Results
98-09-13: This amendment adopts a new airworthiness directive (AD) that applies to certain Alexander Schleicher Segelflugzeugbau (Alexander Schleicher) Model ASK 21 sailplanes. This AD requires inspecting the S-shaped rudder pedal tube for displacement, and correcting any displacement of the plastic tube. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Germany. The actions specified by this AD are intended to prevent rudder control jamming, which could result in loss of directional control of the sailplane.
47-36-01: 47-36-01 DOUGLAS: (Was Mandatory Note 1 of AD-3L-1.) Applies to A-26B and A-26C Aircraft. \n\n\tCompliance required prior to November 15, 1947, on all serial numbers. \n\n\tTo reduce the possibility of failure of the wing bulkhead assemblies and subsequent loss of the ailerons: \n\n\t1.\tMachine face of boss on fitting assemblies P/N 4154028 and 4154028-1, to 0.335 inch, and ream bore to 0.9007 + 0.0000, -0.0005 inch. (See Figure 1.) Replace bearing AN 209K4A with self-aligning bearing, P/N AN 200KS4 and stake in six places each side. Install reworked fitting assemblies, P/N 4154028 and 4154028-1, on original bulkheads as follows: \n\n\n\t\t\n\n\t\t(a)\tOn installations using two screws, P/N 1029421-416-11, or two bolts, P/N AN 4-6A, and three rivets, enlarge the rivet holes in the fitting and bulkhead to 0.191-inch diameter and countersink the holes in bulkhead 100 degrees. Install fitting using two screws, P/N 1029421-416-11 or NAS 214-11, or two bolts, P/N AN4-6A, originally installed, two washers, P/N AN 960D416, and two nuts, AN 365-428, in the top and bottom holes, and three screws, P/N S-1029421-10-12, three washers, P/N AN 960D10, and three nuts, P/N AN 365-1032, in the three remaining holes. \n\n\t\t(b)\tOn installations using four or five screws, P/N S-1029421-10-12, reinstall fitting assemblies with original screws, washers, and nuts. \n\n\t2.\tInspect bulkhead assemblies, P/N 5153663 and 5153663-1, for cracks. If cracks are found, replace bulkhead as follows: \n\n\t\tRemove damaged bulkhead by drilling out the attaching rivets. Using damaged bulkhead as a pattern, fabricate a new bulkhead from 0.081-inch 24SO aluminum alloy sheet, condition A, annealed (Spec. No. QQ-A-362 or AN A-13.) After forming new bulkhead, heat- treat in accordance with AN 01-1A-1, section V, then apply one coat of zinc chromed primer. \n\n\t\tHold new bulkhead in place on the airplane and check for proper alignment between the upper and lower surfaces of the wing and wing tip. (Drill holes to match existing holes in the angle, skin, and fitting.) Install bulkhead using rivets, P/N AN 426AD-(0), length and diameter as required. \n\n\t\tInstall reworked fitting assemblies on new bulkheads as follows: \n\n\t\t(a)\tFor fitting assemblies which incorporate two 1/4-inch bolt holes and three rivet holes, enlarge the rivet holes to 0.191-inch diameter. Drill corresponding holes in bulkhead and countersink 100 degrees. Install fitting assembly using two screws, P/N 1029421-416-11 or NAS214-11, two washers, P/N AN 960D416, two nuts, P/N AN 365-428, three screws, P/N S- 1029421-10-12, three washers, P/N AN 960-D10, and three nuts, P/N AN 365-1032. \n\n\t\t(b)\tFor fitting assemblies which incorporate four 0.191-inch diameter holes, drill corresponding holes in new bulkhead and countersink 100 degrees. Install fitting assembly using four screws, P/N S-1029421-10-12, four washers, P/N AN 960D10, and four nuts, P/N AN 365- 1032. \n\n\tReinstall aileron and check alignment of fitting assembly. Install washers, P/N AN 960D416 or AN 960A416L, or shim stock, as required, to take up the end play between the bearing inner race and bracket assembly, aileron hinge support. \n\n\t(Army Technical Order 01-40AT-40 covers this same subject.)
