Horizon Air

The proposed rule as it is currently written does not take into account handle shafts that may have been replaced with the new single-piece machined handle shaft through attrition. The IPC list the new shaft as directly interchangeable with old shaft. The proposed rule limits operators to incorporating the new shaft through a specific action that documents service bulletin incorporation. The proposed rule as written would force operators to replace an upgraded shaft installed by attrition. The final rule should include language that allows for upgraded shafts that were replaced during normal maintenance to remain in-service. Without this allowance operator would be forced to replace the upgraded shaft because they were not replaced by service bulletin incorporation. Paragraph (h) of the proposed rule is unclear in the FAA’s intention to mandate maintenance tasks 521200-105 and 524100-105 into an operator’s program. Is it the FAA intention to have the task perform every 25000 hours aircraft time or is it the intention to have the 25000 hours apply to the handle shaft time in service? The final rule needs to clearly state how the 25000 hour interval shall be applied. Paragraph (g) of the proposed rule requires the single-piece machined handle shaft to be new. Why is the FAA including this word in the AD? The proposed rule mandates compliance with the accomplish instructions of the service bulletin. The service bulletin clearly states in the accomplish instructions to install a new shaft. The word new is unnecessary and should not be included in the final rule.