EASA SIB 2015-11: Hydrostatic Test Requirement for Pressure Vessels Installed on an Aircraft

What to do

Operators and maintenance organizations should identify the exact source of hydrostatic test tasks for pressure vessels on their aircraft. If the task is derived from MSG-3 analysis, it must be included in the maintenance program for all applicable aircraft. For national regulations, operators must comply only if under the relevant jurisdiction. Vendor recommendations should be considered according to procedures approved by the competent authority. No specific compliance deadlines are stated.

Summary

EASA Safety Information Bulletin No. 2015-11 provides guidance on hydrostatic test requirements for pressure vessels installed on aircraft. It clarifies that hydrostatic test tasks may originate from Maintenance Steering Group-3 (MSG-3) analysis, national regulations, or vendor recommendations, and applicability varies accordingly. The bulletin applies broadly to pressurized bottles installed on aircraft without specifying particular aircraft types or engine models.

What changed

This bulletin addresses confusion arising from the removal of hydrostatic test requirements from various Maintenance Review Board Reports and Maintenance Planning Documents. It introduces a clear framework for identifying the source of hydrostatic test requirements and their applicability based on MSG-3 analysis, national regulations, or vendor recommendations. It does not impose new mandatory requirements but provides clarifications and recommendations.

Why it matters

Understanding the source and applicability of hydrostatic test requirements is critical for operators, maintenance organizations, and compliance teams to ensure proper maintenance program inclusion and regulatory compliance. This clarity helps avoid unnecessary or jurisdictionally irrelevant testing and supports harmonized maintenance practices across different regulatory environments. It also assists in managing vendor recommendations and national regulations effectively.