47-51-15: 47-51-15 DOUGLAS: Applies to DC-6 Serial Numbers 42854 Through 42880; 42882 Through 42888; 42890; and 42891; 43000 Through 43003; 43005 Through 43009; 43055; and 43056. \n\nTo be accomplished not later than next No. 3 inspection. \n\nIn order to prevent malfunctioning of the brakes, the original Raybestos brake lining, P/N 9520535 must be replaced with Goodyear BL-56 lining, P/N 9521091. This new lining is identified with two yellow dots. \n\n(Douglas Service Bulletin DC-6 No. 1 covers this same subject.)
2012-18-07: We are superseding an existing airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211-Trent 875-17, RB211-Trent 877-17, RB211-Trent 884-17, RB211-Trent 884B-17, RB211-Trent 892-17, RB211- Trent 892B-17, and RB211-Trent 895-17 turbofan engines. That AD currently requires initial and repetitive ultrasonic inspections (UIs) of certain low-pressure (LP) compressor blades identified by serial number (S/N). This new AD requires the same actions but expands the population of blades. This AD was prompted by the need to add the inspections of the LP compressor blades listed by S/N in Appendices 3H through 3L of RR plc Alert Service Bulletin (ASB) No. RB.211-72-AG244, Revision 4, dated December 22, 2011. We are issuing this AD to prevent multiple LP compressor blades from failing due to blade root cracks, which could lead to uncontained engine failure and damage to the airplane.
98-09-25: This amendment adopts a new airworthiness directive (AD) that applies to certain The New Piper Aircraft, Inc. (Piper) Models PA-31, PA-31-300, PA-31-325, and PA-31-350 airplanes. This AD requires replacing the lower spar splice plate and reworking the lower spar caps. This AD results from numerous reports of fretting and cracking of the lower spar splice plates on Piper PA-31 series airplanes in Australia, and a report of one incident in the United States. The actions specified by this AD are intended to prevent failure of the lower spar splice plate caused by fretting and cracking, which could result in loss of control of the airplane.
2022-06-04: The FAA is adopting a new airworthiness directive (AD) for certain Schempp-Hirth Flugzeugbau GmbH Model Janus, Mini-Nimbus HS-7, Nimbus-2, and Standard Cirrus gliders. This AD was prompted by 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 a disconnected pendulum elevator. This AD requires installing colored markings and revising the existing aircraft flight manual (FM) and service manual (SM). The FAA is issuing this AD to address the unsafe condition on these products.
98-09-06: This amendment adopts a new airworthiness directive (AD), applicable to certain Saab Model SAAB SF340A and SAAB 340B series airplanes, that requires an inspection to determine the serviceability of the fire extinguisher of the forward lavatory waste bin, and corrective actions, if necessary. This amendment also requires installation of a placard adjacent to the fire extinguisher in the forward lavatory waste bin. 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 leakage of the fire extinguishing agent, which could prevent proper distribution of the agent within the lavatory waste bin in the event of a fire.
2012-19-05: We are adopting a new airworthiness directive (AD) for certain Fokker Services B.V. Model F.28 Mark 0070 and 0100 airplanes. This AD was prompted by reports of burned contacts in a certain production break plug and its corresponding receptacle. This AD requires modifying galley power supply wiring by disconnecting it from the affected plug/ receptacle and reconnecting the power supply wiring through splices. We are issuing this AD to prevent a high electrical load, which might lead to overheating of the galley power supply wiring and/or the electrical connector and consequent smoke or fire in the galley area, which could result in damage to the airplane and injury to occupants.
