DO-160-Section-4.0-Temperature-and-Altitude

RTCA DO-160 Section 4.0 Temperature and Altitude Testing

The purpose of RTCA DO-160 temperature testing and altitude testing is to determine the performance characteristics. The RTCA DO-160 test standard defines the requirements by equipment category. The temperature and altitude test category are based on a number of variables.

One of the equipment category variables of RTCA/DO-160G testing is the location in or on the aircraft. Another variable is the maximum operating altitude of the aircraft. The third variable is whether or not the device is located in a pressure controlled or temperature-controlled area. Each of the equipment categories used by an RTCA DO-160 test lab to complete the testing are detailed at the end of this page.

RTCA/DO-160G Section 4.0 Testing Summary:

This section of the standard covers temperature testing and altitude testing or equipment intended to be installed on aircraft. The altitude testing includes altitude testing, decompression testing and overpressure testing. The altitude testing peaks at 70,00 feet. The decompression testing simulates an emergency descent. The overpressure testing simulates the ordinary aircraft pressurization.

The temperature testing includes operating low and high temperatures, ground survival temperatures and the simulation of short-time operating temperatures and the loss of in-flight cooling. The actual temperature ranges extremes include a non-operational ground survival temperature as low as -55 C and an operational high temperature of 70 C.

RTCA DO-160G Altitude Testing

The RTCA DO-160 Section 4.0 altitude testing completed by an RTCA DO-160G lab includes three primary tests.

Altitude testing is completed by operating the equipment at its maximum duty cycle. The pressure is then decreased in the altitude test chamber. This testing starts at ambient temperature and the temperature is stabilized as the pressure is dropped.

Decompression testing is also completed at ambient temperatures. With the equipment operating, the absolute pressure is moved to an equivalent altitude of 8,000 ft. The absolute pressure is then reduced to the equivalent of the maximum operational altitude for the aircraft on which the equipment will be installed.

Overpressure testing occurs with the equipment not operating, unless otherwise specified in the equipment specification of the DO-160 test standard. The equipment is subjected to an absolute pressure equivalent to -15,000 ft altitude.

RTCA DO-160G Temperature Testing

The RTCA DO-160 Section 4.0 temperature testing completed by an RTCA DO-160 lab like Keystone Compliance involves a variety of different tests. Those temperature tests include the following:

Operating low temperature, which is the lowest temperature at which equipment will normally be exposed to or be required to operate in.

Operating high temperature, which are the maximum levels that the equipment will be exposed to within the specific installation area. These areas can include an enclosed space, behind an instrument panel, equipment racks and power plant areas, among others.

Short-Time operating temperature, which are the startup conditions where equipment is turned on following a ground soak. It is expected that these temperature conditions will occur infrequently and be of short duration. This expectation is made because cooling or heating air circulation or other means of controlling temperature would be enabled concurrent with equipment operation.

Ground survival temperatures, which are the lowest and highest ground temperatures that the equipment is normally expected to be exposed to during aircraft storage or exposure to climatic extremes. The equipment is not expected to operate within specification limits at these temperatures but is expected to survive without damage.

In-Flight Loss of Cooling, which represents the failure of the external or internal system that normally provides dedicated cooling for the equipment. Certain equipment must survive for a limited time in the absence of cooling.

Keystone Compliance is a leader in compliance testing to military standards. As an RTCA DO-160G accredited test lab, we have the experience, equipment and resources to meet every testing need. In addition to being accredited to complete RTCA-DO-160G testing, Keystone is also accredited to all previous versions of the standard as well. Please contact us to see firsthand why so many manufacturers rely on Keystone Compliance to meet their RTCA DO-160 testing.

Looking for other testing to other sections of RTCA DO-160 testing? Click on the links below:

RTCA DO-160 Equipment Categories

RTCA DO-160 Equipment Category A1

Equipment intended for installation in a controlled temperature and pressurized location. This includes on an aircraft within which pressures are normally no lower than the altitude equivalent of l5,000 feet. This is considered Mean Sea Level (MSL). This category may also be applicable to equipment installed in temperature controlled but unpressurized locations. This includes on an aircraft that operates at altitudes no higher than 15,000 feet MSL.

RTCA DO-160 Equipment Category A2

Equipment intended for installation in a partially controlled temperature but pressurized location on an aircraft. This category is applicable where pressures are normally no lower than the altitude equivalent of 15,000 feet MSL. This category may also be applicable to equipment installed in partially controlled temperature but unpressurized locations on an aircraft that operates at altitudes no higher than 15,000 feet MSL.

