DO-160, also known as “Environmental Conditions and Test Procedures for Airborne Equipment,” is a standard used in the aviation industry for testing electronic equipment. It’s primarily used to ensure that avionics systems and components can withstand the demanding conditions they may encounter during operation.
This DO-160 tutorial helps you understand its key elements:
1. Introduction to DO-160
- What is DO-160?
- A standard that specifies environmental test conditions for airborne equipment to ensure reliability under various environmental stresses.
- Defines conditions such as temperature, humidity, vibration, electromagnetic interference, and more.
- Why is it important?
- Ensures that equipment used in aviation performs safely and reliably in different environmental conditions.
2. Structure of DO-160
DO-160 is divided into several sections. Here’s an in-depth look at each section:
Section 1: General
This section outlines the standard’s scope and purpose and provides definitions of key terms used throughout the document.
- Key Terms: Test procedure, environmental conditions, equipment under test (EUT), operational limits, etc.
- Test Categories: EUTs are classified into two categories, Class 1 and Class 2, depending on the equipment’s expected operational environment.
Section 2: Temperature and Altitude
This section specifies how the equipment should handle temperature extremes and varying altitudes.
- Tests include:
- Temperature Range: Equipment should operate within a specified temperature range, usually -55°C to +70°C.
- Altitude: Tests simulate operation at various altitudes, from sea level to altitudes of 50,000 feet.
- Thermal Cycling: Equipment is subjected to rapid temperature changes to assess performance under thermal stresses.
Section 3: Temperature Variation
This section evaluates how the equipment handles rapid changes in temperature.
- Test Method:
- Equipment is exposed to sudden temperature changes (e.g., 15°C to 35°C) and evaluated for functional operation.
- This tests thermal shock resistance and reliability when transitioning from one temperature extreme to another.
Section 4: Humidity
The equipment is tested to ensure it operates reliably in high-humidity environments, which can lead to corrosion, condensation, and electrical failures.
- Test Conditions:
- Exposure: The equipment is exposed to high-humidity conditions (up to 95% RH) for extended periods.
- Temperature and Humidity Cycling: Equipment undergoes cyclic humidity exposure, followed by functional tests to ensure no degradation in performance.
Section 5: Operational Shock and Crash Safety
This section simulates mechanical shock to test equipment durability under crash-like conditions.
- Test Procedure:
- Equipment is subjected to both operational shocks (e.g., turbulence) and crash shocks (e.g., sudden deceleration).
- The standard specifies peak shock values and test durations to ensure equipment survives these extreme conditions without failure.
Section 6: Vibration
This section tests the ability of equipment to withstand vibrations that occur during normal flight and transport.
- Test Conditions:
- Vibration Frequency Range: Equipment is exposed to a range of frequencies, typically from 5 Hz to 2,000 Hz, covering the vibrations encountered in an aircraft.
- Test Duration: Equipment is subjected to continuous vibrations for several hours to simulate operational conditions.
- Testing Methods: Random vibration, sinusoidal vibration, and swept-sine testing are employed to mimic aircraft operational environments.
Section 7: Acoustic Noise
Simulates the acoustic noise environment during operation, typically encountered from engines, air flow, and other aircraft systems.
- Test Procedure:
- The equipment is exposed to high levels of noise (up to 140 dB) across different frequency ranges.
- Acoustic noise levels are applied both during operation and when the equipment is in standby mode.
Section 8: Power Input
Ensures that equipment can operate within a range of input power conditions and protect itself from power surges or outages.
- Test Conditions:
- Voltage Range: Equipment must function across a wide voltage range, typically from 18V to 32V DC for aircraft power systems.
- Voltage Surges: Equipment is subjected to transient voltage spikes to test for electrical robustness.
- Frequency Variations: The equipment should operate correctly at frequencies within the aircraft power system’s tolerance range.
Section 9: Voltage Spike
Tests equipment resistance to electrical spikes, which can occur due to lightning or electrical faults.
- Test Procedure:
- Equipment undergoes exposure to both single and repetitive voltage spikes.
