AD 2021-14-18 Airworthiness Directives; Leonardo S.p.a. (Type Certificate Previously Held by Agusta S.p.A.) Helicopters

Models named: AB139, AW139. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to Leonardo S.p.a. (type certificate previously held by Agusta S.p.A.) Model AB139 and AW139 helicopters, certificated in any category, with tail rotor (T/R) blade, part number (P/N) 3G6410A00131, 3G6410A00132, 3G6410A00133, 4G6410A00131, 4G6410A00132, or 4G6410A00133, installed.

Comply with this AD within the compliance times specified, unless already done.

(1) For T/R blade P/Ns 3G6410A00131 and 4G6410A00131, within 5 hours time-in-service (TIS) after May 3, 2012 (the effective date of AD 2011-18-52), establish a life limit of 600 hours TIS or 1,500 takeoff and landing cycles (cycles), whichever occurs first, on the affected T/R blades and update the helicopter's historical records. If a T/R blade's total number of cycles is unknown, determine the T/R blade cycles by multiplying the T/R blade's hours TIS by 4. (2) For T/R blade P/Ns 3G6410A00131 and 4G6410A00131, thereafter following paragraph (g)(1) of this AD, remove any T/R blade from service before accumulating 600 total hours TIS or 1,500 total cycles, whichever occurs first. (3) For T/R blade P/Ns 3G6410A00132, 3G6410A00133, 4G6410A00132, and 4G6410A00133, within 5 hours TIS after the effective date of this AD, determine the total number of cycles. If a T/R blade's total number of cycles is unknown, determine the T/R blade cycles by multiplying the blade's hours TIS by 4. Before further flight, remove any T/R blade from service that has accumulated or exceeded its life limit as follows. Thereafter, remove any T/R blade from service before accumulating its life limit as follows: (i) T/R blade P/Ns 3G6410A00132 and 4G6410A00132: 1,200 total hours TIS or 3,200 total cycles, whichever occurs first. (ii) T/R blade P/N 3G6410A00133: 40,000 total cycles. (iii) T/R blade P/N 4G6410A00133: 4,033 total hours TIS or 40,000 cycles, whichever occurs first. Note 1 to paragraph (g)(3): A combination of T/R blades having different P/Ns can be installed on the same helicopter. The eligible combinations of T/R blades P/N are listed in AgustaWestland Mandatory Bollettino Tecnico No. 139-265, Revision B, dated February 18, 2014 (BT No. 139-265). (4) For T/R blade P/Ns 3G6410A00131 and P/N 4G6410A00131, within 25 hours TIS after the effective date of this AD, and thereafter at intervals not to exceed 25 hours TIS, visually inspect the T/R blade for a crack and damage that exceeds allowable limits. Inspect in the area depicted in Figure 1 of BT No. 139-265 using a mirror, a 5X or higher power magnifying glass, and a flashlight, or borescope. If there is a crack or damage that exceeds allowable limits, before further flight, remove the T/R blade from service. (5) As of the effective date of this AD, do not install on any helicopter any T/R blade P/N 3G6410A00131 or P/N 4G6410A00131, unless the actions required by paragraphs (g)(1), (2), and (4) of this AD have been accomplished.

This AD defines the unsafe condition as a crack in a T/R blade. This condition could result in failure of a T/R blade and subsequent loss of control of the helicopter.

This AD replaces AD 2011-18-52, Amendment 39-17020 (77 FR 23109, April 18, 2012) (AD 2011-18-52).