retry the calculation using performance at the next flight level relying on the increment value entered. 

  • In this example, the increment is 2000ft (20).

• If additional fuel is required at FL100, NFP looks at cruise performance at FL120 and verifies if additional fuel is required for that scenario. NFP continues to look at cruise data at FL140, FL160, FL180, and so on…..up to FL250 until additional fuel is no longer required.

CRUISE PROFILE

Enter whether the cruise level is fixed <F> or climb permitted <C>.

ADDN CRUISE PROFILING

Enter multiple level off altitudes along with a time constraint at each altitude.

MFL

If climb is permitted in the cruise, indicate the maximum flight level to be permitted. 

The default entry is ACX (aircraft), which implies that the value will be read from the MFL entry in the Aircraft Characteristics record.

SPEED

Enter the cruise speed profile or PLN for the same as the main route. 

• ACX (aircraft) is the default, and if chosen, the aircraft ETP speed which is set in the Aircraft Characteristics WebFOMS screen, is used in the profile. 

• The system will use LRC as the default profile if no speed is set in the Aircraft Characteristics WebFOMS screen.

FINAL DESCENT

Enter either <C> for Calculated or <F> for Fixed as the method for determining final descent burn. 

NOTE: For the descent from 10,000ft to Landing, The final descent calculation in an ETP scenario utilizes the main route's profile key, not the profile key specified for ETP Cruise in the ETP Scenario. For flights using a Cost Index profile for the main route, single engine performance does not exist; when N-Flight Planning executes the final descent burn based on 1 Engine, but is provided a Cost Index Profile Key which does not contain single engine performance, the software performs a more conservative 2 Engine Cost Index calculation of the fuel requirement.

FINAL DESCENT TIME/BURN/DISTANCE

If you have selected Fixed final descent, then you will be required to provide values for Time (number of minutes), Burn (fixed burn value) and Distance (still-air, in NM) for the final descent burn, otherwise these fields will be skipped.

• The Final Descent calculation in the ETP Scenario uses the main route profile key, not the profile key in the Cruise section in the ETP Scenario.

• The Profile and AUX allows you to specify a profile in the profile field, and then you can specify the auxiliary profile (speeds) under AUX.

  • For example, Profile: LRC and AUX: 250/280/M70.

HOLD TIME

Enter the hold time in minutes (1 - 99).

HOLD METHOD

Enter the method for determining hold fuel burn; <C> for Calculate (using Hold performance data tables), <T> for Top of descent (using the fuel flow at top of descent), or <F> for Fixed (use values defined in next field).

Note: If there is no TOD fuel flow (e.g. in the case where driftdown distance is greater than distance from ETP to ETP alternate), the flow is the cruise burn rate at 225 knots using the driftdown altitude/weight/ISA.

FL

Enter the flight level to be used for hold calculations. The range is FL010 to FL250.

HOLD BURN

If you selected Fixed hold burn, enter the desired amount in this field.

APU BURN / Method

Enter method for determining APU burn. Options are:<C> for Calculate or <F> for Fixed. Optionally, this field may be left blank. 

• If you select the <C>, the program will use the APU burn rate defined in the Aircraft Characteristics file, multiplied by the total diversion time from ETP to ETP alternate.

APU TIME/BURN 

If you chose Fixed for APU burn, enter the desired values for Time and Burn here.

Note: The Time entry has no impact on fuel calculations. It is available only to permit a time figure to be printed on the flight plan, if desired.

MISSED APPROACH TIME/BURN/DISTANCE

This field is optional. If desired, enter the Time, Burn, and Distance in the appropriate fields.

Note: The Time entry has no impact on fuel calculations. It is available only to permit a time figure to be printed on the flight plan, if desired.

PENALTIES APPLY TO

This section permits you to define additional fuel penalties to be applied to the ETP calculations, typically for ETOPS purposes. For each category there are three entry fields:

1. The first accepts a numeric value, 

2. The second defines whether this entry is a percentage, or a fixed value, and

3. The third field specifies what the percentage amounts are to be based on (Cruise only, Hold only, or Total diversion time).

• Additional penalties include:

  • Airframe ice accretion

    • Enter whether you want to only apply the icing penalty on 10% of the route time. (REDUCE ICE TIME:) Options are: <Y> for yes or <N> for no.

  • Engine anti-icing

    • Ice Reduction Coeff Percentage %, also known as “Ice Penalty Percentage” in Web FOMS. Reduce icing penalty by only applying icing penalty on this percentage of route time.           

  • Wind uncertainty

• Adds a bias to the burn for the period specified in the penalty to deal with wind being stronger or weaker than forecasted.  Increases are made to the Cruise Burn, Hold or Total, by the Percentage, Fixed amount, or Rate entered.

• Wind Speed Adjustment

  • Increases the wind speed by the percentage entered, then this new wind speed is used to calculate the fuel burn. Essentially, it is a percentage modification to wind value which in turn, affects the route time and burn.

  • Note: the value impacts the performance look-ups for ETP diversions, but not the fuel directly. Rather, the value impacts ground speed, which then affects the time, and subsequently the fuel burn.

• Burn uncertainty

• 180 minute ETOPS

• Other

• Ice penalty percentage

  • Set a specific icing penalty reduction in an ETP scenario. 

  • The Ice Penalty Percentage is only applied if Icing Protection is enabled. If it is disabled or set to Ice Protection if forecasted, the ice penalty percentage is not used. 

  • To enable Ice Protection, right click in the Out or In field in the ETP group on the Plan screen, and select Ice Protection Enabled. When enabled the field turns blue.

Example for Ice Reduction Coeff Percentage.

EXTENDED RANGE ENTRY POINT RADIUS

Enter the distance to be used in determining the point along the route where the aircraft will enter the zone of Extended Range operations.

REMARKS

Enter any remarks associated with this particular scenario.