EN 9110 Calibration Requirements
EN 9110 is the European aerospace maintenance organization quality management standard, published by CEN as the European publication of IAQG 9110:2016. It applies to EASA Part 145-approved organizations — the roughly 2,500 MRO (Maintenance, Repair, and Overhaul) facilities operating in Europe — and is the dominant standard for suppliers that maintain, repair, or overhaul flight hardware rather than manufacture it. EN 9110 builds on the EN 9100 requirements with maintenance-specific additions: tool and test equipment control, work scope authorization, airworthiness release, and return-to-service documentation. Calibration under EN 9110 governs every test equipment used in inspection, adjustment, and post-maintenance verification.
EN 9110 incorporates the EN 9100 baseline and adds maintenance-specific clauses: Section 7.1.3 (infrastructure — requires documented control of test equipment, tooling, and jigs used in maintenance), Section 8.5.1 (production and service provision — adds airworthiness release requirements, EASA Form 1 generation, maintenance release certificate controls), Section 8.5.6 (control of changes — adds work scope authorization requirements before any maintenance task is performed), and specific calibration clauses for tooling that performs torque, alignment, balance, and pressure adjustments on aircraft components. Ground support equipment (GSE) used for post-maintenance functional checks is specifically called out: GSE must be calibrated and identified before it can be used for airworthiness-determining measurements.
EN 9110 calibration scope is broader than EN 9100 manufacturing in one key way: every maintenance task that produces an airworthiness release must be performed with calibrated test equipment. This means torque wrenches used on flight-critical fasteners, alignment tools for control surfaces, vibration meters for balance checks, pitot-static testers, fuel flow calibration rigs, radio test sets, and aircraft weight and balance scales all fall under the calibration control program. Intervals are typically shorter than manufacturing equivalents (6-12 months vs 12-24 months) because maintenance environments are less controlled and usage is heavier. EASA Part 145 AMC 145.A.40 explicitly requires that 'all test and inspection equipment used for assessing the serviceability of aircraft components or systems must be controlled and calibrated against standards acceptable to the competent authority.'
EN 9110 certification is the de facto quality system for EASA Part 145 approved maintenance organizations (AMOs). EASA Part 145 is the regulation — it sets the airworthiness and organizational control framework. EN 9110 is the voluntary quality management standard that demonstrates how the AMO satisfies Part 145's MOE (Maintenance Organization Exposition) requirements, particularly section 2.16 (tool and equipment control) and section 2.17 (calibration). Airbus, Boeing (European operators), Rolls-Royce, and Safran require EN 9110 certification from their preferred MRO partners. The three-year EN 9110 audit cycle integrates naturally with EASA Part 145 continuation audits.
Primary audience: EASA Part 145 approved MROs handling European-registered aircraft, which includes independent MROs (Lufthansa Technik, AFI KLM E&M, SR Technics, Iberia Maintenance, Magnetic MRO, FL Technics, Turkish Technic) and OEM-owned MROs (Airbus Services, Rolls-Royce Aero Repair, Safran Aircraft Engines Services). Secondary audience: component repair stations — specialist shops that repair landing gear, avionics, hydraulics, or engine accessories. Military aviation MROs operating under national defense procurement (DGA Aeronautical Maintenance in France, BAE Systems MRO in the UK, Italian Air Force Logistics Command) also certify to EN 9110 where they also serve commercial customers. Tier 1 aerospace manufacturers that run their own after-sales repair operations typically dual-certify to both EN 9100 (for manufacturing) and EN 9110 (for repair/overhaul).
CalibrationOS is well-matched to MRO operations because it treats every instrument as a first-class entity with full calibration history, movement history (which hangar, which aircraft), and use-event history (which maintenance task used which instrument on which aircraft). The reverse-traceability report — built for EN 9100 — becomes even more important under EN 9110 because an out-of-tolerance torque wrench implicates every aircraft serviced with it since its last verified calibration, potentially triggering airworthiness recalls. CalibrationOS's certificate templates can be configured to align with EASA Form 1 terminology for components leaving the calibration laboratory back into service. Scheduled reminders use the shorter intervals typical of MRO environments and can be configured per aircraft type or per maintenance program.
EN 9110 is the European aerospace maintenance organization quality standard, the MRO-specific companion to EN 9100. It incorporates EN 9100 baseline requirements and adds maintenance-specific clauses on tool and test equipment control, airworthiness release documentation, work scope authorization, and calibration scope extending to ground support equipment. Target audience: EASA Part 145 approved MROs — roughly 2,500 organizations in Europe.
If your scope is maintenance, repair, or overhaul — yes, you need EN 9110. If your scope is manufacturing, EN 9100 is sufficient. Many Tier 1 aerospace suppliers dual-certify (EN 9100 for manufacturing lines, EN 9110 for repair shops) because the scopes are distinct and the audit criteria differ. A single EN 9100 certificate does not cover EASA Part 145 MRO activities.
EASA Part 145 is the regulation; EN 9110 is the voluntary quality management standard demonstrating compliance with Part 145 requirements. Part 145 MOE section 2.16 (tool and equipment control) and 2.17 (calibration) map directly to EN 9110 calibration clauses. Most EASA Part 145 AMOs certify to EN 9110 because their customers (Airbus, Boeing-EU operations, Rolls-Royce, Safran) require it. The three-year EN 9110 audit cycle runs in parallel with EASA Part 145 continuation audits.
Torque tools on flight-critical fasteners, alignment tools for control surfaces and landing gear, vibration analyzers for balance checks, pitot-static testers, fuel flow rigs, radio test sets, aircraft scales, hydraulic pressure calibrators, and ground support equipment used for post-maintenance functional checks. Any measurement that informs an airworthiness release decision is in scope.
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