HB 8704-2023 in English
VALIDMethod of measuring the electromagnetic interference path loss of portableeleetronic devices on civil aireraft
- Issued on:2023-12-29
- Implemented on:2024-07-01
- File Format:PDF
- Delivery:Via email within 5 business days
$350.00
| Standard No: | HB 8704-2023 |
| Document status: | VALID |
| Title in English: | Method of measuring the electromagnetic interference path loss of portableeleetronic devices on civil aireraft |
| Title in Chinese: | 民用飞机便携式电子设备的电磁干扰路径损耗测试方法 |
| Language: | English |
| File Format: | Electronic (PDF) |
| Delivery: | Via email within 5 business days |
| Issued on: | 2023-12-29 |
| Implemented on: | 2024-07-01 |
| Professional Classification: | HB-Aviation |
| Related Keywords: | electromagnetic interference path loss
electromagnetic interference path loss testing electromagnetic interference test method portable electronic devices |
| Related Topics: | electron path
four-electron path Electrostatic interference of electronic equipment |
本文件规定了民用飞机便携式电子设备的电磁干扰路径损耗测试的试验一般要求、试验方法、测试数据处理以及试验结果的分析与评定。
本文件适用于正常类/运输类航空器便携式电子设备的电磁干扰路径损耗测试试验。
Introduction
Standard Overview and Technical Background
HB 8704-2023, "Test Method for Electromagnetic Interference Path Loss of Portable Electronic Devices in Civil Aircraft," is an important standard document for electromagnetic compatibility testing of civil aircraft in China's aviation industry. Released in 2023, this standard was jointly drafted by the Shanghai Aircraft Design and Research Institute of Commercial Aircraft Corporation of China, Ltd. (COMAC) and other organizations, aiming to standardize the test method for electromagnetic interference path loss of portable electronic devices (PEDs) in civil aircraft.
With the rapid development of avionics, the number of portable electronic devices carried by passengers has increased dramatically, and these devices may cause electromagnetic interference to aircraft navigation and communication systems. Interference path loss (IPL), as a key parameter for measuring the aircraft structure's ability to protect against electromagnetic interference, is crucial for ensuring flight safety. This standard is based on the compliance requirements of Clause 1309(a) of CCAR25 "Airworthiness Standards for Transport Category Aircraft," providing a technical basis for aircraft design, manufacturing, and airworthiness certification.
Core Concepts and Terminology Definitions
The standard clarifies two key term definitions, which are crucial for understanding the testing principles:
| Terms | Definitions | Technical Significance |
|---|---|---|
| Front Door Coupling | Electromagnetic energy from portable electronic devices enters the aircraft's external receiving antenna through portholes and openings, resulting in receiver interference | Describes the main propagation path of PED interference and is the focus of testing |
| Interference Path Loss | The amount of energy lost when electromagnetic waves radiated from portable electronic devices inside the aircraft are received by the aircraft's radio receiver | Quantifies the aircraft structure's ability to attenuate electromagnetic interference and is a core indicator for assessing electromagnetic compatibility |
The standard also provides a detailed list of abbreviations, covering Antenna Under Test Handling
Depending on the antenna type, the standard specifies corresponding handling methods:
| Antenna Type | Disconnection Position | Special Requirements |
|---|---|---|
| Passive Antenna | Disconnect the antenna coaxial cable from the receiver under test | Direct Measurement |
| Active Antenna (Discrete Components) | Disconnect the cable from the amplifier signal input terminal | Normal Power supply, amplifier effect deducted during calculation |
| Active Antenna (Integrated Component) | Disconnect coaxial cable at antenna output | Normal power supply, amplifier effect deducted during calculation |
Test Equipment Specification
The standard sets forth specific technical requirements for test equipment: The signal transmitting antenna should be a low-gain, omnidirectional broadband antenna with a gain between -1dBi and 4dBi, and the free-space voltage standing wave ratio (VSWR) should not exceed 2:1. The signal generator should have the ability to continuously transmit sufficiently high power, and the signal receiver should have sufficient dynamic range and sensitivity, with a received signal-to-noise ratio not less than 10dB.
Test Method Technical Points
General Principles
The test process refers to the relevant content of GJB8820, and is required to be able to detect the worst-case IPL of the aircraft.
Test Method Technical PointsGeneral Principles
The test process refers to the relevant content of GJB8820, and is required to be able to detect the worst-case IPL of the aircraft. The polarization direction of the signal transmitting antenna should cover at least two mutually perpendicular polarization modes, generally a horizontal direction parallel to the aircraft opening plane, and a vertical direction. The test equipment should remain in a consistent state during the measurement process, and coaxial cables, etc., must be secured.
Test Setup Specifications
The standard specifies the test setup requirements for different areas in detail:
| Test Area | Antenna Position Requirements | Spacing Specifications |
|---|---|---|
| Door Area | 75cm from the center of the door, height same as the center of the door | Horizontal spacing every 50cm to both sides of the cargo door |
| Passenger Cabin Area | Height same as the center of the passenger window, placed on the center line of the passenger aisle | Arranged at 50cm intervals, covering a 50cm range in front and behind the passenger cabin |
| Cockpit Area | Height same as the center of the main windshield | Covering directly above the central control panel and at 50cm intervals towards the passenger cabin |
Test Procedure Flow
Interference path loss testing includes two parts: baseline measurement and on-board measurement.