- The testing simulates short-duration high-voltage events that might occur due to lightning strikes or power line crosses.
Section 10: Electromagnetic Interference (EMI)
The equipment must be immune to electromagnetic interference (EMI) from external sources and should not emit EMI beyond regulatory limits.
- Test Method:
- Radiated Emissions: The equipment is tested to ensure it does not emit electromagnetic radiation above prescribed limits.
- Immunity Testing: The equipment is subjected to external electromagnetic fields to test its ability to operate without malfunction.
Section 11: Lightning
Simulates the effect of a lightning strike on the equipment.
- Test Conditions:
- Direct Lightning Strike: The equipment undergoes exposure to high-current lightning strikes (typically 200 kA).
- Induced Lightning Effects: The equipment is tested for immunity to induced voltage and currents from nearby lightning strikes.
Section 12: Rain
Simulates conditions where equipment is exposed to rain or high moisture environments.
- Test Procedure:
- The equipment is subjected to rain at specified intensity and drop size while being powered on.
- The test ensures that no water ingress or moisture-related failure occurs.
Section 13: Salt Fog
Simulates exposure to salt-laden air, which can cause corrosion and degradation of equipment.
- Test Conditions:
- The equipment is exposed to a saline mist environment for extended periods to test for corrosion resistance.
Section 14: Sand and Dust
Tests the equipment’s ability to operate in dusty or sandy environments, common in military or desert aircraft operations.
- Test Procedure:
- The equipment is exposed to sand or dust particles in a controlled chamber while operational.
- The standard ensures that no malfunction occurs due to the ingress of foreign particles.
Section 15: Fungus
Ensures the equipment can resist biological degradation from fungi that may grow in moist environments.
- Test Conditions:
- The equipment is exposed to a fungal growth environment to test its resilience to organic damage.
3. Test Procedures and Methods
General Test Setup
Each test should be conducted under controlled conditions in a test chamber or environmental simulator that can replicate the required conditions (e.g., temperature, humidity, pressure).
Test Instrumentation
- Thermometers: For temperature testing.
- Vibration Tables: For simulating mechanical vibrations.
- Acoustic Chambers: For noise testing.
- EMI Test Equipment: For measuring electromagnetic emissions and susceptibility.
- Power Supply and Monitoring Equipment: For voltage and current control.
Test Execution
- Pre-test Measurements: Record baseline equipment conditions (e.g., performance, functionality).
- Test Duration: Adhere to the specified duration for each test condition.
- Post-test Measurements: Evaluate the equipment for any changes in performance, failure, or damage.
4. Compliance and Certification
Once all tests are completed, the manufacturer prepares a report that includes the following:
- Test Results: All relevant data from each test performed.
- Failure Analysis: Any failures observed during the testing and corrective actions.
- Compliance Statement: Declaration of the equipment’s conformity with DO-160 requirements.
The certification process typically involves a third-party body or regulatory authority that will review the test results and verify compliance before granting certification for the equipment’s use in aviation.
5. Best Practices for DO-160 Compliance
- Early Planning: Start environmental testing early in the development process to identify and mitigate risks.
- Document Everything: Maintain detailed records of test setups, procedures, results, and deviations.
- Iterative Testing: Perform tests iteratively to fine-tune equipment performance under each condition.
- Qualified Testing Labs: Use accredited testing laboratories for accurate and compliant testing.
Ready to Learn More About DO-160?
Tonex offers several courses in DO-160, including:
DO-160G Training / Environmental Conditions and Test Procedures for Airborne Equipment
EMI/EMC Test Procedures for Airborne Equipment Training Curriculum (DO-160G Training)
MIL-STD-461G & DO-160G Test Methods and Compliance Workshop
Combo MIL-STD-461G & DO-160G Test Methods and Compliance Workshop
MIL-STD-461G / RTCA DO-160G EMC Test Methods And Compliance Training Essentials
Tonex also has a new DO-160 FAQs page.
For more information, questions, comments, contact us.
