Bell 206 series helicopters fitted with Airwolf Aerospace PMA/STC Tension-Torsion (TT) straps.
CAA received a report from a maintenance provider of finding an Airwolf Aerospace Tension-Torsion strap with a PMA/STC holder log card which specified an incorrect life limit.
During scheduled maintenance of a Bell 206L main rotor hub, the engineer was confirming the time remaining of life limited parts, when an anomaly was identified with the tracked life of an Airwolf Aerospace TT strap.
The strap was being tracked to a life limit of 1200 hours/48 months, as detailed in the PMA/STC holders component log card supplied with the part.
Further investigation determined the FAA approved airworthiness limitation section of the Airwolf Aerospace Instructions for Continued Airworthiness (ICA) states a 1200 hour/36-month life limit.
Had the engineer not identified this anomaly, it is almost certain that the TT strap would have remained in service well beyond the calendar life limit.
This matter has been raised with the PMA/STC holder and the FAA.
This incident highlights the need for diligence when identifying the appropriate airworthiness limitations to be followed.
The primary reference for establishing a life limit should always be the approved airworthiness limitations section of the ICA relevant to the component.
In the case of a PMA/STC life limited part, the requirements in the PMA/STC holders ICA take precedence over the OEM ICA, unless otherwise stated.
Please notify / contact warren.hadfield@caa.govt.nz of any findings, or concerns.
