Operators of Bell 429 helicopters have been instructed to conduct urgent inspections of a tail rotor component after an investigation revealed a potentially dangerous manufacturing defect.
In an emergency airworthiness directive (EAD) effective from 19 January, certification agency Transport Canada warns that corrosion on the part could lead to its failure and subsequent loss of control of the aircraft.
Its warning comes after an in-flight failure of a tail rotor pitch link on a 429. This caused “noticeable vibration” and “difficultly controlling the helicopter”, says Transport Canada.
Bell Helicopter
A subsequent investigation revealed that the pitch link had fractured, with a crack originating at a corrosion pit.
“Further investigation revealed deficiencies in the application of corrosion resistant finishes to the pitch link during the manufacturing process,” Transport Canada says.
Operators are mandated to inspect affected pitch links for signs of corrosion and replace them as necessary.
It is not the first time that the 429 has run into problems with the tail rotor pitch link. An EAD issued last year instructed operators to inspect the assembly for play in the bearings.
Source: FlightGlobal.com
