Results
2012-09-10: We are adopting a new airworthiness directive (AD) for certain Pratt & Whitney Canada PT6A-38, -41, -42, -42A, -61, -64, -66, -66B, - 110, -112, -114, -114A, -121, -135, and -135A series turboprop engines. This AD requires removal from service of certain part manufacturer approval (PMA) replacement Timken Alcor Aerospace Technologies, Inc. (TAATI) first stage sun gears and planet gears installed in the reduction gearbox. This AD was prompted by failures of certain first stage sun gears manufactured by TAATI. We are issuing this AD to prevent failure of the sun gear and planet gears which will result in an engine in-flight shut down, possible uncontained engine failure, aircraft damage, and serious injuries.
2003-08-02: This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-90-30 airplanes. This action requires a one-time inspection for chafing or damage of the cable assemblies and follow-on modification of the cable assemblies of the powered seats located in the first-class cabin. This action is necessary to prevent chafing and damage of the cable assemblies due to contact between the cable and the metal retaining clip on the seat leg, which could result in electrical arcing and consequent smoke and/or fire in the cabin. This action is intended to address the identified unsafe condition.
91-05-06: 91-05-06 BOEING: Amendment 39-6903. Docket No. 90-NM-160-AD. \n\n\tApplicability: Model 767-300 series airplanes certificated in any category listed in Boeing Service Bulletins 767-26-0045, dated May 10, 1990, and 767-26-0048, dated June 21, 1990. \n\n\tCompliance: Required within the next 48 months after the effective date of this AD, unless previously accomplished. \n\n\tTo preclude cross-connection of engine and cargo compartment fire extinguishing systems wiring and plumbing during maintenance, accomplish the following: \n\n\tA.\tModify the engine and cargo compartment fire extinguishing system wiring and plumbing in accordance with Boeing Service Bulletin 767-26-0045, dated May 10, 1990, or 767- 26-0048, dated June 21, 1990, as appropriate. Accomplishment of this modification constitutes terminating action for the repetitive inspections and functional tests required by Airworthiness Directive 89-03-51, Amendment 39-6213, on Boeing Model 767-300 airplanes following maintenance on the engine and cargo compartment fire extinguishing wiring and plumbing. \n\n\tNOTE: The modification described in Boeing Service Bulletin 767-26-0045 was incorporated in production on airplanes starting with line number 275, and the modification described in Boeing Service Bulletin 767-26-0048 was incorporated in production on airplanes starting with line number 290. Accordingly, this paragraph terminates the repetitive inspection and functional test requirements of AD 89-03-51 for those airplanes. \n\n\tB.\tAn alternate means 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 submitted directly to the Manager, Seattle ACO, and a copy sent to the cognizant FAA Principal Inspector (PI). The PI will then forward comments or concurrence to the Seattle ACO. \n\n\tC.\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\tAll persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington. \n\n\tThis amendment (39-6903, AD 91-05-06) becomes effective on March 25, 1991.
81-18-07: 81-18-07 VOLPAR, INCORPORATED: Amendment 39-4204. Applies to Beech Models C-45G, TC-45G, C-45H, TC-45H, TC-45J (SNB-5), RC-45J (SNB-5P), D18C, D18S, E18S-9700, G18S, H18, JRB-6, 3N, 3NM, and 3TM Aircraft with Volpar Tricycle Landing Gear, (STC SA4-1531, STC SA111WE, STC SA1832WE or any other STC modification incorporating the provisions of this installation), certificated in all categories. Compliance required as indicated unless already accomplished. To prevent possible main landing gear collapse due to bolt failure, accomplish the following: (a) Prior to further flight after the effective date of this AD, visually inspect the main landing gear Walking Beam upper attach bolt P/N AN179-46A for integrity and for adequate installation as specified in "Accomplishment Instructions", Part 1, Paragraphs (a) and (b) of Volpar, Inc. Service Bulletin Number 22 dated June 1, 1981. If the bolt has failed, replace with like serviceable part (or replacement part per paragraph (b) of this AD) prior to return to service. (b) Prior to the accumulation of 200 additional hours' time in service, or at the next annual inspection, whichever occurs sooner, remove AN179-46A bolt and associated hardware and install NAS 149-80 bolt and associated hardware as specified in "Description of Change" section of Volpar, Inc. Service Bulletin Number 22, dated June 1, 1981. (c) At intervals not to exceed 3,000 hours' time in service since the installation of Bolt P/N NAS 149-80, visually inspect the bolt installation for integrity and replace with like serviceable part, if necessary. (d) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate aircraft to a base for the accomplishment of inspections or modifications required by this AD. (e) Alternative inspections, modifications or other actions which provide an equivalent level of safety may be used when approved by the Chief, Engineering and Manufacturing Branch, FAA Western Region.The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive, who have not already received these documents from the manufacturer, may obtain copies upon request to Volpar, Incorporated, Van Nuys, California 91406, telephone (213) 994-5023. These documents may also be examined at FAA Western Region Office, 15000 Aviation Boulevard, Hawthorne, California 90261 and at FAA Headquarters, 800 Independence Avenue, S.W., Washington, D.C. 20591. A historical file on this AD, which includes the incorporated material in full, is maintained by the FAA at its headquarters in Washington, D.C. and at FAA Western Region Office. This amendment becomes effective September 10, 1981.
