Results
2013-23-17: We are adopting a new airworthiness directive (AD) for Rolls- Royce plc (RR) RB211-535E4-37, -535E4-B-37, -535E4-C-37, RB211Trent 768-60, 772-60, and 772B-60 turbofan engines. This AD requires removal of certain high-pressure (HP) and intermediate-pressure (IP) turbine discs before their accumulated cyclic lives have reached the revised limits. This AD was prompted by a report of an HP disc contaminated with a steel inclusion. We are issuing this AD to prevent failure of the HP or IP turbine disc, uncontained engine failure, and damage to the airplane.
2013-24-06: We are adopting a new airworthiness directive (AD) for all Thielert Aircraft Engines GmbH TAE 125-01 reciprocating engines. This AD requires applying sealant to close the engine clutch housing (crankcase assembly) opening. This AD was prompted by a report of engine power loss due to engine coolant contaminating the engine clutch. The design of the engine allows the crankcase assembly opening to be susceptible to contamination from external sources. We are issuing this AD to prevent in-flight engine power loss, which could result in loss of control of, and damage to, the airplane.
2013-23-15: We are superseding Airworthiness Directive (AD) 2009-06-02, which applied to certain The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747SR, and 747SP series airplanes. AD 2009-06-02 required repetitive inspections for skin cracks at the shear tie end fastener locations of the fuselage frames, and repair of cracks if necessary. This new AD also requires repetitive inspections for skin cracks next to the shear tie on airplanes with certain existing repair doublers, and corrective actions if necessary. This AD also revises the applicability to include additional airplanes. This AD was prompted by additional cracking found on an airplane not affected by AD 2009-06-02. We are issuing this AD to detect and correct fatigue cracks in the fuselage skin that can propagate and grow, and result in reduced structural integrity and sudden decompression of the airplane in flight.
78-18-02: 78-18-02 MCDONNELL DOUGLAS: Amendment 39-3289. Applies to Model DC-3 Series, DC-3A Series, DC-3C Series, DC-3D, Super DC-3 and R4D Series certificated in all categories, including all military models. \n\n\tCompliance required as indicated. \n\n\tTo minimize the possibility of a jammed elevator control system, due to cable interference accomplish the following: \n\n\t(a)\tWithin the next 25 hours time in service after the effective date of this AD; unless already accomplished within the last 60 days: \n\n\tNOTE: Determine that the elevator control system is properly rigged prior to accomplishment of the inspections required by this AD. \n\n\t\t(1)\tVisually inspect the right and left elevator upper cables and cable fittings for possible interference with the bulkhead frame and channel located just aft of the control column assembly at fuselage station (F.S.) 63 on the DC-3 Series and at F.S. 24 on the Super DC-3. The elevator cable and/or cable fitting must have 3/32 inch minimum clearance relative to the bottom of the cutout hole and both legs of the channel, throughout full cable travel. Pay particular attention to clearance when the elevator horn of the control column is rotated to the lowest point of its movement arc. \n\n\tNOTE: The channel is attached to aft side of bulkhead frame and the upper elevator cables are attached to extreme bottom of control column elevator horn, located forward of the bulkhead frame. Inspection may be accomplished after removal of external access plates on bottom of fuselage, forward and aft of F.S. 63 on DC-3 Series and F.S. 24 on the Super DC-3. \n\n\t\t(2)\tIf existing clearance is less than required by paragraph (a)(1), trim out the cable cutout hole in the bulkhead frame and both legs of the channel to provide a nominal clearance of 1/8 + 1/32 inches using a minimum 1/4 inch corner radius. Break and smooth all edges. \n\n\t(b)\tSpecial flight permits may be issued in accordance with FAR's 21.197 and 21.199 to operate airplanes to abase for accomplishment of the inspection required by paragraph (a)(1). \n\n\t(c)\tEquivalent modifications may be used when approved by the Chief, Aircraft Engineering Division, FAA Western Region. \n\n\tThis amendment becomes effective September 6, 1978.
