Results
2004-15-15: The FAA supersedes Airworthiness Directive (AD) 2002-19-10, which applies to certain Air Tractor, Inc. (Air Tractor) Models AT-402, AT-402A, AT-402B, AT-602, AT-802, and AT-802A airplanes. AD 2002-19-10 currently requires you to repetitively inspect the upper longeron and upper diagonal tube on the left hand side of the aft fuselage structure for cracks and contact the manufacturer for a repair scheme if cracks are found. This AD is the result of reports of the same cracks recently found on AT-500 series airplanes. The manufacturer has also issued new and revised service information that incorporates a modification to terminate the repetitive inspection requirements. Consequently, this AD retains the inspection actions required in AD 2002-19-10, adds certain AT-500 series airplanes to the applicability section, changes the compliance times, and incorporates new and revised manufacturer service information that contains a terminating action for the repetitive inspection requirement. We are issuing this AD to detect and correct cracks in the upper aft longeron, which could cause the fuselage to fail. Such failure could result in loss of control of the airplane.
2022-07-08: The FAA is superseding Airworthiness Directive (AD) 2016-17- 12, which applied to all Airbus SAS Model A318 series airplanes; Model A319-111, -112, -113, -114, -115, -131, -132, and -133 airplanes; Model A320-211, -212, -214, -231, -232, and -233 airplanes; and Model A321- 111, -112, -131, -211, -212, -213, -231, and -232 airplanes. AD 2016- 17-12 required inspecting certain trimmable horizontal stabilizer actuators (THSAs) to determine the number of total flight cycles the THSA has accumulated, and replacing the THSA if necessary. Since the FAA issued AD 2016-17-12, the FAA has determined that a more restrictive airworthiness limitations is necessary for carbon friction disks on the no-back brake (NBB) of the THSA. This AD continues to require the inspections of the THSAs and replacement if necessary. This AD also requires revising the existing maintenance or inspection program, as applicable, to incorporate new or more restrictive airworthiness limitations; as specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference. This AD also limits the installation of affected parts under certain conditions. The FAA is issuing this AD to address the unsafe condition on these products.
2022-07-06: The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 747-8F and 747-8 series airplanes. This AD was prompted by a report of unusual flight instrument and engine indication and crew alerting system (EICAS) behavior. This AD requires inspecting the left, center, and right electronic flight instrument system (EFIS)/EICAS interface unit (EIU) for certain serial numbers and replacement if necessary. The FAA is issuing this AD to address the unsafe condition on these products.
73-12-07: 73-12-07 BRITISH AIRCRAFT CORPORATION: Amdt. 39-1655. Applies to Viscount Model 744, 745D, and 810 Series airplanes. Compliance is required as indicated. To prevent failures of the nacelle structure tubes and end fittings on high time engine nacelle structures due to fatigue and corrosion, accomplish the following: (a) For airplanes which have not been inspected in accordance with paragraph (h) of AD 66-12-3 prior to the effective date of this AD, - (1) Within the next 500 landings or 12 calendar months, whichever occurs sooner, after the effective date of this AD, and thereafter at intervals not to exceed 7,500 landings form the last inspection, comply with paragraph (e); and (2) Within the next 500 landings after the effective date of this AD or before the accumulation of 19,000 total landings, whichever occurs later, and thereafter at intervals not to exceed 7,500 landings from the last inspection, comply with paragraph (d). (b) For airplanes which haveaccumulated 5,500 or more landings since compliance with paragraph (h) of AD 66-12-3, within the next 2,000 landings after the effective date of this AD, or before the accumulation of 19,000 total landings, whichever occurs later, and thereafter at intervals not to exceed 7,500 landings from the last inspection, comply with paragraphs (d) and (e). (c) For airplanes which have accumulated less than 5,500 landings since compliance with paragraph (h) of AD 66-12-3 on the effective date of this AD, within the next 7,500 landings after compliance with paragraph (h) of AD 66-12-3 or, before the accumulation of 19,000 total landings , whichever occurs later, and thereafter at intervals not to exceed 7,500 landings from the last inspection, comply with paragraphs (d) and (e). (d) Inspect the engine nacelle structure tubes and end fittings for cracks at the positions specified for the applicable technique in figures 1 and 2 of British Aircraft Corporation (BAC) Ltd., Preliminary Technical Leaflet (PTL) No. 258, Issue 4 (700 Series), dated August 31, 1971, or No. 122, Issue 4 (800/810 Series), dated August 31, 1971, using dye