Results
72-22-02: 72-22-02 RAZORBACK FABRICS, INC: Amdt. 39-1531 as amended Amendment 39-1541. Applies to airplanes having wings, tail, or control surfaces covered with fiberglass using the "razorback" method, certificated in all categories. This covering process has been approved by numerous Supplemental Type Certificates and FAA Forms 337 as complying with Advisory Circular 20-44, "Glass Fiber Fabric for Aircraft Covering." Compliance required within the next fifty hours' time in service after the effective date of this airworthiness directive, unless already accomplished. To determine if the fabric is attached with plastic coated glass rib stitch cord, inspect the interior of the wings, tail, or control surfaces through inspection openings or by cutting small holes in the fabric. The plastic coating on the rib stitch cord is black in color. a. If the fabric is attached with the plastic coated rib stitch cord, replace the stitching with MIL-C-5649 cord or FAA approved equivalent before fifty hours' time in service from the effective date of this Airworthiness Directive. b. If the fabric is attached with MIL-C-5649 cord, or FAA approved equivalent, no further action is required. c. All work required, including patching holes, may be accomplished in accordance with FAA Advisory Circular 43.13-1. Razorback Fabrics, Inc., Service Bulletin 1-1 dated 3/11/64 covers the same subject. (NOTE: Copies of Razorback Fabrics, Inc., Service Bulletin 1-1 may be obtained from the company at Manila, Arkansas 72442.) This supersedes Amendment 39-1531, 37 F.R. Amendment 39-1531 became effective October 16, 1972. This amendment 39-1541 becomes effective November 15, 1972.
2012-01-02: We are adopting a new airworthiness directive (AD) for Schempp-Hirth Flugzeugbau GmbH Model Discus 2cT gliders. 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 small cracks which have been found on engine pylons in the area of the lower engine support that have not been detected during the standard daily inspection. This condition, if not detected and corrected, could lead to an engine pylon failure resulting in loss of control of the glider. We are issuing this AD to require actions to address the unsafe condition on these products.
2011-18-21: We are superseding an existing airworthiness directive (AD) for the products listed above. That AD currently requires initial and repetitive borescope inspections of the head section and meterpanel assembly of the combustion liner, and replacement if necessary. This new AD requires those same inspections, and replacement. This AD also expands the applicability to include part numbers (P/N) of additional combustion liners. This AD was prompted by an inquiry submitted by an operator, which resulted in RR performing a complete review of the affected front combustion liner part numbers. We are issuing this AD to prevent deterioration of the engine combustion liner, which can result in combustion liner breakup, case burn-through, engine fire, and damage to the airplane.
74-25-08: 74-25-08 CONSOLIDATED AERONAUTICS, INC: Amendment 39-2036. Applies to Colonial Model C-1 and C-2 airplanes certificated in all categories. Compliance required within the next 10 hours' time in service after the effective date of this AD, unless already accomplished within the preceding 90 hours' time in service, and thereafter at intervals not to exceed 100 hours' time in service from the last inspection. To prevent operation with cracked or failed wing rear spar fittings or wing rear spar fittings with distorted bolt holes, accomplish the following: (1) Remove the cover of the compartment containing the aileron control system, located behind the fuel tank area, and visually inspect the wing rear spar left and right fore fittings, P/Ns 3200-151L and 3200-151R, for cracks, failures or distorted bolt holes. (2) Remove the baggage compartment and visually inspect the wing rear spar left and right aft fittings, P/N's 3200-148L and 3200-148R, for cracks, failures or distorted bolt holes. (3) Replace cracked or failed fittings or fittings with distorted bolt holes prior to further flight. This amendment becomes effective December 18, 1974.
2011-26-04: We are superseding an existing airworthiness directive (AD) for certain fuel injected reciprocating engines manufactured by Lycoming Engines. That AD currently requires inspection, replacement if necessary, and proper clamping of externally mounted fuel injector fuel lines. That AD also states that it is not applicable to engines that have a Maintenance and Overhaul Manual with an Airworthiness Limitations Section that requires inspection and replacement, if necessary, of externally mounted fuel injector lines. This new AD requires the same actions. This AD was prompted by Lycoming Engines revising their Mandatory Service Bulletin (MSB) to add engine models requiring inspections. We are issuing this AD to prevent failure of the fuel injector fuel lines that would allow fuel to spray into the engine compartment, resulting in an engine fire.
