Engine — Accessory Gearbox — Modification
- Published
- Effective
- Deadline
- Replaces
- 2020-0261
- Replaces
- 2012-0209
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators must replace affected accessory gearboxes with serviceable units during the first qualifying engine shop visit after specified dates, with final compliance deadlines of 31 December 2026 for CFM56-3 engines and 31 December 2024 for CFM56-7B engines. Until replacement, any maintenance involving removal and re-installation of the AGB hand-cranking cover requires an independent inspection. Installation of affected AGBs is prohibited after modification or from 11 December 2020 for unaffected engines.
Summary
EASA Airworthiness Directive 2020-0261R1 addresses the modification of accessory gearboxes (AGB) on CFM International CFM56-3 and CFM56-7B engines, commonly installed on Boeing 737 aircraft. The directive mandates replacement or modification of affected AGB part numbers to prevent engine oil loss and potential engine failure. It applies to all serial numbers of the specified engine models and includes detailed compliance instructions.
What changed
EASA Airworthiness Directive 2020-0261R1 revises the previous AD 2020-0261 by allowing installation of newly approved serviceable accessory gearboxes and updating compliance instructions accordingly. It retains the original requirements for replacing affected AGBs but introduces updated service bulletin revisions and extends compliance deadlines. This revision reflects the approval of new serviceable AGB parts and associated installation procedures.
Why it matters
This directive is critical for aviation professionals as it addresses a safety issue involving incorrect re-installation of the AGB hand-cranking cover, which has led to engine oil loss and failures. Operators and maintenance organizations must ensure affected engines are modified or inspected properly to maintain airworthiness and prevent in-flight engine shutdowns. Compliance ensures continued safe operation of Boeing 737 aircraft equipped with these engines.
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