EASA AD US-2023-01-05
Time Limits / Maintenance Checks — Airworthiness Limitations Section — Amendment / Pneumatic - Anti-ice Manifold Assembly - Revision of Inspection Program
Summary
The Federal Aviation Administration's Airworthiness Directive 2023-01-05 is a final rule affecting Learjet, Inc. Model 40, 45, 70, and 75 airplanes. It mandates revisions to the airworthiness limitations section, specifically reducing inspection intervals for the pneumatic anti-ice manifold assembly to address safety concerns. This directive aims to prevent metal fatigue that could cause loss of ice protection and potential loss of airplane control.
What Changed
This AD revises the existing inspection program by reducing the inspection interval for the anti-ice manifold assembly from 1,200 flight hours to 600 flight hours for redesigned parts. It also expands applicability to include additional Learjet 70 and 75 models. The directive terminates certain requirements of the previous AD 2001-03-05 by introducing these more restrictive inspection intervals.
Why It Matters
This directive is critical for aviation professionals as it addresses a safety risk from metal fragments breaking off the anti-ice manifold assembly due to fatigue, which could block pneumatic ducts and cause unannunciated ice protection loss. Operators and maintenance teams must update inspection programs to comply with the reduced intervals to ensure continued airworthiness and prevent potential accidents. Compliance ensures regulatory adherence and enhances flight safety.
What To Do
Affected operators must revise their maintenance or inspection programs within 60 days of March 9, 2023, by incorporating the specified Learjet Maintenance Manual Temporary Revisions. Inspections must be performed within 100 flight hours or 60 days if more than 600 flight hours have elapsed since the last inspection, or within 600 flight hours or 100 flight hours after the effective date if less than 600 flight hours have elapsed. Compliance with these revised intervals is mandatory to address the unsafe condition.
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