Airworthiness Directive · Amendment 39-21875 · Engine/transmission coupling
Various Restricted Category Helicopters
This AD applies to restricted category Model UH-1H helicopters; current type certificate holders include but are not limited to Arrow Falcon Exporters Inc.; Global Helicopter Technology, Inc.; Hagglund Helicopters, LLC; JJASPP Engineering Services, LLC.; Northwest Rotorcraft, LLC; Overseas Aircraft Support, Inc.; Richards Heavylift Helo, Inc.; Rotorcraft Development Corporation; Southwest Florida Aviation International, Inc.; and Tamarack Helicopters, Inc., with KAflex main driveshaft part number (P/N) SKCP2180-1, SKCP2281-1, SKCP2281-1R, or SKCP2281-103 installed.
Note 1 to paragraph (c): Helicopters with an SW205 designation are Southwest Florida Aviation International, Inc., Model UH-1H helicopters.
The FAA is adopting a new airworthiness directive (AD) for certain type certificated Model UH-1H restricted category helicopters. This AD was prompted by multiple reports of failure of the main driveshaft. This AD requires establishing a limit to replace certain main driveshafts, and a one-time and repetitive inspections of the main driveshafts. The FAA is issuing this AD to address the unsafe condition on these products.
(1) Before further flight after the effective date of this AD, determine the total hours time-in-service (TIS) of the main driveshaft. If the total hours TIS of the main driveshaft cannot be determined, use the helicopter's total hours TIS as the total hours TIS of the main driveshaft for the action required by this paragraph.
(i) If the main driveshaft has accumulated less than 5,000 total hours TIS, before exceeding 5,000 total hours TIS, replace the main driveshaft. The main driveshaft may be overhauled in accordance with FAA-approved procedures to accomplish the replacement required by this paragraph.
Note 2 to paragraph (g)(1)(i): This note applies to paragraphs (g)(1)(i) and (ii), (g)(2), and (g)(3)(i) through (iv) of this AD. U.S. Army Aviation and Missile Command, Depot Maintenance Work Requirement for Main Drive Shaft DMWR 55-1615-278, Original Issuance, dated September 30, 2009, specifies procedures that are not FAA-approved.
(ii) If the main driveshaft has accumulated 5,000 or more total hours TIS, before further flight, replace the main driveshaft. The main drive shaft may be overhauled in accordance with FAA-approved procedures to accomplish the replacement required by this paragraph.
(2) Thereafter following paragraph (g)(1) of this AD, replace the main driveshaft before accumulating 5,000 total hours TIS. The main drive shaft may be overhauled in accordance with FAA-approved procedures to accomplish the replacement required by this paragraph.
(3) Within 25 hours TIS after the effective date of this AD, remove main driveshaft P/N SKCP2180-1, SKCP2281-1, SKCP2281-1R, or SKCP2281-103 by following “6-24.3. Removal—Main Driveshaft P/N SKCP2281-103” on page 6-24, including “4-24. Removal—Air Inlet Filters” on page 4-17 and “Figure 4-9. Engine Air Inlet Filter Installation” on page 4-16, of Headquarters, Department of the Army, Aviation Unit and Intermediate Maintenance Instructions Army Model UH-1H/V/EH-1H/X Helicopters, Technical Manual TM 55-1520-210-23-1, Change No. 42, dated April 14, 2003 (TM 55-1520-210-23-1 C 42), except where instructed to “refer to figure 6-12.2” in TM 55-1520-210-23-1 C 42, refer to Figure 1 to the introductory text of paragraph (g)(3) of this AD, and where instructed to “see figure 6-12.3” in TM 55-1520-210-23-1 C 42, see Figure 2 to the introductory text of paragraph (g)(3) of this AD, and:
Note 3 to the introductory text of paragraph (g)(3): Figures 6-12.2 and 6-12.3 are missing from TM 55-1520-210-23-1 C 42.
(i) Inspect for any broken, loose, or missing hardware. If there is broken or loose hardware, before further flight, remove the main driveshaft from service. If there is missing hardware, before further flight, replace the main driveshaft. The main drive shaft may be overhauled in accordance with FAA-approved procedures to accomplish the replacement required by this paragraph.
(ii) Visually inspect each flex frame and mount bolt torque stripe (red or yellow) for movement. If there is any torque stripe movement, before further flight, replace the main driveshaft. The main drive shaft may be overhauled in accordance with FAA-approved procedures to accomplish the replacement required by this paragraph.
(iii) Visually inspect each joint for fretting corrosion, which may be indicated by red metallic particles. If there is any grease, oil, or dirt covering a joint, clean the area and visually inspect again. If there is any fretting corrosion, before further flight, replace the main driveshaft. The main drive shaft may be overhauled in accordance with FAA-approved procedures to accomplish the replacement required by this paragraph.
(iv) Inspect the main driveshaft for mechanical damage, corrosion, an edge dent, and nick as shown in Figure 3 to paragraph (g)(3)(iv) of this AD. For the purposes of this inspection, mechanical damage may be indicated by a crack, scratch, or wear; and corrosion may be indicated by corrosion or pitting. If there is a scratch, wear, corrosion, pitting, an edge dent, or a nick within allowable limits, before further flight, repair the main driveshaft in accordance with FAA-approved procedures. If there is a crack, or a scratch, wear, corrosion, pitting, an edge dent, or a nick that exceeds allowable limits, before further flight, replace the main driveshaft. The main drive shaft may be overhauled in accordance with FAA-approved procedures to accomplish the replacement required by this paragraph.
(4) Before installing the main driveshaft following paragraph (g)(3) of this AD, and with the engine adapter installed in the end of the engine output shaft, inspect the alignment of the main driveshaft installation between the transmission input drive quill coupling and the engine output shaft adapter by following “6-24. Alignment—Main Driveshaft,” paragraphs c. through g. on pages 6-21 through 6-23, including “Figure 6-7. Transmission Positioning for Driveshaft Alignment” on page 6-2 (Figure 6-7), and “Figure 6-8. Tool Application—Use of Alignment Tool Set (T47)” on page 6-3 (Figure 6-8), of TM 55-1520-210-23-1 C 42. If there is misalignment, before further flight, adjust the alignment by following “6-24. Alignment—Main Driveshaft,” paragraphs h. through j. on page 6-23, including Figure 6-7 and Figure 6-8, of TM 55-1520-210-23-1 C 42.
(5) Within 300 hours TIS after the effective date of this AD, and thereafter within intervals not to exceed 300 hours TIS, with the main driveshaft installed, accomplish the actions in paragraphs (g)(3)(i) through (iv) of this AD.
(6) As an optional terminating action for the requirements of this AD, you may install KAflex main driveshaft P/N SKCP3303-1.
(7) As an option to accomplishing the actions by following the specified portions in TM 55-1520-210-23-1 C 42 in paragraphs (g)(3) and (4) of this AD, you may accomplish the actions by following those specified portions in Headquarters, Department of the Army, Aviation Unit and Intermediate Maintenance Instructions Army Model UH-1H/V/EH-1H/X Helicopters, Technical Manual TM 55-1520-210-23-1, Change No. 47, dated September 20, 2005 (TM 55-1520-210-23-1 C 47), and disregard exceptions to refer to Figure 1 and see Figure 2 to the introductory text of paragraph (g)(3) of this AD, instead refer to “Figure 6-12.2. Main Driveshaft Installation & Removal Tool” and see “Figure 6-12.3. Work Aid Tool Installed on Main Driveshaft,” on page 6-27 of TM 55-1520-210-23-1 C 47 as instructed in TM 55-1520-210-23-1 C 47.
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.
