Results
2004-12-13: This amendment adopts a new airworthiness directive (AD), applicable to certain Aerospatiale Model ATR42-500 and ATR72-212A series airplanes, that requires repetitive inspections for cracking of the upper closing rib of the vertical fin, related investigative actions, and corrective actions if necessary. This action is necessary to prevent interference between the upper closing rib and the rudder, which could result in a rudder jam and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.
2001-05-02: This amendment supersedes Airworthiness Directive (AD) 98-08-22, which currently requires inspecting the elevator and rudder attachment brackets for cracks and corrosion on certain Pilatus Aircraft Ltd. (Pilatus) Model PC-7 airplanes and replacing any cracked or corrosion-damaged parts . Since the issuance of AD 98-08-22, Pilatus has redesigned the brackets. Installation of these brackets should inhibit corrosion, which resulted in cracks or corrosion damage. This AD requires you to replace the elevator and rudder attachment brackets with parts of improved design. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. The actions specified by this AD are intended to prevent failure of the elevator and rudder attachment brackets because of cracks or corrosion damage. Such failure could result in the elevator or rudder separating from the airplane with consequent loss of airplane control.
2018-07-02: We are adopting a new airworthiness directive (AD) for Agusta S.p.A. (Agusta) Model A109E, A109S, AW109SP, A119, and AW119 MKII helicopters. This AD requires inspecting the main rotor blade (MRB) tip cap for disbonding. This AD is prompted by a report of the in-flight loss of an MRB tip cap. The actions of this AD are intended to prevent an unsafe condition on these products.
2007-16-06: 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 airworthiness authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as failure of an evacuation slide raft to inflate, which could delay the evacuation of passengers in case of an emergency. We are issuing this AD to require actions to correct the unsafe condition on these products.
2018-07-01: We are superseding Airworthiness Directive (AD) 2013-16-14 for Eurocopter Deutschland GmbH (now Airbus Helicopters Deutschland GmbH) Model EC 135 P1, P2, P2+, T1, T2, and T2+ helicopters. AD 2013-16-14 required installing a washer in and modifying the main transmission filter housing upper part. Since we issued AD 2013-16-14, Airbus Helicopters Deutschland GmbH has extended the overhaul interval for the main transmission and determined that other models may have the same unsafe condition. This AD retains the requirements of AD 2013-16-14, adds models to the applicability, and revises [[Page 13381]] the required compliance time for the modification. The actions of this AD are intended to correct an unsafe condition on these products.
2001-05-01: This amendment adopts a new airworthiness directive (AD) that applies to certain DG Flugzeugbau GmbH (DG Flugzeugbau) Model DG-500MB sailplanes equipped with a SOLO 2625 02 engine. This AD requires you to install additional access holes in the propeller mount and modify the engine. This AD also requires you to do a ground test run and replace the digital engine indicator circuit breaker. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the Federal Republic of Germany. The actions specified by this AD are intended to correct an inadequate circuit breaker and unsatisfactory drive belt tension that could cause damage to the engine crankshaft. Such damage could lead to engine failure and loss of control of the sailplane.
2018-06-11: We are adopting a new airworthiness directive (AD) for certain Textron Aviation Inc. Models A36TC, B36TC, S35, V35, V35A, and V35B airplanes. This AD was prompted by a fatal accident where the exhaust tailpipe fell off during takeoff. This AD adds a life limit to the exhaust tailpipe v-band coupling (clamp) that attaches the exhaust tailpipe to the turbocharger and requires an annual visual inspection of the exhaust tailpipe v-band coupling (clamp). We are issuing this AD to address the unsafe condition on these products.
