Reliability Analytics Corporation

MIL-HDBK-217F, Notice 2, Environmental Descriptions and Assumed Default Operating Temperatures


EnvironmentDescriptionParts Count Method Assumed Temperature, Active Parts (TJ, °C)Parts Count Method Assumed Temperature, Passive Parts (TAmbient, °C)
Ground Benign (GB)

Nonmobile, temperature and humidity controlled environments readily accessible to maintenance; includes laboratory instruments and test equipment, medical electronic equipment, business and scientific computer complexes, and missiles and support equipment in ground silos.

5030
Ground Fixed (GF)

Moderately controlled environments such as installation in permanent racks with adequate cooling air and possible installation in unheated buildings; includes permanent installation of air traffic control radar and communications facilities.

6040
Ground Mobile (GM)

Equipment installed on wheeled or tracked vehicles and equipment manually transported; includes tactical missile ground support equipment, mobile communication equipment, tactical fire direction systems, handheld communications equipment, laser designations and range finders.

6545
Naval Sheltered (NS)

Includes sheltered or below deck conditions on surface ships and equipment installed in submarines.

6040
Naval Unsheltered (NU)

Unprotected surface shipborne equipment exposed to weather conditions and equipment immersed in salt water. Includes sonar equipment and equipment installed on hydrofoil vessels.

6545
Airborne Inhabited Cargo (AIC)

Typical conditions in cargo compartments which can be occupied by an aircrew. Environment extremes of pressure, temperature, shock and vibration are minimal. Examples include long mission aircraft such as the C130, C5, B52 and C141. This category also applies to inhabited areas in lower performance smaller aircraft such as the T38.

7555
Airborne Inhabited Fighter (AIF)

Same as AIC but installed on high performance aircraft such as fighters and interceptors. Examples include the F15, F16, F111, F/A 18 and Al0 aircraft.

7555
Airborne Uninhabited Cargo (AUC)

Environmentally uncontrolled areas which cannot be inhabited by an aircrew during flight. Environmental extremes of pressure, temperature and shock maybe severe. Examples include uninhabited areas of long mission aircraft such as the C130, C5, B52 and C141. This category also applies to uninhabited area of lower performance smaller aircraft such as the T38.

9070
Airborne Uninhabited Fighter (AUF)

Same as AUC but installed on high performance aircraft such as fighters and interceptors. Examples include the F15, F16, F111 and A10 aircraft.

9070
Airborne Rotary Wing (ARW)

Equipment installed on helicopters. Applies to both internally and externally mounted such as laser designators, fire control systems, and communications equipment.

7555
Space Flight (SF)

Earth orbital. Approaches benign ground conditions. Vehicle neither under powered flight nor in atmospheric reentry; includes satellites and shuttles.

5030