Parts

Special Ring

No failure report names the special ring. 2 FAA approvals let 1 company make a replacement special ring, Nhbb holding the most (2).

Approved replacement parts 2 parts manufacturer approvals

A parts manufacturer approval (PMA) lets a company other than the aircraft's maker make a special ring and sell it as an approved part for the models named. These are the companies holding such approvals for a special ring:

Nhbb 2

For these models most: Agustawestland Philadelphia AW139 (2), Agusta Spa AB139 (2).

Maker	Part	Replaces	Fits	Granted	Status
Nhbb	Special Ring Upper KF226-4001	AgustaWestland P/N 3G6230V00951	AgustaWestland AW139, AB139	2014-04-10	current
Nhbb	Special Ring Lower K226-4001	AgustaWestland P/N 3G6230V00851	AgustaWestland AW139, AB139	2014-04-10	current

Sources: the FAA's service difficulty reports since 1995 (a report is a part that failed and was fixed, as filed by an airline, repair station or owner; the count shows reporting as much as reliability) and the parts manufacturer approvals in the FAA's Dynamic Regulatory System. The part name is the reporters' and the approval holders' own words, reduced to the first plain words so that spellings meet.