RTCA DO-160 Equipment Category A3

Equipment intended for installation in a controlled or partially controlled temperature but pressurized location within an aircraft. This category is applicable when the pressures are normally no lower than the altitude equivalent of 15,000 feet MSL. Also, the temperatures will be more severe than those for categories A1 and A2.

RTCA DO-160 Equipment Category A4

Equipment intended for installation in a controlled temperature and pressurized location, on an aircraft within which pressures are normally no lower than the altitude equivalent of 15,000 feet.  Mean Sea Level (MSL). Category A4 applies when temperature requirements differ from category A1 as declared by the equipment manufacturer. This category may also be applicable to equipment installed in a temperature controlled but unpressurized locations on an aircraft that operates at altitudes no higher than 15,000 feet MSL. However, temperature requirements differ from category A1 as declared by the equipment manufacturer.

RTCA DO-160 Equipment Category B1

Equipment intended for installation in a non-pressurized but controlled temperature location in an aircraft that is operated at altitudes up to 25,000 feet MSL.

RTCA DO-160 Equipment Category B2

Equipment intended for installation in non-pressurized and non-controlled temperature locations on an aircraft that is operated at altitudes up to 25,000 feet MSL.

RTCA DO-160 Equipment Category B3

Equipment intended for installation in the power plant compartment of an aircraft that is operated at altitudes up to 25,000 feet MSL.

RTCA DO-160 Equipment Category B4

Equipment intended for installation in a non-pressurized location on an aircraft that is operated at altitudes up to 25,000 feet MSL. However, temperature requirements differ from B1 and B2.

RTCA DO-160 Equipment Category C1

Equipment intended for installation in a non-pressurized but controlled temperature location in an aircraft that is operated at altitudes up to 35,000 feet MSL.

RTCA DO-160 Equipment Category C2

Equipment intended for installation in non-pressurized and non-controlled temperature locations within an aircraft that is operated at altitudes up to 35,000 feet MSL.

RTCA DO-160 Equipment Category C3

Equipment intended for installation in the power plant compartment of an aircraft that is operated at altitudes up to 35,000 feet MSL.

RTCA DO-160 Equipment Category C4

Equipment intended for installation on a non-pressurized aircraft that is operated at altitudes up to 35,000 feet MSL. However, the temperature requirements differ from C1 and C2.

RTCA DO-160 Equipment Category D1

Equipment intended for installation in a non-pressurized but controlled temperature location on an aircraft that is operated at altitudes up to 50,000 feet MSL.

RTCA DO-160 Equipment Category D2

Equipment intended for installation in non-pressurized and non-controlled temperature locations on an aircraft that is operated at altitudes up to 50,000 feet MSL.

RTCA DO-160 Equipment Category D3

Equipment intended for installation in the power plant compartment of an aircraft that is operated at altitudes up to 50,000 feet MSL.

RTCA DO-160 Equipment Category E1

Equipment intended for installation in non-pressurized and non-controlled temperature locations on an aircraft that is operated at altitudes up to 70,000 feet MSL.

RTCA DO-160 Equipment Category E2

Equipment intended for installation in the power plant compartment of an aircraft that is operated at altitudes up to 70,000 feet MSL.

RTCA DO-160 Equipment Category F1

Equipment intended for installation in non-pressurized but controlled temperature locations on an aircraft that is operated at altitudes up to 55,000 feet MSL.

RTCA DO-160 Equipment Category F2

Equipment intended for installation in non-pressurized and non-controlled temperature locations on an aircraft that is operated at altitudes up to 55,000 feet MSL.

RTCA DO-160 Equipment Category F3

Equipment intended for installation in the power plant compartment of an aircraft that is operated at altitudes up to 55,000 feet MSL.

Modifications from one Version of RTCA DO-160 to the Next:

Changes from DO-160C Temperature and Altitude Testing to DO-160D Temperature and Altitude Testing

Section 4.3 Equipment Categories added reference categories for in-flight loss of cooling test.

Changes from DO-160D Temperature and Altitude Testing to DO-160E Temperature and Altitude Testing

Section 4.5 Temperature Test was restructured to include sub-section 4.5.2 Operating Low Temperature.

Changes from DO-160E Temperature and Altitude Testing to DO-160F Temperature and Altitude Testing

Section 4.5.3 Ground Survival High Temperature Test and Short Term Operating High Temperature Test clarified soak time upon reaching short time operating low and high temperature.  Section 4.5.5, In-Flight Loss of Cooling Test in the note clarified cooling source and power.

Changes from DO-160F Temperature and Altitude Testing to DO-160G Temperature and Altitude Testing

Clarified paragraph 4.5.1, Note 2 and paragraph 4.5.3, Note 2.