### U.S. Department of Transportation Federal Aviation Administration Small Ai rplane Directorat e Wichita Aircraft Certification Office 1801 Airport Road, Room 100 Wichita, Kansas 67209 In Reply, refer to: L115W-15-7 Mr. Randolph Shields Director, Safety & Certification B099-A02 Beechcraft Corporation 

# JAN · .. 

# 'J20!5 10511 E Central Ave Wichita, KS 67206 Subject: AD 2014-21-06 Beechcraft Undocumented Comments in the AD Docket
Dear Mr. Shields:
Tllis letter addresses comments from Shawn Kohr/Beechcraft Corporation, posted September 1 1,2014, to Docket FAA-2014-0345, Direct orate Identifier 2013

-NM-230-AD. These comments can be found at: http://www.regulations.gov/#!documentDetail;D=FAA2014-0345-0003. The following italicized sentences are issues noted in Mr. Kohr's comments, followed by the FAA's responses. 1. However , at nopoint has Whippany Actuation Systems recommended replacement of thejackscrew other than on an "on condition " basis. Mandat01y replacement of thejackscrew assembly regardless of condition is unnecessmy. FAA Response: The FAA disagrees with this statement. During discussions with Beechcraft regarding this issue, it was brought to light that GE had proposed
a safety action to recall26 high time PTA's (21 commercial; 5 military) to replace ACME nuts and jackscr ew as required per the CS Repair Shop Lead directive. Based upon these discussions, replacement ofthe ACME nut and jackscrew are required per the repair shop lead directive. To our knowledge, this directive is not a published document but is a verbal direction that was provided to those personnel overhauling these units at GE Aviation. This understanding is also consistent with the Beech Safety Review Board minutes dated May 12, 2011 , which state "HBC requested (20 1 0) that GE revise their overhaul requirements to change both thejackscrew and ACME nut at overhaul."
The FAA had to conservatively select the replacement lif e for the ACME nut andjackscrew of 1800 hours since Beechcraft has not provided any engineering data to support a longer life. The FAA worked with Beechcraft engineers to see ifthere was a way to extend the 1800 hour life, but we could not fmd a way without generating a fatigue spectrum for the ACME nut andj ackscrew.
2. Of the units involved in the investigation, which was the basis for this NP 

### RM, two units were identified as being improperly installed while improperPage 3 replacement ofthe Acme nut and jackscrew every 1800 hours. Also, the ALM has not been mandated by an AD, so it is not a requirement for all airplanes. An AD is the appropriate vehicle for mandating the replacement.
5. The proposedAD is in effect requiring the replacement of parts within the appliance at the established overhaul interval andBeechcraft C01poration believes an appliance AD may be a more appropriate vehicle to enforce this requirement.
FAA Response: The FAA disagrees with this statement. The PTA does not have a separate design approval. For this component and its installation, HBC is the design approval holder and the approval was accomplished under the certification procedures for the Beechjet type certificate. Also perFAA-IR-M8040.1 C, the Airworthiness Directives Manual, because the unsafe condition results from the installation ofthe appliance on an aircraft, the AD action is to be issued against the aircraft, engine, or propeller (not the appliance).
Ifyou have any questions or comments regarding this subject, please contact Ann Johnson at (316) 946-4105 or ann.jolmson@faa.gov. Sincerely, 

# C-'D

.**~** ;J

,n Robert P. Busto [)'-Associate ACO Manager, Continued Operational Safety Wichita Aircraft Certification Office