2010-11-08: We are superseding an existing airworthiness directive (AD) for the products listed above. 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: AD 2007-0315-E was issued to address a possible fuel leakage in the gear compartment in front of the engine and mandated inspections and replacement of fuel plastic-made connectors by connectors made of metal. Since its publication, another fuel leakage has been reported on a S10-VT which had implemented the STEMME Service Bulletin (SB) A31-10-082 as required by AD 2007-0315-E. It has been determined that the fuel leak may have been caused by the deformation that the originally installed clamps created on the fuel hoses and thus preventing the new clamps from being sufficiently pinched to perform a correct tightening. We are issuing this AD to require actions to correct the unsafe condition on these products. DATES: This AD becomes effective July 6, 2010. On July 6, 2010, the Director of the Federal Register approved the incorporation by reference of STEMME F & D Service Bulletin A31-10-083, Am-Index: 01.b, dated May 6, 2009, listed in this AD. As of June 23, 2008 (73 FR 31355, June 2, 2008), the Director of the Federal Register approved the incorporation by reference of STEMME F & D Service Bulletin A31-10-083, Am-Index: 01.a, dated February 26, 2008, listed in this AD. As of February 20, 2008 (73 FR 5733, January 31, 2008), the Director of the Federal Register approved the incorporation by reference of STEMME F & D Service Bulletin A31-10-082, AM.-Index: 01.a, dated November 30, 2007, listed in this AD.
98-09-08: This amendment adopts a new airworthiness directive (AD) that applies to all Avions Pierre Robin (Avions) Model R3000/160 airplanes. This action requires repetitively inspecting the flap control shaft and the welds of the flap levers for cracks; replacing the cracked part, if cracks are found; and adjusting the flap travel, if no cracks are found. Reports of cracked flap control shafts found during routine maintenance prompted this action. The actions specified by this AD are intended to prevent cracks on the flap control shaft and around the welds of the flap levers, which, if not detected and corrected, could result in loss of airplane control during flight.
56-13-01: 56-13-01 DOUGLAS: Applies to All DC-6, DC-6A and DC-6B Aircraft. \n\n\tCompliance required as indicated. \n\n\tNumerous instances have been reported on wing skin and stringer 22 cracking aft of the main landing gear fittings at the center spar, Stations 122 and 175, on DC-6 aircraft having high flight time. The following must be accomplished as indicated on all DC-6 Series aircraft having in excess of 10,000 hours total flight time. \n\n\t1. Accomplish inspection of the wing skin in area aft of the center spar at approximately Stations 122 and 175, especially for cracks emanating from the radii in the skin cutouts, as soon as practicable but not later than next periodic inspection nearest 300 hours. In case complete radii cannot be inspected directly by visual means from underneath the lower wing surface, then a reliable alternate method of inspection must be employed. X-ray may fall into this category. If a skin crack is detected, stringer 22 must also be inspected for cracks. Any skin crack or stringer 22 crack found during the inspection must be repaired prior to further passenger flight. \n\n\t2. Skin cracks less than 3/4 inch in length are to be repaired as outlined on Service Rework Drawing 5593157. \n\n\t3. Skin cracks in excess of 3/4 inch but less than 1 1/2 inches in length are to be repaired as outlined on Service Rework Drawing 5613739. \n\n\t4. Skin cracks in excess of 1 1/2 inches in length at Station 175 are to be repaired as outlined in Service Rework Drawing 5610926 together with the preventive rework shown on 5593157 and 5610629. \n\n\t5. Skin cracks in excess of 1 1/2 inches in length at Station 122 will require entire skin replacement between center and rear bottom spar caps, Wing Station 60 to Station 149, together with the preventive rework shown on 5593157 and 5610629. \n\n\t6. Stringer cracks (in horizontal leg only) are to be repaired as outlined on Service Rework Drawing 5610629. Cracks found in stringer 22 which are more extensive than through one horizontal leg of the stringer will require a complete stringer replacement. \n\n\t7. All aircraft which do not require repairs are to be reinspected at each periodic inspection period nearest 2,500 hours until preventive repairs per 5593157 and 5610629 are installed. \n\n\t8. After rework per paragraphs 1 through 6 has been accomplished or preventive rework per Drawings 5593157 and 5610629 is installed, no further special inspection periods are required. Also, further special inspections are not required on DC-6 aircraft upon which Kits A and B of Douglas Service Bulletin DC-6 No. 569 have been incorporated. \n\n\tUpon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA Western Region, may adjust the repetitive inspection intervals specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for such operator. \n\n\t(Douglas Alert Service Bulletin No. A-673 revised May 8, 1956, covers the above subject.) \n\n\tThis supersedes AD 56-04-03. \n\n\tRevised July 7, 1962.
