AD 2024-07-51 Airworthiness Directives; Bell Textron Canada Limited Helicopters

Models named: 429. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to Bell Textron Canada Limited Model 429 helicopters, serial number 57001 and subsequent, certificated in any category, with a tail rotor (T/R) blade part number 429-016-101-105 having a serial number identified in Table 1 of Bell Alert Service Bulletin 429-24-63, dated March 21, 2024 (ASB 429-24-63), installed.

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

(1) For each T/R blade identified in paragraph (c) of this AD, within three days or prior to the second flight after the effective date of this AD, whichever occurs first, accomplish the actions required by paragraph (g)(1)(i) or (ii) of this AD, as applicable. (i) If there is any coating (such as a protective tape or protective coating) over the T/R blade abrasion strip, accomplish further actions in accordance with a method approved by the International Validation Branch, FAA; or Transport Canada; or Bell Textron Canada Ltd.'s Design Approval Organization (DAO). If approved by the DAO, the approval must include the DAO-authorized signature. (ii) If there is no coating over the T/R blade abrasion strip, clean the abrasion strip by following the Accomplishment Instructions, part I, paragraph 3, of ASB 429-24-63. Using a flashlight, visually inspect both sides of the T/R blade abrasion strip for a chordwise crack in the area shown in Figure 1 of ASB 429-24-63. Figure 2 of ASB 429-24-63 shows an example of a T/R blade abrasion strip crack. (A) As a result of the actions required by paragraph (g)(1)(ii) of this AD, if there is any chordwise crack, before further flight, remove the T/R blade from service and replace it with an airworthy T/R blade. (B) As a result of the actions required by paragraph (g)(1)(ii) of this AD, if there is not a crack, before further flight, mark an “X” on the T/R blade with a paint marker as shown in Figure 1 of ASB 429-24-63, except do not use the color blue, orange, red, or green. The letter “X” must have a minimum height of 3 inches. (2) For each T/R blade marked with an “X,” accomplish the actions required by paragraph (g)(2)(i) and (ii) of this AD. (i) Before the second flight after accomplishing the actions required by paragraph (g)(1)(ii)(B) of this AD, and thereafter before each subsequent flight, using a flashlight, visually check both sides of each abrasion strip for a chordwise crack. A chordwise crack runs from the direction of the leading edge to the trailing edge. A chordwise crack may be a straight or hairline crack. The owner/operator (pilot) holding at least a private pilot certificate may perform this check and must enter compliance with this paragraph of the AD into the helicopter maintenance records in accordance with 14 CFR 43.9(a) and 91.417(a)(2)(v). The record must be maintained as required by 14 CFR 91.417, 121.380, or 135.439. (ii) As a result of the actions required by paragraph (g)(2)(i) of this AD, if there is any chordwise crack, before further flight, remove the T/R blade from service and replace it with an airworthy T/R blade. (3) For each T/R blade marked with an “X,” within 25 hours time-in-service after accomplishing the actions required by paragraph (g)(1)(ii)(B) of this AD and thereafter within intervals not to exceed 25 hours time-in-service, clean each abrasion strip by following the Accomplishment Instructions, part III, paragraph 2, of ASB 429-24-63. Using a flashlight, visually inspect each side of the T/R blade abrasion strip for a chordwise crack in the area shown in Figure 1 of ASB 429-24-63. Figure 2 of ASB 429-24-63 shows an example of a T/R blade abrasion strip crack. The actions required by this paragraph do not terminate the actions required by paragraph (g)(2)(i) of this AD. (i) As a result of the actions required by the introductory text of paragraph (g)(3) of this AD, if there is any chordwise crack, before further flight, remove the T/R blade from service and replace it with an airworthy T/R blade. (ii) As a result of the actions required by the introductory text of paragraph (g)(3) of this AD, if there is not a crack and the “X” marking is deteriorated or not clearly visible, before further flight, reapply the “X” marking on the T/R blade with a paint marker as shown in Figure 1 of ASB 429-24-63, except do not use the color blue, orange, red, or green. The letter “X” must have a minimum height of 3 inches. (4) If there is any chordwise crack as a result of any action required by paragraph (g)(1)(ii), (g)(2)(i), or (g)(3) of this AD, within 7 days after completing the action, report the information in Appendix 1 to this AD by email to OperationalSafety@faa.gov. (5) As of the effective date of this AD, do not install a T/R blade that is identified in paragraph (c) of this AD on any helicopter.

This AD was prompted by multiple reports of T/R blade abrasion strip cracks. The FAA is issuing this AD to detect a cracked T/R blade abrasion strip. The unsafe condition, if not addressed, could result in severe imbalance, T/R blade failure, loss of the T/R gearbox, loss of directional control, and subsequent loss of control of the helicopter.

None.