78-23-04: 78-23-04 PIPER: Amendment 39-3340. Applies to Piper Model PA-38-112 Serial Nos. 38-78A0001, 38-78A0005 thru 38-78A0016, 38-78A0018 thru 38-78A0039, 38-78A0042 thru 38-78A0130, 38-78A0132 thru 38-78A0212, 38-78A0214 thru 38-78A0233, 38-78A0235 thru 38-78A0270, 38-78A0272 thru 38-78A0324, 38-78A0326 thru 38-78A0329, 38-78A0331, 38-78A0333 thru 38-78A0356, 38-78A0358 thru 38-78A0372, 38-78A0374, 38-78A0375, 38-78A0377 thru 38-78A0385, 38-78A0387 thru 38-78A0399, 38-78A0401 thru 38-78A0410, 38-78A0413, 38-78A0415, 38-78A0416, 38-78A0418 thru 38-78A0421, 38-78A0424 thru 38-78A0426, 38-78A0428, 38-78A0429, 38-78A0431, 38-78A0432, 38-78A0434, 38-78A0435, 38-78A0437 thru 38-78A0439, 38-78A0441 thru 38-78A0443, 38-78A0445, 38-78A0446, 38-78A0449 thru 38-78A0455, 38-78A0457 thru 38-78A0466, 38-78A0468, 38-78A0469, 38-78A0471, 38-78A0472, 38-78A0474, 38-78A0475, 38-78A0477, 38-78A0478, 38-78A0480, 38-78A0481, 38-78A0483, 38-78A0484, 38-78A0486, 38-78A0489, 38-78A0490, 38-78A0492 thru 38-78A0494, 38-78A0496 thru 38-78A0498, 38-78A0500 thru 38-78A0502, 38-78A0504 thru 38-78A0506, 38-78A0509, 38-78A0510, 38-78A0512 thru 38-78A0526, 38-78A0528 thru 38-78A0532, 38-78A0534, 38-78A0535, 38-78A0537, 38-78A0538, 38-78A0540, 38-78A0541, 38-78A0544, 38-78A0546 thru 38-78A0548, 38-78A0550, 38-78A0552, 38-78A0555, 38-78A0556, 38-78A0558, 38-78A0559, 38-78A0561, 38-78A0565, 38-78A0567, 38-78A0568, 38-78A0570, 38-78A0573, 38-78A0574, 38-78A0576, 38-78A0578, 38-78A0581, 38-78A0584, 38-78A0585, 38-78A0587, 38-78A0588, 38-78A0606 and 38-78A0622. To prevent weakening of the wing rear spar to fuselage attach fitting connection due to missing rivets, accomplish the following: (a) Within the next 10 hours in service after the effective date of this AD, unless already accomplished, perform the steps 1 thru 4 as indicated under the Instructions section in Piper Service Bulletin No. 618, dated September 5, 1978, or equivalent. (b) Equivalent inspections, repairs, and alterations must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region. (c) The affected airplanes may be flown in accordance with FAR 21.197 to a location where the AD may be accomplished. (d) Upon submission of substantiating data through an FAA Maintenance Inspector, the compliance time specified in this AD may be adjusted by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region. This amendment is effective November 10, 1978.
2007-16-05: The FAA is adopting a new airworthiness directive (AD) for all Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This AD requires repetitive inspections for discrepancies of the elevator tab control rod assemblies and/or damage to the surrounding structure, and related corrective action. This AD results from reports indicating loose jam nuts and/or thread wear at the rod ends on the elevator tab control rod assembly. We are issuing this AD to find and fix discrepancies of the elevator tab control rod assembly, which could result in excessive freeplay in the elevator tab control rods. Such freeplay could cause loss of both load paths, subsequent elevator tab flutter, and consequent reduced structural integrity and loss of controllability of the airplane.
2001-05-05: This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 747 series airplanes. This action requires repetitive detailed visual inspections to find discrepancies of the installation of the midspar fuse pins of the inboard and outboard struts, and follow-on actions, if necessary. This action also provides for an optional terminating modification for the repetitive inspections. This action is necessary to find and fix discrepancies of the installation of the midspar fuse pins, which could result in loss of the secondary retention capability of the fuse pins, migration of the fuse pins, and consequent loss of the strut and engine from the airplane. This action is intended to address the identified unsafe condition.
2019-17-05: The FAA is adopting a new airworthiness directive (AD) for certain Airbus SAS Model A330-200 Freighter, -200, and -300 series airplanes; and certain Airbus SAS Model A340-200, -300, -500, and -600 series airplanes. This AD was prompted by a determination that certain wing slat tracks that were inadvertently indicated as eligible for installation on all Model A330 and A340 series airplanes are unable to sustain the ultimate loads relative to the weight variant of certain airplane configurations. This AD requires identifying affected parts, inspecting for and repairing cracks, and replacing affected parts with serviceable parts, as specified in a European Aviation Safety Agency (EASA) AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.
