AD 2015-05-04 Airworthiness Directives; Bell Helicopter Textron Canada Helicopters

This AD becomes effective April 20, 2015.

(1) The Manager, Safety Management Group, FAA, may approve AMOCs for this AD. Send your proposal to: Sharon Miles, Aviation Safety Engineer, Regulations and Policy Group, Rotorcraft Directorate, FAA, 2601 Meacham Blvd., Fort Worth, Texas 76137; telephone (817) 222-5110; email sharon.y.miles@faa.gov. (2) For operations conducted under a 14 CFR part 119 operating certificate or under 14 CFR part 91, subpart K, we suggest that you notify your principal inspector, or lacking a principal inspector, the manager of the local flight standards district office or certificate holding district office, before operating any aircraft complying with this AD through an AMOC.

The subject of this AD is addressed in Transport Canada Civil Aviation (TCCA) AD No. CF-2011-42, dated November 9, 2011. You may view the TCCA AD on the Internet at http://www.regulations.gov in Docket No. FAA-2014-0070.

Within 50 hours time-in-service (TIS), or prior to reaching 1,250 hours TIS since new, whichever occurs later, visually inspect the helicopter's aft fuselage upper skin (upper skin) for a crack using a 10X or higher power magnifying glass. (1) If there is a crack in the upper skin, before further flight, remove the skin and inspect the longeron assembly, paying attention to the upper flange, for a crack, corrosion, or other damage using a 10X or higher power magnifying glass. (i) If there are no cracks, corrosion, or other damage in the longeron assembly, before further flight, replace the upper skin with an airworthy upper skin. Repeat the inspection of the longeron assembly at intervals not to exceed 50 hours TIS. (ii) If there is a crack, corrosion, or other damage in the longeron assembly, before further flight: (A) Repair the longeron assembly or replace it with an airworthy longeron assembly, part number (P/N) 206-031-314-237B, and reinstall the upper skin or replace it with an airworthy upper skin. (B) Install three external strap doublers in accordance with Part III, paragraphs 5 through10 of Bell Helicopter Alert Service Bulletin 407-11-95, Revision C, dated April 20, 2012 (ASB). (C) Repeat the inspection of the longeron assembly at intervals not to exceed 50 hours TIS. (2) If there is no crack in the upper skin, within 10 hours TIS, visually inspect the longeron assembly using a 10X or higher power magnifying glass for a crack, corrosion, or other damage. (i) If there is a crack, corrosion, or other damage in the longeron assembly, before further flight: (A) Repair the longeron assembly or replace it with an airworthy longeron assembly, P/N 206-031-314-237B. (B) Install three external strap doublers in accordance with Part III, paragraphs 5 through 10 of the ASB. (C) Repeat the inspection of the upper skin and longeron assembly at intervals not to exceed 50 hours TIS. (ii) If there are no cracks, corrosion, or other damage in the longeron assembly, repeat the inspection of the upper skin and longeron assembly at intervals not to exceed 50 hours TIS. (3) Replacing the longeron assembly with longeron assembly, P/N 206-031-314-237B, and installing three external strap doublers constitutes terminating action for this AD. (4) If there is no crack in the upper skin and there is no crack, corrosion, or other damage in the longeron assembly, you may install three external strap doublers in accordance with Part III, paragraphs 5 through 10 of the ASB. This option extends the recurring 50 hours TIS inspection interval to 150 hours TIS.

This AD defines the unsafe condition as a crack in the aft fuselage upper skin or a crack, corrosion, or defect in the longeron assembly. This condition could cause structural failure and consequently, loss of helicopter control.