Aircraft Attitude Integrity System Failure Isolation
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Solution Overview
Problem
Aircraft require multiple attitude sources to ensure accurate navigation and prevent misleading information, leading to increased costs and complexity in maintaining redundant systems to avoid flight delays or cancellations.
Innovation Solution
A specialized attitude integrity and display system that reduces the number of primary attitude sources needed by introducing a hybrid reference unit and attitude integrity system, allowing the aircraft to operate with one failed primary ADIRU, using a non-navigation grade attitude source to isolate misleading information and determine failed channels with +/- 5 degrees of pitch and +/- 10 degrees of roll accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple primary attitude sources are required to be operational for aircraft departure, then misleading information can be identified through cross-verification, but the cost of maintaining redundant equipment pools increases significantly
Solution Approach 1:
A non-navigation grade attitude source acts as an intermediary reference system to monitor and compare against primary attitude sources. This intermediary system enables failure detection with fewer primary sources by providing an additional reference point for cross-verification, reducing the need for maintaining large pools of spare primary attitude instrumentation.
Solution Approach 2:
The patent uses a simplified copy of the attitude measurement function through non-navigation grade sensors. This copy provides sufficient data for failure detection purposes without requiring full navigation-grade redundancy, allowing the system to identify misleading information from primary sources while reducing equipment complexity and maintenance costs.
2Reliability
If three attitude sources are required to be operable prior to takeoff, then flight safety is improved through cross-checking, but flight delays or cancellations occur when any source fails
Solution Approach 1:
The non-navigation grade attitude source serves as a mediator that enables safe operation with reduced primary source redundancy. By providing an additional reference for cross-verification, it allows the aircraft to depart with fewer primary attitude sources while maintaining the ability to detect misleading information, thus improving flight operational availability without compromising safety.
3Ease of repair
If spare attitude instrumentation pools are maintained to replace failed devices, then aircraft can return to operational configuration quickly, but the cost of maintaining these pools remains very significant
Solution Approach 1:
The patent employs a simplified attitude measurement copy using non-navigation grade sensors that is sufficient for failure detection. This reduces the complexity and cost of spare equipment pools, as the system can identify failures with fewer redundant primary sources, allowing for more economical spare inventory while maintaining quick replacement capability.
Data Source
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AI summary
Systems and methods for isolating attitude failures are provided. In one embodiment, an attitude integrity and display system comprises a display system comprising a primary system displaying a first attitude solution and a standby system displaying a second attitude solution;an attitude integrity system generating an attitude integrity (AI) solution calculated from measurements from an attitude solution data source, the AI solution comprising an aircraft roll and pitch, the data source providing data independent from any data generated by inertial sensor flight instruments and not displayed on either the primary or the standby systems; and an attitude monitor that compares the first solution against the second solution. When the first solution deviates from the second solution by more than a threshold, the monitor identifies on the display system which of either the first or the second solution is failed based on which has a greater deviation from the AI solution.