Airworthiness Directive · Amendment 39-15509 · Bell Helicopter Textron Model 204B, 205A, 205A-1, 205B, 210, 212, 412, 412CF, and 412EP Helicopters
Bell Helicopter Textron Model 204B, 205A, 205A-1, 205B, 210, 212, 412, 412CF, and 412EP Helicopters
Superseded. A later AD replaced this one: AD 2013-15-02. Comply with the one in force.
The following model helicopters, with the specified tail rotor blade assembly (T/R blade) installed, certificated in any category:
| Helicopter model | With T/R blade, part number (P/N) |
|---|---|
| 204B, 205A, 205A-1, 212, 412, 412CF, and 412EP | 212-010-750-(all dash numbers). |
| 205B | 212-010-750-(all dash numbers). 212-015-501-(all dash numbers). |
| 210 | 210-010-001-(all dash numbers). 212-010-750-(all dash numbers). |
This amendment adopts a new airworthiness directive (AD) for the specified Bell Helicopter Textron (Bell) model helicopters. This action requires certain checks and inspections of each tail rotor blade assembly (T/R blade) at specified intervals and repairing or replacing, as applicable, any unairworthy T/R blade. This amendment is prompted by three failures of a T/R blade occurring during flight and a recent incident of a cracked T/R blade discovered during a scheduled visual inspection. The actions specified in this AD are intended to detect damage to a T/R blade that could lead to cracking of a T/R blade and subsequent loss of control of the helicopter.
Required as indicated.
To detect any damage in a T/R blade, prevent cracking of a T/R blade leading to failure from static overload, and subsequent loss of control of the helicopter, accomplish the following:
(a) Before each start of the engines, visually check both sides of each T/R blade for a crack. An owner/operator (pilot) holding at least a private pilot certificate may perform this visual check and must enter compliance with this paragraph into the aircraft maintenance records in accordance with 14 CFR 43.11 and 91.417(a)(2)(v).
(b) Within 25 hours time-in-service (TIS) or 30 days, whichever occurs first, unless accomplished previously, and thereafter at intervals not to exceed 25 hours TIS or 30 days, whichever occurs first:
(1) Clean each T/R blade by hand using a mild degreaser and water to remove soot and grime on both sides of the blade using a coarse, loosely woven cotton cloth in a spanwise direction. Use a cloth with a color that contrasts with the color of the T/R blade so that a snag will be visible.
(2) Using a 3-power or higher magnifying glass and a bright light, visually inspect the T/R blade skins, leading edge spar, doublers, grip plates, and trailing edge for a crack, corrosion (may be indicated by blistering, peeling, flaking, bubbling, or cracked paint) and any other damage (including a nick, scratch, or dent). See Figure 1 of this AD. Pay particular attention to both sides of the T/R blade in the area located 16 to 26 inches from the T/R blade tip (blade station 25 to 35—the T/R blade tip is located at blade station 51) and to the inboard blade butt area near the attachment of the external balance weights and screws. Also pay particular attention to any blade surface that was snagged by the cloth, as that may be an indication of a crack or paint chip that could lead to corrosion.
(3) If any blistering, peeling, flaking, bubbling, or cracked paint is detected, remove the paint from the affected area and visually inspect the affected area for corrosion or a crack using a 10-power or higher magnifying glass. If any corrosion is found, measure the depth of the corrosion (a digital optical micrometer is one tool that can be used for this measurement).
(4) If a nick, scratch, or dent is found, visually inspect for a crack using a 10-power or higher magnifying glass and measure the depth of the damage (a digital optical micrometer is one tool that can be used for this measurement).
(c) Before further flight:
(1) Replace any T/R blade that has a crack with an airworthy blade.
(2) Replace any T/R blade that has any corrosion, nick, scratch, dent, or other damage that exceeds any maximum repair limit with an airworthy blade.
Note 1: The maximum repair limits are specified in the applicable maintenance manual.
(3) 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.
Note 2: The repair procedures are specified in the applicable maintenance manual and component repair and overhaul manuals.
(d) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Manager, Rotorcraft Certification Office, Rotorcraft Directorate, FAA, ATTN: Michael Kohner, Aviation Safety Engineer, Fort Worth, Texas 76193-0170, telephone (817) 222-5447, fax (817) 222-5783, for information about previously approved alternative methods of compliance.
(e) This amendment becomes effective on May 21, 2008.
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.