91-22-04: 91-22-04 BOEING: Amendment 39-8064. Docket No. 91-NM-105-AD. \n\n\tApplicability: Model 707/720 series airplanes with a main cargo door, listed in Boeing Service Bulletin 3477, dated July 26, 1990; and Models 727-100C and 727-200F series airplanes, listed in Boeing Service Bulletin 727-52-0142, dated July 26, 1990; certificated in any category. \n\n\tCompliance: Required as indicated, unless previously accomplished, or unless the main cargo door has been deactivated in accordance with Boeing Service Bulletin 3311, dated May 26, 1978 (for Model 707/720 series airplanes), or Boeing Service Bulletin 727-29-0053, dated July 8, 1977 (for Model 727 series airplanes). \n\n\tTo prevent inadvertent opening of the main cargo door, accomplish the following: \n\n\t(a)\tWithin the next 30 days after the effective date of this AD, change the operating procedures for the main cargo door to include the following requirements, and thereafter comply with those revised procedures until the inspection required by paragraph (b) of this AD has been accomplished: Prior to takeoff following each operation of the door, conduct a visual verification, through the external viewports, to ensure proper engagement of the latching cams to ensure that the door is fully latched closed. This information must be relayed to and acknowledged by the flight crew. \n\n\t\t(1)\tThe procedures required by this paragraph must be accomplished by a qualified and trained mechanic or flight officer, and the training program must be approved by the FAA Principal Maintenance Inspector (PMI). \n\n\t\t(2)\tDocumentation of compliance with these procedures is required and the method of documentation must be approved by the FAA PMI.\n \n\t(b)\tWithin the next 18 months after the effective date of this AD, perform a visual inspection for wear of the mating surfaces of the pressure relief door hinge fittings and latch cams of the main cargo door, in accordance with Section III, Part I, of the Boeing Service Bulletin 3477, dated July 26, 1990 (for Model 707/720 series airplanes), or Boeing Service Bulletin 727-52-0142, dated July 26, 1990 (for Model 727 series airplanes). \n\n\t\t(1)\tIf wear exceeds the limits specified in the applicable service bulletin: Prior to further flight, replace worn parts, as follows. Do not intermix original configuration parts with modified parts in the same door. \n\n\t\t\t(i)\tReplace worn parts with modified parts in accordance with Section III, Part II, of the applicable service bulletin; or \n\n\t\t\t(ii)\tReplace worn parts with airworthy parts of the original configuration in accordance with FAA-approved procedures. \n\n\t\t(2)\tThe inspection and replacement of parts, if necessary, in accordance with this paragraph constitutes terminating action for the special operating procedures required by paragraph (a) of this AD. \n\n\t(c)\tWithin 36 months after the effective date of this AD, accomplish the following in accordance with Section III, Part II, of Boeing Service Bulletin 3477, dated July 26, 1990 (for Model 707/720 series airplanes), or Boeing Service Bulletin 727-52-0142, dated July 26, 1990 (for Model 727 series airplanes). \n\n\t\t(1)\tReplace the latch cams, \n\n\t\t(2)\tReplace the latch cam bellcranks, \n\n\t\t(3)\tReplace the pressure relief door hinge fittings, and \n\n\t\t(4)\tPerform the operation, control, and door warning system tests. \n\n\t(d)\tFor airplanes on which the main cargo door has been deactivated: \n\n\t\t(1)\tPrior to reactivating the main cargo door, accomplish the inspection required by paragraph (b) of this AD. \n\n\t\t(2)\tWithin the next 18 months after reactivation, or within 36 months after the effective date of this AD, whichever is later, accomplish the requirements of paragraph (c) of this AD. \n\n\t(e)\tThe accomplishment of Section III, Part II, of Boeing Service Bulletin 3477, dated July 26, 1990 (for Model 707/720 series airplanes), or Boeing Service Bulletin 727-52-0142, dated July 26, 1990 (for Model 727 series airplanes), as applicable, constitutes terminating action for the requirements of this AD. \n\n\t(f)\tAn alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. \n\n\tNOTE: The request should be forwarded through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Seattle ACO. \n\n\t(g)\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD. \n\n\t(h)\tThe inspection and repair requirements shall be done in accordance with Boeing Service Bulletin 3477, dated July 26, 1990, or Boeing Service Bulletin 727-52-0142, dated July 26, 1990, as applicable. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. Copies may be inspected at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington; or at the Office of the Federal Register, 1100 L Street NW., Room 8401, Washington, D.C. \n\n\tThis amendment (39-8064, AD 91-22-04) becomes effective on November 29, 1991.
