What Is Humidity?
This test is carried out to evaluate the equipment in high relative humidity conditions within the scope of Chapter 6 (“Humidity”) of the RTCA DO-160 “Environmental Conditions and Test Procedures for Airborne Equipment” standard. DO-160 is the exact same text as EUROCAE ED-14 and is recognized by ISO as ISO 7137.
Purpose of Humidity
The aim is to certify that aviation equipment meets the requirements for evaluation of equipment in high relative humidity conditions in flight and ground conditions and to complete equipment qualification.
Which Products Is Humidity Applied To?
- Avionics units and displays
- In-flight electronic equipment
- Communication and navigation devices
- Cabin and cargo compartment equipment
- Sensors and actuators
In Which Sectors Is Humidity Used?
Standards Related to Humidity
- RTCA DO-160Environmental conditions and test methods in aviation equipment test
- EUROCAE ED-14
- ISO 7137
- MIL-STD-810environmental engineering assessments and laboratory tests test
- MIL-STD-461electromagnetic interference in military systems test
- MIL-STD-202Testing methods in electronic parts test
- MIL-STD-883Test methods in microelectronic devices test
- MIL-STD-167mechanical vibration in ship equipment test
- MIL-S-901high intensity shock testing on ship equipment test
- MIL-STD-704aircraft electrical power characteristics test
- MIL-STD-127528 V electrical system in military vehicles test
- NATO STANAG TestsTests within the scope of NATO standardization agreements test
Humidity Conditions
- Kategoriler
- A (standard humidity), B (severe humidity), C
- Cycle
- Temperature and humidity cycles; number of days by category
- Relative humidity
- High humidity levels defined in the standard
- Function check
- At the end of the cycle and, if necessary, in the cycle
Equipment for Humidity
- Temperature-humidity chamber
- Insulation resistance measuring instrument
- Function monitoring
Sample Requirements for Humidity
- Category must be defined
- Initial insulation resistance should be measured
- Condensation management should be planned
Duration of Humidity
It depends on the category; The severe humidity category may exceed ten days.
Humidity Procedure
- 1The category and cycle program are determined.
- 2The specimen is placed in the chamber.
- 3Temperature-humidity cycles are applied.
- 4At the end of the cycle, function and insulation are measured.
- 5A visual inspection is performed.
Humidity Acceptance Criteria
The acceptance criteria are that the function continues, the insulation resistance meets the limit and there is no corrosion.
Evaluation of Results
Moisture ingress usually occurs at connector and housing junctions.
Humidity Report
- Applied standard, revision and Chapter 6
- Selected equipment category and justification
- Applied conditions and measurement results
- Function monitoring method and observations
- Environmental Qualification Form (DO-160 Environmental Qualification Form) entry
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- Aviation equipment qualification requirements
- EASA/FAA certification principles
Savunma Testleri — What Does This Testing Field Cover?
The section below describes the field that the Humidity test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Defence testing shows that equipment keeps working in a military mission environment. What distinguishes it from civil testing is not only the severity of the levels; the ASSUMPTION ITSELF is different. The equipment must work on the first attempt, after months of storage, in an environment where maintenance is not available, inside a platform crowded with its own transmitters and receivers.
This assumption shapes the test plan. For a civil product "normal use" can be defined; for military equipment what is defined is the LIFE CYCLE ENVIRONMENTAL PROFILE: the exposure of every stage is listed — from manufacture to storage, from storage to shipment, to transport on a vehicle, to use in the field and to maintenance — and the testing is derived from that list.
On the environmental side, MIL-STD-810 methods are applied: temperature, humidity, altitude, rain, sand and dust, salt fog, fungus, shock, vibration, explosive atmosphere and gunfire vibration. The standard itself sets no acceptance criterion; which method is applied at which level, and what is acceptable, come from the programme specification.
On the electromagnetic side, MIL-STD-461 requirements come into play and interference within the platform is controlled. It measures the same physics as civil EMC but with a different assumption: the equipment will operate on a platform crowded with its own radars and radios, and interference inside the platform puts the mission directly at risk. The limits are therefore far stricter.
Power quality is a separate body of work. MIL-STD-1275 for military vehicles and MIL-STD-704 for aircraft define the supply characteristics: voltage ranges, transients, ripple and interruption behaviour. This is where commercially derived equipment most often gets stuck when integrated into a military platform.
On the shock side, naval vessels carry their own regime: the MIL-S-901 high-impact shock test simulates the effect of an underwater explosion and tests the equipment on a real impact machine. This is an entirely different scale from classical laboratory shock testing.
The suitability of commercial off-the-shelf (COTS) equipment for military use is a growing subject in the field. Cost and lead time pressures encourage the use of commercial products; but a commercial product is not considered suitable unless it has been through the military profile, and a gap analysis plus additional qualification is required.
In this family the test plan comes from the PROGRAMME SPECIFICATION. The phrase "complies with MIL-STD-810" is therefore not a verifiable claim on its own; which method, which procedure, which level and which revision must all be answered.
Method groups in this field
Environmental
MIL-STD-810 methods: temperature, humidity, altitude, solar radiation, rain, sand and dust, fungus, salt fog, immersion, explosive atmosphere.
Mechanical
Vibration (random, sine, gunfire), shock, acceleration, free fall and transport simulation.
Electromagnetic
MIL-STD-461 CE/CS/RE/RS requirements; MIL-STD-464 at platform level.
Power quality
Conformity to the MIL-STD-1275 vehicle and MIL-STD-704 aircraft supply characteristics.
High-impact shock
The MIL-S-901 naval shock test; simulation of the effect of an underwater explosion.
Component qualification
MIL-STD-883 microelectronics and MIL-STD-202 electronic parts test methods.
Commonly confused in this field
- The phrase "MIL-STD-810 certified" is incorrect; the standard produces no certificate, the output is a qualification report.
- A conformity claim that does not state the method, procedure and level cannot be verified.
- The revision letter (F, G, H) changes the content of methods and the procedure numbers; the specification must state the revision.
- A civil EMC report does not replace MIL-STD-461; the limits, distances and set-ups are different.
- Power quality is the requirement most often skipped when integrating a commercial product into a military platform.
- Applying a method does not show that the equipment maintains its function in that environment; the functional acceptance criterion is defined separately.
Which decisions these results support
- Qualification under a supply contract
- Component verification before platform integration
- Suitability of commercially derived equipment for military use and gap analysis
- Specification compliance in NATO and export programmes
- Establishing the life cycle environmental profile
Related Tests
Frequently Asked Questions About Humidity
How is the equipment category determined?
The category is selected based on the equipment's mounting location on the aircraft (pressurized/non-pressurized, heated/unheated area) and aircraft type. Category selection directly determines the test conditions and is declared in the qualification form.
Is there any difference between DO-160 and ED-14?
No. RTCA DO-160 and EUROCAE ED-14 are exactly the same text; the two are considered equivalent.