Commonwealth legislation

AD/AL 250/65 - Engine Power and Accessory Gearbox - New Magnetic Plug Introduction

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Plain English Summary

2/10 complexity

This Airworthiness Directive requires operators of Allison 250‑C30 and C30S engines (and their power/accessory gearboxes) installed in, or intended for, S‑76 helicopters to replace magnetic plug P/N 23001915 with P/N 6871534. Installed units must be modified by the next Maintenance Release after 30 April 1985; uninstalled parts must be fitted with the new plug before installation. The change restores early oil‑contamination detection lost because the old plug’s "fuzz burn off" feature masked contamination; operators pay and must schedule the replacement.

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AD/AL 250/65 - Engine Power and Accessory Gearbox - New Magnetic Plug Introduction

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Allison Turbine Engines - 250 Series

AD/AL 250/65 Engine Power and Accessory Gearbox - New

Magnetic Plug Introduction

4/85

Applicability: Model 250-C30 and C30S engines (and power and accessory gearboxes) installed in or intended for installation in S-76 Helicopters and which incorporate magnetic plug P/N 23001915.

Requirement: Fit new magnetic plugs P/N 6871534 in lieu of old plugs P/N 23001915.

Allison 250-C30, C30S CEB-A-72-3098 Revision 1.

Compliance: 1. For installed Engine/gearbox assemblies:

Unless already accomplished, prior to issue of the next Maintenance Release after 30 April 1985.

For uninstalled engines, power and accessory gearboxes, housings and covers: Prior to installation in an aircraft.

Background: In service experience with automatic fuzz burn off magnetic plugs P/N 23001915 has indicated that early detection of oil system contamination is being lost due to the effectiveness of the fuzz burn off feature.

CEB-A-72-3098 replaces the auto fuzz burn off plug with the 6871534 plug which is currently fitted to the 250-C20 engine and has proven to be reliable in providing an early indication of engine or gearbox oil contamination.

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

1 AD/AL 250/65 - Engine Power and Accessory Gearbox - New Magnetic Plug Introduction