Crack Found On The Main Rotor Hub Inboard Strap Fitting

The FAA has issued an Emergency AD (EAD) (2010-24-51) prompted by a recent accident that resulted in several fatalities. During the investigation of the accident, a crack was found on the main rotor hub inboard strap fitting (fitting). Subsequently, 4 additional fittings from the same manufacturing lot were inspected and two were found to exhibit the same type of cracking as found on the fitting installed on the helicopter involved in the accident. A cracked fitting could result in failure of the fitting, loss of a main rotor blade, and subsequent loss of control of the helicopter.

FAA officials reviewed Bell Alert Service Bulletin No. 212-10-141, dated November 11, 2010 (ASB), which specifies the immediate removal of certain serial-numbered fittings from service. Bell states that they have determined that the fitting may not have been manufactured in accordance with the engineering design requirements and may fracture as a result of the non-conformance. Bell further states that their investigation is ongoing and indicates that fittings serial numbers A-9956 through A-10005 inclusive are affected by the ASB.

The FAA says it is issuing the EAD because we evaluated all the relevant information and determined the unsafe condition described is likely to exist or develop in other products of this same type design.

Bell 212 File Photo

The EAD requires, before further flight, removing each affected fitting and replacing it with an airworthy fitting. Any fitting with a part and serial number identified in the Applicability section of this EAD is no longer eligible for installation on any helicopter.

This EAD differs from the ASB in that the FAA does not require returning parts to Bell.

FMI: www.faa.gov