2018-07-09: We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model CL-600-2C10 (Regional Jet Series 700, 701, & 702), Model CL-600-2D15 (Regional Jet Series 705), Model CL-600-2D24 (Regional Jet Series 900), and Model CL-600-2E25 (Regional Jet Series 1000) airplanes. This AD was prompted by a report of a smoke-in-cabin event due to a non-sustaining electrical fire. This AD requires installation of protective sleeves on the bonding jumper wires of affected galleys and lavatories. We are issuing this AD to address the unsafe condition on these products.
2013-23-13: We are adopting a new airworthiness directive (AD) for certain Airbus Model A300 series airplanes; Model A300 B4-600, B4-600R, and F4- 600R series airplanes; and Model A300 C4-605R Variant F airplanes (collectively called Model A300-600 series airplanes). This AD was prompted by a report that cracking was found in area 2 of the frame base fittings between frame 41 and frame 46. This AD requires a check of maintenance records to determine if certain repairs were done in area 1 of the frame base fittings, and, for affected airplanes, a detailed inspection for cracking in area 2 of the frame base fittings between frame 41 and frame 46, and repair if necessary. We are issuing this AD to detect and correct cracking in area 2 of the frame base fittings between frame 41 and frame 46, which could adversely affect the structural integrity of the airplane.
2013-23-08: We are adopting a new airworthiness directive (AD) AQUILA-- Aviation by Excellence AG Model AT01 airplanes. This AD results from mandatory continuing airworthiness information (MCAI) issued by the aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as a defective sealing of a tapped through bore hole at the inside of the fuel tank openings in combination with prolonged periods at maximum fuel level. We are issuing this AD to require actions to address the unsafe condition on these products.
2003-13-04: This amendment adopts a new airworthiness directive (AD) that applies to all Pilatus Aircraft Ltd. (Pilatus) Model PC-6 airplanes. This AD requires you to inspect the integral fuel tank wing ribs for cracks and the top and bottom wing skins for distortion, repair any cracks or distortion before further flight, and accomplish a fuel tank ventilating system installation. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. The actions specified by this AD are intended to detect and correct cracks in the ribs of the inboard integral fuel tanks in the left and right wings, which could lead to wing failure during flight.
2013-23-01: We are adopting a new airworthiness directive (AD) for all Rolls-Royce Deutschland Ltd & Co KG (RRD) model Tay 620-15, 650-15, and 651-54 turbofan engines. This AD requires a one-time inspection of the high-pressure (HP) air bleed valve operating mechanism and, depending on findings, corrective action. This AD was prompted by excessive deterioration of the HP air bleed valve operating mechanism, which is influencing the aerodynamic fan flutter margin. This condition, if not corrected, could lead to multiple fan blade failure. We are issuing this AD to prevent multiple fan blade failure, which could result in uncontained engine failure and damage to the airplane.
2013-23-05: We are adopting a new airworthiness directive (AD) for all Fokker Services B.V. Model F.28 Mark 0070 and 0100 airplanes. This AD was prompted by a design review, which revealed that, under certain failure conditions, wiring in the main fuel tank could develop a short circuit that might cause a hot spot on the wiring conduit or puncture the wiring conduit wall. This AD requires installing fuses in the power supply wiring and/or return wiring for various components in the fuel system; and revising the airplane maintenance program by incorporating critical design configuration control limitations. We are issuing this AD to prevent an ignition source in the main fuel tank vapor space, which could result in a fuel tank explosion and consequent loss of the airplane.