The baseline measurement involves measuring the coaxial cable in the test system to eliminate the influence of losses from non-aircraft structures and components in the signal transmission path. After completing the baseline measurement, IPL on-board measurements are performed using the signal transmitting antenna and the airborne receiver antenna. The transmit power of the signal generator and the resolution bandwidth (RBW) settings of the receiver can be adjusted as needed, but the RBW should remain consistent throughout the test in the same frequency band. The standard specifically emphasizes that if the maximum received signal value increases by 3dB when the signal generator's transmit power, it indicates that the signal receiver is operating in the linear region. Test Data Processing Methods When the antenna under test is a passive antenna, the IPL is calculated using the formula: IPLTest = PTT - PMT - (PTC - PMC), where each parameter represents the output power of the signal generator and the received signal power in the IPL measurement test and baseline measurement, respectively.Active Antenna Data Processing
When the antenna under test is an active antenna, the effect of the built-in amplifier gain should be considered: IPLTest = PTT - PMT - (PTC - PMC) + GAA, where GAA is the amplifier gain of the active antenna.
Data Processing with Amplifiers/Attenuators
When using amplifiers and/or attenuators, these devices should be included in the reference measurement or processed according to the formula: IPLCal = IPLTest + GAmp - ILAtt, where GAmp is the amplifier gain and ILAtt is the insertion loss of the attenuator.
Data Processing with Amplifiers/Attenuators
Test Result Analysis and Evaluation Standards
When the calculated IPL of the airborne antenna in all areas of the aircraft is greater than the target IPL value, it can be used to indicate that the tested aircraft's protection capability against the front door coupling effect of PED meets the standard requirements. The standard establishes differentiated IPL target values based on aircraft passenger capacity:
| Receiver Type | Operating Frequency (MHz) | Less than 10 passengers | 10-19 passengers | More than 19 passengers |
|---|---|---|---|---|
| ILS Localizer (Cat I) | 108-112 | 24 dB | 26 dB | 34 dB |
| VOR | 108-118 | 20 dB | 22 dB | 30 dB |
| VHF voice communication | 118-137 | 24 dB | 23 dB | 34 dB |
| TCAS receiver | 1090 | 37 dB | 33 dB | 38 dB |
| GNSS L1 | 1559-1610 | 40 dB | 39 dB | 43 The standard also specifies the selection principles for IPL target values in different areas: for aircraft carrying more than 19 passengers, the IPL target value for the passenger cabin should be consistent with the corresponding value in the table; the IPL target values for the cockpit and cargo hold can be the corresponding values for aircraft carrying 10-19 passengers. The standard also specifies the selection principles for IPL target values in different areas: for aircraft carrying more than 19 passengers, the IPL target value for the passenger cabin should be consistent with the corresponding value in the table; for aircraft carrying 10-19 passengers, the IPL target value can be taken from the corresponding value in the cockpit and cargo hold. The standard also specifies the selection principles for IPL target values in different areas ... When the test is interrupted, the status of all equipment in the test system and the aircraft should be recorded in detail to facilitate the resumption of the test. Data Processing StageDuring data processing, an appropriate calculation formula should be selected according to the antenna type, paying particular attention to the processing of the gain of active antenna amplifiers. For cases using amplifiers or attenuators, these devices should be included in the reference measurement or corrected according to the standard formula. Result Evaluation StageDuring result evaluation, the correct IPL target value should be selected according to the aircraft passenger capacity and test area. The test report should clearly determine whether the aircraft's airborne antenna meets the standard requirements, and clearly explain and analyze any deviations from the test outline and other contents that may affect the validity of the test. Technological Evolution and Development TrendsThe release of HB 8704-2023 marks a new stage in the standardization of electromagnetic compatibility testing for civil aircraft in my country. With the popularization of 5G communication technology and the emergence of new portable electronic devices, the electromagnetic environment of aircraft is becoming increasingly complex. Future standards may further expand the test frequency bands, increase coverage of new equipment types, and introduce more advanced test methods and evaluation technologies. International standards such as RTCA DO-160 and EUROCAE ED-14 are also constantly being updated. my country's aviation industry should closely monitor international development trends and revise and improve relevant standards in a timely manner to ensure that my country's civil aircraft electromagnetic compatibility testing technology keeps pace with international advanced levels. Typical Application Case Analysis During the development of a certain type of civil passenger aircraft, comprehensive PED electromagnetic interference path loss testing was conducted according to the HB 8704-2023 standard. The test covered multiple areas including the passenger cabin, cockpit, and cargo hold, and detailed evaluations were performed on key navigation and communication systems such as VOR, ILS, and TCAS. The test results showed that the IPL values in most areas met the standard requirements, but in some locations at the rear of the cabin, the IPL values of the GNSS L1 system approached the target limit. By optimizing the structural design and cable routing in this area, the IPL values at all test points ultimately met the standard requirements, providing strong support for the aircraft's airworthiness certification.
Sample only — not a preview of HB 8704-2023
 Loading PDF document... Error loading PDF. Please make sure the file is valid and try again. We also recommend
All Rights Reserved © 2026 WWW.CHINASTANDARDS.NET
|