penetrant, radiographic, and ultrasonic resonance methods in accordance with Techniques 1, 3, and 4, respectively, of the applicable PTL or an FAA-approved equivalent. (e) Inspect the engine nacelle structure tubes for internal corrosion at the positions specified for Technique 2 in figures 1 and 2 of BAC Ltd. PTL No. 258, Issue 4 (700 Series), dated August 31, 1971, or No. 122, Issue 4 (800/810 Series), dated August 31, 1971, using the radiographic method in accordance with Technique 2 of the applicable PTL or an FAA-approved equivalent. (f) If, during an inspection required by paragraph (a), (b), or (c), any end fittings are found cracked, or any tubes are found cracked or corroded beyond the limits specified in the applicable PTL, before further flight replace the affected parts with serviceable parts of the same part number. Thissupersedes Amendment 39-231 (31 F.R. 6790), AD 66-12-3. This Amendment becomes effective July 5, 1973.
2022-07-14: The FAA is adopting a new airworthiness directive (AD) for certain Viking Air Limited (type certificate previously held by Bombardier Inc. and de Havilland, Inc.) Model DHC-6-400 airplanes. 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 corrosion of the fuel system components located in the fuel gallery due to inadequate corrosion protection. This AD requires repetitively inspecting the fuel gallery for corrosion, rectifying any deficiencies, and accomplishing modifications to the fuel gallery system. The FAA is issuing this AD to address the unsafe condition on these products.
2022-06-15: The FAA is adopting a new airworthiness directive (AD) for all De Havilland Aircraft of Canada Limited Model DHC-8-401 and -402 airplanes. This AD was prompted by reports of bleed air leaks in the wing box area and failure of the leak detection shroud. This AD requires removing and inspecting the affected V-band coupling and check valve seals, doing corrective actions if necessary, and replacing the coupling and seals with a redesigned assembly. The FAA is issuing this AD to address the unsafe condition on these products.
2004-15-20: This amendment adopts a new airworthiness directive (AD), applicable to certain EMBRAER Model EMB-135 and -145 series airplanes, that requires replacing the electrical harness for the tail boom strobe light with a new, improved harness that has a built-in metallic overbraid, and performing an operational test following the replacement. This action is necessary to ensure that there is sufficient lightning bonding at the electrical harness for the tail boom strobe light, and to prevent the simultaneous failure of multiple avionics systems in the event of a lightning strike, which could result in reduced controllability of the airplane. This action is intended to address the identified unsafe condition.
72-16-09: 72-16-09 HUGHES: Amendment 39-1497. Applies to Hughes Model 369A and 369H Series Helicopters certificated in all categories. Compliance required as indicated. To prevent possible failure of the input gearshaft assembly, accomplish the following: (a) For those helicopters incorporating tail rotor input gearshaft assemblies (see NOTE for P/N's) which have accumulated 2,000 hours' or more time in service on the effective date of this AD, accomplish (c) and (d), below, unless already accomplished, prior to further flight. (b) For those helicopters incorporating tail rotor input gearshaft assemblies (see NOTE for P/N's) which have accumulated 1,800 hours' or more time in service on the effective date of this AD, accomplish (c) and (d), below, within 100 additional time in service, unless already accomplished. If the additional time in service would result in a total time in service in excess of 2000 hours, the 100 hours' compliance time shall be reduced by that amount necessary to prevent any tail rotor input gearshaft assemblies from being operated beyond 2000 hours before accomplishment of this AD. (c) Revise the helicopter logbook, as applicable, to record both the input and the output gearshaft assemblies incorporated in the 369A5406 tail rotor gear set, per the instructions of Part I of Hughes Service Information Notice No. HN-53, dated July 24, 1972, or later FAA approved revisions. (d) Retire and replace the 369A5425 and 369A5425-3 input gearshaft assemblies (input part of 369A5406 gearset), per the instructions of Part II of Hughes Service Information Notice No. HN-53, dated July 24, 1972, or later FAA approved revisions. Owners and operators may exercise the options specified in Part II of the Notice. NOTE: The part number assemblies and finite life are: TAIL ROTOR INPUT FINITE GEARSHAFT ASSEMBLY LIFE P/N 369A5406 (input only) 1,800 hours P/N 369A5425, -3 1,800 hours P/N 369A5425-5 27,600 hoursNOTE: The P/N 369A5406 tail rotor gearset is comprised of an input gearshaft assembly and a pinion output gearshaft assembly. The finite life of all existing pinion output gearshaft assemblies remains unchanged at 2,940 hours. This amendment becomes effective August 8, 1972.