78-22-07: 78-22-07 PIPER AIRCRAFT CORPORATION: Amendment 39-3332. Applies to the following model PA-32RT-300 and PA-32RT-300T aircraft, certificated in all categories: PA-32RT-300 Lance II 32R-7885001 to 32R-7885216 Inclusive 32R-7885218 to 32R-7885253 Inclusive 32R-7885255, 32R-7885257 to 32R-7885260 Inclusive PA-32RT-300T Turbo Lance II 32R-7887001 to 32R-7887110 Inclusive 32R-7887112 to 32R-7887173 Inclusive 32R-7887175 to 32R-7887182 Inclusive 32R-7887184 to 32R-7887196 Inclusive 32R-7887198 to 32R-7887201 Inclusive 32R-7887203 to 32R-7887205 Inclusive 32R-7887207, 32R-7887208, 32R-7887210, 32R-7887212 to 32R-7887215 Inclusive 32R-7887217, 32R-7887218, 32R-7887220, 32R-7887222, 32R-7887224 and 32R-7887226. Compliance required within the next 10 hours of operation, or at the next regularly scheduled or annual inspection, whichever occurs first. To insure full travel of the control column, replace the control column stop sleeve and checkcontrol column travel and stabilator travel in accordance with the instructions contained in Piper Service Bulletin 619 (and Control Column Stop Modification Kit Number 763 895V) or later revision approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Southern Region, or in an equivalent manner approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Southern Region. This amendment becomes effective November 15, 1978.
2007-16-11: The FAA is adopting a new airworthiness directive (AD) for certain Fokker Model F27 Mark 050 airplanes equipped with Dowty Type R.352 or R.410 series propellers. This AD requires checking the maintenance records to determine whether Minnesota Mining and Manufacture Co. (3M) 1300L adhesive was used to attach the de-icer assembly overshoes (boots) to the propeller blades, repetitive inspections of affected boots, and replacing boots attached with defective adhesive. This AD results from three events of propeller blade de-icer assembly boots debonding and detaching during flight. This condition was caused by using 3M 1300L adhesive to attach the boot to the propeller blade. We are issuing this AD to detect and correct boots attached with defective adhesive, which could result in debonding and separation of a boot from the airplane, consequent reduced structural integrity of the airplane, and possible injury to passengers and crew.
2019-17-03: The FAA is adopting a new airworthiness directive (AD) for certain Airbus SAS Model A320-214 and -271N airplanes and Model A321- 211 and -231 airplanes. This AD was prompted by a test of a new wall partition for a certain cabin attendant seat model that revealed the backrest was permanently deformed and did not allow the seat pan to return to a full-up position; investigation results identified that a heat treatment had not been applied on certain backframes. This AD requires modifying the affected cabin attendant seats, as specified in a European Aviation Safety Agency (EASA) AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.
2001-04-15: This amendment adopts a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model DC-8-31, DC-8-32, DC-8-33, DC-8-41, DC-8-42, DC-8-43, DC-8-51, DC-8-52, DC-8-53, DC-8-55, DC-8-61, DC-8-61F, DC-8-62, DC-8-62F, DC-8-63, DC-8-63F, DC-8F-54, and DC-8F-55 series airplanes. This action requires modification of the flow control system by rerouting the bleed air ducts to warm the pitot tube lines. This action is necessary to prevent the pitot lines from freezing, which could result in erroneous or total loss of airspeed indications to the flight crew, and consequent loss of control of the airplane. This action is intended to address the identified unsafe condition.
2004-16-05: This amendment adopts a new airworthiness directive (AD), applicable to all Boeing Model 747 series airplanes, that requires a one-time inspection to determine whether the outer cylinder of the wing landing gear has certain part numbers, and replacement of the outer cylinder of the wing landing gear with a new, improved, or reworked part if necessary. This amendment also requires removal of the load evening system, if such a system is installed. This action is necessary to prevent fracture of the outer cylinder of the wing landing gear, which could result in collapse of the wing landing gear. This action is intended to address the identified unsafe condition.
2019-16-10: The FAA is adopting an airworthiness directive (AD) for certain The Boeing Company Model 787-8 airplanes. This AD requires a one-time inspection of the horizontal stabilizer pivot pin assemblies for misalignment and incorrect gapping, and applicable on-condition actions. This AD was prompted by a report of possible misalignment of the horizontal stabilizer pivot pin lock ring, outer pivot pin, and outboard spacer at final assembly. The FAA is issuing this AD to address the unsafe condition on these products.