90-04-06 R1: 90-04-06 R1 TEXTRON LYCOMING: Amendment 39-6427 as revised by Amendment 39-6915. Docket No. 89-ANE-21. \n\n\tApplicability: All Textron Lycoming four cylinder piston engines equipped with a rear mounted propeller governor and external oil line, manufactured prior to January 1, 1990. \n\n\tCompliance: Required as indicated, unless already accomplished. \n\n\tTo prevent oil line fracture and loss of engine oil, accomplish the following:\n \n\t(a)\tWithin the next 25 hours time in service or whenever the propeller governor oil line is removed, whichever occurs first, accomplish the following: \n\n\t\t(1)\tInspect the propeller governor external oil line for abrasions, cracks, and oil leaks along the length of the line and at the end attachment fittings. Inspect to determine that the two cushion type support clamps or clips are properly installed as shown in Figure 1 of Appendix 1 to this AD, and assure that sufficient clearances exist between the oil line and adjacent components.(2)\tIf any leaks, chafing, or interference condition exists or if the two support clamps or clips are not properly installed, replace the governor oil line and its attachment end fittings with new parts even though the parts show no visible damage. Refer to Figure 1 in Appendix 1 to this AD, for parts identification, line routing, and location of support clamps or clips. The fittings in the engine case and governor must be replaced if they are damaged or are made of aluminum.\n \n\t(b)\tAt the next engine overhaul or anytime the governor oil line is removed for any reason, whichever occurs first, but no later than May 1, 1992, remove any governor oil line assembly having integral aluminum connecting nuts and reinstall an oil line assembly with corresponding steel connecting nuts. Replace any engine case/governor aluminum fittings with corresponding steel fittings as shown in Figure 1 of Appendix 1 to this AD. \n\n\tNOTE: The attachment nuts are components of the governor oil line tube assembly and have been changed by Textron Lycoming from aluminum to steel without changing the oil line part number. Aluminum nuts may be identified by their blue colored anodized surface. The attachment nuts as well as the elbow/nipple end fittings may also be identified by using a magnet to differentiate aluminum from steel.\n \n\t(c)\tAn optional method of compliance with paragraph (a)(2) and (b) is the installation of steel fittings and a fire resistant flexible hose assembly which meets the standards in FAA Technical Standard Order TSO- C53a Type D, and is installed in accordance with Appendix 2 of this AD. \n\n\tNOTE: Further guidance pertaining to installation can be obtained from FAA Advisory Circular 43.13-1A, Chapter 10, Maintenance Standards. \n\n\t(d)\tAircraft may be ferried in accordance with the provisions of FAR 21.197 and 21.199 to a base where the AD can be accomplished. \n\n\t(e)\tUpon submission of substantiating data by an owner or operator through an FAA Inspector(maintenance, avionics, or operations, as appropriate), an alternate method of compliance with the requirements of this AD or adjustments to the compliance times specified in this AD, may be approved by the Manager, New York Aircraft Certification Office, Engine and Propeller Directorate, Aircraft Certification Service, FAA, 181 South Franklin Avenue, Room 202, Valley Stream, New York 11581.\n \n\tThis amendment revises Amendment 39-6427 (55 FR 3577, February 2, 1990) AD 90-04-06. \n\n\tThis amendment (39-6915, AD 90-04-06 R1) becomes effective on May 28, 1991. \n\n\n\nAD 90-04-06 R1 \n\n\n\nAPPENDIX 2 \n\nIf -5 (5/16") fittings have been installed on some standard cylinder flange crankcase model engines, the propeller governor drive fitting and front crankcase fitting must be changed to the appropriate steel fitting to accommodate the new -6 (3/8") line. When re-installing new stainless steel tube assembly, appropriate -5 steel fittings must be re-installed. \n\nCAUTION \n\n\tIT IS MANDATORY THAT THIS FLEXIBLE HOSE BE REPLACED \n\tAT EACH OVERHAUL. \n\nWhen this engine modification is accomplished, Textron Lycoming recommends that a copy of the approved FAA Form 337 - plus the proper logbook entry become a permanent part of the aircraft records. \n\n\n\nInstallation is as follows: \n\t\ta.\tDetermine proper hose length as required for your particular installation. \n\n\t\tb.\tNo sharp bends are permissible. Ascertain that no "kinks" exist while routing and clamping hose. \n\n\t\tc.\tHose must not be routed near a heat source, such as any portion of the exhaust system. \n\n\t\td.\tHose is to be clamp supported to the engine (not to an airframe component) at a minimum of two locations.\n \n\t\te.\tNo clamping to cylinder head drain back tubes is allowed. \n\n\t\tf.\tAfter installation is complete, ensure that hose is not pinched. Make certain that engine motion during startup and shutdown does not pull or pinch the hose.
