Editing aircraft specific schedule information

This page enables you to edit the schedules defined for a specific aircraft maintenance program. Tell me more.

Select the “Edit Schedule Information” link in the “Edit Aircraft Specific Maintenance Program” page.

The “Edit Aircraft Maint. Schedule Information” page appears.

The system displays the following field:

Date Format

The format in which the date fields are displayed and to be entered, in this page. This format is displayed from the "User Preferences" business component based on the login user ID. In case the format is not defined, the system displays the date format from the "Enterprise Modeling" business component by default.

The system displays the following details in the “Aircraft Details” group box:

Aircraft Reg #	The registration number of the aircraft that is associated to the program.
Aircraft Model #	The aircraft model to which the aircraft belongs.
Sub Fleet #	The sub fleet number to which the aircraft belongs.

The system displays the following fields in the “Maintenance Program Information” group box:

Maintenance Program #	The maintenance program for which the schedule information must be modified.
Revision #	The revision number of the maintenance program.
Program Desc	The description of the maintenance program.
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Status	The status of the maintenance program, which can be “Fresh”, “Active”, “Inactive” or “Return”.

Enter the following field in the “Work Unit Details” group box:

Work Unit #

Use the drop-down list box to select the work unit for which the schedule information must be modified. The system lists all the work units specified for the maintenance program along with the sequence numbers.

Click the “Get Details” pushbutton.

The system displays the following details:

Work Unit Desc	The description of the work unit.
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Work Unit Type	The type of the work unit, which can be “Task”, “Standard Procedure”, “Aircraft Work Package” or “Component work Package”.
Execution Type	The execution type of the work unit, which can be “Major” or “Minor”.
Job Type	Indicates whether the work unit must be performed on the aircraft or on the components fitted to the aircraft. The system displays either “Aircraft” or “Onwing”.

Enter the following fields in the “Schedule Details” group box:

Schedule Type

Use the drop-down list box to specify whether the work unit must be executed only once or repeated at certain intervals. The system provides the following options:

One Time – Select this option if the work unit must be executed only once.
Recurring – Select this option if the work unit must be repeated at certain defined intervals.

Update Basis

Use the drop-down list box to select the mode by which the due dates for executing the work units must be calculated. The system provides the following options:

Schedule – Select this option if the next due dates for carrying out the work units must be calculated based on a fixed interval.
Actual Completion – Select this option if the next due dates for carrying out the work units must be calculated based on its previous completion.

Example

Assume that the scheduled start date for a work unit is 11-10-2003. However, the work unit was deferred for 10 days and the execution for the work unit was started on 21-10-2003 and completed on the same date.

If the Updation Basis is Schedule, the next schedule date of the work unit is calculated by adding the interval period to 11-10-2003.
If the Updation Basis is Actual Completion, the next schedule date of the work unit is calculated by adding the interval period to 21-10-2003.

Enter the following fields in the “Date Based Schedule Details” group box:

Time Unit	Use the drop-down list box to specify the time unit for the date based schedule. The system lists the options "Days", "Months", "Month End" and "Years" and sets the field to "Days" by default.
Threshold Interval	The period from the induction date or the operational date, from which the due dates for the work units must be calculated (Decimal). Data entry in this field is mandatory if you are specifying date-based schedules and if the “Schedule Type” field is set to “One Time”.

