Commonwealth legislation

AD/JT9D/25 - Fan Blade Inspection/Revised Shroud Angle

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Commonwealth

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legislative instrument

Plain English Summary

3/10 complexity

This directive requires owners/operators of Pratt & Whitney JT9D-7R4 engines to perform recurring inspections of fan‑blade leading edges (every 200 cycles, starting within 200 cycles of 21 July 1994) and to install revised‑shroud fan blades (by 21 July 1996) as specified in Pratt & Whitney service bulletins.

It aims to reduce fan‑blade failures from vibration and foreign‑object damage; operators bear inspection and modification costs but can stop the recurring inspections once the revised blades are fitted.

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AD/JT9D/25 - Fan Blade Inspection/Revised Shroud Angle

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Pratt and Whitney Turbine Engines - JT9D Series

AD/JT9D/25 Fan Blade Inspection/Revised Shroud Angle 8/94

Applicability: All JT9D-7R4 Series engines.

Requirement: 1. Inspect fan blade leading edges in accordance with Pratt and Whitney Service Bulletin 72-255 Revision 5.

Incorporate fan blades featuring a revised shroud angle in accordance with Pratt and Whitney Service Bulletin 72-309 Revision 10.

Incorporation of Pratt and Whitney Service Bulletin 72-309 Rev 10 constitutes terminating action for the repetitive inspection per Requirement 1.

Note: FAA AD 94-08-06 also refers.

Compliance: 1. Initially within 200 cycles in service from 21 July 1994, and thereafter, at intervals not to exceed 200 cycles.

No later than 21 July 1996.

Background: This Directive is issued to prevent fan blade failures that have been attributed to a combination of high vibratory stresses and foreign object damage.

Source text

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

1 AD/JT9D/25 - Fan Blade Inspection/Revised Shroud Angle