Results
98-07-07: This amendment supersedes existing airworthiness directive (AD) 96-13-04, applicable to Rolls-Royce, plc RB211 series turbofan engines, that currently requires removing and replacing a rigid low pressure (LP) fuel system tube assembly with a tube assembly incorporating flexible sections and revised clip points in order to preclude cracking and subsequent fuel leakage. This amendment requires replacing one of the flexible fuel tube assemblies installed in accordance with AD 96-13-04 with an alternate flexible fuel tube assembly that is not prone to rupture. This AD also requires immediate replacement of any rigid fuel tubes not previously removed from service as required by AD 96-13-04. The amendment is prompted by reports of fuel line rupture on one of the flexible fuel tube assemblies installed in accordance with AD 96-13-04. The actions specified by this AD are intended to prevent high volume fuel leaks and reported fuel collection inside the engine nacelle, which couldresult in an uncontrolled engine fire. The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of April 29, 1998. Comments for inclusion in the Rules Docket must be received on or before June 15, 1998.
98-08-16: This amendment adopts a new airworthiness directive (AD), applicable to certain Saab Model SAAB SF340A and 340B series airplanes, that requires a one-time inspection to detect discrepancies of the flight idle stop override mechanism, and corrective action, if necessary. This amendment is prompted by the issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent increased braking distance for landings that require the flight idle stop override, resulting from the combination of failure of the override mechanism and inability of the power levers to be moved below the flight idle position after touchdown.
2012-15-07 R1: We are revising an existing airworthiness directive (AD) for Glasflugel Models Standard Libelle-201B, Club Libelle 205, Mosquito, and Kestrel gliders. That AD currently requires actions to address the unsafe condition on these products. This new AD includes clarification that the replacement control rod has an additional drain hole at the rod bottom between the forks and is the acceptable configuration for compliance. 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 corrosion damage to the elevator control rod that could lead to failure of the elevator control rod, possibly resulting in loss of control of the glider. We are issuing this AD to require actions to address the unsafe condition on these products.
98-08-17: This amendment adopts a new airworthiness directive (AD), applicable to various turbo-propeller powered General Dynamics (Convair) Model 240, 340, and 440 series airplanes, that requires revising the Airplane Flight Manual (AFM) to modify the limitation that prohibits positioning the power levers below the flight idle stop during flight, and to provide a statement of the consequences of positioning the power levers below the flight idle stop during flight. This amendment is prompted by incidents and accidents involving airplanes equipped with turboprop engines in which the ground propeller beta range was used improperly during flight. The actions specified by this AD are intended to prevent loss of airplane controllability, or engine overspeed and consequent loss of engine power caused by the power levers being positioned below the flight idle stop while the airplane is in flight.
98-08-14: This amendment adopts a new airworthiness directive (AD) applicable to Eurocopter France (Eurocopter) Model SA-365N, N1 and AS-365N2 helicopters that requires inspections of the main gearbox suspension diagonal cross-member (diagonal cross-member) for cracks, and removal of the diagonal cross-member and replacement with an airworthy diagonal cross-member if any crack is found. This amendment is prompted by several reports of the discovery of cracks in diagonal cross-members. The actions specified by this AD are intended to prevent failure of the diagonal cross-member which could cause the main gearbox to pivot, resulting in severe vibrations and a subsequent forced landing.
2012-17-12: We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 747-400 series airplanes. This AD was prompted by reports of water leaking into electrical and electronic equipment in the main equipment center (MEC). This AD requires modifying the floor panels; removing drains; installing floor supports, floor drain trough doublers, drain troughs, and drains; and sealing and taping the floor panels. We are issuing this AD to prevent water from entering the MEC, which could result in an electrical short and potential loss of several functions essential for safe flight.
