Harris Corporation developed a Wireless Engine Monitoring System (WEMS) module that monitors aircraft engines in real-time without resorting to a larger ground data link unit that interfaces with many aircraft systems. The WEMS module is disclosed in commonly assigned U.S. Pat. Nos. 6,943,699; 7,456,756; 7,595,739; 7,755,512; and 9,026,336; the disclosures which are hereby incorporated by reference in their entirety. In one example, the WEMS module transmits its engine data to a Cabin Wireless LAN Unit (CWLU) for further processing at the flight deck or for transmission via a satellite to a ground based engine service provider.
The WEMS module is interfaced in one example to the Full Authority Digital Engine Controller (FADEC)/Engine Control Unit (ECU) and mounted on the engine, and can record, store, encrypt and transmit “full flight” engine data by recording hundreds of engine parameters, for example, with a one second or less sampling frequency. It has a preferred conformal antenna and RF transceiver to download (and upload) data using RF/802.11/cellular techniques, including other spread spectrum techniques as non-limiting examples.
This collection and storage of “full flight” engine data using the WEMS module allows advanced prognostics and diagnostics on the engine and increases engine “time-on-wing” (TOW) and decreases engine maintenance cost per hour (MCPH). The WEMS data is downloaded in one example using a RF/(802.11) spread spectrum/cellular signal to an airport server for processing and/or transported over the internet, PSTN, cellular or other communications network to another workstation for post flight analysis. Data can also be uploaded to the WEMS module, including algorithms for on-board processing. The WEMS module provides an automated wireless solution installed directly on the engine, recording full flight engine data for both large and small turbine engines in large megabyte files and using a high speed data link to extract.
Recently, the Federal Aviation Administration (FAA) has been working with airlines to identify pollutants emitted from aircraft engines and study their impact on the environment and climate change. Aircraft engines emit carbon dioxide (CO2), water vapor (H2O), oxides of nitrogen such as nitrogen oxide or dioxide, oxides of sulfur, carbon monoxide (CO), partially combusted or unburned hydrocarbons (HC), particulate matter (PM), and other compounds and pollutants. Many of these compounds and pollutants are emitted by aircraft close to the surface of the earth, for example, less than 3,000 feet above ground level. Excessive carbon monoxide and some hydrocarbons are produced when the aircraft engines are operating at their lowest combustion efficiency, for example, while wheels are on the ground at initial take-off or landing. The greater quantities of aircraft engine emissions and pollutants are emitted at the airport or just after or before landing at the airport. For this reason, many civil aviation authorities require monitoring of these aircraft engine emissions. Some countries have even suggested that fines be imposed on aircraft companies that emit pollutants that exceed a threshold when the aircraft is in their area.
Related to these issues of reducing aircraft emissions are the safety-related applications of the numerous sensors contained within the aircraft and ensuring redundant operation in cases of emergency. An aircraft has redundant wiring that adds weight to the aircraft, which in turn increases pollutants emitted from the aircraft engine. This also creates a point of failure since there are large numbers of redundant wires. For that reason, new standards have been developed for a Wireless Avionics Intra Communications (WAIC) system to allow wireless radio communication between two or more points on a single aircraft while also communicating with integrated wireless and/or installed components in the aircraft, such as wireless sensors. A WAIC is based on short range radio technology having distances usually less than 100 meters and low transmit power levels of 10 milliwatts for low rate data communications and 50 milliwatts for high rate data applications. WAIC systems provide dissimilar redundancy, fewer wires and reduced connector pin failures. These systems also lower the risk of cracked insulation and broken conductors, and permit mesh networking between gateway network nodes that communicate with wireless sensors, including displays and activators, and provide communication redundancy in emergencies when wired connectors fail. The reduced wiring and resultant reduced aircraft weight also enables less fuel burn, helping to reduce emissions and meet more stringent environmental standards and thresholds required by some jurisdictions. The WAIC systems may also increase reliability by reducing the amount of aged wiring, simplifying and reducing the life-cycle cost of airplane wiring, and obtaining more data from aircraft systems and surfaces with new wireless sensors.