Airworthiness Directive · Amendment 39-17518 · Tail rotor blades
Bell Helicopter Textron Helicopters
This AD applies to Bell Helicopter Textron (Bell) Model 205A, 205A-1, 205B, 210, 212, 412, 412CF, and 412EP helicopters with a tail rotor blade assembly (T/R blade), part number (P/N) 210-010-001-(all dash numbers) or 212-010-750-(all dash numbers), certificated in any category.
We are superseding Airworthiness Directive (AD) 2008-10-03 for Bell Helicopter Textron Helicopters (Bell) Model 204B, 205A, 205A-1, 205B, 210, 212, 412, 412CF, and 412EP helicopters. AD 2008-10-03 required certain checks and inspections of each tail rotor blade assembly (T/R blade) at specified intervals and repairing or replacing, as applicable, any cracked or damaged T/R blade. Since we issued AD 2008-10-03, an accident attributed to a T/R failure occurred. This new AD retains the requirements of AD 2008-10-03 and adds a second, more detailed inspection that allows for an earlier detection of a crack or other damage in a T/R blade. These actions are intended to prevent a failure of the T/R blade and subsequent loss of helicopter control.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
(1) Within 25 hours time-in-service (TIS) or 30 days, whichever occurs first, and thereafter at intervals not to exceed 25 hours TIS or 30 days, whichever occurs first:
(i) Clean each T/R blade by hand using a mild soap and cheesecloth (C-486) on both sides of the blade in a spanwise direction and dry thoroughly.
(ii) Using a 3X or higher power magnifying glass and a bright light, visually inspect the T/R blade skins, leading edge spar, doublers, grip plates, and trailing edge on both sides of each blade for a crack, corrosion (may be indicated by blistering, peeling, flaking, bubbling, or cracked paint), a nick, scratch, dent, or other damage. Pay particular attention to both sides of the T/R blade in the area located 16 to 35 inches from the T/R blade tip (blade station 20.00 to 35.00—the T/R blade tip is located at blade station 51) as shown by the shaded area of Figure 1 of Bell Alert Service Bulletin (ASB) No. 205-13-109; ASB No. 205B-13-61; ASB No. 212-13-147; ASB 412-13-155; or ASB No. 412CF-13-52, all dated February 4, 2013, as applicable to your helicopter. Also, pay particular attention to the inboard blade butt area near the attachment of the external balance weight and screws, and to any blade surface that was snagged by cheesecloth, as that may be an indication of a crack or paint chip that could lead to corrosion.
Note 1 to Paragraph (f) of this AD: Figure 1 of the Bell ASB No. 205-13-109; ASB No. 205B-13-61; ASB No. 212-13-147; ASB 412-13-155; and ASB No. 412CF-13-52, all dated February 4, 2013, show the shaded area as part of the 10X inspection only. This AD requires the shaded area to be inspected during both the 3X and 10X inspections.
(iii) Using a 10X or higher magnifying glass and a bright light, visually inspect both sides of each blade for a crack or other damage between blade station 20.00 to 35.00 as shown by the shaded area of Figure 1 of Bell ASB No. 205-13-109; ASB No. 205B-13-61; ASB No. 212-13-147; ASB 412-13-155; or ASB No. 412CF-13-52, all dated February 4, 2013, as applicable to your helicopter.
(iv) If any blistering, peeling, flaking, bubbling, or cracked paint is detected anywhere on the blade, remove the paint from the affected area by sanding in a spanwise direction with abrasive cloth or paper (C-406) 240-grit or finer, and a final sanding using abrasive cloth or paper (C-406) 400-grit or finer. Visually inspect the affected area for any corrosion or a crack using a 10X or higher magnifying glass and a bright light. If any corrosion is found, measure the depth of the damage. (A digital optical micrometer is one tool that can be used for this measurement.)
(v) If a nick, scratch, or dent is found anywhere on the blade, visually inspect for a crack using a 10X or higher power magnifying glass and a bright light. Measure the depth of the damage. (A digital optical micrometer is one tool that can be used for this measurement.)
(2) Before further flight:
(i) Replace with an airworthy blade anyT/R blade that has a crack or that has any corrosion, nick, scratch, dent, or other damage that exceeds any of the maximum repair limits.
(ii) Repair or replace with an airworthy blade any T/R blade that has any corrosion, nick, scratch, dent or other damage that is within the maximum repair limits.
(3) Replacing a T/R blade with T/R blade, P/N 412-016-100-111, on eligible helicopter models is considered terminating action to this AD.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
