Design requirements represent the low-level implementation specifications that fulfill system and subsystem requirements in the aerospace safety domain.
Design requirements bridge the gap between what the system must do (system requirements) and how individual components achieve those behaviors. In aerospace development, they are subject to strict traceability rules under DO-178C (software), DO-254 (hardware), and ARP 4754A (system development assurance).Each design requirement is classified for safety criticality (SC/CC) and linked to DO-160G environmental categories when environmental qualification is required. The classification flows down from parent system requirements and determines verification strategy, evidence requirements, and certification scope.
This reference covers the core desReq type structure and custom fields as defined in the Aerospace Safety Solution RTM model. Implementation-level details should be verified in your Polarion project configuration.
Safety classification flows from parent system requirement. All desReq under an SC sysReq should be SC; under a CC sysReq, should be CC.
The Classification Consistency Report verifies this alignment. SC requirements receive higher scrutiny in design reviews, testing, and configuration management.
Filters design requirements by engineering discipline for DO-178C (Software) vs DO-254 (Hardware) compliance paths.
Subtype enables traceability segregation: Software design requirements are verified through code inspection, unit testing, and integration testing per DO-178C; Hardware design requirements use design analysis, inspection, and environmental qualification per DO-254.
Links design requirements to DO-160G Environmental Conditions for Test Category. When set, corresponding environmental test cases must be specified.
The DO-160G Environmental Qualification PowerSheet uses this field to expand design requirements into their corresponding environmental specifications (characteristics) and qualification tests.
Indirect relationship: A design requirement linked to a characteristic is implicitly assessed by failure modes targeting that characteristic in the component DFMEA.
When a design requirements document is linked to a specific system element (subsystem or component), the requirement picker applies a context-aware constraint:
Allowed Parent: Only system/subsystem requirements for the current subsystem context
Purpose: Prevents accidental linking to requirements from other subsystems
Implementation: Picker configuration uses applyCurrentDocumentTo with the systemElementId field
Example: The SUBRS-SUB-001 (Sensor Interface Subsystem) requirements document can only refine requirements allocated to the Sensor Interface Module system element — not requirements for Processing Core or Actuator Bus modules.
Design requirements that specify environmental operating conditions must link to corresponding environmental test categories and verification tests.The DO-160G Environmental Qualification PowerSheet automates this expansion: start with design requirements, expand to characteristics, then expand to test cases — all filtered by environmental category.
Maps each design requirement to its verification test(s). Enables test case creation directly in the Testing/DesignReqsVerification module.Column Groups:
Every design requirement must have at least one linked test case. The Test Coverage Report tracks verification percentage by subsystem:Coverage below 90% triggers a design review gate.
The Power Supply Unit (PSU) component illustrates typical design requirement decomposition:Parent System Requirement (SYS-045):
“The flight control computer electrical power subsystem shall provide regulated power to all components and shall maintain system operability during all flight phases.”
Refining Design Requirements (DRS-CMP-006-xxx):
ID
Title
subType
environmentalCategory
Test Cases
DRS-CMP-006-001
PSU input voltage regulation shall maintain output within ±5% of nominal
Electrical
sec17 (Power)
TC-006-001, TC-006-002
DRS-CMP-006-002
PSU shall survive -40°C to +85°C ambient without performance degradation
Electrical
sec4 (Temperature)
TC-006-003, TC-006-004
DRS-CMP-006-003
PSU shall reject conducted noise per MIL-STD-461 CE101
Electrical
sec19 (Conducted Susc.)
TC-006-005
DRS-CMP-006-004
Power supply connectors shall be captive and keyed to prevent reversal
Mechanical
—
TC-006-006 (Inspection)
DRS-CMP-006-005
PSU case shall be labeled with voltage, current, and safety warnings
Labeling
—
TC-006-007 (Inspection)
Each design requirement specifies an implementation detail, links to a verification test, and (where applicable) references an environmental category for qualification scope.
The environmental categories, test standards, and field constraints listed above should be verified against your specific Aerospace Safety Solution configuration, as subType values and environmental test mappings may be customized per project.
