ISO 7137:1995

Overview

ISO 7137:1995, "Aircraft - Environmental conditions and test procedures for airborne equipment", is an international endorsement of selected sections of EUROCAE/ED-14C and RTCA/DO-160C (amended by Revision No. 2). This fourth edition replaces the 1992 version and lists environmental conditions and standardized test procedures applicable to airborne equipment, primarily for civil and transport aircraft. The standard provides a consistent reference model for specifying, referencing and applying environmental tests for avionics and other onboard systems.

Key Topics

ISO 7137 maps environmental test procedures to standard sections and related ISO test methods. Major technical topics include:

• Temperature and altitude (temperature variation, operational envelope)
• Humidity and water ingress (sealing, impermeability)
• Fluids susceptibility (exposure to hydraulic/chemical fluids)
• Contaminants (sand, dust, salt fog, fungus resistance)
• Mechanical environment:
  • Operational shocks and crash safety
  • Vibration (broadband, acoustic vibration)
  • Steady-state acceleration (referenced ISO 2669)
• Electromagnetic environment:
  • Magnetic effects, power input variations, voltage spikes
  • Audio-frequency conducted susceptibility, induced-signal susceptibility
  • Radio-frequency susceptibility (radiated and conducted) and emissions
  • Lightning-induced transient susceptibility and direct lightning effects
  • Insulation resistance and high-voltage testing (referenced ISO 2678)
• Explosion and fire protection:
  • Explosion proofness
  • Fire resistance in designated fire zones (referenced ISO 2685)
• Cross-references to ISO 2671 for acoustic vibration and other ISO test methods are provided.

The document instructs how to reference specific ISO 7137 test procedures in performance specifications (example format: “Test procedure ISO 7137 - 1.6”).

Applications

ISO 7137 is practical for:

• Avionics and aircraft equipment designers defining environmental qualification requirements
• Test laboratories and integrators planning environmental and EMC test campaigns
• Certification bodies and regulatory reviewers assessing compliance with environmental test criteria
• Procurement and specification writers who need to reference standardized test procedures in contracts
• Maintenance and reliability engineers using test data to support in-service evaluation

Using ISO 7137 helps ensure repeatable, internationally recognized environmental testing for airborne equipment, reducing ambiguity between manufacturers and authorities.

Related Standards

• EUROCAE ED-14C (sections referenced)
• RTCA DO-160C (sections referenced; amended Rev No. 2)
• ISO 2669 - Steady-state acceleration tests
• ISO 2671 - Acoustic vibration tests
• ISO 2678 - Insulation resistance and high-voltage tests
• ISO 2685 - Fire resistance in designated fire zones

Keywords: ISO 7137, environmental testing, airborne equipment, aircraft environmental conditions, RTCA DO-160, EUROCAE ED-14, avionics testing, vibration testing, electromagnetic susceptibility, fire resistance.