92-26-06: 92-26-06 BRITISH AEROSPACE: Amendment 39-8433. Docket No. 92-NM-143-AD. Applicability: All Model BAe 125-800A series airplanes on which Modification No. 253284A has not been installed; certificated in any category. Compliance: Required as indicated, unless accomplished previously. To prevent the crew from failing to disable all appropriate circuit breakers in an emergency, accomplish the following: (a) Within 3 months after the effective date of this AD, install Modification No. 253284A by painting the perimeters of the "A SCRN" and "B SCRN" heat control circuit breakers with matte white (non-cellulose) paint, in accordance with British Aerospace Service Bulletin SB.24-288-3284A, dated February 7, 1992. (b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate. Operators shall submittheir requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Standardization Branch. NOTE: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113. (c) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished. (d) The installation shall be done in accordance with British Aerospace Service Bulletin SB.24-288-3284A, dated February 7, 1992. (NOTE: The issue date of that service bulletin is indicated only on "page 1 of 7"; no other page of the document is dated.) 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 British Aerospace, PLC, Librarian for Service Bulletins, P.O. Box 17414, Dulles International Airport, Washington, DC 20041-0414. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. (e) This amendment becomes effective on February 1, 1993.
98-08-13: This amendment adopts a new airworthiness directive (AD) that is applicable to Eurocopter France Model SA 330F, G, and J, and AS 332C, L, L1, and L2 helicopters. This action requires daily inspections of the root of each tail rotor head pitch change spider arm (spider arm) for cracks, and an inspection of the tail rotor head pitch change spider (spider) for cracks and fretting corrosion. A terminating action for the requirements of this AD is the installation of an airworthy modified spider, an airworthy replacement spider, or an airworthy repaired spider. This amendment is prompted by one in-service report of fatigue cracking on a Model AS 332 helicopter. This condition, if not corrected, could result in failure of the spider arm, loss of control of the tail rotor blade, and subsequent loss of control of the helicopter.
91-04-09: 91-04-09 BRITISH AEROSPACE: Amendment 39-6896. Docket No. 90-NM-232-AD. Applicability: All Model ATP series airplanes, certificated in any category. Compliance: Required as indicated, unless previously accomplished. To detect damaged wires in the primary flight control cables, accomplish the following: A. For airplanes in Pre-Modification 10060A configuration: 1. Within 250 hours time-in-service after the effective date of this AD, and thereafter at intervals not to exceed 125 hours time-in-service, perform a visual inspection of the aileron primary control cables in the wings for wear and broken wires, in accordance with the Accomplishment Instructions in British Aerospace Service Bulletin ATP-27-26, dated April 5, 1990. 2. Prior to the accumulation of 2,500 hours time-in-service or within 200 hours time-in-service after the effective date of this AD, whichever occurs later, and thereafter at intervals not to exceed 2,500 hours time-in-service,perform a visual inspection of the fuselage primary control cables for wear and broken wires, in accordance with the Accomplishment Instructions in British Aerospace Service Bulletin ATP-27-26, dated April 5, 1990. NOTE: The repetitive inspection intervals shown herein should not be interpreted as extending the published life limits of any control cables being inspected. B. For airplanes in Post-Modification 10060A configuration: Within 125 hours time-in-service after the effective date of this AD, or within 750 hours time-in-service following accomplishment of Modification 10060A, whichever occurs later, and thereafter at intervals not to exceed 250 hours time-in-service, perform a visual inspection of the aileron primary control cables in the wings for wear and broken wires, in accordance with the Accomplishment Instructions in British Aerospace Service Bulletin ATP-27-26, dated April 5, 1990. C. If defective wires are found as a result of the inspections required by this AD, prior to further flight, accomplish the following in accordance with the Accomplishment Instructions in British Aerospace Service Bulletin ATP-27-26, dated April 5, 1990. 1. In the event of a single wire break, the ends must be trimmed to lie flush with the cable assembly and a full and free check of control travel must be carried out to ensure that the wire ends do not "snag". If cables do "snag", the cable must be replaced prior to further flight, in accordance with the service bulletin. 2. If two or more wires are found to be broken, prior to further flight, replace the damaged cable and replace any associated damaged fairlead rollers, in accordance with the service bulletin. D. An 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, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate. NOTE: Manager, Standardization Branch, ANM-113, and a copy sent to the cognizant FAA Principal Inspector (PI). The PI will then forward comments or concurrence to the Manager, Standardization Branch, ANM-113. E. Special 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. All persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to British Aerospace, PLC, Librarian for Service Bulletins, P.O. Box 20041-0414. These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington. This amendment (39-6896, AD 91-04-09) becomes effective on March 22, 1991.
