Results
76-05-09: 76-05-09 AER PEGASO (AEROMERE & AVIONAUTICA RIO): Amendment 39-2544. Applies to M100S gliders, certificated in all categories. Compliance is required within the next 50 hours time in service after the effective date of this AD, unless already accomplished. To prevent separation of lower rudder hinge pin from the rudder hinge bracket and the consequent loss of rudder control, accomplish the following: Replace the lower rudder hinge pin with a new pin made of SAE 1024 steel and inspect the new pin's weld for cracks, using the dye penetrant method, in accordance with the steps (1) through (9) of the Description section of Ingg. A. & P. Morrelli (Aer Pegaso) Technical Bulletin No. 11/M100S, dated March 16, 1971, or an FAA- approved equivalent. This amendment becomes effective March 25, 1976.
2025-09-01: The FAA is adopting a new airworthiness directive (AD) for certain Bell Textron Canada Limited (BTCL) Model 505 helicopters. This AD was prompted by reports of possible chafing in certain locations between the basic and supplemental helicopter wiring and the structure. This AD requires repetitively inspecting the wire harnesses at certain locations for damage, and if any wire damage is found, repairing the damaged wire/bundles, as specified in a Transport Canada AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.
2025-09-03: The FAA is superseding Airworthiness Directive (AD) 2021-24- 09, which applied to certain Bell Textron Canada Limited Model 430 helicopters. AD 2021-24-09 required a visual inspection of the main rotor (M/R) pitch link clevis (clevis), rod end, and a certain part- numbered universal bearing, performing a purge grease, and performing a magnetic particle inspection of each M/R clevis, and depending on the inspection results, removing or replacing certain parts and performing additional actions. AD 2021-24-09 also required recurring inspections of each M/R clevis and each universal bearing. Since the FAA issued AD 2021-24-09, the manufacturer has reduced the life limits of the affected parts and introduced new M/R pitch link assemblies by re- identifying the M/R pitch link assemblies that were required to be inspected by AD 2021-24-09. This AD requires similar actions as AD 2021-24-09 but reduces the life limits and requires replacing the M/R pitch link assemblies with re-identified part numbered assemblies. These actions are specified in a Transport Canada AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.
2012-16-05: We are adopting a new airworthiness directive (AD) for certain Airbus Model A330-200 and -200 freighter series airplanes; and Model A340-200, -300, -500, and -600 series airplanes. This AD was prompted by fuel system reviews conducted by the manufacturer. This AD requires modification of the control circuit for the fuel pumps for the center fuel tanks for certain airplanes, and center and rear fuel tanks for certain other airplanes. We are issuing this AD to prevent the potential of ignition sources inside fuel tanks, which, in combination with flammable fuel vapors, could result in fuel tank explosions and consequent loss of the airplane.
99-09-18: This amendment supersedes an existing airworthiness directive (AD), applicable to certain Fokker Model F.28 Mark 0070 and Mark 0100 series airplanes, that currently requires a one-time inspection for heat damage of the fuselage skin and stubwing structure; either repetitive tests of certain seals or repair of heat damage, as necessary; and eventual replacement of corrujoint seals with new, improved seals. This amendment adds a requirement for repetitive inspections for heat damage of the subject area, and provides for a new optional terminating action for the repetitive inspections. This action is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent leakage of hot air from the corrujoint seals of certain valves in the stubwings, and subsequent heat damage of the fuselage skin and stubwing structure, which could result in reduced structural integrity of theairplane. The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of June 8, 1999. The incorporation by reference of certain other publications as listed in the regulations, was approved previously by the Director of the Federal Register as of May 14, 1998 (63 FR 17318, April 9, 1998).