2001-04-11: This amendment adopts a new airworthiness directive (AD) that is applicable to certain Pratt & Whitney (PW) JT9D series turbofan engines. This amendment requires initial and repetitive detailed eddy current inspections for cracks in 1st stage high pressure turbine (HPT) disks, and, if necessary, replacement with serviceable parts. This amendment is prompted by the discovery of a crack in the web of one cooling air hole on a 1st stage HPT disk. The actions specified by this AD are intended to prevent 1st stage HPT disk cracking, which could result in an uncontained engine failure and damage to the aircraft.
2001-03-51: This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 2001-03-51, which was sent previously to all known U.S. owners and operators of Sikorsky Aircraft Corporation (Sikorsky) Model S-76B and S-76C helicopters by individual letters. This AD requires, for certain main rotor shafts, initial and recurring fluorescent penetrant inspections. Replacing each affected main rotor shaft (shaft) on or before reaching 1,000 hours time-in-service (TIS) is also required. This amendment is prompted by four reports of shaft cracks. The actions specified by this AD are intended to prevent failure of the shaft and subsequent loss of control of the helicopter.
78-22-01: 78-22-01 PIPER: Amendment 39-3323. Applies to Piper Model PA-38-112, Serial Numbers 38-78A0001 thru 38-78A-0400 certificated in all categories. To prevent possible binding of the rudder or elevator in flight, accomplish the following: (a) Applies to Model PA-38-112, Serial Numbers 38-78A0001 thru 38-78A0215 and 38-78A0217 thru 38-78A0226. Before further flight, unless already accomplished, and at intervals thereafter not to exceed 25 hours in service inspect for proper clearance between the rudder leading edge and fin trailing edge and repair in accordance with the "instructions" of Piper Service Bulletin Nos. 607 or 607A dated May 19, 1978, and June 2, 1978, or equivalent. (b) Applies to Model PA-38-112, Serial Nos. 38-78A0001 thru 38-78A0215 and 38-78A0217 thru 38-78A0226. Within the next fifty hours in service after the effective date of this AD, unless already accomplished, install Piper Kit 763 872 Rudder Leading Edge Modification or equivalent. The inspections of (a) may be dispensed with upon incorporation of this modification. (c) Applies to Model PA-38-112 Serial Nos. 38-78A0001 thru 38-78A0400. Within the next fifty hours in service after the effective date of this AD, unless already accomplished, inspect and repair the elevator leading edge in accordance with the procedure under "instructions" of Part II of Piper Service Bulletin No. 607A dated June 2, 1978, or equivalent. (d) Equivalent inspections, repairs and modifications must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region. (e) The affected airplanes may be flown in accordance with FAR 21.197 to a location where the AD compliance procedures can be accomplished. (f) Upon submission of substantiating data through an FAA Maintenance Inspector, the compliance times specified in this AD may be adjusted by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region. This amendment is effective October 30, 1978.
2004-16-04: This amendment adopts a new airworthiness directive (AD), applicable to all Short Brothers Model SD3 series airplanes. This AD requires testing for stiffness of the aft pintle pin bushing of the main landing gear (MLG), and inspecting and measuring the aft pintle pin bushings of the MLG for damage, and for out-of-limit dimensions of the bushing bore. This AD also requires corrective action if necessary. This action is necessary to detect and correct corrosion and deterioration of the aft pintle pin bushings of the MLG. Corrosion and deterioration of the bushings, if not detected and corrected, could result in the MLG not extending fully during landing, with consequent damage to the airplane structure. This action is intended to address the identified unsafe condition.
2004-16-03: This amendment adopts a new airworthiness directive (AD), applicable to certain Gulfstream Aerospace LP Model Galaxy and Model Gulfstream 200 airplanes, that requires a one-time detailed inspection of the wing flap actuators for proper bonding of the flap actuator fairings to the lower skin of the wings, and related corrective or preventative actions. These actions are necessary to prevent possible separation of the flap actuator fairings from the lower skin of the wings from causing possible damage to adjacent structural elements (such as the horizontal stabilizer), which could result in reduced controllability of the airplane. These actions are intended to address the identified unsafe condition.
2019-16-05: The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 777 airplanes. This AD was prompted by reports of uncommanded fore/aft movements of the Captain's and First Officer's seats. This AD requires an identification of the part number, and if applicable the serial number, of the Captain's and First Officer's seats, and applicable on-condition actions for affected seats. The FAA is issuing this AD to address the unsafe condition on these products.
