Airworthiness Directive · Amendment 39-17494 · Main rotor head
Various Restricted Category Helicopters
This AD applies to Arrow Falcon Exporters, Inc. (previously Utah State University); Firefly Aviation Helicopter Services (previously Erickson Air-Crane Co.); California Department of Forestry; Garlick Helicopters, Inc.; Global Helicopter Technology, Inc.; Hagglund Helicopters, LLC (previously Western International Aviation, Inc.); International Helicopters, Inc.; Precision Helicopters, LLC; Robinson Air Crane, Inc.; San Joaquin Helicopters (previously Hawkins and Powers Aviation, Inc.); S.M.&T. Aircraft (previously US Helicopters, Inc., UNC Helicopter, Inc., Southern Aero Corporation, and Wilco Aviation); Smith Helicopters; Southern Helicopter, Inc.; Southwest Florida Aviation International, Inc. (previously Jamie R. Hill and Southwest Florida Aviation); Tamarack Helicopters, Inc. (previously Ranger Helicopter Services, Inc.); US Helicopter, Inc. (previously UNC Helicopter, Inc.); West Coast Fabrication; and Williams Helicopter Corporation (previously Scott Paper Co.) Model HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P Helicopters; and Southwest Florida Aviation Model UH-1B (SW204 and SW204HP) and UH-1H (SW205) Helicopters with main rotor grip (grip) part number (P/N) 204-011-121-009, 204-011-121-121, or ASI-4011-121-9, installed, or with grip P/N 204-011-121-005 or 204-011-121-113, if the grip was ever installed on a Model 205B or a Model UH-1N helicopter, or P/N 204-011-121-117, installed, if the grip was ever installed on a Model 205B helicopter, certificated in any category.
We are adopting a new airworthiness directive (AD) for Arrow Falcon Exporters, Inc. (previously Utah State University); Firefly Aviation Helicopter Services (previously Erickson Air-Crane Co.); California Department of Forestry; Garlick Helicopters, Inc.; Global Helicopter Technology, Inc.; Hagglund Helicopters, LLC (previously Western International Aviation, Inc.); International Helicopters, Inc.; Precision Helicopters, LLC; Robinson Air Crane, Inc.; San Joaquin Helicopters (previously Hawkins and Powers Aviation, Inc.); S.M.&T. Aircraft (previously US Helicopters, Inc., UNC Helicopter, Inc., Southern Aero Corporation, and Wilco Aviation); Smith Helicopters; Southern Helicopter, Inc.; Southwest Florida Aviation International, Inc. (previously Jamie R. Hill and Southwest Florida Aviation); Tamarack Helicopters, Inc. (previously Ranger Helicopter Services, Inc.); US Helicopter, Inc. (previously UNC Helicopter, Inc.); West Coast Fabrication; and Williams Helicopter Corporation (previously Scott Paper Co.) Model HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P Helicopters; and Southwest Florida Aviation Model UH- 1B (SW204 and SW204HP) and UH-1H (SW205) Helicopters. This AD requires creating a component history card or equivalent record for each main rotor grip (grip); determining and recording the total hours time-in- service (TIS) for each grip; visually inspecting the upper and lower tangs of the grip for a crack; inspecting the grip buffer pads for delamination and if delamination is present, inspecting the grip surface for corrosion or other damage; inspecting the grip for a crack using ultrasonic (UT) and fluorescent penetrant inspection methods; and establishing a retirement life for certain grips. This AD was prompted by three in-flight failures of grips installed on Bell Helicopter Textron (Bell) Model 212 helicopters, which resulted from cracks originating in the lower main rotor blade bolt lug. The actions are intended to prevent failure of the grip, separation of a main rotor blade, and subsequent loss of control of the helicopter.
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 10 hours time-in-service (TIS), create a component history card or equivalent record and determine and record the total hours TIS for each grip. If the total hours TIS cannot be determined from the helicopter records, assume and record 50 hours TIS for each month for which the hours cannot be determined with the grip installed on any helicopter. Continue to count and record the hours TIS and begin to count and record the number of times the helicopter engine(s) are started (engine start/stop cycles).
(2) Within 10 hours TIS, and then at intervals not to exceed 25 hours TIS, without removing the main rotor blades:
(i) Clean the exposed surfaces of the upper and lower tangs of each grip with denatured alcohol and wipe dry.