2022-06-18: The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 767-2C series airplanes. This AD was prompted by a report of multiple nuisance caution ''RECIRC SMOKE'' engine indication and crew alerting system (EICAS) messages that may occur when water accumulates in the alternative ventilation system (AVS) duct. This AD requires replacing the alternative ventilation duct having a certain part number with a new part number, and for certain airplanes, changing the insulation blanket to install the drain hose. This AD also prohibits the installation of an alternative ventilation duct, part number (P/N) 216T2101-704, on any airplane. The FAA is issuing this AD to address the unsafe condition on these products.
98-08-11: This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 98-08-11 that was sent previously to all known U.S. owners and operators of certain McDonnell Douglas Model MD-11 and MD-11F series airplanes by individual notices. This AD requires opening the circuit breaker of the pneumatic sense line heater tape, installing an inoperative ring, and coiling and stowing the electrical wire to the circuit breaker of the pneumatic sense line heater tape. This AD also provides for an optional inspection, which, if accomplished, constitutes terminating action for deactivation of the pneumatic sense line heater tape. This action is prompted by a report indicating that, while an airplane was on the ground, fuel was found leaking from the fuel feed pipe of the number 2 engine due to inadequate clearance between the fuel feed pipe and the pneumatic sense line heater tape. The actions specified by this AD are intended to detect and correct such inadequate clearance, which could result in a hole in the fuel feed pipe caused by electrical arcing, and consequent fuel leakage and possible ignition of the fuel vapors.
98-09-02: This amendment supersedes an existing airworthiness directive (AD), applicable to McDonnell Douglas Helicopter Systems (MDHS) Model 369 (YOH-6A), 369A (OH-6A), 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, and 369HS helicopters, that currently requires replacing overrunning clutch outer races (outer races) having certain heat treatment numbers. This amendment requires replacing all outer races with airworthy outer races, regardless of the heat treatment number, and is applicable to a particular model helicopter that was not included in the existing AD (Model 500N helicopters). This amendment is prompted by several reports of failed clutch races having heat treatment numbers other than the ones addressed in the earlier AD. The actions specified by this AD are intended to prevent failure of the overrunning clutch assembly outer race, which could result in loss of engine drive to the rotor system and a subsequent forced landing.
2012-18-16: We are adopting a new airworthiness directive (AD) for certain The Cessna Aircraft Company Model 750 airplanes. This AD was prompted by reports of direct current (DC) generator overvoltage events. This AD requires replacing the auxiliary power unit (APU) generator control unit (GCU). We are issuing this AD to prevent DC generator overvoltage events, which could result in smoke in the cockpit and loss of avionics and electrical systems.
2012-18-08: We are adopting a new airworthiness directive (AD) for Eurocopter France (Eurocopter) Model SA330F, SA330G, SA330J, AS332C, AS332L, AS332L1, and AS332L2 helicopters to require cleaning, inspecting, and lubricating each tangential gearbox (gearbox) and adjusting, as necessary, the fuel shut-off control lever. This AD was prompted by the jamming of one of two fuel shut-off control levers because of solidified grease in the gearbox. A companion gearbox had extensive corrosion. In case of an emergency, pilots may need to use the control levers to shut off fuel going into the engine and to shut off the helicopter's electrical power system. The jamming of the levers prevents the shut off of the engine fuel and prevents the parallel- mounted micro switches from switching off the electrical power system. These actions are intended to prevent the jamming of the control levers, which could prevent shut-off of the engine fuel and electrical power system during an emergency shutdown.
2010-11-05: We are adopting a new airworthiness directive (AD) for certain AVOX Systems and B/E Aerospace oxygen cylinders, as installed on various 14 CFR part 23 or CAR 3 airplanes. This AD requires you to inspect for and remove substandard oxygen cylinders from the airplane. This AD was prompted by the reported rupture of a high-pressure gaseous oxygen cylinder, which had insufficient strength characteristics due to improper heat treatment. We are issuing this AD to prevent an oxygen cylinder from rupturing, which, depending on the location, could result in structural damage and rapid decompression of the airplane, damage to adjacent essential flight equipment, deprivation of the necessary oxygen supply for the flightcrew, and injury to cabin occupants or other support personnel.
