AD 2015-21-09

We are superseding Airworthiness Directive (AD) 2015-19-02 for all The Boeing Company Model 767 airplanes. AD 2015-19-02 required revising the maintenance or inspection program to include new airworthiness limitations. This AD continues to require a maintenance or inspection program revision, but with revised language. This AD was prompted by a determination that certain language in the airworthiness limitation was not accurate in AD 2015-19-02. We are issuing this AD to detect and correct latent failures of the fuel shutoff valve to the engine and auxiliary power unit (APU), which could result in the inability to shut off fuel to the engine and APU and, in case of certain fires, an uncontrollable fire that could lead to structural failure.

Final rule; request for comments.

Adoption of the Amendment \n\n\n\tAccordingly, under the authority delegated to me by the Administrator, the FAA amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n0 1. The authority citation for part 39 continues to read as follows: \n\n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n\n\nSec. 39.13 (Amended) \n\n0 2. The FAA amends Sec. 39.13 by removing Airworthiness Directive (AD) 2015-19-02, Amendment 39-18265 (80 FR 55512, September 16, 2015), and adding the following new AD: \n\n2015-21-09 The Boeing Company: Amendment 39-18302; Docket No. FAA- 2015-4209; Directorate Identifier 2015-NM-156-AD. \n\n(a) Effective Date \n\n\n\tThis AD is effective October 28, 2015. \n\n(b) Affected ADs \n\n\n\tThis AD replaces AD 2015-19-02, Amendment 39-18265 (80 FR 55512, September 16, 2015). \n\n(c) Applicability \n\n\n\tThis AD applies to all The Boeing Company Model 767-200, -300, - 300F, and -400ER series airplanes, certificated in any category. \n\n(d) Subject \n\n\n\tAir Transport Association (ATA) of America Code 28, Fuel. \n\n(e) Unsafe Condition \n\n\n\tThis AD was prompted by reports of latently failed fuel shutoff valves discovered during fuel filter replacement. We are issuing this AD to detect and correct latent failures of the fuel shutoff valve to the engine and auxiliary power unit (APU), which could result in the inability to shut off fuel to the engine and APU and, in case of certain fires, an uncontrollable fire that could lead to structural failure. \n\n(f) Compliance \n\n\n\tComply with this AD within the compliance times specified, unless already done. \n\n(g) Revision of Maintenance or Inspection Program \n\n\n\tWithin 30 days after the effective date of this AD, revise the maintenance or inspection program, as applicable, to add airworthiness limitation numbers 28-AWL-ENG, 28-AWL-MOV, and 28-AWL- APU, by incorporating the information specified in figure 1, figure 2, and figure 3 to paragraph (g) of this AD into the Airworthiness Limitations Section of the Instructions for Continued Airworthiness. The initial compliance time for accomplishing the actions specified in figure 1, figure 2, and figure 3 to paragraph (g) of this AD is within 10 days after accomplishing the maintenance or inspection program revision required by this paragraph. \n\n((Page 65123)) \n\n\n\n\n\n\n\tFigure 1 to Paragraph (g) of This AD: Engine Fuel Shutoff Valve (Fuel Spar Valve) Position Indication \n\tOperational Check ---------------------------------------------------------------------------------------------------------------- \n\tAWL No. Task Interval Applicability Description ---------------------------------------------------------------------------------------------------------------- 28-AWL-ENG................ ALI DAILY............... 