70-09-01: 70-09-01\tBOEING: Amdt. 39-976. Applies to Model 737 series airplanes. \n\n\tCompliance required within the next 250 hours time in service after the effective date of this ad, unless already accomplished. \n\n\tAs a result of FAA evaluations of the 737 electrical system sufficient cause has been found to prevent inadvertent operation of the battery switch located on the forward overhead panel. Inadvertent operation of the battery switch during some operating conditions could result in loss of the standby electrical system. To prevent inadvertent operation of the battery switch on the forward overhead panel on the subject 737 series airplanes, accomplish one of the following: \n\n\t\t(1)\tInstall a switch guard and light plate per the Boeing Service Bulletin No. 24- 1010 Revision (1) dated April 24, 1970, or later FAA approved revisions. \n\n\t\t(2)\tReplace the battery switch with a detent lock type switch, P/N MS 24659-23D or an equivalent MS type, provided the galley switch is a toggle type. \n\n\t\t(3)\tPerform an equivalent installation approved by the Chief, Aircraft Engineering Division, FAA, Western Region. \n\n\tThis amendment becomes effective April 23, 1970.
2011-25-51: We are adopting a new airworthiness directive (AD) for certain Continental Motors, Inc. (CMI) models TSIO-520, TSIO-550-K, TSIOF-550K, and IO-550-N series reciprocating engines. This emergency AD was sent previously to all known U.S. owners and operators of these engines. This AD requires replacing affected CMI starter adapters with starter adapters eligible for installation. This AD was prompted by 5 reports received of fractures in starter adapter shaft gears in certain part number (P/N) CMI starter adapters. We are issuing this AD to prevent failure of the starter adapter gear shaft, leading to an inoperable oil scavenge pump and engine in-flight shutdown.
2011-25-01: This amendment adopts a new airworthiness directive (AD) for the Apical emergency float kits installed on certain model helicopters under supplemental type certificates. This AD requires adding placards on each side of the fuselage to identify the location and operation of the liferaft external inflation handle. This AD also requires replacing each liferaft operation placard to state that external liferafts are installed. This amendment is prompted by a report of a helicopter that crashed into the water, and the pilot did not deploy the floats and liferafts. Two external T-handles were available for deployment of the liferafts but were not used by the passengers because they were unaware of their location. The actions specified by this AD are intended to prevent helicopter occupants from further injury due to unnecessary exposure to harsh water conditions and to aid in deploying liferafts when liferafts are available on the helicopter and can be activated after a water landing.
75-24-05: 75-24-05 LOCKHEED-CALIFORNIA COMPANY: Amendment 39-2429. Applies to L-1011-385 series airplanes, except serial numbers 193( )-1004, 193( )-1005, and 193( )-1007 through 193( )-1023 inclusive, certificated in all categories, incorporating a fuel line tube assembly, P/N 1515816-121, bearing the manufacturing date identification number 533X190, or, if the manufacturing date identification number cannot be ascertained. Compliance required as indicated, unless already accomplished, to prevent a potential fire hazard due to a massive fuel spillage from Tank One into the center section, accomplish the following: (A) Within the next day after receipt of this telegram, and thereafter at intervals not to exceed one day, until the modification described in paragraph (B), below, is accomplished, perform a close visual check by a flight crew member or other qualified person of the drain mast beneath the hydraulic service center for evidence of fuel leakage. If fuel leakage is detected,perform the modification described in paragraph (B), below, before further flight. (B) Within the next 300 hours additional time in service after receipt of this telegram, replace the fuel line tube assembly, P/N 1515816-121, with a tube assembly, P/N 1515816-179 or -121 that has a legible manufacturing date identification number other than 533X190, in accordance with Lockheed Service Bulletin 093-28-033, dated October 17, 1975, or later FAA- approved revisions. (C) Equivalent checks and modifications may be approved by the Chief, Aircraft Engineering Division, FAA Western Region. (D) Special flight permits may be issued per FAR's 21.197 and 21.199 to operate the airplane to a base to perform the modification described in paragraph (B), above, provided there is no evidence of fuel leaks at the tube assembly coupling, P/N 1515816-121. This amendment becomes effective November 24, 1975, for all persons except those to whom it was made effective by telegram, dated October31, 1975.