75-24-11: 75-24-11 BEECH: Amendment 39-2437. Applies to all civilly certificated Models A45 (Military T-34A, B-45) and D45 (Military T-34B) airplanes. Compliance: Required as indicated, unless already accomplished. To prevent failure of the P/N 45-524504 and 45-524505 rudder-aileron bungee interconnect cable assembly and the P/N 45-524697 or P/N 45-524028 bellcrank assembly, accomplish the following: A) On Model A45 (Military T-34A, B-45) airplanes not incorporating P/N MS- 20219-2 pulleys (1.75 inch O.D.) per Beech Kit 45-325 and Beech P/N 105740B-ZF-0105 bronze bushings per Beech Drawing 45-000060, Rev. C, or later revision, within 50 hours' time in service after the effective date of this AD, or within 100 hours' time in service after the last inspection per AD 62-27-01, and thereafter at intervals not to exceed 100 hours' time in service from the last inspection, accomplish Paragraphs 1(a) and 1(b). B) On Models A45 (Military T-34A, B-45) and D45 (Military T-34B) airplanes incorporating P/N MS-20219-2 pulleys (1.75 inch O.D.) per Beech Kit 45-325 and Beech P/N 105740B-ZF-0105 bronze bushings per Beech Drawing 45-000060, Rev. C, or later revision, within 50 hours' time in service after the effective date of this AD, and thereafter at intervals not to exceed 300 hours' time in service from the last inspection, accomplish Paragraphs 1(a) and 1(b). 1. (a) Disconnect the turn buckles P/N 45-524504 and 45-524505 rudder-aileron bungee interconnect cable assemblies, visually inspect the cables and replace frayed, internally broken or excessively worn cables. (b) Disconnect the two AN 161-8RS forks that attach to the P/N 45- 524697 or P/N 45-524028 bellcrank assembly and visually inspect the 3/16-inch diameter holes in the bellcrank for elongation or cracks. If elongation exceeds 0.02 inches or if cracks are found, replace the bellcrank. If no elongation or cracks are found, lubricate the holes in the bellcrank prior to reinstallation of theAN 161-8RS forks. 2. The airplane may be flown in accordance with FAR 21.197 to a location where parts replacement can be accomplished. 3. Any equivalent method of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region. Beechcraft Service Bulletin No. 32 on Model A45 (Military T-34A, B-45) airplanes covers the cable inspection. This AD supersedes AD 62-27-01. This amendment becomes effective November 28, 1975.
2012-16-10: We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by chafing on high pressure fuel lines due to improper installation of an expandable pin on the lower cowl assembly. This AD requires installing spring clips and repositioning the lanyard attachment points at the forward end and the forward firefloor of the lower cowl. We are issuing this AD to prevent chafing of the high pressure fuel lines, which if not corrected, could cause fuel leakage in a fire zone.
75-04-12: 75-04-12 BELLANCA: Amendment 39-2093. Applies to Model 8GCBC Airplanes, Serial Numbers 1-74 through 119-74, 120-75 through 153-75 certificated in all categories. Compliance required within the next 10 hours time in service after the effective date of this airworthiness directive, unless already accomplished. To prevent possible resonant vibratory conditions with McCauley Model 1A200/HFA fixed pitch propellers installed on Lycoming 0-360-C2A, or -C2E type engines, accomplish the following in accordance with Bellanca Service Letter Number 115 and Bellanca Service Kit Number 245. (a) Remove existing markings on the tachometer instrument glass and affix Mylar decal, Bellanca P/N 1-10443. The decal is properly affixed when: a green arc extends from 500 to 1700 RPM; a yellow arc from 1700 to 2100 RPM; a green arc from 2100 RPM to 2700 RPM; and a red radial is positioned at 2700 RPM. (b) Install Bellanca P/N 1-10437, placard "AVOID 1700-2100 DURING DESCENT", on thetachometer instrument glass below the hour meter. (c) Accomplish Revision Number 1 to existing FAA Approved Airplane Flight Manual (AFM) in accordance with AFM revisions page. This amendment becomes effective February 21, 1975.
2012-16-06: We are adopting a new airworthiness directive (AD) for all Airbus Model A300 B4-600 series airplanes and Model A310-203, -204, - 221, and -222 airplanes. This AD was prompted by a report of a capacitive density condensator (cadensicon) coil overheating during testing. This AD requires an inspection to determine if a certain fuel quantity indication computer (FQIC) is installed, replacement of identified FQICs, and modification of the associated wiring. We are issuing this AD to detect and correct potential overheating of the cadensicon coil, which could create an ignition source inside a fuel tank, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.
