AD 2015-26-10

final rule
Data completeness: 70%

Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters

AD Number
2015-26-10
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Docket No. FAA-2014-0335
FR Citation
81 FR 147

Applicability

TypeManufacturerModelDetails
aircraft Sikorsky Aircraft Corporation Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters

Unsafe Condition

Unsecured jet bore liners that have protruded, leading to MGB low oil pressure warnings and potential loss of oil in the MGB, which could result in failure of the MGB and subsequent loss of control of the helicopter.

AI-generated summary from the source AD text. Verify against the official source before acting.

Required Actions

Inspect the main gearbox (MGB) lower housing jet bores for leaks, paint or caulk blistering, and liner protrusion. Replace the MGB if there is oil leakage or protrusion of a jet bore liner. Replace the MGB within 3,750 hours time-in-service (TIS).

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

Within 50 hours time-in-service (TIS) for initial inspection; within 3,750 hours TIS for MGB replacement.

AI-generated summary from the source AD text. Verify against the official source before acting.

Affected Aircraft

Sikorsky Aircraft Corporation Model S-76A, S-76B, and S-76C helicopters with a main gearbox (MGB) installed that has undergone certain repairs, specifically those with MGB part numbers 76351-09000 series, 76351-09500 series, and 76351-09600 series, and repaired in accordance with Sikorsky ORI No. 76350-065 or earlier revisions.

AI-generated summary from the source AD text. Verify against the official source before acting.

Source: Official FAA Source ↗

Retrieved: Apr 6, 2026

Rights: U.S. Government Public Domain

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