2013-26-09: We are adopting a new airworthiness directive (AD) for all Turbomeca S.A. ASTAZOU XIV B and XIV H engines. This AD was prompted by reports of cracks on the 2nd-stage turbine disk. This AD requires replacement of the 2nd-stage turbine disk. We are issuing this AD to prevent disk cracking, uncontained 2nd-stage turbine blade release, damage to the engine, and damage to the helicopter.
78-05-06: 78-05-06 GOODYEAR AEROSPACE CORPORATION: Amendment 39-3151 as amended by Amendment 39-3173 is further amended by Amendment 39-3249. Applies to Goodyear flexible fuel cells, construction type BTC-39 series manufactured between 1961 and 1971, installed on, but not necessarily limited to the following aircraft models, all series, manufactured between January 1961 and December 1973, or in which these fuel cells may have been installed as replacements after those dates. Beech - H18, 35-B33, 35-C33, E33 and F33; 35-C33A, E33A, and F33A; E33C and F33C; P35, S35, V35, V35-TC, V35A, V35A-TC, V35B and V35B-TC; 36 and A36; 45 (T34A), B45 and D45 (T34B); D50E, J50; 95-A55, 95-B55 and 95-B55A; 95-C55, 95-C55A, D55, D55A, E55 and E55A; 95-B55B (T42A); 56TC and A56TC; 58 and 58A; 60, A60 and B60; 65, A65 and A65-8200; 70; 65-80, 65-A80, 65-A80-8800 and 65-B80; 65-88; 65-90, 65-A90; B90; C90; E90; D95A and E95A; 99, 99A, A99A and B99; 100 and A100; and any other Beechcraft airplane models orserial numbers other than those listed above on which Goodyear BTC-39 construction fuel cells have been installed as spares replacements; Cessna - 180, 182, 185, 188 with wing tanks, 205, 206, 207, 210, 310, 320, 340, 401, 402, 411, 414, 421; Israel Aircraft (including Aero Commander/Rockwell International) 1121 and 1123; Piper - PA-25 and PA-31; Rockwell International General Aviation Division - All models prefixed by 500, 560, 680, 681, 685, 690 and 720. Compliance is required, as indicated, unless already accomplished. To prevent a hazard to the airplane due to fuel cell leakage caused by deterioration of the cell or cell nipples, accomplish the following: (a) Within the next 25 hours time in service after the effective date of this A.D., or within the next 30 calendar days after the effective date of this A.D., whichever occurs first, check aircraft records and manufacturer's instructions. If aircraft records or manufacturer's service data confirm that no Goodyear construction BTC-39 series cells are installed, no further action is required, except entry in the aircraft maintenance records that this check has been accomplished. If any or all fuel cells installed are of the Goodyear BTC-39 construction series or are of unknown manufacturer or construction, conduct the checks, test and inspection specified in (b) and (c). NOTE: Information to assist in identifying BTC-39 fuel cells, and applicable aircraft serialization, may be found in the following service instructions, or later approved revisions: Beech Service Instruction Number 0895; Cessna Single Engine Service Letter SE78-10; Cessna Multi-Engine Service Letter ME78-7; Israel Aircraft Service Bulletins CJ-17 for Model 1121, and WW-20 for Model 1123; Piper Service Bulletin No. 591; and Rockwell General Aviation Division Service Bulletin No. 165. (b) Within the next 25 hours time in service after the effective date of this A.D.,or within the next 30 calendar days after the effective date of this A.D., whichever occurs first, fill the fuel tanks and perform a visual check of the exterior of the aircraft wings and/or fuselage for signs of fuel leakage. Fuel wetness or color dye stains may be noted, especially in the vicinity of vents and compartment drains. Fuel stains due to overfill are not considered leakage. The visual check required by this paragraph may be performed by the pilot. Notation in the aircraft records is required by FAR 91.173(a)(2)(v). (1) If signs of fuel leakage are observed, determine the leakage source. (2) If leakage source is other than fuel cells or fuel cell nipples, correct in accordance with aircraft manufacturer's instructions prior to further flight. (3) If leakage is from fuel cell or nipples, proceed with the inspection required in (c)(8) prior to further flight. (c) Within the next 100 hours time in service after the effective date of this A.D. or within the next 180 calendar days after the effective date of this A.D., whichever occurs first, determine whether the vent nipples and fuel cell material, including the material end fittings, above the normal fuel level are intact and secure by accomplishing the fuel system integrity test and inspection as required in accordance with the applicable manufacturer's service information listed in (a) above, or as prescribed below: (1) Position the airplane in an area of stable temperature, free from radiant heat and strong air currents, with the aircraft in approximately normal ground attitude, wings