767-200, -300, and - Engine Fuel Shutoff Valve \n\t300F airplanes. (Fuel Spar Valve) \n\tPosition Indication \n\tOperational Check. \n\tINTERVAL NOTE: The APPLICABILITY NOTE: Concern: The fuel spar \n\toperational check Applies to valve actuator design \n\tis not required on airplanes with an can result in airplanes \n\tdays when the actuator installed operating with a failed \n\tairplane is not at the engine fuel fuel spar valve actuator \n\tused in revenue spar valve position that is not reported. A \n\tservice. having part number latently failed fuel \n\tThe check must be (P/N) MA20A2027 spar valve actuator \n\tdone before further (S343T003-56) or P/ could prevent fuel \n\tflight once the N MA30A1001 shutoff to an engine. In \n\tairplane is (S343T003-66). the event of certain \n\treturned to revenue engine fires, the \n\tservice. potential exists for an \n\tengine fire to be \n\tuncontrollable. \n\tPerform one ofthe \n\tfollowing checks/ \n\tinspection of the fuel \n\tspar valve position \n\t(unless checked by the \n\tflightcrew in a manner \n\tapproved by the \n\tprincipal operations \n\tinspector): \n\tA. Operational Check \n\tduring engine shutdown. \n\t1. Do an operational \n\tcheck of the left engine \n\tfuel spar valve \n\tactuator. \n\ta. As the L FUEL CONTROL \n\tswitch on the quadrant \n\tcontrol stand is moved \n\tto the CUTOFF position, \n\tverify the left SPAR \n\tVALVE disagreement light \n\ton the quadrant control \n\tstand illuminates and \n\tthen goes off. \n\tb. If the test fails \n\t(light fails to \n\tilluminate), before \n\tfurther flight, repair \n\tfaults as required \n\t(refer to Boeing \n\tairplane maintenance \n\tmanual (AMM) 28-22-11). \n\t2. Do an operational \n\tcheck of the right \n\tengine fuel spar valve \n\tactuator. \n\ta. As the R FUEL CONTROL \n\tswitch on the quadrant \n\tcontrol stand is moved \n\tto the CUTOFF position, \n\tverify the right SPAR \n\tVALVE disagreement light \n\ton the quadrant control \n\tstand illuminates and \n\tthen goes off. \n\tb. If the test fails \n\t(light fails to \n\tilluminate), before \n\tfurther flight, repair \n\tfaults as required \n\t(refer to Boeing AMM 28- \n\t22-11). \n\tB. Operational check \n\tduring engine start. \n\t1. Do an operational \n\tcheck of the left engine \n\tfuel spar valve \n\tactuator. \n\ta. As the L FUEL CONTROL \n\tswitch on the quadrant \n\tcontrol stand is moved \n\tto the RUN (or RICH) \n\tposition, verify the \n\tleft SPAR VALVE \n\tdisagreement light on \n\tthe quadrant control \n\tstand illuminates and \n\tthen goes off. \n\tb. If the test fails \n\t(light fails to \n\tilluminate), before \n\tfurther flight, repair \n\tfaults as required \n\t(refer to Boeing AMM 28- \n\t22-11). \n\t2. Do an operational \n\tcheck of the right \n\tengine fuel spar valve \n\tactuator. \n\ta. As the R FUEL CONTROL \n\tswitch on the quadrant \n\tcontrol stand is moved \n\tto the RUN (or RICH) \n\tposition, verify the \n\tright SPAR VALVE \n\tdisagreement light on \n\tthe quadrant control \n\tstand illuminates and \n\tthen goes off. \n\tb. If the test fails \n\t(light fails to \n\tilluminate), before \n\tfurther flight, repair \n\tfaults as required \n\t(refer to Boeing AMM 28- \n\t22-11). \n\tC. Operational check \n\twithout engine \n\toperation. \n\t1. Supply electrical \n\tpower to the airplane \n\tusing standard \n\tpractices. \n\t2. Make sure all fuel \n\tpump switches on the \n\tOverhead Panel are in \n\tthe OFF position. \n\t3. If the auxiliary power \n\tunit (APU) is running, \n\topen and collar the L \n\tFWD FUEL BOOST PUMP \n\t(C00372) circuit breaker \n\ton the Main Power \n\tDistribution Panel. \n\t4. Make sure LEFT and \n\tRIGHT ENG FIRE switches \n\ton the Aft Aisle Stand \n\tare in the NORMAL (IN) \n\tposition. \n\t5. Make sure L and R ENG \n\tSTART Selector Switches \n\ton the Overhead Panel, \n\tare in the OFF position. \n\t6. Do an operational \n\tcheck of the left engine \n\tfuel spar valve \n\tactuator. \n\n((Page 65124)) \n\n\n\n\n\ta. Move L FUEL CONTROL \n\tswitch on the quadrantcontrol stand to the RUN \n\tposition and wait \n\tapproximately 10 \n\tseconds. \n\tNOTE: It is normal under \n\tthis test condition for \n\tthe ENG VALVE \n\tdisagreement light on \n\tthe quadrant control \n\tstand to stay \n\tilluminated. \n\tb. Move L FUEL CONTROL \n\tswitch on the quadrant \n\tcontrol stand to the \n\tCUTOFF position. \n\tc. Verify the left SPAR \n\tVALVE disagreement light \n\ton the quadrant control \n\tstand illuminates and \n\tthen goes off. \n\td. If the test fails \n\t(light fails to \n\tilluminate), before \n\tfurther flight, repair \n\tfaults as required \n\t(refer to Boeing AMM 28- \n\t22-11). \n\t7. Do an operational \n\tcheck of the right \n\tengine fuel spar valve \n\tactuator. \n\ta. Move R FUEL CONTROL \n\tswitch on the quadrant \n\tcontrol stand to the RUN \n\tposition and wait \n\tapproximately 10 seconds \n\tonce the FUEL CONTROL \n\tswitch is in the RUN \n\tposition. \n\tNOTE: It is normal under \n\tthis test condition for \n\tthe ENG VALVE \n\tdisagreement light on \n\tthe quadrant control \n\tstand to stay \n\tilluminated. \n\tb. Move R FUEL CONTROL \n\tswitch on the quadrant \n\tcontrol stand to the \n\tCUTOFF position. \n\tc. Verify the right SPAR \n\tVALVE disagreement light \n\ton the quadrant control \n\tstand illuminates and \n\tthen goes off. \n\td. If the test fails \n\t(light fails to \n\tilluminate), before \n\tfurther flight, repair \n\tfaults as required \n\t(refer to Boeing AMM 28- \n\t22-11). \n\t8. If the L FWD FUEL \n\tBOOST PUMP circuit \n\tbreaker was collared in \n\tstep 3, remove collar \n\tand close. \n\tD. Perform an inspection \n\tof the fuel spar valve \n\tactuator position. \n\tNOTE: This inspection may \n\tbe most useful whenever \n\tthe SPAR VALVE light \n\tdoes not function \n\tproperly. \n\t1. Make sure the L FUEL \n\tCONTROL switch on the \n\tquadrant control stand \n\tis in the CUTOFF \n\tposition. \n\tNOTE: It is not necessary \n\tto cycle the FUEL \n\tCONTROL switch to do \n\tthis inspection. \n\t2. Inspect the left \n\tengine fuel spar valve \n\tactuator located in the \n\tleft rear spar. \n\tNOTE: The Fuel Spar Valve \n\tactuators are located \n\tbehind main gear doors \n\ton the rear spar. \n\ta. Verify the manual \n\toverride handle on the \n\tengine fuel spar valve \n\tactuator is in the \n\tCLOSED position. \n\tb. Repair or replace any \n\tfuel spar valve actuator \n\tthat is not in the \n\tCLOSED position (refer \n\tto Boeing AMM 28-22-11). \n\t3. Make sure the R FUEL \n\tCONTROL switch on the \n\tquadrant control stand \n\tis in the CUTOFF \n\tposition. \n\tNOTE: It is not necessary \n\tto cycle the FUEL \n\tCONTROL switch to do \n\tthis inspection. \n\t4. Inspect the right \n\tengine fuel spar valve \n\tactuator located in the \n\tright rear spar. \n\tNOTE: The Fuel Spar Valve \n\tactuators are located \n\tbehind main gear doors \n\ton the rear spar. \n\ta. Verify the manual \n\toverride handle on the \n\tengine fuel spar valve \n\tactuator is in the \n\tCLOSED position. \n\tb. Repair or replace any \n\tfuel spar valve actuator \n\tthat is not in the \n\tCLOSED position (refer \n\tto Boeing AMM 28-22-11). ---------------------------------------------------------------------------------------------------------------- \n\n\n\n((Page 65125)) \n\n\n\n\n\tFigure 2 to Paragraph (g) of This AD: Engine Fuel Shutoff Valve (Fuel Spar Valve) Actuator Inspection ---------------------------------------------------------------------------------------------------------------- \n\tAWL No. Task Interval Applicability Description ---------------------------------------------------------------------------------------------------------------- 28(dash)AWL(dash)MOV...... ALI 10 DAYS............. 767-400ER series Engine Fuel Shutoff Valve \n\tairplanes. (Fuel Spar Valve) \n\tActuator Inspection. \n\tINTERVAL NOTE: The APPLICABILITY NOTE: Concern: The fuel spar \n\tinspection is not Applies to valve actuator design \n\trequired on days airplanes with an can result in airplanes \n\twhen the airplane actuator installed operating with a