Alert Interval	The period at which an alert message must be displayed about an impending due date for performing the work unit (Decimal). Ensure that you enter a non-negative value in this field. Also, ensure that the value entered in this field is greater than the sum of the “Threshold Interval” and “Positive Tolerance”.
Repeat Fixed Interval	The interval after which the work unit must be repeated irrespective of whether its previous execution is completed or not (Decimal). Ensure the following: Specify the interval period only when the “Schedule Type” field has been set to “Recurring”. Enter a positive value in this field. The interval must be greater than the “Positive Tolerance” and the “Negative Tolerance”.
Repeat Floating Interval	The interval after which the work unit must be repeated, from the period of its last execution and completion (Decimal). Ensure the following: Specify the interval period only when the “Schedule Type” field has been set to “Recurring”. Enter a positive value in this field. The interval must be greater than the “Positive Tolerance” and the “Negative Tolerance”.
Note: For a recurring task with date-based schedule, it is mandatory to specify either Repeat Fixed Interval or Repeat Floating Interval. Note: For a ‘Recurring’ task with both date-based and usage-based schedules, it is mandatory to specify one of the following: a) Repeat Fixed Interval/Repeat Floating Interval for the date-based schedule, or b) Repeat Fixed Interval/Repeat Floating Interval for one or more parameter.
Positive Tolerance	The upper limit of the parameter value greater than the next schedule value, within which the work unit must be performed (Decimal). Ensure that you enter a positive value in this field.
Negative Tolerance	The lower limit of the parameter value lesser than the next schedule value, within which the work unit could be performed (Decimal). Ensure that you enter a positive value in this field.

Terminating Interval

The period, reaching which the work on the work unit must be terminated (Decimal). Ensure that you enter this field only when the “Schedule Type” field has been set to “Recurring”. Also, ensure that you enter a positive value in this field.

Enter the following fields in the “Usage Based Schedule Details” multiline:

Parameter	The parameter based on which the work unit must be performed (Alphanumeric, 30). Ensure that the parameter is defined in the “Create Parameter” activity of the “Aircraft” business component and is specified for the aircraft. Also, ensure that the parameter is of type “Consumption”.
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UOM	The unit of measurement of the parameter (Alphanumeric, 10).
Threshold Value	The parameter value at which the first execution of the work unit is due (Decimal). Data entry in this field is mandatory if you are specifying usage-based schedules and if the “Schedule Type” field is set to “One Time”. Ensure that you enter a positive value in this field. If only one parameter is defined for a recurring task, the Threshold Value is mandatory for the lone parameter. However, if more than one parameter is available for the task, you must specify the Threshold Value for at least one of the parameters.
Repeat Fixed Interval	The interval after which the work unit must be repeated irrespective of the completion of its last execution (Decimal). Ensure the following: Specify the interval period only when the “Schedule Type” field has been set to “Recurring”. Enter a positive value in this field. The value is greater than the value entered in the “Positive Tolerance” and “Negative Tolerance” fields.

Note: For example, if the repeat fixed interval is 100 flight hours, the work unit would be repeated after the expiry of 100 flight hours of the aircraft, irrespective of whether the previous execution of the work unit was completed or not.

Repeat Floating Interval

The interval after which the execution of the work unit must be repeated, from the period when it was last executed (Decimal). Ensure the following:

Specify the interval period only when the “Schedule Type” field has been set to “Recurring”.
Enter a positive value in this field.
The value is greater than the value entered in the “Positive Tolerance” and “Negative Tolerance” fields.

Note: You must specify Threshold Interval, Repeat Fixed Interval or Repeat Floating Interval for a parameter of a usage-based task.

Note: For a ‘Recurring’ task with both date-based and usage-based schedules, it is mandatory to specify one of the following: a) Repeat Fixed Interval/Repeat Floating Interval for the date-based schedule, or b) Repeat Fixed Interval/Repeat Floating Interval for one or more parameter.

Alert Interval	The parameter value at which an alert message would be displayed about an impending work due on the work unit (Decimal). Ensure that you enter a positive value in this field.
Positive Tolerance	The starting range of parameter value by which the work on the work unit must be started (Decimal). Ensure that you enter a positive in this field.
Negative Tolerance	The ending range of the parameter value by which the work unit must be started (Decimal). Ensure that you enter a positive value in this field.
Terminating Value	The parameter value, reaching which the work on the work unit must be terminated (Decimal). Ensure that you enter a positive value in this field.

The system displays the following field on clicking the “Edit Schedules” pushbutton.

Parameter Description

The description of the parameter.

Click the “Edit Schedules” pushbutton.