67-18-03: 67-18-03 LOCKHEED: Amendment 39-423 as amended by Amendment 39-1601. Applies to Model 382 and 382B series airplanes, serial numbers 3946 and 4101 through 4196. Compliance as indicated. (a) For airplanes with 2350 or more hours' total time in service on the effective date of this AD comply with paragraph (c) within the next 50 hours' time in service, and thereafter at intervals not to exceed 800 hours' time in service from the last inspection. (b) For airplanes with less than 2350 hours' total time in service on the effective date of the AD comply with Paragraph (c) before the accumulation of 2400 hours' total time in service, and thereafter at intervals not to exceed 800 hours' time in service from the last inspection. (c) Inspect all eight affected engine mount truss assemblies in accordance with the tooling and inspection instructions given in Lockheed-Georgia Service Bulletin 82-153 dated December 1, 1966, Section 1f and 2a through 2e, respectively, or later FAA approved revision, or in an equivalent manner approved by the Chief, Engineering and Manufacturing Branch, FAA Southern Region. (1) Cracked parts shall be replaced with new parts having the same part number, or with the applicable updated part specified in Section 2g of Lockheed-Georgia Service Bulletin 82-153 dated December 1, 1966, or later FAA approved revision. Replacement truss assemblies shall be installed according to the replacement instructions given in Section 2h through 2aa in the above Service Bulletin, or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA, Southern Region. (2) Replacement of cracked trusses shall be accomplished before further flight, except that one flight may be made for the purpose of obtaining the necessary replacements in accordance with the provisions of FAR 21.197. (d) When a particular truss assembly is replaced with the applicable updated part specified in Section 2g of Lockheed-Georgia Service Bulletin 82-153dated December 1, 1966, or later FAA approved revision, the repetitive inspection of that truss as required by this AD may be discontinued. Lockheed-Georgia Service Bulletin 82-153, dated December 1, 1966, covers this same subject. Amendment 39-423 became effective June 25, 1967. This Amendment 39-1601 becomes effective March 12, 1973.
2018-05-06: We are superseding Airworthiness Directive (AD) 2016-09-12, which applied to certain The Boeing \n\n((Page 9689)) \n\nCompany Model 787-8 and 787-9 airplanes. AD 2016-09-12 required repetitive inspections of the bilge barriers located in the forward and aft cargo compartments for disengaged decompression panels, and reinstalling any disengaged panels. This AD retains the actions required by AD 2016-09-12 and requires replacing the existing decompression panels with new panels and straps, which terminates the repetitive inspections. This AD also removes airplanes from the applicability. This AD was prompted by a terminating modification developed to address the unsafe condition. We are issuing this AD to address the unsafe condition on these products.
2003-09-06: This amendment adopts a new airworthiness directive (AD), that is applicable to General Electric Company (GE) CF6-50 series turbofan engines. This amendment requires removal from service of eight serial number (SN) low-pressure turbine (LPT) stage 1 disks, part number (P/N) 9061M21P03, at the next engine shop visit. This amendment is prompted by a report of the potential for iron-rich inclusions introduced during manufacture in the affected disks. The actions specified by this AD are intended to prevent LPT stage 1 disk cracking, due to iron-rich inclusions introduced during manufacture, leading to uncontained disk failure.
65-13-04: 65-13-04 GRUMMAN: Amdt. 39-80 Part 39 Federal Register June 12, 1965. Applies to Model G-159 Aircraft Equipped with Bendix Nose Gear Strut Assembly, P/N 1722-40 or 2570890. Compliance required as indicated. To prevent failure of the nose gear trunnion, accomplish the following: (a) Inspect the nose gear trunnion, Bendix P/N 171467 in accordance with (c) within the next 20 hours' time in service after the effective date of this AD unless replaced within the next 20 hours' time in service after the effective date of this AD, or unless already inspected within the last 80 hours' time in service, and thereafter at intervals not to exceed 100 hours' time in service from the last inspection. (b) Within the next 20 hours' time in service after replacement of a nose gear trunnion, and thereafter at intervals not to exceed 100 hours' time in service from the last inspection, inspect the replacement trunnion in accordance with (c). (c) Inspect the retract shaft attachment lugs on the nose gear trunnion forward flanges for cracks in the radii above and below the area where the retract shaft attachment lugs blend into the trunnion flanges, using the dye penetrant method with a 10 power or greater glass or an FAA-approved equivalent. (d) Replace cracked trunnions with a trunnion of the same part number or an equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, before further flight except that the aircraft may be flown in accordance with the provisions of FAR 21.197, after approval by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, to a base where the repair can be made. This directive effective June 12, 1965.
