airworthiness · Rule · Final rule. · Published 2012-06-25 · Effective 2012-07-30 · 77 FR 37779
Document
Document number
2012-14797
Federal Register citation
77 FR 37779
Type
Rule
Action
Final rule.
Category
airworthiness
Manufacturer
Agusta S.p.A.
Publication date
2012-06-25
Effective date
2012-07-30
FAA docket
Docket No. FAA-2012-0013
Abstract
We are adopting a new airworthiness directive (AD) for Agusta S.p.A. (Agusta) Model AB139 and AW139 helicopters with a certain generator control unit (GCU), to require replacing each affected GCU with an airworthy GCU. This AD was prompted by laboratory tests which revealed a potential fault in the overvoltage protection on a certain part-numbered GCU. The actions are intended to prevent failure of the overvoltage protection of the GCU, degraded performance of the electrical power generation and distribution systems, a fire, and subsequent loss of control of the helicopter.