Models overview

A model defines the engineering reference data for an aircraft or piece of equipment. A model contains a collection of build items that include configuration-managed parts, configurations, and configuration rules. The build data interpreter (BDI) service validates changes to a configuration-managed part to ensure that operational changes to the associated aircraft or piece of equipment comply with the model definition.

Build items and parts

A model can represent aircraft or it can represent an equipment subassembly, such as an engine . A build item represents a part or an assembly of parts.

For example, in a model that represents the aircraft, a build item for the engine can contain a parts assembly that makes up the engine. Build items are organized in a hierarchy to represent the physical hierarchy of the aircraft and equipment.

When the aircraft or piece of equipment is operational, any changes to their statuses are validated against the rules that are defined for the associated parts on the model.

Configurations

Each model has a default configuration with a configuration type of variant. You can create configurations at the following levels:
Sibling
A configuration that is at the same level as the selected node.
Child
A configuration that is a level under the selected node.
Model system
A configuration that is at the top-level node of the hierarchy of the model system.

The OMP application creates configurations with a configuration type of OMP. OMP configurations are associated with the operator maintenance program for the model that is approved by your aviation authority. You can view OMP configurations in the Models application, but you cannot change their statuses. You can simultaneously associate an aircraft or piece of equipment with a variant configuration type and an OMP configuration type.

Build positions

A build position indicates the location at which you can install a build item. You can define build positions at a sibling level to a build item or at a child level beneath it. When you specify a build position, you can configure the following features for it:
  • Provide position information to support regulatory compliance.
  • Add formulas for calculated meters that are created in the Meters application.
  • Add consumable parts for the position.
  • Add measurement points for condition monitoring.
  • Associate the position with warranty contracts.
  • Configure information about the access items that must be opened and closed to work on this position.
  • Associate the position with the zone or zones where the build item is located.

You can move the positions of build items in the hierarchy tree. When you move a node, the LCN is recalculated. The logistics support analysis record (LSAR) control number (LCN) indicates where a node is within the build hierarchy. For example, an engine that is attached to the aircraft has an LCN code of L0008, which means that the engine is on the eighth build position under the airframe. The following table describes the moves that you can make when you right-click a node in the hierarchy tree:

Action Description Application action
Move up Move up one position the selected LCN. Subtracts 1 from LCN suffix. All subpositions inherit the move. If an LCN with the new value exists, it is moved down.
Move down Move the selected LCN down one position. Adds 1 to the LCN suffix. All subpositions inherit the move. If an LCN with the new value exists, it is moved up.
Push up Move up one position the selected LCN. Subtracts 1 from LCN suffix. All subpositions inherit the move. If an LCN with the new value exists, it is pushed up.
Push down Move the selected LCN down one position. Adds 1 to the LCN suffix. All subpositions inherit the move. If an LCN with the new value exists, it is pushed down.

Model systems

A model system represents a functional capability of the design of the aircraft. When you define a model system in a model, you create a configuration relationship between the model system and the model. You can view the model systems that are associated with the aircraft by using the functional hierarchy view.

Build positions represent the model systems that are in functional relationships with an aircraft model. For example, an electrical model system can be represented by multiple build positions in an aircraft model.

Associated engineering reference data

When you specify engineering reference data in a number of other applications, you can associate those records with specific build positions. You can view the following associated records for builds position in the Models application:
  • Parts
  • Master task cards
  • Meter records
  • Labels
  • Zones

Configuration rules

Configuration rules define which build positions and parts are valid for a specific model or configuration. In the Models application, to the following data you select which of the primary configuration rules apply:

  • Minimum equipment list (MEL) rules for a model
  • Build positions
  • Parts
  • Labels
  • Master task cards
  • Formulas

Additionally, you can create secondary rules that apply to primary rules to specify the conditions when changes are validated to an aircraft or piece of equipment. You specify secondary rules in the form of Boolean expressions in the Advanced tab of the Models application.

Model revisions

A revision is a snapshot of a model and its configuration rules at a specific time. After you create a revision, you can update the model without affecting the revision. The BDI service monitors revisions that are in the active status, and only active revisions are used to validate the configurations of aircraft or equipment. The status of a revision is set according to the following rules:

  • The revision is set to a status of pending if an active date set for the revision that is in the future.
  • The revision is set to a status of inactive if an inactive date for the revision and the active date is in the past.
  • The revision is set to active when the active date is current.

When you create a revision on the Configurations tab, you can select whether to allow different automatic upgrade options for aircraft or equipment.

Series of related models

You can group related models together into a series and define event groups that affect all models in the series. For example, for a series of related aircraft engines, if a fuel leak occurs in one model in the series, you can check other models for fuel leak.

You can associate a series with models, build positions, and dynamic value list (DVL) values.

Weight and balance

You define the units of measurement that are used to measure the weight and balance of all aircraft that are associated with a model. In the Models application, you define the units of measurement for the following attributes:
  • Weight
  • Arm
  • Moment