Transport Canada is now mandating fluorescent penetrant inspections (FPIs) of Bell 505 helicopter collective sticks every 25 flight hours, rather than the one-time inspections it ordered last week.
The new guidance is found in a revision to its original emergency airworthiness directive (AD) and has an effective date of Feb. 26, 2021. According to the revised AD, it was determined that a one-time visual inspection is not adequate for detecting potential fatigue cracking in the collective sticks, and that operators should conduct repetitive FPIs capable of detecting smaller cracks.
The AD was prompted by an incident in which a Bell 505 pilot collective stick assembly broke above the cabin floor at the junction with the collective jackshaft. Bell confirmed that the fracture — which was discovered prior to engine start during a pre-flight check of the flight controls — occurred on a Bell 505 operated by the Stockton Police Department.
Like the original AD, the revision follows guidance in an alert service bulletin released by Bell. The FPI is to be performed prior to next flight. If it is necessary to ferry the helicopter to the nearest approved maintenance facility to perform the inspection, the helicopter must be flown from the copilot seat only. If a crack is discovered during the FPI, the collective stick is considered unserviceable and must be replaced with a new or undamaged assembly.
“As the collection and analysis of inspection findings are still ongoing, this AD is considered an interim action. [Transport Canada] may mandate further corrective actions,” the AD states.
According to Bell’s alert service bulletin, operators who comply with the instructions in the bulletin will be eligible to receive non-prorated replacement parts as applicable. Bell is also offering some compensation for labor hours and the FPI.
Transport Canada is the original certifying agency for the Bell 505, and therefore the primary source for ADs affecting the model, with other regulators typically following close behind.