The following provides a real-time monitoring method for the B737 aircraft angle of attack detector.
The overall architecture of the system based on the above method is mainly divided into three modules: the airborne ACMS monitoring module, the ground engineering monitoring module, and the user terminal. The overall system architecture diagram is asfigure 2 Shown.
1. Airborne ACMS monitoring module
This module is mainly composed of digital flight data interface component DFDAU, aircraft status monitoring system ACMS, printer, control display unit MCDU, communication management component CMU, wireless WQAR and air data sensor. The airborne ACMS monitoring module is mainly responsible for monitoring the health status of the aircraft's angle of attack detectors, collecting atmospheric data and key flight parameters, and triggering AOA messages, and then sending the messages to the aircraft's communication management component CMU, and then connecting them through the ACARS data link The AOA message is sent to the ground. The trigger logic of ACMS has a suppression function based on the event code CODE, ensuring that each sub-monitoring logic of a flight can only trigger a message once. Control the display unit MCDU page to view the left and right AOA, left and right airspeed, left and right altitude parameters.
2. Ground engineering monitoring module
The ground engineering monitoring module is composed of ground message decoder, QAR decoder, database, etc. It mainly decodes the ACARS messages and QAR data transmitted by the data service provider to the airline's ground, and stores them in the database.
Three, user terminal
The user terminal serves the ground crew, receives real-time messages, and provides WEB page query services.
The realization of each module function
1. Airborne ACMS monitoring module
AOA monitoring events
Install the ACMS software with AOA function in the digital flight data interface component DFDAU of the B737 aircraft, and then use the ACMS to collect and calculate the corresponding parameters in real time. When a related fault warning occurs, the corresponding atmospheric data system parameters are collected to trigger the AOA report The text goes down to the ground to help maintenance troubleshooting and fault location. The specific monitoring logic is as follows:
(1) AOA discordance "AOA DISAGREE"
AOA inconsistency "AOA DISAGREE" mainly monitors when the angle of attack detector AOA on one side has measurement accuracy and reading error, the cockpit effect FDE appears AOA inconsistency "AOA DISAGREE" warning, through the ACMS software monitoring logic: |AOA1 -AOA2|>10. Continue for 10 seconds, then obtain atmospheric data and key flight parameters, generate AOA messages and event code 1001, and determine the faults of the left and right AOA. Prompt the ground maintenance fault location. See the AOA monitoring event table for details.
If the cockpit does not have optional "AOA DISAGREE" warning, the instrument display system will not show "AOADISAGREE" warning. When an AOA sensor on one side has an error, the auxiliary monitoring "AOA DISAGREE" warning can be performed.
(2) Inconsistent airspeed "CAS DISAGREE"
The airspeed is inconsistent "CAS DISAGREE". The main monitoring is that when one side of the airspeed has measurement accuracy, reading errors or AOA failures leading to correction errors, the cockpit effect FDE appears airspeed inconsistent "CAS DISAGREE" warning, through the ACMS software monitoring logic: |CAS1-CAS2|>5. It lasts for 5 seconds, then obtains atmospheric data and key flight parameters, generates AOA messages and event code 1002, and judges the failure of the atmospheric data source. Prompt the ground maintenance fault location. See the AOA monitoring event table for details.
(3) Height inconsistency "ALT DISAGREE"
Height inconsistency "ALT DISAGREE". The main monitoring is that when one side of the altitude has measurement accuracy, reading errors or AOA failures that lead to correction errors, the cockpit effect FDE appears altitude inconsistency "ALT DISAGREE" warning, through the ACMS software monitoring logic: |ALT1-ALT2|>200, lasts 5 seconds, then obtains atmospheric data and key flight parameters, generates AOA messages and event code 1003, and judges the failure of the atmospheric data source. Prompt the ground maintenance fault location. See the AOA monitoring event table for details.
(4) AOA signal failure "AOA SIGNAL FAIL"
AOA signal failure "AOA SIGNAL FAIL". It mainly monitors AOA signal failures, and monitors logic through ACMS software: AOAF parameters are true, and then atmospheric data and key flight parameters are obtained, and AOA messages and event code 1004 are generated. Since it is impossible to distinguish between left and right AOA signal failures, it can only assist AOA inconsistency "AOA" DISAGREE" warning). See the AOA monitoring event table for details.
(5) "STICK SHAKER" stall stick
The stall stick "STICK SHAKER". It mainly monitors the left and right stall shaker, and monitors the logic through the ACMS software: the left or right stall parameter is true, then the atmospheric data and key flight parameters are obtained, and the AOA message and event code 1005 are generated to judge the failure of the atmospheric data source. Prompt the ground maintenance fault location. See the AOA monitoring event table for details.
Table 1 AOA monitoring event table
In this embodiment, the AOA event code Code and each type of logic monitoring form a unified specification, which can facilitate the communication between engineers and the ground frontline maintenance, and also facilitate the ground to quickly find and troubleshoot.
ACMS software detailed design
The detailed design of ACMS software mainly includes AOA trigger logic (also called monitoring logic), AOA message setting, MCDU page setting, etc.