If the Eng. doc reference # exists for the task, the system allows you to modify the following Eng. Doc. schedule details in the Maintenance Program, only if the process parameter “Allow modification of Eng. Doc. task in Maintenance Program” is set as “Allowed” in the “Define Process Entities” activity of the “Common Master” business component.

Schedule Type
Update Basis
Date Based Schedule details
Usage Based Schedule details

The system performs the following:

Computes the Next Scheduled Date (NSD) in the following way, for tasks with calendar-based schedule:

NSD = Threshold Value + Reference Date (Induction date or Operational date)

If the Last Performed Date of the work unit is available,

NSD = Last Performed Date + Repeat Fixed Interval/Repeat Floating Interval.

Computes the Next Scheduled Value (NSV) in the following way, for tasks with usage-based schedule:

If the Last Performed Value of the work unit is not available,

NSV = Threshold Value (if the Threshold Value is greater than the current value of the parameter)

If the Last Performed Value of the work unit is available,

NSV = Last Performed Value + Repeat Fixed Interval / Repeat Floating Interval.

However, if the Threshold Value is available for one or more parameters and if the Repeat Fixed Interval/Repeat Floating Interval is available for more than one parameter, the system computes the NSV as illustrated by an example.

Usage-based schedule values as on 20^th July, 2009

Parameter	Threshold Value	Repeat Fixed Interval/Repeat Floating Interval	NSV
FH	100	NULL	100
FC	NULL	50	NULL
EH	NULL	250	NULL
APUH	NULL	250	NULL

Let us assume the FH parameter reached 100 on 22nd July, 2009 and the task was compiled on the same day in accordance with the schedule in the maintenance program. The values of other parameters as on the task compliance date are used to update the schedules as follows:

Parameter	Last Performed Value	Threshold Value	Repeat Fixed Interval/Repeat Floating Interval	NSV
FH	100	100	NULL	NULL
FC	20	NULL	50	70
EH	95	NULL	250	345
APUH	55	NULL	250	305

Computes the NSD and NSV in the following way, for tasks with both calendar-based and usage-based schedules, on the basis of the attributes available including Last Performed Date, Last Performed Value and Repeat Fixed Interval/Repeat Floating Interval. More details

Scenario 1: Calendar-based schedule: Threshold Value available, Repeat Fixed Interval/Repeat Floating Interval not available. Usage-based schedule: Threshold Value not available, Repeat Fixed Interval/Repeat Floating Interval available.

Date-based schedule values as on 20^th July, 2009

Threshold Value

Repeat Fixed Interval/Repeat Floating Interval

NSD

3 Days

NULL

23^rd July, 2009

Usage-based schedule values as on 20th July, 2009

Parameter	Threshold Value	Repeat Fixed Interval/Repeat Floating Interval	NSV
FH	NULL	225	NULL
FC	NULL	50	NULL
EH	NULL	250	NULL
APUH	NULL	250	NULL

Let us assume the task was compiled on 23rd July, 2009, the values recorded for usage-based parameters on the compiled date, and the NSD updated as follows:

Parameter

Threshold Value

Repeat Fixed Interval/Repeat Floating Interval

NSD

3 Days

23^rd July, 200

NULL

The updated attributes of the calendar-based schedule on 23^rd July, 2009would be, as given below.

Parameter	Threshold Value	Las Performed Value	Repeat Fixed Interval/Repeat Floating Interval	NSV (Last Performed Value + Repeat Interval)
FH	NULL	200	225	425
FC	NULL	40	50	90
EH	NULL	225	250	475
APUH	NULL	225	250	475

Scenario 2: Calendar-based schedule: Threshold Value not available, Repeat Fixed Interval/Repeat Floating Interval available. Usage-based schedule: Threshold Value available, Repeat Fixed Interval/Repeat Floating Interval not available.