2012-19-02: We are superseding an existing airworthiness directive (AD) for all Airbus Model A330-243, -341, -342 and -343 airplanes. That AD currently requires modifying certain cowl assemblies of the left- and right-hand thrust reversers. This new AD requires removing certain C- duct assemblies of the left- and right-hand thrust reversers from service at certain designated life limits, and also adds airplanes to the applicability. This AD was prompted by new life limits on certain thrust reverser C-duct assemblies. We are issuing this AD to prevent fatigue cracking of the hinges integrated into the 12 o'clock beam of the thrust reversers, which could result in separation of a thrust reverser from the airplane, and consequent reduced controllability of the airplane.
74-10-09: 74-10-09 BOEING: Amendment 39-1838 as amended by Amendment 39-2825. Applies to Boeing Model 707-100 series, -100B series and -200 series airplanes certificated in all categories. \n\tCompliance required as indicated. To detect cracks in the upper wing splice plate and upper rib cap at wing station 360, accomplish the following: \n\tUnless X-Ray or low frequency eddy current inspected within the last 300 flights, X-Ray or low frequency eddy current inspect the upper wing surface splice plate and rib cap at wing station 360 within the next 25 flights after the effective date of this AD, on airplanes with more than 24,000 flights, or within the next 50 flights after the effective date of this AD, on airplanes with more than 17,000 flights in accordance with instructions in Boeing Alert Service Bulletin No. 3160 dated April 19, 1974, or later FAA approved revisions, or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA, Northwest Region. If cracks are found, repair prior to further flight in accordance with Part VII or VIII or install external doubler in accordance with Part IX of Boeing Service Bulletin No. 2576, Revision 2, or later approved revisions or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region. \n\tThe 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 may obtain copies upon request to The Boeing Company, P.O. Box 3707, Seattle, Washington 98124. These documents may also be examined at FAA Northwest Region, Boeing Field, Seattle, Washington. \n\n\tAmendment 39-1838 became effective on May 10, 1974. \n\tThis amendment 39-2825 becomes effective February 21, 1977.
98-08-25: This amendment supersedes Airworthiness Directive (AD) 96-12-08 on certain Twin Commander Aircraft Corporation (Twin Commander) 500, 680, 690, and 695 series airplanes, which currently requires replacing the nose landing gear (NLG) drag link bolt with one that has been manufactured with the proper heat-treatment. This action will retain the requirements of AD 96-12-08, add an additional model and additional serial numbers to the applicability section of the AD, and require replacing bolt part number (P/N) ED10055 with bolt P/N 750076-1 on certain Models 690D and 695A airplanes. This action is prompted by a defective manufacture of a certain lot of drag link bolts used in the NLG. The actions specified by this AD are intended to prevent the NLG from collapsing caused by a failed drag link bolt, which could result in loss of control of the airplane during landing operations.
2012-18-09: We are adopting a new airworthiness directive (AD) for the Bell Helicopter Textron Canada Limited (BHTC) Model 407 helicopters. This AD requires you to replace tailboom-attachment hardware (attachment hardware), and perform initial and recurring determinations of the torque on the nuts of the tailboom-attachment bolts (bolts) at all four attachment locations. This AD was prompted by a review of the tailboom-attachment installation, which revealed that the torque value of the bolts specified in the BHTC Model 407 Maintenance Manual and applied during manufacturing was incorrect and exceeded the torque range recommended for the bolts. The actions required by this AD are intended to prevent an over-torque of a bolt, bolt failure, loss of the tailboom, and subsequent loss of control of the helicopter.
2010-11-15: We are adopting a new airworthiness directive (AD) for the products listed above. 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 Civil Aviation Authority of the United Kingdom (UK) has informed EASA that significant quantities of Halon 1211 gas, determined to be outside the required specification, have been supplied to the aviation industry for use in fire extinguishing equipment. Halon 1211 (BCF) is used in portable fire extinguishers, usually fitted or stowed in aircraft passenger cabins and flight decks. EASA published Safety Information Bulletin (SIB) 2009-39 on 23 October 2009 to make the aviation community aware of this safety concern. The results of the ongoing investigation have now established that LyonTech Engineering Ltd, a UK-based company, has supplied further consignments of Halon 1211 (BCF) to L'Hotellier that do not meet the required specification. This Halon 1211 has subsequently been used to fill certain P/N 863520-00 portable fire extinguishers that are now likely to be installed in or carried on certain TBM700 aeroplanes. The contaminated nature of this gas, when used against a fire, may provide reduced fire suppression, endangering the safety of the aeroplane and its occupants. In addition, extinguisher activation may lead to release of toxic fumes, possibly causing injury to aeroplane occupants. We are issuing this AD to require actions to correct the unsafe condition on these products.