2012-09-06: We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-700 series airplanes. This AD was prompted by reports that the aft seat leg fittings span the station (STA) 521.45 ''stay-out zone.'' This AD requires for certain airplanes, replacing the seat track pivot link assemblies, seat track sections, and floor panels. For certain airplanes, this AD also requires moving certain rows of passenger seats. For certain other airplanes, this AD also requires inspecting certain areas of the seat tracks for damage, and corrective actions if necessary. We are issuing this AD to prevent failure of the seat attachment structure and possible injury to passengers during an emergency landing.
2012-08-17: We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes equipped with analog transient suppression devices (ATSDs) installed in accordance with Supplemental Type Certificate ST00146BO. This AD was prompted by multiple reports of corrosion on ATSDs. This AD requires revising the maintenance program to incorporate certain limitations. We are issuing this AD to detect and correct corrosion on ATSDs, which could result in the loss of high voltage transient protection (e.g., lightning protection) in the fuel tanks and consequent fuel tank explosion and loss of the airplane.
75-22-22: 75-22-22 PRESSED STEEL TANK COMPANY: Amendment 39-2409. Applies to all transport category airplanes incorporating DOT-3HT-3000 compressed gas cylinders manufactured by Pressed Steel Tank Company with original test dates on the cylinder from January 1975 through April 1975 and the following serial numbers: 50793R through 51284R 51913R through 52295R 52413R through 52648R 52663R through 52759R 10316S through 10468S 10516S through 10723S 11316S through 11415S Compliance required within 30 days after the effective date of this Airworthiness Directive, unless already accomplished. To identify and prevent service use of DOT-3HT-3000 cylinders which were manufactured with the wrong composition steel, accomplish the following: (a) Remove affected cylinders from aircraft, or before installing affected cylinders in aircraft, retest hydrostatically in accordance with Title 49 Code of Federal Regulations, Part 178; or (b) Use an equivalent method approved bythe Chief, Engineering and Manufacturing Branch, Great Lakes Region, to determine that the affected cylinder is manufactured with the intended composition steel. The amendment becomes effective November 10, 1975.
2012-08-02: We are adopting a new airworthiness directive (AD) for all Model A330-200 and -300 series airplanes; Model A330-223F and -243F airplanes; and Model A340-200, -300, -500, and -600 series airplanes. This AD was prompted by a report that during the evaluation of engine failures at take-off on Airbus flight simulators, it has been shown that with flight control primary computer (FCPC) 1 inoperative, in worst case scenario when FCPC2 and FCPC3 resets occur during rotation at take off, a transient loss of elevator control associated with a temporary incorrect flight control law reconfiguration could occur. This AD requires revising the Limitations section of the applicable airplane flight manual. We are issuing this AD to prevent movement of the elevators to zero position, which could result in inducing a pitch down movement instead of a pitch up movement needed for lift off, resulting in loss of controllability of the airplane.
