Time Limits / Maintenance Checks – Main Gearbox Magnetic Plugs – Inspection; Main Rotor Drive – Planet Gear Assemblies – Replacement
Superseded. Comply with 2018-0263, which replaces this document.
- Published
- Effective
- Deadline
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators of EC 155 B and B1 helicopters must perform inspections of the MGB magnetic plugs and oil filter within specified flight hour intervals, and conduct a one-time inspection of the MGB oil sump. If particles exceeding defined criteria are found, corrective actions must be taken before the next flight. Replacement of affected planet gear assemblies or MGBs must be completed within the compliance times outlined, with no installation of type Y planet gear assemblies allowed after 16 June 2017.
Summary
EASA Airworthiness Directive 2018-0052 is an airworthiness directive applicable to Airbus Helicopters EC 155 B and B1 models. It addresses safety concerns related to the main gearbox (MGB) planet gear assemblies, specifically types Y and Z, which have been found susceptible to spalling and cracking. The directive mandates inspections and replacements to ensure continued airworthiness of affected helicopters.
What changed
This directive introduces repetitive inspections of the MGB oil filter and a one-time inspection of the MGB bottom housing (oil sump) for particles. It also reduces the life limit of type Z planet gear assemblies and requires replacement of affected MGBs or epicyclic reduction gears within specified flight hour limits. EASA AD 2018-0052 takes over requirements for EC 155 helicopters from EASA AD 2017-0116R1, which is revised to exclude EC 155 helicopters.
Why it matters
This directive is critical for aviation professionals as it addresses a known unsafe condition that could lead to MGB failure, impacting flight safety. Operators and maintenance organizations must comply to prevent potential accidents caused by planet gear assembly failures. The directive ensures improved reliability and safety of the EC 155 helicopter fleet by enforcing timely inspections and part replacements.
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