72-21-02: 72-21-02 BRANTLY: Amdt. 39-1534 as amended by Amendment 39-1569. Applies to Model B-2, B-2A and B-2B Helicopters certificated in all categories. Compliance required as indicated, unless already accomplished: To prevent fatigue failure of the pylon outboard bearing shaft, Part Number 280-5 or 280- 6, replace these parts (three per helicopter) with serviceable parts having Part Number 280-6 within the next 10 hours time in service after the effective date of this AD, or upon the accumulation of 500 hours total time in service, whichever occurs later. The replacement pylon outboard bearing shafts must be torqued to 2500 plus or minus 100 inch-pounds and secured with an AN435-4-9 rivet or equivalent. This AD effectively revises the service life limits published in Type Certificate Data Sheet No. 2H2 for Part Numbers 280-5 and 280-6, which are a part of the hub and inboard blade assembly Part Number 305-1. Part Numbers 280-5 and 280-6 pylon outboard bearing shafts, willnow have a service life limit of 500 hours time in service. Type Certificate Holder, Mr. M. K. Hynes, 1241 Lake Horney Drive, Lakeland, Florida, 33801, may be contacted for information regarding installation tools, replacement parts, etc. Amendment 39-1534 became effective October 14, 1972, for all persons except those to whom it was made effective upon receipt of the air mail letter dated October 3, 1972, which contained this amendment. This Amendment 39-1569 becomes effective on December 8, 1972
2013-22-22: We are superseding airworthiness directive (AD) 2013-01-07 for all Turbomeca S.A. Arriel 2D turboshaft engines. AD 2013-01-07 required replacing the hydromechanical metering unit (HMU) at a reduced life. This AD maintains that requirement and also requires conducting inspections of the HMU. This AD was prompted by further cases of deterioration of HMU rotating components. We are issuing this AD to prevent an uncommanded in-flight shutdown of the engine and possible loss of the helicopter.
2013-23-03: We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, and 747SR series airplanes. This AD requires inspecting to determine the part number of the inboard actuator attach fittings of the outboard flap. For affected attach fittings, this AD requires doing a detailed inspection of the attach fittings for a cylindrical defect and replacing if necessary. As an option to the detailed inspection, this AD allows replacement of affected attach fittings. This AD was prompted by a report of the fracture of an inboard actuator attach fitting of the outboard flap. An inspection of the attach fitting revealed that it was incorrectly machined with a cylindrical profile instead of a conical profile, resulting in reduced wall thickness. We are issuing this AD to detect and correct defective inboard actuator attach fittings which, combined with loss of the outboard actuator load path, could result in uncontrolled retraction of the outboard flap, damage to flight control systems, and consequent reduced controllability of the airplane.
69-15-07: 69-15-07 BELL: Amendment 39-801. Applies to Bell Model 204B, 205A, and 205A-1 helicopters equipped with the Float Kit Installation, Part No. 204-706-053, or Part No. 205-706- 050. Compliance required as indicated. To prevent possible failure of the aft cross tube, Part No. 204-706-053-5, or Part No. 205-050-114-1, due to fatigue cracks, accomplish the following: (a) Remove and replace aft cross tubes with 900 or more hours' time in service on the effective date of this AD within the next 100 hours' time in service. (b) Remove and replace aft cross tubes with less than 900 hours' time in service on the effective date of this AD, prior to accumulating 1000 hours' time in service. (c) Remove and replace all subsequent replacement aft cross tubes prior to accumulating 1000 hours' time in service. (d) Operators not having kept time in service records on individual cross tubes should use float kit hours' time in service for the purpose of Paragraphs (a), (b), and (c) above. (Bell Helicopter Company Service Bulletin No. 204B-5, 205A-3, dated April 2, 1969, pertains to this subject.) This amendment becomes effective August 16, 1969.
2013-20-17: We are adopting a new airworthiness directive (AD) for ECD Model BO105C (C-2 and CB-2 Variants) and BO105S (CS-2 and CBS-2 Variants) helicopters with a certain third stage turbine wheel installed. This AD requires installing a placard on the instrument panel and revising the limitations section of the rotorcraft flight manual (RFM). This AD is prompted by several incidents of third stage engine turbine wheel failures, which were caused by excessive vibrations at certain engine speeds during steady-state operations. These actions are intended to alert pilots to avoid certain engine speeds during steady-state operations, prevent failure of the third stage engine turbine, engine power loss, and subsequent loss of control of the helicopter.
74-17-03: 74-17-03 DEHAVILLAND: Amendment 39-1914. Applies to Model DHC-2 (Mk I) Beaver Airplane. Compliance required within the next 110 hours in service after the last inspection pursuant to this directive and thereafter at intervals not to exceed 110 hours in service from a preceding inspection. To prevent carbon monoxide from entering the airplane cabin, accomplish the following: (a) For airplanes using the intensifier tube cabin heater system, remove the tube and perform a visual inspection on both the intensifier tube and the exhaust pipe for any holes, cracks, flaking or weld separations. (b) For airplanes using heater jackets, remove the jacket and perform the same inspection as in (a) above. Replace or repair parts found to have any holes, cracks flaking or weld separations. Make welding repairs in accordance with Advisory Circular AC 43.13-1 or an FAA approved equivalent. Upon submission of substantiation data through an FAA Maintenance Inspector, the Chief, Engineering and Manufacturing Branch, Eastern Region, may adjust the repetitive inspection intervals specified in this AD. This Directive supersedes Airworthiness Directive 57-13-02. This amendment is effective August 12, 1974.
