A Mechanic with inspection authority (IA); reports about a routine FAA inspection of a 133/135 helicopter operation inquiring about a Bell JetRanger 206B main yoke calendar life. The IA could not find documentation to properly determine how long the yoke had been in service.
Synopsis
A Mechanic with inspection authority (IA); reports about a routine FAA inspection of a 133/135 helicopter operation inquiring about a Bell JetRanger 206B main yoke calendar life. The IA could not find documentation to properly determine how long the yoke had been in service.
Narrative
In May 2009 during a routine FAA inspection of a 133/135 helicopter operation; the FAA inquired about main rotor yoke calendar life. The yoke installed was P/N 206-010-101-021. Current 'newer' yokes have no calendar life and airworthiness is categorized as an 'On Condition' item. It was brought to my attention; that this particular part number was affected by Bell ASB206-79-4; which limits its useful life to 10 years. The yoke was installed on this airframe in July 2008. I performed the annual inspection in August 2008 and performed several 100 hour inspections since installation and this was an oversight on my part during inspections. After the FAA inquired about the 10 year life limit on this part; I could not find documentation to properly determine how long this part had been in service. There was no way to determine the calendar life of this part and it was immediately removed from service. It was noted that this aircraft has not carried passengers for hire during the time of this yoke installation. There was no way to determine if the calendar life had been exceeded due to lack of documentation of this part.
NASA callback
Reporter stated the Part Number noted in their paperwork for the Main Rotor Hub Yoke indicated the part had exceeded the ten year life allowed and was affected by the Alert Service Bulletin (ASB) 206-79-4. Reporter stated he just could not understand how he could have missed recognizing the Yoke as being an Out of Date part during his Annual Inspections. Reporter stated the answer came when he reviewed the paperwork from the Repair Shop that had overhauled the Rotor Head and performed a Non-Destructive Testing (NDT) of the Yoke. After the Repair Shop had accomplished the NDT; an incorrect part number had been entered into the records document. That number ended up being the Part Number for the 'older' Yokes that had been phased out for time.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.