level. Install an adapter with a standpipe on the tank filler neck and another adapter and standpipe on the tank vent exit tube. The open ends of the two standpipes should terminate at approximately the same level, 12 to 14 inches above the highest part of the tank. The tank selector should be OFF. NOTE: Some aircraft incorporate a vent system that interconnects the vent outlets of two or more tanks. Since fuel or air may flow through the interconnects from one tank to another, this characteristic must be considered in conducting the integrity test for leakage. On such aircraft it will be acceptable to conduct the integrity pressure test simultaneously on the interconnected tanks instead of on each tank individually. CAUTION: Observe appropriate safety measures for handling fuel, fuel systems and fueled aircraft. (2) Fill tank and standpipe and inspect for evidence of fuel leakage. Allow one or two minutes for the fuel level to stabilize. CAUTION: Do not overpressurize tank as structural damage might occur. The 12-inch standpipe pressure specified will not exceed allowable limits for tank/fuel system pressure. Maintain the standpipe fuel level for not less than 15 minutes after fuel level stabilization occurs, unless fuel leakage is observed sooner. Fuel tank or system leakage may also be revealed by a reduction in the height of fuel in the standpipe. (3) If the standpipe fuel level remains stabilized for 15 minutes, and if there is no evidence of fuel leakage, the test may be discontinued for that tank. (4) Repeat the test of (c)(1) and (c)(2) for each tank that incorporates a cell of BTC-39 or a tank cell of unknown type construction. (5) If no leaks are observed, the test may be terminated. The fuel system should be returned to normal flight configuration, and the aircraft may be returned to service. Make notation in the aircraft records in accordance with FAR 91. (6) If there is evidence of fuel leakage, determine the source of the leak. (7) Repair fuel system leaks, other than fuel cell or nipple leaks, in accordance with the appropriate aircraft manufacturer's instructions. (8) If evidence of fuel cell or nipple leakage is observed, conduct the following inspection of each cell and all nipples for the source of the leak. (i) Drain fuel tanks and remove access covers or plates. (ii) After thorough purging of the tank interiors to remove fuel vapors, use explosion-proof light and mirror and visually inspect the interior and exterior (where accessible) of each cell suspected of leakage for cracking, peeling or other signs of deterioration. (iii) Inspect the tank retaining fasteners and determine that they are properly positioned and fastened. (iv) Inspect vent, drain and all nipples. These may be inspected by the fingernail test to give an indication of the condition of the nipple. The fingernail test consists of using the fingernail to attempt to scrape the compound off the nipple fitting. If the compound has not degraded, the fingernail will glide across the surface without damage to the compound. If an unsatisfactory condition exists, the fingernail will tend to dig into the compound. The deteriorated compound will have a consistency of either art gum or chewing gum. (v) Remove any fuel cell found leaking or with deteriorated nipples. BTC-39 series type cells which have been removed are not repairable, and must not be installed as a serviceable cell in an aircraft. Other type cell construction may be repaired in accordance with the applicable manufacturer's instructions by a person authorized in FAR Part 43. (vi) Install serviceable fuel cells, reconnect fuel cell and fuel system, and access covers, and functionally pressure check fuel system in accordance with aircraft manufacturer's service data or item (c). (d) Repeat the integrity pressure test and inspection required in (c) at intervals not to exceed 12 months until all BTC-39 type construction fuel cells or cells of unknown construction have been replaced. (e) An equivalent means of compliance with this A.D. is to comply with the aircraft manufacturer's instructions listed in (a), provided that the visual check is accomplished at the compliance time required in (b) and that the inspection and tests are conducted at the intervals specified by (c) and (d). Any other method must be approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Southern Region. (f) Upon request of the operator, an FAA maintenance inspector may adjust the inspection interval specified in (c) and the repetitive inspection interval specified in (d) of this A.D. to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for that operator. The time for conducting the checks required by (a) and (b) may not be adjusted. Amendment 39-3151 became effective March 17, 1978. Amendment 39-3173 became effective April 10, 1978. This amendment 39-3249 becomes effective June 30, 1978.