Scott Lania

Comments on proposed Pilatus PC-12/47E Airworthiness Directive Docket No. FAA-2009-1158, Directorate Identifier 2009-CE-063-AD concerning Honeywell ADAHRS units installed in the aircraft. While in aggreement with the intent of the Airworhiness Directive I have two suggestions to simplify implemenation. First the Applicability applies to all serial number Pilatus model PC-12/47E aircraft. Since the aircraft model is still in production it would be prudent to limit the applicability to manufacturers serial number 545, and 1001 through 1180 which have had the ADAHRS unit in question installed. Paragraph (4) of the Actions and Compliance section adaquately addresses the issue of installing the incorrect part number ADAHRS units on other Pilatus PC-12/47E aircraft. Second in paragraph (2)(ii) of the Actions and Compliance section the word "new" should be replaced with the word "servicable" or "modified". When accomplishing the Pilatus service bulletin 34-022 to comply with this airworthiness directive the ADAHRS unit is not being replaced with a new unit it is being modified with upgraded software and the ADAHRS units data plate is being change to the new part number. Ultimately in the accomplishent of this airworthiness directive on all the effected aircraft, relatively few it any of the ADAHRS unit will be replaced with new units.