AD 2013-16-07 Airworthiness Directives; Eurocopter France Helicopters

This AD becomes effective September 24, 2013.

(1) The Manager, Safety Management Group, FAA, may approve AMOCs for this AD. Send your proposal to: Gary Roach, Aviation Safety Engineer, Regulations and Policy Group, Rotorcraft Directorate, FAA, 2601 Meacham Blvd., Fort Worth, TX 76137; telephone (817) 222-5110; email gary.b.roach@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 the Direction Générale de L'Aviation Civile (DGAC) France AD No F-2007-027, dated January 2, 2008. You may view the DGAC AD in the AD Docket on the Internet at http://www.regulations.gov.

Within 50 hours time-in-service (TIS): (1) Inspect the TGB aft attachment fitting to measure the dimension for a blind hole as follows: (i) Remove the TGB attachment bolt (c) but retain washer (d) as depicted in Detail A, Figure 1, of Eurocopter Emergency Alert Service Bulletin (EASB) No. 53.01.58 and EASB No. 53A012, both Revision 1, and both dated January 4, 2008. (ii) Use a depth gauge to measure dimension “x” between the top face of the washer (d) and the bottom of aft fitting (a) as depicted in Detail A, Figure 1, of the EASB. (2) If the measurement is equal to or greater than 81 mm, then the blind hole is present. Install the TGB attachment bolt (c) with its washer (d) as depicted in Detail A, Figure 1, of EASB No. 53.01.58 or No. 53A012. Lock with lockwire. (3) If the measurement is less than 81 mm, then the blind hole is missing. Inspect the end of the threaded section of bolt (c) for chafing or a contact mark, as depicted in Area 1, Figure 1, of the EASB. (i) If there is no chafing and no contact marks, install bolt (c) with washer (d) and additional washer (2) as depicted in Detail B, Figure 1, of EASB No. 53.01.58 or No. 53A012. (ii) If there is chafing or a contact mark, replace the TGB attachment bolt (c) with an airworthy bolt and install with washer (d) and additional washer (2) as depicted in Detail B, Figure 1, of EASB No. 53.01.58 or No. 53A012. Lock with lockwire. (iii) Within the next 825 hours TIS, replace the TGB aft attachment fitting with an airworthy attachment fitting. (4) Inspect the right and left attachment points of the TGB forward attachment to measure the dimension for a blind hole, as follows: (i) Remove both TGB attachment bolts (c) but retain washers (d), as depicted in Detail A, Figure 2, of EASB No. 53.01.58 or No. 53A012. (ii) Use a depth gauge to measure dimension “x” between the top face of washer (d) and the bottom of forward fitting (b) at the right and left attachment points, as depicted in Detail A, Figure 2, of EASB No. 53.01.58 or No. 53A012. (5) If both measurements are equal to or greater than 81 mm, then the blind hole is present. Install TGB attachment bolt (c) with its washer (d), as depicted in Detail A, Figure 2, of EASB No. 53.01.58 or No. 53A012. Lock with lockwire. (6) If one or both measurements are less than 81 mm, then the blind hole is missing. Inspect the end of the threaded section of each bolt (c) for chafing or a contact mark, as depicted in Area 1, Figure 2 of EASB No. 53.01.58 or No. 53A012. (i) If there is no chafing and no contact marks, for each attachment point, install bolt (c) with washer (d) and additional washer (2), as depicted in Detail B, Figure 2, of EASB No. 53.01.58 or No. 53A012. (ii) If there is chafing or a contact mark, replace each the TGB attachment bolt (c) with an airworthy bolt and install bolt (1) with washer (d) and additional washer (2), as depicted in Detail B, Figure 2, of EASB No. 53.01.58 or No. 53A012. Lock with lockwire. (iii) Within the next 825 hours TIS, replace the TGB forward attachment fitting with an airworthy attachment fitting.

This AD defines the unsafe condition as interference between the tail gearbox (TGB) attachment bolt and the structure fitting. This condition could result in insufficient tightening of the TGB casing, damage to the TGB attachment, cracking under the attachment bolt, loss of the TGB and consequently, loss of helicopter control.