55-15-05: 55-15-05 DOUGLAS: Applies to All DC-7 Aircraft Below Fuselage No. 486 Equipped With Hamilton Standard Propellers. \n\n\tCompliance required by first scheduled engine change after November 1, 1955, but not later than November 1, 1956. \n\n\tTo increase the integrity of the propeller feathering system in the event of a powerplant fire, all existing propeller feathering lines located forward of the firewall in zone 2 must be replaced with lines and flexible hose assemblies which will meet current fireproof and fire resistant requirements. \n\n\t(a)\tInstall Aeroquip 304 protective sleeves on the propeller feathering line forward of the feathering pump, in accordance with Aeroquip Drawing 304005-10S-46. Resistoflex SSFR-3800-10 hose assembly and Aeroquip 309009-10S hose assembly are also considered acceptable for this application. \n\n\t(b)\tRemove the existing short 304 sleeves from the feathering pump supply line between the oil tank and feathering pump and install a fireproof cover, Douglas P/N 3500614-2. Aeroquip 601000 hose assembly equipped with Aeroquip 304 full-length protective sleeve, or Aeroquip 680-16S hose assembly equipped with Aeroquip 304 short sleeves covering the end fittings are also considered acceptable for this application. \n\n\t(Douglas Service Bulletin DC-7 No. 74 dated July 19, 1955, covers this same subject.)
67-30-03: 67-30-03 FAIRCHILD-HILLER: Amdt. 39-503 Part 39 Federal Register November 2, 1967. Applies to Type FH-227 Airplanes, and Type F-27A, F-27F, F-27G and F-27J Airplanes. Compliance required as indicated. To detect cracks in the rudder skin, stiffeners, and rear spar flange located between the ribs of the lower section of the rudder, accomplish the following: (a) Within the next 50 hours' time in service after the effective date of this AD, unless already accomplished within the last 150 hours' time in service, and thereafter at intervals not to exceed 200 hours' time in service from the last inspection, comply with (b). (b) Visually inspect for cracks the left and right rudder skins from Stations 10 to 71 between the middle and rear spars. By manual compression of the left and right rudder skins, inspect for indications of cracks in the rudder stiffeners at Stations 16, 28, 40, 52 and 64 between the middle and rear spars, and in the rear spar flanges at these stations, or use an FAA-approved equivalent inspection. If a skin crack or indications of a crack in the stiffeners or rear spar flanges are found, comply with (d). (c) Within the next 100 hours' time in service after the effective date of this AD, unless already accomplished within the last 300 hours' time in service, and thereafter at intervals not to exceed 400 hours' time in service from the last inspection, comply with (b) on FH-227 airplanes modified in accordance with Fairchild-Hiller Service Bulletin No. 27-4 (FH 227) dated December 27, 1966 or later FAA-approved revision, and on F-27 airplane modified in accordance with Fairchild-Hiller Service Bulletin No. 27-42 (F-27) dated December 27, 1966 or later FAA-approved revision, or an FAA-approved equivalent modification. If a skin crack or indications of a crack in the stiffeners or rear spar flanges are found, comply with (d). (d) Repair cracked parts in accordance with Part 43 of the Federal Aviation Regulations or replace them with an unused part of the same part number or an FAA-approved equivalent before further flight, except that the airplane may be flown in accordance with FAR 21.197 to a base where the repair can be performed. (e) The repetitive inspection specified in (c) may be discontinued on FH-227 airplanes modified in accordance with Fairchild-Hiller Service Bulletin No. 27-11 (FH-227) Revision No. 1, dated September 7, 1967 or later FAA-approved revision, and on F-27 airplanes modified in accordance with Fairchild-Hiller Service Bulletin No. 27-54 (F-27) Revision No. 1, dated September 7, 1967 or later FAA-approved revision, or an FAA approved equivalent modification. (f) Equivalent inspections may be approved by an FAA maintenance inspector, Equivalent parts, Service Bulletin revisions, and modifications, must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region. (g) Upon request with substantiating data submitted through an FAA maintenance inspector, the compliance times specified in this AD may be increased by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region. This supersedes Amendment 39-390 (Part 39 F.R. April 8, 1967), AD 67-12-03. This amendment effective November 1, 1967.