71-20-05: 71-20-05 HUGHES: Amdt. 39-1301 as amended by Amendment 39-1359. Applies to Model 269A, 269A-1, and 269B Helicopters. Compliance required as indicated. To prevent failures of idler pulley bearings accomplish the following: (a) Within 50 hours time in service after the effective date of this AD, unless already accomplished, remove from service the aluminum idler pulley shaft, P/N 269A5440 (if installed) and idler pulley bearings, and install steel idler pulley shaft, P/N 269A5438 and idler pulley bearings, P/N 269A5050-58, in accordance with Hughes Service Information Notice N-1.4, dated September 15, 1971, or later FAA approved revision, or an equivalent installation and procedure approved by the Chief, Aircraft Engineering Division, FAA Western Region. Mutilate bearings and aluminum shafts to prevent return to service. (b) After the accomplishment of (a), above, at intervals not to exceed 200 hours time in service thereafter, replace the idler pulley bearingsin accordance with Hughes Service Information N-95, dated September 15, 1971, or later FAA approved revisions, or an equivalent replacement and procedure approved by the Chief, Aircraft Engineering Division, FAA Western Region. Mutilate old bearings to prevent return to service. This supersedes Amendment 39-77, (30 F.R. 7371), AD 65-12-02, as revised on February 2, 1966 (31 F.R. 1267). Amendment 39-1301 became effective October 1, 1971. This amendment 39-1359 becomes effective December 18, 1971.
2012-08-18: We are adopting a new airworthiness directive (AD) for all Turbomeca S.A. Arriel 2B and 2B1 turboshaft engines. This AD was prompted by the discovery of non-conformities of certain power turbine (PT) blade fir-tree roots. This AD requires removing the affected PT blades from service on or before reaching a new reduced life limit for those certain PT blades. We are issuing this AD to prevent PT blade rupture, which could result in an uncommanded in-flight engine shutdown, forced autorotation landing, or accident.
2012-08-03: We are adopting a new airworthiness directive (AD) for certain Airbus Model A300 B4-2C, B4-103, and B4-203 airplanes; Model A300 B4- 600, B4-600R, and F4-600R series airplanes, and Model C4-605R Variant F airplanes (collectively called A300-600 series airplanes); and Model A310 series airplanes. This AD was prompted by reports of cracking in the forward lug wing of the aft bearing at rib 5 of the main landing gear (MLG). This AD requires installing new bushes with increased interference fit in the forward lug wing of the aft bearing at rib 5 of the MLG on the right-hand (RH) and left-hand (LH) wing. We are issuing this AD to prevent cracking of the forward lug wing of the aft bearing at rib 5 of the MLG, which could adversely affect the structural integrity of the MLG attachment, and could result in the collapse of the MLG.
2012-08-08: We are adopting a new airworthiness directive (AD) for all Learjet Inc., Model 45 airplanes. This AD was prompted by changes to the Airworthiness Limitations Section (ALS) of the maintenance manual, which adds life-limits, revises life-limits, or adds inspections not previously identified. This AD requires revising the maintenance program to include new or more restrictive life-limits and inspections. We are issuing this AD to limit exposure of flight critical components to corrosion, cracking, or failure due to life-limits, which if not corrected, could result in loss of roll control, fatigue cracking, or loss of structural components.
2012-08-16: We are adopting a new airworthiness directive (AD) for certain Learjet Inc. Model 60 airplanes. This AD was prompted by two incidents of swapped fire extinguishing wires. This AD requires inspecting the electrical leads routed to the fire extinguishing containers for proper identification and missing labels, and to ensure the electrical leads are connected to the correct squibs; and corrective actions if necessary. We are issuing this AD to prevent the extinguishing agent of the fire extinguishing container from being delivered to the wrong engine in the event of an engine fire, and a consequent uncontrolled fire.
74-14-05: 74-14-05 BEECH: Amendment 39-1892. Applies to those Model B-19 (Serial Numbers MB-481 through MB-634 and MB-649) and those Model C-23 (Serial Numbers M-1285 through M-1493, except M-1437 and M-1491) airplanes which were originally approved in the Acrobatic Category and intentional spins in the Utility and Acrobatic Categories. Compliance: Required as indicated, unless already accomplished. To prevent inflight situations in which prompt spin recovery may not be assured, accomplish the following: A) Effective immediately intentional spins in the Utility and Acrobatic Categories are prohibited. B) Within the next 20 hours' time in service or ten (10) calendar days, whichever comes first, after the effective date of this AD, unless already accomplished per AD 73-14-8, Amendment 39-1683, remove all placards pertaining to intentional spins and acrobatic flight and install in place thereof a placard to be conspicuously located on the instrument panel which reads as follows: "THIS AIRPLANE MUST BE OPERATED AS A NORMAL OR UTILITY CATEGORY AIRPLANE. INTENTIONAL SPINS ARE PROHIBITED. NO ACROBATIC MANEUVERS APPROVED EXCEPT: CHANDELLES, LAZY EIGHTS, STEEP TURNS, AND STALLS (EXCEPT WHIP STALLS)." C) To reinstate the acrobatic category for those airplanes originally approved in the Acrobatic Category and intentional spins in Utility and Acrobatic Categories, install Beech spin improvement Kit No. 23-4007-1 S in accordance with instructions contained therein, or any equivalent method approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Central Region. Upon installation of said Kit, requirements of Paragraphs A) and B) of this AD are no longer applicable. This AD supersedes AD 73-14-8, Amendment 39-1683. This amendment becomes effective July 10, 1974.