Date-based schedule values as on 20^th July, 2009

Threshold Value

Repeat Fixed Interval/Repeat Floating Interval

NSD

NULL

3 Months

NULL

Usage-based schedule values as on 20^th July, 2009

Parameter

Threshold Value

Repeat Fixed Interval/Repeat Floating Interval

NSV

200

NULL

200

We assume the FH parameter reached 200 on 22^nd July, 2009 and the task was compiled on the same day in accordance with the pre-defined schedule. The NSD on 22^nd July, 2009 would be as follows:

Threshold Value

Last Performed Date

Repeat Fixed Interval/Repeat Floating Interval

NSD

NULL

22^nd July, 2009

3 Months

22^nd October, 2009

The attribute values on 22^nd July, 2009 for the usage-based schedule were as follows,

Parameter

Threshold Value

Last Performed Value

Repeat Fixed Interval/Repeat Floating Interval

NSV

200

NULL

If the schedule type of the work unit is “Recurring”, the system calculates the Next Schedule Date for the work unit as follows:

a) If the Last Performed Date of the work unit is not available,

Next Schedule Date = Threshold Value + Reference Date corresponding to the aircraft registration number.

b) If the Last Performed Date of the work unit is available,

Next Schedule Date = Last Performed Date + Repeat Fixed Interval + Repeat Floating Interval.

Note: If the time unit for date-based calculation is set as “Years” or “Months”, the system converts it into “Days” for calculation.

If the time unit is “Month End”, the system considers the last performed date as the last day of that month. For example, if the actual last performed date is 6th April 2004 and if the time unit is set as “Month End”, the system considers 30th April 2004 as the last performed date for calculating the next schedule date.

If the schedule type is “Recurring”, the system calculates the Earliest Schedule Date, Latest Schedule Date and Alert Date for the work unit based on the Next Schedule Date, as follows:

Earliest Schedule Date = Next Schedule Date – Negative Tolerance.

Latest Schedule Date = Next Schedule Date + Positive Tolerance.

Alert Date = Next Schedule Date – Alert Value.

Note: If the time unit for date-based calculation is set as “Years” or “Months”, the system converts it into “Days” for the calculation.

On modification of interval or threshold, Next Schedule Date / Value is not recomputed, if there exist an open escalation for a task.

Computation of NSD / NSV based on ‘Change Type’

If the ‘Change Type’ is set as “Correction”, on modification of interval, NSV needs to be recomputed based on:

- Threshold value or Repeat Interval if task is not complied at least once.
- ‘Update Basis’ (Time Window, Schedule or Actual Completion) set in the last instance of compliance.

If the ‘Change Type’ is set as “Correction”, on modification of interval, NSD needs to be recomputed based on:
1. "Reference Basis" (Induction or Operational date) if task is not complied at least once.
1. ‘Update Basis’ (Time Window, Schedule or Actual Completion) set in the last instance of compliance.
If the ‘Change Type’ is set as “Re-baseline”, on modification of interval:
1. On re-baseline of LPD / LPV, NSD / NSV must be computed based on re-baselined LPD / LPV.
1. On re-baseline of NSD / NSV, NSD / NSV must not be recomputed.

To proceed carry out the following

Select the “Edit Dependent Schedule Information” link at the bottom of the page to define schedules for the dependent work units.
Select the “Edit Schedule Dates & Values for Aircraft” link to view the information on the schedules that are due on the aircraft for the maintenance program.

What you can do in this page

Specify the schedule type for the execution of the work unit

Specify the mode for calculating next due dates for the work units

Specify the schedule type for the execution of the work unit

Set the “Schedule Type” field to “One Time” if the work unit must be performed only once.
Set the “Schedule Type” field to “Recurring” if the work unit must be repeated at certain intervals.

Specify the mode for calculating next due dates for the work units

Set the “Update Basis” field to “Schedule” if the next due dates for carrying out the work units must be calculated based on a fixed interval.
Set the “Update Basis” field to “Actual Completion”, if the next due dates for carrying out the work units must be calculated based on its previous completion.

Editing aircraft specific schedule information– An overview

This page enables you to edit the schedules defined for a specific aircraft maintenance program.

For more details on schedule definitions for a maintenance program, refer the topic, “Editing schedule information for the maintenance program – An overview”.

You can retrieve a specific work unit that must be performed as a part of the program and modify the details of the date based and usage based schedules that are defined for it.