(1) AOA trigger logic
The trigger logic is the core of the ACMS software. The ACMS software contains a lot of trigger logic. The trigger logic events involved in this patent are listed in Table 1 AOA monitoring events. The trigger logic is detailed asimage 3 The main logic diagram of AOA monitoring inFigure 4 AOA inconsistency monitoring subroutine inFigure 5 In the airspeed inconsistency monitoring subroutine,Figure 6 Subroutines for monitoring height inconsistency inFigure 7 AOA signal fault monitoring subroutine inFigure 8 The stall monitoring subroutine in.
The AOA monitoring logic of the onboard ACMS software, each event code CODE can set trigger suppression conditions. Each event corresponds to a code CODE, which indicates a situation. Each CODE is set with a flag. The initial value of the flag is 0 by default, which means that it is not suppressed. The user can set it to 1 on the MCDU page, which means that the event is suppressed. Before the execution of the monitoring logic, first judge the suppression condition. If it is 0 and do not suppress, then execute the judgment of the monitoring logic. If the trigger condition is met, trigger the message corresponding to the event code, and modify the suppression flag corresponding to the CODE to 1. , To ensure that each CODE is triggered only once for each flight. This saves the traffic cost of ACARS messages and can quickly distinguish the first occurrence time of each CODE.
(2) AOA message settings
ACMS messages are generally generated by trigger logic. The present invention designs AOA ALERT message. It contains key flight parameters such as atmospheric data and flight control. AOA message includes two formats: print format and ACARS format. The ACARS format is downloaded to the ground, and the ground is decoded according to ARINC specifications. The print format is used for ground maintenance viewing or printing and viewing through the MCDU page. The following figure is a sample of AOA message printing format.
Table 2 shows the atmospheric data and key flight parameters collected by the AOA message of the present invention.
Table 2 Atmospheric data and key flight parameters
(3) MCDU page settings
Atmospheric data parameters such as AOA, airspeed and altitude can be viewed on the MCDU page to facilitate the determination of the left and right fault source parameter values.
MCDU page setting mainly includes the following two steps, asPicture 10 with11Shown.
First, add a CSN AOA REPORT routing page on the OPERATOR APPLICATION page in MCDU, see for detailsPicture 10 CSN AOA REPORT routing page.
Then, the AOA, airspeed, altitude and other parameters are displayed on the CSN AOA REPORT page, and the generated AOA message can be printed. See detailsPicture 11 AOA parameter page.
2. Ground engineering monitoring module
The ground engineering monitoring module is mainly responsible for the ACMS message decoding and message push of AOA monitoring, QAR decoding monitoring, etc.
(1) ACMS message decoding
The message decoder is responsible for the decoding of AOA messages. The specific operations are as follows:
1) The message decoder scans the AOA message pool regularly to obtain the file list, and then pre-parses the ARINC620 header fields of the AOA message according to the ARINC620 specification one by one.
2) Then judge the body part of the AOA message. If the message SMI=DFD and the beginning of the message content="AOA", it means that this is an AOA message required for monitoring, and then decode the message. If not, proceed to the next message decoding.
3) After the decoding is completed, the AOA message is stored in the database, and then it is judged whether the message is subscribed. The subscription rule is to subscribe to the message according to the event code CODE. If there is a news subscription, send a news email.
4) After completing steps 2)-3), proceed to the next message decoding.
(2) QAR decoding monitoring
QAR decoding monitoring is mainly to decode QAR data, extract left and right AOA parameters, and then calculate the rolling average difference. The specific operations are as follows, seePicture 12QAR data decoding flow chart.
1) The QAR decoding monitoring main program scans the QAR data pool regularly to obtain the file list, and then determines whether the parsed file name contains the aircraft number required for monitoring, otherwise skip it.
2) Then analyze the data frame according to ARINC717 rules, and then extract the AOA1 and AOA2 parameters of each data frame.
3) Then perform average rolling processing on the AOA1/AOA2 parameters, and make a rolling average every 30 seconds. Then get AOA1' and AOA2'.
4) Then calculate the absolute difference △, the formula is: △=ABS(AOA1'-AOA2'). If the difference is 0, discard it and return.
5) If the difference △ is greater than 5, set the warning attribute.
6) Finally, save the database and return to the timing scan until all the QAR data is solved.
Aiming at the operational risks that may be caused by the AOA failure and airspeed failure of the B737 aircraft, the present invention provides a universal method for real-time monitoring of the B737 aircraft angle of attack detector. In the airborne ACMS system, by adding monitoring logic for autonomous monitoring of aircraft left and right AOA inconsistency, left and right airspeed inconsistency, left and right altitude inconsistency, AOA signal failure, stall and other events, the message format containing atmospheric data and key flight parameters is customized. When related fault warnings occur, collect key system parameters, trigger downlink ACARS message information to the ground and display key parameter information through MCDU, so as to facilitate maintenance and crew troubleshooting. In the ground engineering system, the left and right AOA parameters in the QAR data are also decoded to monitor the inconsistent performance degradation trend of AOA, so as to monitor the performance trend. In this way, the real-time health monitoring of the angle of attack detector integrated with the aircraft, air and ground is realized to ensure flight safety.
Please refer to Table 3 for abbreviations and key terms in the text.
Table 3 Abbreviations and key term definitions