65-22-04: 65-22-04 VICKERS: Amdt. 39-141 Part 39 Federal Register September 28, 1965. Applies to Viscount Models 744, 745D and 810 Series Airplanes. Compliance required as indicated. To prevent failure of the main landing gear retraction jack attachment bolt, accomplish the following: (a) For Models 744 and 745D Series airplanes with attachment bolts, P/N's 70150-495, 74450-103, 72450-275, or 74550-51, and Model 810 Series airplanes with attachment bolts, P/N's 74450-103 or 74550-51, comply with (c) within the next 350 hours' time in service after the effective date of this AD, unless already accomplished. (b) For Models 744 and 745D Series airplanes with attachment bolts, P/N's 72450-291 or 74550-67, and Model 810 Series airplanes with attachment bolts, P/N's 74550-67 comply with (c) within the next 1,300 hours' time in service after the effective date of this AD unless already accomplished. (c) Remove and inspect attachment bolts, P/N's 70150-495, 72450-275, 74450-103,74550-51, 72450-291, or 74550-67, in accordance with B.A.C. Ltd. PTL No. 259 (744 and 745D) and PTL No. 123 (810) or FAA-approved equivalent. Replace bolts having helical markings or surface cracks in accordance with PTL No. 259 or No. 123 as applicable. If a bolt is found to be completely broken through, inspect the associated trunnion or eye end for cracks. Replace any cracked trunnions or eye ends before further flight with a part of the same part number or an FAA-approved equivalent. This directive effective September 25, 1965.
2012-08-04: We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. This AD was prompted by reports of the air driven generator (ADG) failing to power essential buses during functional tests, due to the low threshold setting of the circuit protection on the ADG's generator control unit (GCU) preventing the ADG from supplying power to the essential buses. This AD requires installing a new or serviceable ADG GCU. We are issuing this AD to prevent loss of power from the ADG to the essential buses which, in the event of an emergency, could prevent continued safe flight.
98-21-27: This amendment adopts a new airworthiness directive (AD) that applies to Pilatus Aircraft Ltd. (Pilatus) Models PC-12 and PC-12/45 airplanes that are equipped with the "corporate commuter cabin layout." This layout is a Pilatus designation only and the affected airplanes are not certificated for commuter operation. This AD requires modifying the passenger seats and seat rail covers. 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 prevent passenger injuries because the passenger seat configuration has been found to not fully meet current head injury criteria regulations.
2012-08-05: We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model CL-600-2C10 (Regional Jet Series 700, 701, & 702), CL-600-2D15 (Regional Jet Series 705), CL-600-2D24 (Regional Jet Series 900), and CL-600-2E25 (Regional Jet Series 1000) airplanes. This AD was prompted by reports of the air driven generator (ADG) failing to power essential buses during functional tests, due to the low threshold setting of the circuit protection on the ADG's generator control unit (GCU) preventing the ADG from supplying power to the essential buses. This AD requires installing a new [[Page 24365]] or serviceable ADG GCU. We are issuing this AD to prevent loss of power from the ADG to the essential buses which, in the event of an emergency, could prevent continued safe flight.
2011-18-52: We are publishing a new airworthiness directive (AD) for certain Agusta S.p.A. (Agusta) Model AB139 and AW139 helicopters that requires establishing a revised life limit for each tail rotor (T/R) blade and updating the helicopter's historical records, repetitively inspecting T/R blades for a crack, and replacing certain T/R blades. This AD is prompted by a fatal accident involving an Agusta Model AW139 helicopter, which may have been caused by cracks in a T/R blade. These actions are intended to detect and prevent a crack in a T/R blade, which could lead to failure of a T/R blade and subsequent loss of control of the helicopter.