2022-07-03: The FAA is adopting a new airworthiness directive (AD) for Bell Textron Inc., Model 412, 412EP, and 412CF helicopters. This AD was prompted by evaluation results showing flight loads that impact the collective lever fatigue life. This AD requires adding a permanent hours time-in-service (TIS) penalty for certain collective levers and prohibits installing those collective levers unless the permanent hours TIS penalty has been added. The FAA is issuing this AD to address the unsafe condition on these products.
89-07-09: 89-07-09 SIKORSKY AIRCRAFT: Amendment 39-6172. Applicability: All Model S-61 series helicopters, certificated in any category, equipped with main rotor gearbox helical gear Part Number S6135-20620-003, Serial Numbers 1086, 1087, 1089, and 1090 through and including 1099, 1101, 1103, through and including 1113, 1116, 1117, 1130, 1132. (Docket No. 89-ASW-4). Compliance: Required within the next 100 hours' time in service, unless already accomplished. To prevent possible failure of the helical gear, accomplish the following: (a) Inspect the main rotor gearbox to identify the serial number of the helical gear installed. If the helical gear is identified with a serial number listed in this AD, replace it with an airworthy helical gear which has a serial number other than listed in this AD. NOTE: Sikorsky Aircraft message CBT-TS-89-002 dated January 23, 1989, applies to this AD. (b) Aircraft may be ferried in accordance with the provisions of FAR Sections 21.197 and 21.199 to a base where the provisions of the AD can be accomplished. (c) An alternate means of compliance or an adjustment of the initial compliance time which provides an equivalent level of safety may be used if approved by the Manager, Boston Aircraft Certification Office, Federal Aviation Administration, 12 New England Executive Park, Burlington, MA 01803. The noted service information may be obtained from Sikorsky Aircraft, 6900 Main Street, Mail Stop S409A, Stratford, CT 06601-1381. This amendment (39-6172, AD 89-07-09) becomes effective on April 20, 1989.
2010-10-16: This amendment adopts a new airworthiness directive (AD) for the Aeronautical Accessories, Inc. (AAI) Low Skid Landing Gear Forward Crosstube (Crosstube) on certain Bell and Agusta model helicopters. This action requires replacing certain AAI serial-numbered crosstubes installed on these model helicopters. This amendment is prompted by the discovery of a defect in the raw material used in manufacturing certain crosstubes. The actions specified in this AD are intended to prevent failure of a crosstube and subsequent collapse of the landing gear.
98-08-07: This amendment adopts a new airworthiness directive (AD) that applies to certain Pilatus Aircraft Ltd. (Pilatus) Model PC-7 airplanes. This AD requires replacing the rudder and elevator pivot arms with parts of improved design. This AD results from reports of cracks in the elevator and rudder trim tab pivot arms on the above-referenced airplanes. The actions specified by this AD are intended to prevent failure of the elevator and rudder caused by fatigue cracking of the pivot arms, which could result in reduced airplane controllability and possible loss of control of the airplane.
98-08-10: This amendment adopts a new airworthiness directive (AD), applicable to all Saab Model SAAB 2000 series airplanes, that requires revising the Airplane Flight Manual (AFM) to modify the limitation that prohibits positioning the power levers below the flight idle stop during flight, and to provide a statement of the consequences of positioning the power levers below the flight idle stop during flight. This amendment is prompted by incidents and accidents involving airplanes equipped with turboprop engines in which the ground propeller beta range was used improperly during flight. The actions specified by this AD are intended to prevent loss of airplane controllability, or engine overspeed and consequent loss of engine power caused by the power levers being positioned below the flight idle stop while the airplane is in flight.