(ii) Using a 10X or higher magnifying glass, visually inspect the exposed surfaces of the upper and lower tangs of each grip for a crack. Pay particular attention to the lower surface of each lower grip tang from the main rotor blade bolt-bushing flange to the leading and trailing edge of each grip tang as depicted in Figure 5-7, Inspection of Main Rotor Hub Grip (1200 Hours), Revision 9, dated August 8, 2008, of Chapter 5, Inspections and Component Overhaul Schedule, Revision 11, dated April 30, 2010, of Bell Helicopter Textron, Inc. (BHTI), BHT-212-MM-1, Revision 13, dated September 16, 2010.
(iii) At the intervals shown in Table 1 to Paragraph (e) of this AD, ultrasonic (UT) inspect each grip for a crack in accordance with the BHTI Nondestructive Inspection Procedure, Log No. 00-340, Revision E, dated April 9, 2002. The UT inspection of the grip must be performed by a Nondestructive Testing (NDT) UT Level I Special, Level II, or Level III inspector who is qualified under the guidelines established by MIL-STD-410E, ATA Specification 105, AIA-NAS-410, or an FAA-accepted equivalent for qualification standards of NDT Inspection/Evaluation Personnel.
| Within 30 days, for a grip with the following or more hours TIS: | Thereafter, at intervals not to exceed the following number of hours TIS or the engine start/stop cycles, whichever occurs first: | Hours TIS | Engine start/stop cycles |
|---|---|---|---|
| 204-011-121-009 or ASI-4011-121-9 | 4,000 | 400 | 1,600 |
| 204-011-121-121 | 500 | 150 | 600 |
| 204-011-121-005 or -113, if the grip was EVER installed on a Model 205B or Model UH-1N helicopter | 4,000 | 400 | 1,600 |
| 204-011-121-117, if the grip was EVER installed on a Model 205B helicopter | 500 | 150 | 600 |
(3) At intervals not to exceed 1,200 hours TIS or 24 months, whichever occurs first:
(i) Remove each main rotor blade, and
(ii) Inspect each grip buffer pad on the inner surfaces of each grip tang for delamination as depicted in Figure 5-7, Inspection of Main Rotor Hub Grip (1200 Hours), Revision 9, dated August 8, 2008, of Chapter 5, Inspections and Component Overhaul Schedule, Revision 11, dated April 30, 2010, of Bell Helicopter Textron, Inc., BHT-212-MM-1, Revision 13, dated September 16, 2010. If there is any delamination, remove the buffer pad and inspect the grip surface for corrosion or other damage.
(4) Within 2,400 hours TIS or at the next overhaul of the main rotor hub, whichever occurs first, and then at intervals not to exceed 2,400 hours TIS:
(i) Remove each main rotor blade.
(ii) Remove each grip buffer pad (if installed) from the inner surfaces of each grip tang.
(iii) Visually inspect the grip surfaces for corrosion or other damage.
(iv) Fluorescent-penetrant inspect (FPI) the grip for a crack, paying particular attention to the upper and lower grip tangs. When inspecting a grip, P/N 204-011-121-005, 204-011-121-009, or 204-011-121-113, or ASI-4011-121-9, pay particular attention to the leading and trailing edges of the grip barrel.
(5) Before further flight:
(i) Replace any cracked grip with an airworthy grip.
(ii) Replace any grip with any corrosion or other damage with an airworthy grip, or repair the grip if the corrosion or other damage is within the maximum repair limitations.
(iii) Remove any grip, P/N 204-011-121-009 or ASI-4011-121-9, that has been in service for 15,000 or more hours TIS.
(iv) Remove any grip, P/N 204-011-121-121, that has been in service for 25,000 or more hours TIS.
(6) Revise the Airworthiness Limitations section of the applicable maintenance manual or the Instructions for Continued Airworthiness (ICA) by establishing a new retirement life of 15,000 hours TIS for grip, P/N 204-011-121-009 or ASI-4011-121-9, and 25,000 hours TIS for grip, P/N 204-011-121-121, by marking pen and ink changes or inserting a copy of this AD into the maintenance manual or ICA.
(7) Record a 15,000 hour TIS life limit for each grip, P/N 204-011-121-009 or ASI-4011-121-9, and a 25,000 hour life limit for each grip, P/N 204-011-121-121, on the applicable component history card or equivalent record.
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.