98-09-01: This amendment adopts a new airworthiness directive (AD) that is applicable to certain Gulfstream Model GV series airplanes. This action requires inspections and functional tests of the elevator Hardover Prevention System (HOPS) to detect any miswiring of electrical connectors, correction of any discrepancy found, and eventual modification of the HOPS wiring. This amendment is prompted by reports of incorrect matching of electrical connectors to the hydraulic deactivation valves of the elevator HOPS. The actions specified in this AD are intended to prevent the incorrect operation of the elevator HOPS, which could result in loss of control of the airplane
91-12-13: 91-12-13 DORNIER: Amendment 39-7024. Docket No. 90-CE-48-AD. Applicability: Model Dornier 228-100, Dornier 228-101, Dornier 228-200, Dornier 228- 201, Dornier 228-202, and Dornier 228-212 airplanes (serial numbers (S/N) 7005 through 7167, S/N 8002 through 8161, and 8163 through 8190), certificated in any category. Compliance: Required within the next 600 hours time-in-service after the effective date of this AD, unless already accomplished. To retain the reliability of the horizontal stabilizer electric trim system, accomplish the following: (a) Replace relays 4CC, 5CC, 8CC, and 9CC with improved relays and modify the electrical connections of these relays in accordance with the following: (1) For airplanes that utilize the autopilot and/or trim coupling option, perform the replacements and modification in accordance with the instructions in Dornier Service Bulletin No. SB-228-164, Revision 1, dated August 28, 1990. (2) For airplanes that do not utilize the autopilot and the trim coupling option, perform the replacements and modification in accordance with the instructions in Dornier Service Bulletin No. SB-228-160, dated December 18, 1989. (b) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes 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, Brussels Aircraft Certification Office, Europe, Africa and Middle East Office, FAA, c/o American Embassy, 1000 Brussels, Belgium. The request should be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Brussels Aircraft Certification Office. (d) The replacements and modifications required by this AD shall be done in accordance with Dornier 228 Service Bulletin (SB) No. SB-228-160, dated December 18, 1989, and Dornier 228 SB No. SB-228-164, Revision 1, dated August 28, 1990. 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 Dornier Luftfahrt GmbH, Product Support, P.O. Box 3, D-8031 Wessling, Federal Republic of Germany. Copies may be inspected at the FAA, Central Region, Office of the Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the Office of the Federal Register, 1100 L Street, NW; Room 8401, Washington, DC. This amendment (39-7024, AD 91-12-13) becomes effective on July 19, 1991.
2012-18-17: We are superseding an existing airworthiness directive (AD) for all Pratt & Whitney Division (Pratt & Whitney) PW4052, PW4056, PW4060, PW4062, PW4062A, PW4074, PW4077, PW4077D, PW4084D, PW4090, PW4090-3, PW4152, PW4156A, PW4158, PW4164, PW4168, PW4168A, PW4460, and PW4462 turbofan engines. That AD currently requires initial and repetitive fluorescent penetrant inspections (FPI) for cracks in the blade loading and locking slots of the high-pressure compressor (HPC) drum rotor disk assembly rear drum. This new AD requires the same actions, requires replacement of the 13th, 14th, and 15th stage HPC seals with redesigned HPC seals as an additional action, and adds an optional terminating action to the repetitive inspection requirements by allowing replacement of the entire HPC drum rotor disk assembly with a redesigned HPC drum rotor disk assembly. This AD was prompted by Pratt & Whitney developing a redesigned HPC drum rotor disk assembly for certain affected engine models. We are issuing this AD to prevent failure of the HPC drum rotor disk assembly, which could lead to an [[Page 57008]] uncontained engine failure, and damage to the airplane.