87-17-12: 87-17-12 SHORT BROTHERS PLC: Amendment 39-5717. Applies to Model SD3-30 series airplanes, serial numbers SH3002 through SH3099, SH3102, and SH3105, certificated in any category. Compliance required as indicated, unless previously accomplished. To prevent interference with the elevator and rudder control system, accomplish the following: A. Within 180 days after the effective date of this AD, install an extended guard behind the overhead lockers in accordance with the Accomplishment Instructions of Shorts Service Bulletin No. SD330-27-31, dated March 1986. B. An 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, Standardization Branch, ANM-113, FAA, Northwest Mountain Region. C. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of the modifications required by this AD. All persons affected by this directive who have not already received the appropriate service document from the manufacturer may obtain copies upon request to Shorts Aircraft, 2011 Crystal Drive, Suite 713, Arlington, Virginia 22022-3702. This document may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or the Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington. This amendment becomes effective September 28, 1987.
98-08-04: This amendment adopts a new airworthiness directive (AD) that applies to all AERMACCHI S.p.A. Models S.208 and S.208A airplanes. This AD requires inspecting the landing gear rod springs to assure they are made with a wire diameter of 4.5 millimeters (mm), and replacing any that have a wire diameter of 4.0 mm. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Italy. The actions specified by this AD are intended to prevent failure of the landing gear caused by an insufficient wire diameter of the rod springs, which could result in loss of control of the airplane during landing operations.
87-24-10: 87-24-10 AVIONS MARCEL DASSAULT - BREGUET AVIATION (AMD-BA): Amendment 39-5776. Applies to all Falcon 10 airplanes, certificated in any category, unless AMD-BA modification M736 has been accomplished. Compliance is required as specified, unless previously accomplished. To prevent structural damage to aircraft frames and skin in the vicinity of the electrical grounding connection for the air conditioning freon compressor motor, accomplish the following: A. Within 30 days after the effective date of this AD, and thereafter at intervals not to exceed 30 days, conduct a visual inspection and a resistance test of the electrical grounding connection, located on frame 35, for the air conditioning freon compressor motor. Perform the inspection and test in accordance with the AMD-BA Service Bulletin F10-262, dated December 22, 1986 (reference Maintenance Manual Chapter 20-40-40). 1. If the measured resistance value of the grounding connection bonding exceeds the limits referenced in paragraph B. of the Accomplishment Instructions of the service bulletin, then prior to further flight, repair the grounding connection in accordance with the service bulletin. 2. If the resistance value specified for the grounding connection bonding cannot be obtained, then prior to further flight, install a new grounding cable in accordance with paragraph C. of the Accomplishment Instructions of the service bulletin. B. Within 4 months after the effective date of this AD, install a new electrical grounding cable for the air conditioning freon compressor motor, in accordance with the Accomplishment Instructions of AMD-BA Service Bulletin F10-262, dated December 22, 1986. C. Installation of a new electrical grounding cable for the air conditioning freon compressor motor, in accordance with AMD-BA Service Bulletin F10-262, dated December 22, 1986, constitutes terminating action for the repetitive inspection and testing requirements of paragraph A. above. D.Any structural damage due to the effects of existing electrical arcing across a loose grounding connection identified during the inspections required by paragraph A., above, must be repaired, prior to further flight, in a manner approved by the FAA. E. An 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, Standardization Branch, ANM-113, FAA, Northwest Mountain Region. F. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of inspections and/or modifications required by this AD. All persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to the AMD-BA Representative, c/o Falcon Jet Corporation, Teterboro Airport, Teterboro, N.J. 07608. These documents may be examined at the FAA, NorthwestMountain Region, 17900 Pacific Highway South, Seattle, Washington, or at the Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington. This amendment becomes effective December 29, 1987.