2011-24-09: We are adopting a new airworthiness directive (AD) for certain Airbus Model A340-200 and -300 series airplanes. 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: [T]he FAA published SFAR 88 (Special Federal Aviation Regulation 88) [(66 FR 23086, May 7, 2001)]. [[Page 73487]] By mail referenced 04/00/02/07/01-L296 of March 4th, 2002 and 04/00/02/07/03-L024 of February 3rd, 2003 the JAA [Joint Aviation Authorities] recommended to the National Aviation Authorities (NAA) the application of a similar regulation. The aim of this [EASA] regulation is to require * * * a definition review against explosion hazards. * * * * * This AD requires inspections to verify electrical bonding to prevent the potential of ignition sources inside fuel tanks, which, in combination with flammable fuel vapors, could result in fuel tank explosions and consequent loss of the airplane. This AD requires actions that are intended to address the unsafe condition described in the MCAI.
74-24-01: 74-24-01 BELL: Amendment 39-2011. Applies to Bell Models 206A, 206B, 206A-1 and 206B-1 helicopters certificated in all categories. Compliance required as indicated, unless already accomplished. To prevent possible failure of certain main rotor blade grips, conduct the following: a. Within five hours' time in service after September 23, 1974, inspect the serial numbers of both main rotor grips and replace the following grips, P/N 206-010-102-9, before further flight: S/N JI1-5824, JI1-5861, JI1-5875 through and including 5878; JI1-5880 through and including 5903; JI1-5906 through and including 5912; JI1-5914 through and including 5938; JI1-5940 and 5941; and JI1-5944 through and including 5953. b. Within five hours' time in service after November 15, 1974, inspect the serial numbers of both main rotor grips and replace the following grips P/N 206-010-102-9, before further flight: S/N JI1-5393 through and including 5413; JI1-5417; JI1-5420 through andincluding 5439; JI1-5469; JI1-5516 through and including 5519; JI1-5521 through and including 5531; JI1-5533 through and including 5544; JI1-5546 through and including 5550; JI1-5552 through and including 5587; JI1-5589 through and including 5594; JI1-5595 through and including 5632; JI1-5634 through and including 5636; JI1-5638 through and including 5642; JI1- 5644 through and including 5646; JI1-5648 through and including 5654; JI1-5656 through and including 5695; JI1-5697 through and including 5710; JI1-5712 through and including 5759; JI1 5761 through and including 5785; JI1-5787; JI1-5789 through and including 5794; JI1-5796 through and including 5803; JI1-5805 through and including 5823; JI1-5825 through and including 5860; JI1-5862 through and including 5874; JI1-5972; JI1-5993 and 5994; JI1-6045 and 6046; JI1-6160. c. Main rotor grips that have been inspected by the manufacturer and found airworthy will be given a new serial number by Bell Helicopter Company and may be returned to service. (Telefax messages dated September 6, and October 10, 1974 from Bell Helicopter Company to all 206 operators pertains to this subject.) This supersedes Amendment 39-1973 (39 F.R. 33790), AD 74-20-3. This amendment becomes effective November 15, 1974.
2011-23-13: We are adopting a new airworthiness directive (AD) for Honeywell International Inc. LTS101-600A-2, -3, -3A, and LTS101-700D-2 turboshaft engines with certain power turbine governors (PTG) model AL- AB1, installed, that are marked with compliance symbol N or P, or with no compliance symbol, on the PTG identification plate. This AD requires initial and repetitive replacements of the affected PTGs. This AD was prompted by reports of two accidents where the engines suddenly lost power and the helicopters had to make emergency autorotation landings, leading to substantial damage to the helicopters. We are issuing this AD to prevent loss of engine power, leading to emergency autorotation landing and damage to the helicopter.