75-06-01: 75-06-01 UNITED AIRCRAFT OF CANADA LIMITED and PRATT & WHITNEY AIRCRAFT: Amendment 39-2118 as amended by Amendment 39-2182, 39-2208 and 39-2574 is further amended by Amendment 39-2858. Applies to all PT6A-6, -6A, -6B, -6/C20, -20, -20A, -20B, -27, -28, and -34 series turboprop engines. Compliance required as indicated unless previously accomplished. To ensure the early detection of reduction gearbox deterioration which could result in an engine failure and provide for improved blade containment accomplish the following: (a) Within the next 50 hours in service after effective date of this AD, unless previously accomplished, remove the main engine oil filter element and visually inspect the element for magnetic and non-magnetic metal particles. (1) If the inspection reveals less than 40 non-magnetic metal and no magnetic metal particles, clean oil filter and reinspect after every 50 hours in service. (2) (i) If the inspection reveals more than 40 non-magnetic metal particles, clean oil filter and reinspect after 10 hours in service. (ii) If the reinspection, in accordance with paragraph (a)(2) (i) reveals less than 40 non-magnetic metal particles, clean oil filter and reinspect after every 50 hours in service thereafter. (iii) If the reinspection, in accordance with paragraph (a)(2) (i) reveals more than 40 non-magnetic metal particles, clean oil filter and reinspect after 10 hours in service. (iv) If the reinspection, in accordance with paragraph (a)(2) (iii) reveals more than 40 non-magnetic metal particles, the engine must be removed from service for an overhaul inspection. (v) If the reinspection in accordance with paragraph (a)(2) (iii) reveals less than 40 non-magnetic metal particles, clean oil filter and reinspect after every 50 hours in service thereafter. (3) (i) If the inspection reveals less than 40 magnetic metal particles clean oil filter and reinspect after 10 hours in service. (ii)If the reinspection in accordance with paragraph (a)(3) (i) reveals the presence of similar quantity of magnetic metal particles, the engine must be removed from service for an overhaul inspection. (iii) If the reinspection in accordance with paragraph (a)(3) (i) reveals the presence of lesser quantity of magnetic metal particles clean oil filter and reinspect every 50 hours time in service thereafter. (4) (i) If the inspection reveals more than 40 magnetic metal particles, clean oil filter, drain and change oil, perform a ground run for one hour and reinspect oil filter. If the inspection after one hour ground run reveals more than 40 magnetic metal particles, the engine must be removed from service for an overhaul inspection. (ii) If the inspection after one hour ground run reveals less than 40 magnetic metal particles, clean oil filter and reinspect after 10 hours in service. (iii) If the reinspection after 10 hours in service reveals a similar quantityof magnetic metal particles, the engine must be removed from service for an overhaul inspection. (iv) If the reinspection after 10 hours in service reveals a lesser quantity of magnetic metal particles, clean oil filter and reinspect every 50 hours in service thereafter. (b) For the PT6A-6, -6A, -6B, -6/C20, -20, -20A, -20B, -27, -28 and 34 engines, within the next 8000 hours in service after the effective date of the AD, alter part number 3010548, power turbine shaft housing assembly in accordance with paragraph 2, accomplishment instructions in United Aircraft of Canada Limited Engine Service Bulletin No. 1138 or approved equivalent, or replace said assembly with any other power turbine shaft housing assembly listed as eligible in the engine parts catalog. (c) For the PT6A-6, -6A, -6B, -6/C20, -20, -20A and -20B engines within the next 2000 hours in service after the effective date of this AD alter all the power turbine blades in accordance with paragraph 2, accomplishment instructions in Pratt & Whitney Aircraft of Canada Limited Engine Service Bulletin No. 1233, or approved equivalent alteration. (d) For the PT6A-27, -28 and -34 engines, within the next 4000 hours in service after the effective date of this AD install the improved power turbine containment ring in accordance with paragraph 2, accomplishment instructions in Pratt & Whitney Aircraft of Canada Limited Engine Service Bulletin No. 1220 or approved equivalent alterations and modified combustion chamber liner and related