2022-07-10: The FAA is adopting a new airworthiness directive (AD) for all Airbus SAS Model A350-941 and -1041 airplanes. This AD was prompted by a report that certain overheat detection system (OHDS) sensing elements may not properly detect thermal bleed leak events due to a quality escape during the manufacturing process. This AD requires revising the operator's existing FAA-approved minimum equipment list (MEL) to include dispatch restrictions as specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference. This AD also prohibits the installation of affected parts. This AD also allows operators to inspect affected parts for discrepancies, and do applicable replacements, in order to terminate the revision of the operator's existing MEL required by this AD. The FAA is issuing this AD to address the unsafe condition on these products.
2004-15-11: This amendment adopts a new airworthiness directive (AD) for the specified Eurocopter France (ECF) model helicopters that requires cleaning the auxiliary system unit (ASU) board and modifying the wiring and wiring harness. If a temporary modification is done, the AD requires inserting a placard regarding on-ground operation of the emergency landing gear pump (pump). Also, this AD revises the Limitations section of the Rotorcraft Flight Manual (RFM) to limit the operation of the pump. Permanently modifying the wiring and wiring harness and removing the placard and limitations from the RFM is terminating action for the requirements of this AD. This amendment is prompted by the report of an emergency landing with the landing gear retracted. The landing gear failed to extend in normal and emergency extension modes following failure of the ASU board 10 Alpha 2. The actions specified by this AD are intended to prevent an electrical short circuit, failure of landing gear to extend, and a landing gear-up emergency landing.
2022-06-17: The FAA is adopting a new airworthiness directive (AD) for all Airbus Helicopters Model EC130T2 helicopters. This AD was prompted by the determination of a certain part needing a life limit and re- identification. This AD requires re-identifying a certain part-numbered engine-to-main gearbox (engine-MGB) coupling shaft, and creating a log card or equivalent record, as specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.
66-22-01: 66-22-01\tBOEING: Amdt. 39-284 Part 39 Federal Register September 7, 1966. Applies to Model 707-300B, 707-300B (ADV), and 707-300C Series Airplanes.\n \n\tWithin the next 100 hours' time in service after the effective date of this AD, until an antiskid HF filter is installed in accordance with Boeing Service Bulletin 2367 (R-2), dated June 16, 1966, or later FAA-approved revision, or an equivalent approved by the Chief, Aircraft Engineering Division, FAA Western Region, amend the Certification Limitation Section I of FAA-approved Airplane Flight Manuals, Boeing Model 707-300B (Boeing Document D6-1571), Model 707-300B (ADV) (Boeing Documents D6-1576 and D6-1588) and Model 707-300C (Boeing Documents D6-1575 and D6-1587) to include the following or an FAA-approved equivalent: \n\n\tANTISKID LIMITATIONS \n\n\tUntil antiskid HF filter installation is accomplished either during airplane manufacturer or by Service Bulletin, do not use HF to transmit between 2 and 6.5 mc. with antiskid on during taxi takeoff roll and landing.\n \n\tThis directive effective September 7, 1966.