2011-23-11: We are adopting a new airworthiness directive (AD) for Pacific Aerospace Limited Model FU24 Airplanes. 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: Investigation of a recent Cresco 08-600 accident identified a risk of the hopper lid interfering with the opening of the canopy in the event of an emergency landing. The pilot was prevented from opening the canopy by the hopper lid in the fully forward open position. This AD is issued due to the fact that the hopper lid installation on the accident aircraft was an unapproved modification and the Fletcher FU24 hopper installation is a similar design to the Cresco 08-600. We are issuing this AD to require actions to correct the unsafe condition on these products.
75-24-06: 75-24-06 HAWKER SIDDELEY AVIATION LIMITED: Amendment 39-2427. Applies to Hawker Siddeley DH-104 "Dove" airplanes, Serial Numbers 04465 and below certificated in all categories, except those that incorporate "Dove" Modification 870. Compliance is required within the next 50 hours' time in service after the effective date of this AD, unless already accomplished. To detect spanwise cracks in the upper and lower wing main spar joint, accomplish the following: (a) Inspect the upper and lower wing main spar joints for cracks in accordance with the X-ray technique specified in Appendix I, Issue 2 as amended June 16, 1975, of Hawker Siddeley Technical News Sheet (T.N.S.) No. 134, Issue 5, dated March 17, 1975, or an FAA- approved equivalent. (b) If, during the inspection required by paragraph (a) of this AD, a crack is found in a wing main spar joint, before further flight modify the joint in accordance with Appendix 2 of Hawker Siddeley Technical News Sheet (T.N.S.) No. 134, Issue 5, dated March 17, 1975, or an FAA-approved equivalent. This supersedes AD 57-05-02 that was contained in Supplement 2 to Part 507 of the Regulation of the Administrator (22 FR 6046) and that was transferred to Section 39.13 of the Federal Aviation Regulations upon the adoption of Part 39 (29 FR 14403). NOTE: Copies of X-rays or of the results of the equivalent inspections as required by paragraph (a) of this AD are requested to be transmitted to DOT/FAA, Chief, Aircraft Certification Staff, Africa, and Middle East Region, c/o American Embassy, APO New York, N.Y. 09667. (Reporting approved by the Bureau of the Budget under B.O.B. No. 04-R0174). This amendment becomes effective November 28, 1975.
2011-21-13: This amendment adopts a new airworthiness directive (AD) for ECD Model MBB-BK 117 C-2 helicopters. This action requires revising the Rotorcraft Flight Manual (RFM) by inserting certain temporary pages into the Emergency and Performance Data sections of the RFM to alert the operators to monitor the power display when a generator is deactivated and provides appropriate actions. This amendment is prompted by reports of too high a current flow when one generator is deactivated. The actions specified in this AD are intended to prevent failure of the remaining generator when one generator is deactivated, loss of electrical power, loss of systems necessary for flight safety, and subsequent loss of control of the helicopter.
2011-23-06: We are adopting a new airworthiness directive (AD) for Sicma Aero Seat Model 9401, 9402, 9404, 9405, 9406, 9407, 9408, and 9409 series passenger seat assemblies, installed on, but not limited to, ATR-GIE Avions de Transport R[eacute]gional Model ATR42 and ATR72 airplanes. 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: Several occurrences of cracked central and lateral spreaders on passenger seats models 9401 and 9402 * * *. This condition, if not corrected, can lead to further cracking of the seat spreaders, causing injury to passengers or crew members during heavy turbulence in flight or in the event of an emergency landing. * * * * * This AD requires actions that are intended to address the unsafe condition described in the MCAI.