70-12-07: 70-12-07 GENERAL DYNAMICS: Amdt. 39-1004. Applies to all Model 340 and 440 Series airplanes including those modified in accordance with STC SA4-1100 or STC SA1096WE. Compliance required as indicated. To detect cracks and prevent failure of the main landing gear axle: Within the next 150 hours' time in service after the effective date of this AD, unless already accomplished within the last 850 hours' time in service, visually inspect MLG Piston/Axle Assemblies P/N 528039 with 10,000 or more hours' time in service for crack indications in the fillet radius area between the axle and the outboard face of both brake attachment flanges, by dye penetrant inspection procedures, in accordance with Part I of General Dynamics 640(340D) Service Bulletin No. 32-3, dated October 31, 1969, or later FAA approved revision, or by magnetic particle inspection procedure, or an equivalent inspection procedure approved by the Chief, Aircraft Engineering Division, FAA Western Region. a) If no cracks are found, repeat the inspection specified above at intervals not to exceed 1000 hours' time in service from the last inspection. This 1000 hour inspection interval may be discontinued when the area identified above has been reworked in accordance with paragraphs C, D, and E of Part II of S.B. 32-3, dated October 31, 1969, or later FAA approved revision, or an equivalent rework approved by the Chief, Aircraft Engineering Division, FAA Western Region. Subsequent to the accumulation of 2000 hours' time in service after this rework, and prior to 2,500 hours' time in service after rework, perform an inspection for cracks as described above. If no cracks are found as a result of this inspection, further inspections are not required by this A.D. If cracks are found, accomplish (b), below. b) If cracks are found as a result of any of the inspections outlined above, accomplish the following before further flight: 1) Rework the cracked area in accordance with all of the provisions of Part II of S.B 32-3, dated October 31, 1969, or later FAA approved revision, or an equivalent rework approved by the Chief, Aircraft Engineering Division, FAA Western Region, provided axle wall thickness remaining after rework is a minimum of 0.30 inches. After rework, repeat the inspection procedure specified above at intervals not to exceed 2500 hours' time in service from the last inspection. 2) If cracks are found which require removal of material that would leave a minimum axle wall thickness of less than 0.30 inches, the axle must be replaced. NOTE: The holder of STC SA4-1100, Allison Division of General Motors Corp., has determined that Part-II of General Dynamics Service Bulletin 32-3 is applicable to all aircraft modified in accordance with STC SA4-1100. This amendment becomes effective June 12, 1970.
91-23-02: 91-23-02 AVIAT (formerly Christen Industries): Amendment 39-8071. Docket No. 91-CE-54-AD. Applicability: Christen Model A-1 Husky airplanes (serial numbers 1001 through 1045), certificated in any category. Compliance: Required within the next 50 hours time-in-service after the effective date of this AD, unless already accomplished. To prevent loss of airflow to the carburetor and possible loss of engine power, which could result in loss of control of the airplane, accomplish the following: (a) Remove the carburetor air intake box and replace it with a new carburetor air intake box, part number 35453. Reinstall the same bolts and safety wire. Ensure that there is at least a 0.25-inch clearance between the actuating arm and the side of the air intake scoop and that the box and intake screen fit properly at the forward end of the scoop. NOTE: Carburetor air intake boxes, part number 35453, are available free of charge on an exchange basis from the manufacturer at the address specified in paragraph (d) of this AD. (b) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished. (c) An alternative method of compliance or adjustment of the compliance time that provides an equivalent level of safety may be approved by the Manager, Denver Aircraft Certification Field Office, FAA, 2390 Syracuse Street, Denver, Colorado 80207. The request should be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Denver Aircraft Certification Field Office. (d) All persons affected by this directive may obtain a new carburetor air intake box, part number 35453, on an exchange basis by contacting Aviat, Inc., P.O. Box 1149, Afton, Wyoming 83110; Telephone (307) 886-3151. Information that is related to this AD may be examined at the FAA, Central Region, Office of the Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106. This amendment (39-8071, AD 91-23-02) becomes effective on December 10, 1991.