99-12-03: This amendment adopts a new airworthiness directive (AD), applicable to Pratt & Whitney JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR series turbofan engines, that requires revisions to the engine manufacturer's Time Limits Section (TLS) of the JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR Turbofan Engines Manual to include enhanced inspection of selected critical life-limited parts at each piece-part exposure. This amendment will also require an air carrier's approved continuous airworthiness maintenance program to incorporate these inspection procedures. This amendment is prompted by a Federal Aviation Administration (FAA) study of in-service events involving uncontained failures of critical rotating engine parts that indicated the need for improved inspections. The improved inspections are needed to identify those critical rotating parts with conditions that if allowed to continue in service, could result in uncontained failures. The actions specified by this AD are intended to prevent critical life-limited rotating engine part failure, which could result in an uncontained engine failure and damage to the airplane.
2004-15-17: This amendment adopts a new airworthiness directive (AD), applicable to certain Fokker Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 series airplanes, that requires a one-time inspection to determine the part number of the engine mounting frames, brace struts, and attachment fittings; and related corrective action. This action is necessary to ensure the structural integrity of the engine-to-wing load path and prevent possible separation of the engine from the airplane. This action is intended to address the identified unsafe condition.
2022-07-02: The FAA is adopting a new airworthiness directive (AD) for certain Bell Textron Inc. Model 205A, 205A-1, 205B, 210, 212, 412, 412CF, and 412EP helicopters with a certain part-numbered tailboom left hand fin spar cap (spar cap) installed. This AD was prompted by reports of cracked spar caps. This AD requires inspecting each spar cap and depending on the inspection results, removing the spar cap from service. The FAA is issuing this AD to address the unsafe condition on these products.
2004-01-20: The FAA is adopting a new airworthiness directive (AD) for Rolls-Royce plc (RR) RB211-22B series, RB211-524B, -524C2, -524D4, -524G2, -524G3, and -524H series, and RB211-535C and -535E series turbofan engines with high pressure compressor (HPC) stage 3 disc assemblies, part numbers (P/Ns) LK46210, LK58278, LK67634, LK76036, UL11706, UL15358, UL22577, UL22578, and UL24738 installed. This AD allows disc assemblies not modified by a certain RR service bulletin to reach their full life only after the disc assemblies are modified with anti-corrosion protection. This AD results from the manufacturer's reassessment of the corrosion risk on HPC stage 3 disc assemblies that have not yet been modified with sufficient application of anti-corrosion protection. We are issuing this AD to prevent corrosion-induced uncontained disc failure, resulting in damage to the airplane.
72-14-02: 72-14-02 SIAI-MARCHETTI: Amdt. 39-1477. Applies to SIAI Marchetti Model S.205 airplanes, Serial Nos. 001 through 003, 101 through 384, 385 through 4-255, and Model S.208 airplanes, Serial Nos. 001 through 003, 1-03 through 2-19, 369, 3-100, 4-231, 4-233, 4-256 through 4-258. Compliance is required as indicated. To prevent the entrance of fuel or fumes into areas of the wing external to the fuel tanks or into the cabin, accomplish the following: (a) Within the next 10 hours' time in service after the effective date of this AD, unless already accomplished within the last 40 hours' time in service, and thereafter at intervals not to exceed 50 hours' time in service from the last inspection until the modification specified in paragraph (c) is accomplished - (1) On Model S.205 airplanes, Serial Nos. 001 through 003 and 101 through 384, which do not incorporate scupper drains, remove the right hand and left hand wing tank fuel level transmitter access covers and visuallyinspect the fuel level transmitter supper recessed areas for water deposits or corrosion. (2) On Model S.205 airplanes, Serial Nos. 385 through 4-255, and Model S.208 airplanes, Serial Nos. 001 through 003, 1-03 through 2-19, 369, 3-100, 4-231, 4-233, and 4-256 through 4-258, which incorporate straight scupper drain tubes, remove the right hand and left hand wing tank fuel level transmitter access covers and visually inspect the welding area between the tubes and fuel level transmitter scupper recessed areas for cracks or signs of fuel seepage into the recessed areas. (b) If water deposits or corrosion are found during an inspection required by subparagraph (a)(1) or cracks or signs of fuel seepage are found during an inspection required by subparagraph (a)(2), comply with paragraph (c) before further flight, except that the airplane may be flown in accordance with Section 21.197 of the Federal Aviation Regulations to a base where the repair can be made. (c) For all ModelsS.205 and S.208 airplanes, within the next 500 hours' time in service after the effective date of this AD, unless already accomplished, install new right hand and left hand wing tank fuel transmitter scupper drain tubes, P/N 205-8-112-37 and P/N 205-8- 112-38, and reinforcing washers, P/N 205-8-112-27, in accordance with SIAI Marchetti Service Bulletin No. 205B29A dated December 15, 1971, or an FAA-approved equivalent. Identify the new scupper drain tubes by painting a ring of white paint approximately 1/8 inch wide on the recessed area of the scupper around the new drain tube where it extends through the scupper. This amendment becomes effective 3 July, 1972.