74-18-16: 74-18-16 AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Amendment 39-1949. Applies to AiResearch Model TFE731-2-1C and TFE731-2-2B engines installed in, but not limited to, the Lear-Gates Learjet model 35/36 and the AMD Falcon 10 aircraft, certificated in all categories. (A) Before further flight, unless previously accomplished, and prior to the installation of replacement fuel control computers internally inspect the fuel control computer, P/N 949572-5, in accordance with AiResearch campaign wire TFE731-A76-3005, dated August 7, 1974, or later FAA-approved revisions. (B) Equivalent procedures may be approved by the Chief, Aircraft Engineering Division, FAA Western Region, upon submission of adequate substantiation data. (C) Aircraft may be flown to a base for performance of maintenance required by this AD per FAR's 21.197 and 21.199. This amendment is effective September 6, 1974, for all persons except those to whom it was made effective immediately by telegram dated August 7, 1974.
2011-23-03: We are adopting a new airworthiness directive (AD) for certain SOCATA Model TBM 700 airplanes. 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: A TBM700 operator reported an occurrence where, as a result of handling the standby compass lighting bulb cover in flight, both essential bus bars (ESS BUS 1 and ESS BUS 2) failed, leading to loss of a number of instruments and navigation systems. The technical investigations carried out by SOCATA have shown that the cause of this occurrence was that the electrical protection of some TBM 700 aeroplanes is insufficient to allow in-flight handling of the standby compass lighting cover when energized. This condition, if not corrected, may compromise the ability of the pilot to safely operate the aeroplane under certain flight conditions dueto the increase of workload. We are issuing this AD to require actions to correct the unsafe condition on these products.
75-07-06: 75-07-06 DETROIT DIESEL ALLISON: Amendment 39-2141. Applies to Detroit Diesel Allison Model 501-D22A engines with turbine assemblies having the following serial numbers: 750137, 750138, 750139, 750140, 750142, 750143, 750145, 750146A, 750147A, 750149, 750150, 750151, 750154, 750158, 750160, 750166, 750176, 750177, 750179, 750181, 750182A, 750184, 750194, 750195, 750201A, 750204, 750205, 750208, 750212, 750213, 750214, 750229, 750230, 750231, 750235, 750241A, 750263A, 750266, 750272, 750301, 750305, 750309, 750312 Within the next 300 hours' time in service after the effective date of this Airworthiness Directive, unless already accomplished, remove the part number 6852228 second stage turbine blades and replace with part number 6890508 second stage turbine blades. Detroit Diesel Allison Commercial Overhaul Information Letter Number COIL-1019 pertains to this subject. This amendment is effective April 7, 1975.
74-19-07: 74-19-07 BOEING: Amendment 39-1961. Applies to Boeing Model 747 Series aircraft certificated in all categories with more than 2,000 flights. Compliance required as noted: \n\n\t(A)\tWithin the next 100 flights, determine the thickness of the flap control handle detent pin in accordance with FAA approved Boeing Service Bulletin 747-27-2121, Revision 1, dated June 14, 1974, or later FAA approved revisions, or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region. Flap control handle detent pins with more than .110 inch thickness remaining are to be inspected at intervals not to exceed 2,000 flights. Pins with .110 or less but more than .070 inch thickness are to be inspected at intervals not to exceed 750 flights. Pins with .070 or less but more than .050 inch thickness remaining are to be inspected at intervals not to exceed 250 flights. Pins with .050 or less but more than .045 inch thickness must be replaced within 100 flights. Pins with .045inch or less thickness remaining are to be replaced with an approved flap control handle prior to further flight. \n\t(B)\tOn or before September 1, 1975, relocate the bias spring in accordance with FAA approved Boeing Service Bulletin 747-27-2121, Revision 1, dated June 14, 1974, or later FAA approved revisions, or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA, Northwest Region. \n\t(C)\tRework of the flap control handle detent pin, refinish of the detent plate and relocation of the bias spring, in accordance with Boeing Service Bulletin 747-27-2121, Revision 1, dated June 14, 1974, or later FAA approved revisions, or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA, Northwest Region, constitutes terminating action under the provisions of this AD. \n\t(D)\tUpon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA, Northwest 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 adjustment period. \n\n\tThis amendment becomes effective 30 days after September 20, 1974.