2012-16-04: We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 777-200 and -300 series airplanes equipped with Rolls-Royce RB211 Trent 800 engines. This AD was prompted by reports of events related to thermal damage of the thrust reverser (T/ R) inner wall on Rolls-Royce RB211 Trent 800 engines. This AD requires replacing the bleed valve parts and tubing with new parts and tubing on the left and right engines; and installing Aero-Engine database (AEDB) software in the airplane information management system (AIMS) hardware. We are issuing this AD to prevent T/R thermal damage caused by excessive heat downstream of the 8th stage IP8 exhaust ports, which could result in T/R structural failure. This failure could result in large pieces of the T/R or adjacent components departing the airplane. A separated T/R piece could result in a rejected takeoff and cause asymmetric thrust and consequent loss of control of the airplane during reverse thrust operations.Separated components could also cause structural damage to the airplane, damage to other airplanes due to debris left on the runway, or injury to people on the ground.
2010-11-02: We are superseding an existing airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) originated 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: * * * * * Incomplete closure of the MED [main entry door] may be followed by in-flight opening of the door. As a result, the MED and the adjacent fuselage structure may be damaged during opening and landing impact. Damage to the left engine by flying debris and objects may also occur. We are issuing this AD to require actions to correct the unsafe condition on these products.
97-08-02 R1: This document clarifies information in an existing airworthiness directive (AD) that applies to certain Schempp-Hirth K.G. (Schempp-Hirth) Models Standard-Cirrus, Nimbus-2, Nimbus-2B, Mini-Nimbus HS-7, Mini-Nimbus B, Discus a, and Discus b sailplanes. That AD currently requires accomplishing a load test of the elevator control system, and replacing the elevator vertical actuating tube either immediately or at a certain time period depending on the results of the load test. The actions specified in that AD are intended to prevent corrosion in the elevator caused by water entering the elevator control rod, which could result in elevator failure and consequent loss of control of the sailplane. The Schempp-Hirth Models Nimbus 2, Mini-Nimbus HS-7, and Standard Cirrus sailplanes are not equipped with elevator control systems, and should not be affected by the current AD. This action eliminates all reference to the Shempp-Hirth Models Nimbus 2, Mini-Nimbus HS-7, and Standard Cirrus sailplanes in the current AD.
2012-17-05: We are adopting a new airworthiness directive (AD) for certain Honeywell International Inc. models TFE731-4, -4R, -5, -5R, -5AR, and - 5BR series turbofan engines. This AD was prompted by a report of a rim/ web separation of a first stage low-pressure turbine (LPT1) rotor assembly. This AD requires replacing affected LPT1 rotor assemblies with assemblies eligible for installation. We are issuing this AD to prevent uncontained disk separation, engine failure, and damage to the airplane.
2012-16-01: We are adopting a new airworthiness directive (AD) for Pratt & Whitney Division PW4052, PW4152, PW4056, PW4156A, PW4060, PW4060A, PW4060C, PW4062, PW4062A, PW4158, PW4460, PW4462, PW4164, PW4164C, PW4164C/B, PW4168, and PW4168A turbofan engines with certain high- pressure turbine (HPT) stage 1 front hubs installed. This AD was prompted by Pratt & Whitney's updated low-cycle-fatigue analysis that indicated certain HPT stage 1 front hubs could initiate a crack prior to the published life limit. This AD requires removing the affected HPT stage 1 front hubs from service using a drawdown plan. We are issuing this AD to prevent failure of the HPT stage 1 front hub, which could lead to an uncontained engine failure and damage to the airplane.
2012-16-16: We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 757 airplanes. This AD was prompted by a report of extensive corrosion of the ballscrew of the drive mechanism of the horizontal stabilizer trim actuator. This AD requires repetitive detailed inspections for discrepancies of the horizontal stabilizer ballscrew assembly; repetitive lubrication of the horizontal stabilizer trim control system; repetitive measurements for discrepancies of the ballscrew to ballnut freeplay; and corrective actions, if necessary. We are issuing this AD to prevent undetected failure of the primary and secondary load paths for the ballscrew in the horizontal stabilizer, which could lead to loss of control of the horizontal stabilizer and consequent loss of control of the airplane.