parts in accordance with paragraph 2, accomplishment instructions in Pratt & Whitney Aircraft of Canada Limited Engine Service Bulletin No. 1216, or approved equivalent alterations. (e) For the PT6A-20, -20A, and -20B, -6/C20 engines within the next 4000 hours in service after the effective date of this AD install the improved power turbine containment ring in accordance with paragraph 2, accomplishment instructions in Pratt & Whitney Aircraft of Canada Limited Engine Service Bulletin No. 1246 or approved equivalent alterations and modified combustion chamber liner and related parts in accordance with paragraph 2, accomplishment instructions in Pratt & Whitney Aircraft of Canada Limited Engine Service Bulletin No. 1245 or approved equivalent alterations. The main oil screen inspection requirements of this AD are no longer required when the engines have been modified as required by paragraph (b), (c), (d), and (e) as applicable. Aircraft may be flown to a base for performance of maintenance required by this AD per FAR 21.197 or FAR 21.199. Upon submission of substantiating data through an FAA Maintenance Inspector, the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, may adjust the repetitive inspection times specified in this Airworthiness Directive. All equivalent alterations must be approved by the Chief, Engineering and Manufacturing Branch of the Eastern Region of the FAA. Amendment 39-2118 was effective March 10, 1975. Amendment 39-2182 was effective April 28, 1975. Amendment 39-2208 was effective May 20, 1975. Amendment 39-2574 was effective April 14, 1976. This amendment 39-2858 is effective April 1, 1977.
48-03-06: 48-03-06 BELL: Applies to All 47B Series Through Serial Number 78. Compliance required at next 25-hour inspection. If the play between the two bolts which connect links 47-612-048, to the side and aft sprag systems and the adapter plate, exceeds 0.010 inch, bushing 78B6-8-11 should be added to the tube assembly fittings and the clevis end of the link; bushings 75B6-8-11-5 should be added to the opposite end of the link; and bushings 75B6-8-8, 47-612-053-1 or 47-612-053-2 should be installed in the adapter plate. (Bell Service Bulletin 47C62 dated December 2, 1947, covers this subject and gives more detailed reaming and dimensional information.)
2012-16-03: We are adopting a new airworthiness directive (AD) for all HPH s. r.o. Models 304C, 304CZ, and 304CZ-17 sailplanes. This AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as the lack of a drain hole in the elevator control rod, which may allow water to accumulate in the control rod and lead to possible corrosion. This condition could cause the elevator control rod to fail, which could result in loss of control of the sailplane. We are issuing this AD to require actions to address the unsafe condition on these products.
67-12-05: 67-12-05 PILATUS: Amdt. 39-387, Part 39, Federal Register April 4, 1967. Applies to Model PC-6 Series Airplanes, Serial Numbers to 632. Compliance required with the next 200 hours' time in service after the effective date of this AD, unless already accomplished. To prevent rubbing and wear of the two pulley flanges as a result of a change in direction of the aileron control system cables in excess of 3 degrees from the plane of their pulleys, install fairleads at the pulley support bracket on bulkhead Number 3 in accordance with Pilatus Service Bulletin No. 68 or later Swiss Federal Air Office-approved issue, or an FAA-approved equivalent. This directive effective May 4, 1967.
99-06-15: This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 99-06-15 which was sent previously to all known U.S. owners and operators of Bell Helicopter Textron Canada (BHTC) Model 407 helicopters by individual letters. This AD requires installing a tail rotor pitch-limiting left-pedal stop, installing an airspeed limitation placard, marking a never-exceed velocity (Vne) placard on all airspeed indicators, and revising the Limitations section of the Rotorcraft Flight Manual (RFM). This amendment is prompted by three accidents involving in-flight tail rotor blade strikes against the tailboom. The actions specified by this AD are intended to prevent the tail rotor blades from striking the tailboom, which could result in separation of the aft section of the tailboom with the tail rotor gearbox and vertical fin, and subsequent loss of control of the helicopter.