2022-07-11: The FAA is superseding Airworthiness Directive (AD) 2021-17- 18, which applied to all Leonardo S.p.a. Model A109C, A109K2, A109E, A109S, and AW109SP helicopters. AD 2021-17-18 required an inspection of certain tail rotor (TR) sleeve assemblies for discrepancies, an inspection of certain TR shaft assemblies for discrepancies, a repetitive measurement of the position of the bushing of the TR sleeve assembly in relation to the pitch change slider assembly, and corrective actions if necessary. This AD retains the requirements of AD 2021-17-18, and also requires repetitive inspections of the TR sleeve assemblies, and corrective actions if necessary, as specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference. This AD was prompted by a determination that additional actions are required to address the unsafe condition. This AD was also prompted by a report of a crack on the TR mast. The FAA is issuing this AD to address the unsafe condition on these products.
72-19-05: 72-19-05 PITTS AVIATION ENTERPRISES, INC: Amdt. 39-1520. Applies to Pitts Model S-2A series Airplanes, S/N 2001 through 2030. Compliance required as indicated. (a) Within the next 10 hours time in service after the effective date of this AD, unless already accomplished, to prevent failure of the horizontal stabilizer leading edge support tube, accomplish the following: (1) Remove the left and right horizontal stabilizers as follows: NOTE: Keep track of all hardware and replace the same parts in their original locations, unless other options are indicated. (i) Disconnect the elevator trim tab push rods from the horns beneath the stabilizers (leave the rods connected to the tab horns). NOTE: Some airplanes may have AN310-1032 nuts and AN380 cotter pins installed on the AN3 bolts, instead of AN365-1032 nuts. If so, you may either reinstall the AN310-1032 nuts with new AN380 cotter pins, or use AN365-1032 self-locking nuts and undrilled AN3 bolts.(ii) Remove the two AN4 bolts through the flying wire lugs and elevator hinges, left and right. NOTE: It is not necessary to loosen the flying wires. (iii) Remove the 4 AN3 bolts through the stabilizer leading edge and trailing edge tubes, left and right. NOTE: It is not necessary to remove the stabilizer root fairings. (iv) Remove the access plates adjacent to the stabilizer trailing edge, reach inside the aft fuselage and remove the two AN3 bolts through the elevator trim control shaft. NOTE: It is not necessary to disconnect the elevator horn. (v) Remove the left and right horizontal stabilizers by pulling them straight outboard. (2) Thoroughly clean with solvent the exposed portions of the 2-2123 stabilizer leading edge support tube which protrudes from the fuselage. Dye-check this tube in the vicinity of the AN3 bolt holes, and visually inspect for cracks. (i) If cracks are found, order a replacement P/N 2-2123 assembly fromthe manufacturer. (ii) If cracks are not found, accomplish the following. (3) Cut off the outer ends of the stabilizer leading edge support tube, P/N 2- 2123, so that the dimension from the center of the AN3 bolt hole to the outer end of the tube is 1/2 inch, left and right sides. Remove all burrs and rough edges. (4) Redrill the AN3 bolt holes in the stabilizer leading edge support tube, P/N 2-2123, and through the mating holes in the stabilizer leading edge tubes with a number 10 drill (.193 to .199 diameter), left and right. (5) Apply zinc chromate to bare metal surfaces. (6) Reassemble in the reverse order of Step 1. (7) Stencil on upper surfaces of both the left and right horizontal stabilizers, near the leading edge, the words "No lift", in letters one-half inch high or higher, and in a color which contrasts sharply with the paint finish on the stabilizer. Pitts Service Bulletin Number 6 pertains to this same subject. This amendmentbecomes effective September 20, 1972.
