Aircraft maintenance systems and methods for ECS fouling predictions

A maintenance system for an environmental conditioning element of an environmental control system (ECS) of an aircraft, comprising:

• a processor;
• and
• memory storing one or more computer programs executable by the processor to implement one or more modules, including
• a data acquisition module configured to receive aircraft data, including an ambient temperature of an aircraft environment and an altitude of the aircraft determined by a flight management system (FMS) and a measured ECS compressor temperature based on measurements from one or more compressor exit temperature sensors, the data acquisition module configured to determine the ambient temperature, the altitude, and the measured ECS compressor temperature from the aircraft data;
• a fouling module configured to
• receive the ambient temperature, the altitude, and the measured ECS compressor temperature from the data acquisition module,
• estimate a baseline ECS compressor temperature based on the ambient temperature and the altitude,
• compare the measured ECS compressor temperature and the baseline ECS compressor temperature and generate residuals of the measured ECS compressor temperature and the baseline ECS compressor temperature based on the comparison,
• filter the residuals with a filter coefficient,
• perform persistency checks on the filtered residuals, and
• generate a fouling condition of the environmental conditioning element based on at least the ambient temperature, the altitude, the measured ECS compressor temperature, the filtered residuals, and the persistency checks, the fouling module generating the fouling condition as a fouling factor representing a numerical value indicating a severity of fouling of the environmental conditioning element of the ECS;
• a reporting module coupled to receive the fouling condition from the fouling module and configured to generate a report for a user that includes the fouling condition;
• and
• a user interface coupled to receive the report generated by the reporting module and comprising a display device that presents the report to the user.

A method of monitoring a heat exchanger of an environmental control system (ECS) of an aircraft, the method comprising the steps of:

• determining, at a flight management system (FMS), an ambient temperature associated with the aircraft;
• determining, at the FMS, an altitude of the aircraft;
• measuring, with one or more compressor exit temperature sensors, an ECS compressor temperature as a measured ECS compressor temperature;
• collecting, with a data acquisition module implemented with a processor executing one or more computer programs stored in memory, the ambient temperature, the altitude, and the measured ECS compressor temperature;
• estimating, with a fouling module implemented with the processor executing the one or more computer programs stored in the memory, a baseline ECS compressor temperature based on the ambient temperature and the altitude;
• comparing, with the fouling module, the measured ECS compressor temperature and the baseline ECS compressor temperature;
• generating, with the fouling module, residuals of the measured ECS compressor temperature and the baseline ECS compressor temperature based on the comparison;
• generating, with the fouling module, a fouling condition of the heat exchanger based on at least the ambient temperature, the altitude, the measured ECS compressor temperature, and the residuals of the measured ECS compressor temperature and the baseline ECS compressor temperature, the fouling condition representing a degree of fouling severity of the environmental conditioning element of the ECS;
• reporting, with a reporting module implemented with the processor executing the one or more computer programs stored in the memory, the fouling condition to the user in a report;
• and displaying, on a display device, the report to a user.