56-20-03: 56-20-03 BELL: Applies to All Models 47B, 47B3, 47D, 47D1, 47G, 47G2 and 47H1. Compliance required as soon as possible but not later than October 20, 1956. Failure of the tail rotor hub retention bolts P/N 47-641-052-1 has occurred in service. The probable cause of the bolt failures experienced to date has not been determined and this problem is currently being investigated. At the conclusion of this investigation Bell anticipates supplying a newly designed hub retention bolt as a replacement for the present bolts. In the interim it is mandatory that a service life of 300 hours be established for the subject bolt. At this time it is necessary to remove the two tail rotor retention bolts and replace them with new retention bolts of the same part number. (Bell Mandatory Service Bulletin No. 112 dated August 8, 1956, covers this same subject.)
74-19-03: 74-19-03 BELL: Amendment 39-1954. Applies to Bell Model 206A and 206B helicopters as noted herein, certificated in all categories. Compliance required within 100 hours time in service after the effective date of this A.D., unless already accomplished. To prevent possible failure of the inboard ribs with possible loss of a stabilizer on Model 206A and 206B helicopters, serial numbers 1 through 913 equipped with horizontal stabilizer, P/N 206-020-119, replace any cracked inboard ribs and modify all inboard ribs by installing a doubler specified in and using the applicable procedures described in Items 3 through 24, Bell Helicopter Company Service Bulletin No. 206-01-73-7, Revision A, dated December 11, 1973 or later FAA approved revision. To prevent excessive movement of the horizontal stabilizer install Horizontal Stabilizer Stop Kit, P/N 206-704-096-3, on Model 206A and 206B helicopters, Serial Numbers 1 through 1251, in accordance with Bell Helicopter Company Service Bulletin No. 206-01-74-1, Revision A, dated May 6, 1974, or later FAA approved revision. This amendment becomes effective October 13, 1974.
2011-21-08: We are adopting a new airworthiness directive (AD) for Sicma Aero Seat 88xx, 89xx, 90xx, 91xx, 92xx, 93xx, 95xx, and 96xx series passenger seat assemblies, installed on various transport category airplanes. 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: \n\n\n\tCracks have been found on seats (with) backrest links P/N (part number) 90-000200-104-1 and 90-000200-104-2. These cracks can significantly affect the structural integrity of seat backrests. \n\nFailure of the backrest links could result in injury to an occupant during emergency landing conditions. We are issuing this AD to require actions to correct the unsafe condition on these products.
2011-09-07: 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: During manufacture of a number of HP Compressor Stage 1 and 2 discs with axial dovetail slots, anomalies at the disc post corners have been found. Fatigue crack initiation and subsequent crack propagation at the disc post may result in release of two blades and the disc post. This may potentially be beyond the containment capabilities of the engine casings. Thus, these anomalies present at the disc posts constitute a potentially unsafe condition. We are issuing this AD to detect cracks in the high-pressure compressor (HPC) Stage 1 and 2 disc posts, which could result in failure of the disc post and release of HPC blades, release of uncontained engine debris, and damage to the airplane.
76-04-02: 76-04-02 BEECH: Amendment 39-2518. Applies to Models C90 (Serial Numbers LJ- 654 and LJ-674 thru LJ-676), E90 (Serial Numbers LW-134 and LW-157 thru LW-163), A100 (Serial Numbers B-178 thru B-221, B-224 and B-225), 200 (Serial Numbers BB-6 thru BB-87, BB-89 thru BB-99 and BB-101 thru BB-106) and A200 (Serial Numbers BC-1 thru BC-8, and BD-1 thru BD-8) airplanes. Compliance: Required as indicated, unless already accomplished. To preclude inadvertent disengagement of the seat locking pins, within the next 50 hours' time in service after the effective date of this AD, replace Beech P/N 50-534436-127 seat locking pins (3.38 inch length) with Beech P/N 101-530412-1 seat locking pins (3.69 inch length) in accordance with Beechcraft Service Instructions No. 0789-314 or C-12A-0001 (military airplanes), or later approved revisions, or any equivalent modification approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region. This amendment becomes effectiveFebruary 26, 1976.