Commonwealth legislation

AD/AL 250/70 - No. 8 Bearing Scavenge Line Air/Oil Separator

RepealedCTH

This Act has been repealed and is no longer in force. It is retained for historical reference.

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Commonwealth

Collection

legislative instrument

Plain English Summary

2/10 complexity

What this does: This is a mandatory safety order requiring owners to modify the oil system in specific Allison turbine engines by installing an air/oil separator in the No. 8 bearing scavenge line (the pipe that drains oil away from the bearing). The modification must be done exactly as specified in the referenced technical document (Allison Alert CEB-A-72-2138).

Who it affects: Owners and operators of Allison 250-C28B and 250-C28C series turbine engines with specific serial numbers listed in the technical requirement document.

Why it matters: This prevents dangerous pressure buildup in the No. 8 bearing oil sump. Without this fix, excess pressure can cause an internal oil fire and lead to catastrophic failure of the No. 1 turbine wheel, which could destroy the engine and endanger the aircraft.

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AD/AL 250/70 - No. 8 Bearing Scavenge Line Air/Oil Separator

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

View image in the official source Allison Turbine Engines - 250 Series

AD/AL 250/70 No. 8 Bearing Scavenge Line Air/Oil Separator 8/86

Applicability: 250-C28B and C28C series engines with engine and turbine serial numbers listed in the Requirement Document.

Requirement: Modify the engine oil system in accordance with Allison Alert CEB-A-72-2138 dated 15 May 1986.

Compliance: Within 100 hours of engine operation after 31 August 1986 but no later than 31 January 1987.

Background: This Directive is issued to install an air/oil separator in the No. 8 bearing scavenge line to improve venting of the No. 8 bearing oil sump. Excess pressure in the No. 8 bearing sump may result in internal oil fire and cause a No. 1 turbine wheel failure.

Source text

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