98-21-26: This amendment adopts a new airworthiness directive (AD) that applies to certain Mooney Aircraft Corporation (Mooney) Models M20J, M20K, M20M, and M20R airplanes. This AD requires grinding the surface of the main landing gear (MLG) leg bracket, inspecting this area for cracks, and replacing any cracked MLG leg bracket. This AD is the result of the manufacturing of several of the MLG leg brackets using laser pattern cutting. The brackets, when manufactured using this process, develop minor cracks at the bends, which could propagate over time. The actions specified by this AD are intended to prevent failure of the MLG side brace bolt caused by cracking of the MLG leg bracket, which could result in MLG collapse with consequent loss of control of the airplane during taxi, takeoff, or landing operations.
2012-03-04: We are superseding an existing airworthiness directive (AD) for certain Airbus Model A310 series airplanes. That AD currently requires, for certain airplanes, modifying the wire routing and installing additional protective sleeves. This new AD adds, for certain airplanes, modifying wire routings and installing a modified bracket. This AD was prompted by analyses of the wire routing showing that the route of the fuel electrical circuit in the right-hand wing must be modified in order to ensure better segregation between fuel quantity indication wires and the 115-volt alternating current wires. We are issuing this AD to prevent short circuits leading to arcing, and possible fuel tank explosion.
54-12-02: 54-12-02 MCCAULEY: Applies to All McCauley Propellers Having 41D5926 Hub With SS-135-6 Blades and D-1093 Hub With SS-135-6M or SS-138-6 Blades. Compliance required as indicated. On the basis of satisfactory vibration stress surveys conducted on the 102-inch diameter configuration, these propellers were approved vibration wise for installation on the Continental W-670-6A and W-670-6N and Lycoming R680 engines. When installed on the Continental engine, the propeller must be indexed in the 0 degree position (blades in line with the crankthrow) and operation is to be restricted between 1,500 and 1,650 r.p.m. Additional approval were given for the installation of propellers in reduced diameters at a time when the effects on the vibratory stresses resulting from such a reduction were not generally appreciated. Accordingly, some installations were made where the propeller diameter was reduced, as in the Fairchild M-62C. Service experience with this installation and a more thorough knowledge of the vibration problems indicate that diameters below the normal 2 percent reduction that is usually permissible on the basis of a stress survey have resulted in serious failures. Accordingly, to preclude additional propeller failures, the following should be performed. Compliance required prior to July 1, 1954. (a) To preclude failures due to vibratory conditions, remove from service all of these propellers in diameters outside the 102- to 100-inch limits. (b) To preclude fatigue failures due to corrosion or galling in the blade shank region and/or hub, disassemble propellers maintained in service (diameters 102 to 100 inches) and magnetically inspect hub and blades at intervals not exceeding 100 hours. The propeller blade and hub surface must be kept free from corrosion at all times. If 100 hours operating time has not been accumulated since an inspection was conducted on the propeller as provided in AD 47-43-09, it will be satisfactory to operate until 100 hours have been accumulated. This supersedes AD 47-43-09.
98-08-25 R1: This amendment revises Airworthiness Directive (AD) 98-08-25, which currently requires replacing the nose landing gear (NLG) drag link bolt with an approved heat-treated bolt that has the manufacturer's serial number, manufacture date, and the last three digits of the drawing number (055) on the bolt head on certain Twin Commander Aircraft Corporation (Twin Commander) 500, 680, 690, and 695 series airplanes; and changing the bolt part number (P/N) to be installed on Models 690D and 695A from P/N ED10055 to P/N 750076-1. The FAA inadvertently transposed the serial numbers of the 4 affected Model 695A airplanes. This AD retains the same actions of AD 98-08-25, and corrects the serial numbers of these 4 airplanes. Three of the four airplanes are not on the U.S. Register and the other one is already in compliance with the actions of AD 98-08-25. The actions specified in this AD are intended to continue to prevent the NLG from collapsing due to failure of a drag link bolt, which could result in loss of control of the airplane during landing operations.
2012-07-05: We are adopting a new airworthiness directive (AD) for certain Fokker Services B.V. Model F.27 Mark 050 airplanes. This proposed AD would require performing a low frequency eddy current inspection for cracks of the lap joint of the rear fuselage, and repair if necessary. This AD was prompted by reports of cracking in the fuselage lap joint. We are issuing this AD to detect and correct exponential crack growth, which could lead to failure of the lap joint over a certain length and consequent in-flight decompression of the airplane.