2013-22-21: We are adopting a new airworthiness directive (AD) for Bell Helicopter Textron, Inc. (Bell), Model 206A, 206B, 206L, 206L-1, 206L- 3, 206L-4, and 407 helicopters with an Apical Industries, Inc. (Apical) emergency float kit installed under Supplemental Type Certificate (STC) Number SR01535LA. This AD was prompted by an incident in which the floats installed on a helicopter failed to deploy. This AD requires inspecting, labeling, and replacing the float inflation hoses. We are issuing this AD to prevent failure of the emergency floatation gear to deploy during an emergency event.
56-20-06: 56-20-06 HAMILTON STANDARD: Applies to All Hamilton Standard Governors Installed on Wright TC18DA and TC18EA Series Turbocompound Engines. Compliance required prior to October 15, 1956. Subsequent to October 15, 1956, no Hamilton Standard governor drive gear shafts P/N 67035 shall be used in their governors installed on Wright TC18 Series turbocompound engines. This supersedes AD 56-02-02.
2000-24-25: This amendment adopts a new airworthiness directive (AD), applicable to certain Raytheon Model Hawker 800A (U-125A) and Hawker 800XP series airplanes, that requires inspecting the roller clearance in the nose landing gear drag stay and making any necessary adjustments. This amendment is prompted by reports indicating multiple findings of roller clearances that are in excess of specifications. The actions specified by this AD are intended to prevent the inability to extend the nose landing gear, which could result in damage to the airplane upon landing.
2000-23-14: This amendment adopts a new airworthiness directive (AD) that is applicable to certain Pratt & Whitney JT9D series turbofan engines. This AD will require installation of an improved No. 4 bearing internal oil pressure tube, initial and repetitive inspections of the No. 4 bearing oil pressure tube for turbine exhaust case (TEC) strut clearance and alignment, and, if necessary, replacement with serviceable parts. This amendment is prompted by loss of integrity in the oil system that allows oil to migrate into high temperature metal cavities in the turbine exhaust case and cause oil fires. The actions specified by this AD are intended to prevent oil fires in and around the No. 4 bearing area that could cause excessive thermal growth of the sixth stage low pressure turbine (LPT) disk, liberation of the sixth stage LPT disk, uncontained engine failure, and damage to the airplane.
2013-22-15: We are adopting a new airworthiness directive (AD) for Sikorsky Model S-76A, B, and C helicopters to require certain inspections of each spindle cuff assembly or blade fold cuff assembly for a crack. If there is a crack, this AD requires replacing the cracked part. If there is no crack, this AD requires applying white paint to the inspection area to enhance the existing inspection procedure. This AD was prompted by discovery of cracks in the spindle cuffs. The actions are intended to prevent failure of a spindle cuff assembly or blade fold cuff assembly, loss of a rotor blade, and subsequent loss of control of the helicopter.
54-13-01: 54-13-01 SIKORSKY: Applies to All Model S-55 Helicopters. Compliance required as indicated. 1. The twelve (12) AN 73A bolts which clamp the S510170 retainer to the bottom of S10-10-4302 rotating star, and the eight (8) AN 73A bolts which clamp the S510156 retainer to the top of the S10-10-4302 rotating star should be replaced. The 20 new bolts should be torqued to 25-35 inch-pounds. These replacements are to be accomplished every 60 hours until the AN 74A bolts called for in item 2. are incorporated. 2. At the next major overhaul period of the star assembly S10-10-4300, replace the twenty (20) AN 73A bolts covered in 1 with 1/4-inch diameter AN 74A bolts. The AN 74A bolts should be relocated between the existing holes. When the AN 74A bolts have been incorporated, the replacements of 1 are no longer required. 3. At the next major overhaul period of the star assembly S10-10-4300, replace the twelve (12) AN 509-10R-35 screws which secure the clamp the S12-10-4015 liner and the Y96PW1-DB bearings to the S12-10-4013 stationary star. The screws should be torqued to 35- 40 inch-pounds. (Sikorsky Service Information Circular No. 1410-222 dated March 4, 1952, through Revision D dated April 15, 1954, covers this same subject.)