71-04-03: 71-04-03 AMERICAN AVIATION: Amdt. 39-1155. Applies to American Aviation Corp., Model AA-1, certificated in all categories S/N AA1-0001 through AA1-0432. (a) Within the next 10 hours in service after the effective date of this AD unless already accomplished, inspect and test the nose gear strut in accordance with the procedures of American Aviation Service Bulletin No. 121A dated 1/8/71 or with an equivalent method. (b) Replace defective parts prior to further flight with a part received from the manufacturer after 1 June 1970 or inspected and tested in accordance with this directive. (c) Equivalent methods and parts must be approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region. This airworthiness directive is effective February 25, 1971 and was effective as to all recipients of the letter dated January 12, 1971 which contained this airworthiness directive.
2004-15-12: This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A330-202, -203, -223, and -243 airplanes, and A330-300 series airplanes, that requires modification of the control box of the auxiliary power unit (APU). This action is necessary to prevent uncommanded in-flight shutdown of the APU, which could result in loss of critical electrical systems when the airplane is operated in emergency electrical configuration, and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.
96-18-20: This amendment adopts a new airworthiness directive (AD), applicable to certain Piaggio Model P-180 airplanes, that requires replacement of outflow/safety valves with serviceable valves. This amendment is prompted by a report of cracking and subsequent failure of outflow safety valves in the pressurization system. The actions specified by this AD are intended to prevent such cracking and subsequent failure of the outflow/safety valves, which could result in rapid decompression of the airplane.
2021-03-16R1: The FAA is removing Airworthiness Directive (AD) 2021-03-16, which applied to all Airbus Helicopters Model AS350B, AS350B1, AS350B2, AS350B3, AS350BA, AS350D, AS355E, AS355F, AS355F1, AS355F2, AS355N, and AS355NP helicopters. AD 2021-03-16 required inspecting each sliding door and replacing the upper rail or front roller or removing the front roller from service if necessary. Since the FAA issued AD 2021-03-16, inspection results and further investigation have confirmed that the in-flight loss of a sliding door, which prompted AD 2021-03-16, was an isolated case resulting from incorrect operation and maintenance error. Therefore, the FAA has determined that no unsafe condition is likely to exist or develop on the sliding doors on other helicopters in the fleet. Accordingly, AD 2021-03-16 is removed.
72-08-01: 72-08-01 BOEING: Amdt. 39-1428. Applies to Boeing Model 747 airplanes, listed in Boeing Service Bulletin 747-32-2118, dated December 20, 1971, or later FAA-approved revisions except the Model 747-131. \n\tCompliance required within the next 100 hours' time in service after the effective date of this AD, unless already accomplished within the last 400 hours' time in service, and thereafter at intervals not to exceed 500 hours' time in service from the last inspection, until modified per Boeing Service Bulletin 747-32-2118, dated December 20, 1971, or later FAA-approved revisions. \n\tTo detect failed landing gear alternate extension actuators, accomplish the following: \n\tInspect landing gear alternate extension actuators in accordance with Boeing Service Bulletin 747-32-2118, dated December 20, 1971, or later FAA-approved revisions, until modified in accordance with Boeing Service Bulletin 747-32-2118, dated December 20, 1971, or later FAA-approved revision, or an equivalent inspection approved by the Chief, Aircraft Engineering Division, FAA Western Region. \n\tThis amendment becomes effective April 7, 1972.
96-18-11: This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-10-10 and -15 series airplanes, that requires repetitive inspections to detect cracks in the bulkhead tee caps, and repair and follow-on actions, if necessary. It also provides for an optional terminating modification for the repetitive inspections. This amendment is prompted by reports of cracking in the bulkhead tee caps at a fuselage station in the area of certain longerons due to fatigue. The actions specified by this AD are intended to prevent such fatigue cracking, which could result in loss of pressurization and damage to adjacent structure.