2012-15-14: We are adopting a new airworthiness directive (AD) for certain Airbus Model A300 B4-103, B4-203, and B4-2C airplanes, and Model A300 B4-600, B4-600R, and F4-600R series airplanes, and Model A300 C4-605R Variant F airplanes (collectively called A300-600 series airplanes). This AD was prompted by reports of cracking in the forward lug of the main landing gear (MLG) rib 5 aft bearing attachment. This AD requires repetitive inspections for cracking of the left-hand (LH) and right- hand (RH) wing MLG rib 5 aft bearing forward lugs, and repair if necessary. We are issuing this AD to detect and correct cracking of the LH and RH wing MLG rib 5 aft bearing forward lugs, which could affect the structural integrity of the MLG attachment, resulting in MLG collapse during landing or rollout with consequent damage to the airplane and injury to occupants.
2012-15-12: We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 767 airplanes. This AD was prompted by reports of cracks of the underwing longeron fittings in the wing center section. This AD requires repetitive inspections of the underwing longeron fitting for cracking, and related investigative and corrective actions if necessary. We are issuing this AD to detect and correct such cracking, which could result in loss of the primary load path between the fuselage and the wing box, and consequent catastrophic damage to the wing box and failure of the wing.
74-14-08: 74-14-08 GENERAL ELECTRIC: Amendment 39-1894. Applies to Models CF6-6D, 6D1, and 6H Turbofan Engines. Compliance required by September 30, 1974. To prevent expulsion from the engine of fifth stage low pressure turbine blades, unless already accomplished, install improved blade retainer P/N 9083M19P07 per the instructions of General Electric Service Bulletin (CF6-6) 72-399 Revision 1 dated March 20, 1974, or subsequent FAA approved revision. This amendment becomes effective July 12, 1974.
73-07-03: 73-07-03 GENERAL DYNAMICS: Amdt. 39-1612. Applies to Model 22M Series airplanes certificated in all categories. Compliance required as indicated. To detect cracks and prevent further failures of the actuator fitting, accomplish the following: (1) Within the next 150 hours' time in service after the effective date of this A.D., unless already accomplished within the last 250 hours' time in service, and thereafter at intervals not to exceed 400 hours' time in service from the last inspection, inspect the rudder boost actuator fitting P/N 30-15701-1 in accordance with General Dynamics 880M S.B. No. A27-47 dated 1 March 1973, or later FAA-approved revision. (2) If, as a result of the inspection required by paragraph (1), cracks are found, replace the defective fittings with an identical part. This amendment becomes effective March 29, 1973.
2012-15-01: We are adopting a new airworthiness directive (AD) for various aircraft equipped with Rotax Aircraft Engines 912 A series engine. 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 deviation in the manufacturing process of fuel hoses installed on the pressure side of part number 893114 fuel pumps. The fuel hoses may not be fuel resistant, which could lead to detachment of particles from the fuel hose and cause irregularities in the carburetor function and possibly result in rough engine operation, engine misfire, in-flight engine shutdown, and forced landing. We are issuing this AD to require actions to address the unsafe condition on these products.
76-03-02: 76-03-02 SIKORSKY AIRCRAFT: Amendment 39-2507. Applies to S-61L, S-61N, S- 61NM, and S-61R helicopters certified in all categories including Military CH-3C, HH-3C, CH- 3E, and HH-3E helicopters using NAS 577-10 or NAS 577-10A barrel nuts for attaching the transmission main gearbox to the fuselage structure. Compliance required as indicated. To prevent fractures in the attaching nuts accomplish the following: Remove the NAS 577-10 or NAS 577-10A barrel nuts and replace with RMLH 2577-108 barrel nuts within the next 30 days after the effective date of this AD, unless already accomplished. (NOTE: Sikorsky Service Bulletin No. 61B35-36B covers this subject.) This supersedes Amendment 39-2202 (40 FR 24355), AD 75-12-13. This amendment becomes effective February 17, 1976.
99-07-17: This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 99-07-17 which was sent previously to all known U.S. owners and operators of Robinson Helicopter Company (RHC) Model R22 helicopters by individual letters. This AD requires, before further flight, inserting a Special Pilot Caution into the Normal Procedures section of the Rotorcraft Flight Manual (RFM). This amendment is prompted by several reports of sprag clutch assemblies with cracked or fractured sprag ends. The sprag clutch failures, determined to be due to a change in the manufacturing process, could result in loss of main rotor revolutions-per-minute (RPM) during autorotations. The intent of this AD is to alert pilots of the potential for the sprag clutch failing to overrun during autorotation, loss of main rotor RPM, and subsequent loss of control of the helicopter.