failed \n\tis not used in at the engine fuel fuel spar valve actuator \n\trevenue service. spar valve position that is not reported. A \n\tThe inspection must having part number latently failed fuel \n\tbe done before (P/N) MA20A2027 spar valve actuator \n\tfurther flight if (S343T003-56) or P/ would prevent fuel \n\tit has been 10 or N MA30A1001 shutoff to an engine. In \n\tmore calendar days (S343T003-66). the event of certain \n\tsince last engine fires, the \n\tinspection. potential exists for an \n\tengine fire to be \n\tuncontrollable. \n\tPerform an inspection of \n\tthe fuel spar valve \n\tactuator position. \n\tNOTE: The fuel spar valve \n\tactuators are located \n\tbehind main gear doors \n\ton the rear spar. \n\t1. Make sure the L FUEL \n\tCONTROL switch on the \n\tquadrant control stand \n\tis in the CUTOFF \n\tposition.NOTE: It is not necessary \n\tto cycle the FUEL \n\tCONTROL switch to do \n\tthis inspection. \n\t2. Inspect the left \n\tengine fuel spar valve \n\tactuator located in the \n\tleft rear spar. \n\ta. Verify the manual \n\toverride handle on the \n\tengine fuel spar valve \n\tactuator is in the \n\tCLOSED position. \n\tb. Repair or replace any \n\tfuel spar valve actuator \n\tthat is not in the \n\tCLOSED position (refer \n\tto Boeing AMM 28-22-11). \n\t3. Make sure the R FUEL \n\tCONTROL switch on the \n\tquadrant control stand \n\tis in the CUTOFF \n\tposition. \n\tNOTE: It is not necessary \n\tto cycle the FUEL \n\tCONTROL switch to do \n\tthis inspection. \n\t4. Inspect the right \n\tengine fuel spar valve \n\tactuator located in the \n\tright rear spar. \n\ta. Verify the manual \n\toverride handle on the \n\tengine fuel spar valve \n\tactuator is in the \n\tCLOSED position. \n\tb. Repair or replace any \n\tfuel spar valve actuator \n\tthat is not in the \n\tCLOSED position (refer \n\tto Boeing AMM 28-22-11). ---------------------------------------------------------------------------------------------------------------- \n\n\n\n\n\tFigure 3 to Paragraph (g) of This AD: Auxiliary Power Unit (APU) Fuel Shutoff Valve Position Indication \n\tOperational Check ---------------------------------------------------------------------------------------------------------------- \n\tAWL No. Task Interval Applicability Description ---------------------------------------------------------------------------------------------------------------- 28-AWL-APU................ ALI 10 DAYS............. ALL................. APU Fuel Shutoff Valve \n\tPosition Indication \n\tOperational Check. \n\tINTERVAL NOTE: The APPLICABILITY NOTE: Concern: The APU fuel \n\toperational check Applies to shutoff valve actuator \n\tis not required on airplanes with an design can result in \n\tdays when the actuator installed airplanes operating withairplane is not at the APU fuel a failed APU fuel \n\tused in revenue shutoff valve shutoff valve actuator \n\tservice. The position having that is not reported. A \n\toperational check part number (P/N) latently failed APU fuel \n\tmust be done before MA20A2027 (S343T003- shutoff valve actuator \n\tfurther flight with 56) or MA30A1001 could prevent fuel \n\tan operational APU (S343T003-66). shutoff to the APU. In \n\tif it has been 10 the event of certain APU \n\tor more calendar fires, the potential \n\tdays since last exists for an APU fire \n\tcheck. to be uncontrollable \n\tPerform the operational \n\tcheck of the APU fuel \n\tshutoff valve position \n\tindication (unless \n\tchecked by the \n\tflightcrew in a manner \n\tapproved by the \n\tprincipal operations \n\tinspector). \n\tA. Do an operational \n\tcheck of the APU fuel \n\tshutoff valve position \n\tindication. \n\t1. If the APU is running, \n\tunload and shut down the \n\tAPU using standard \n\tpractices. \n\t2. Supply electrical \n\tpower to the airplane \n\tusing standard \n\tpractices. \n\t3. Make sure the APU FIRE \n\tswitch on the Aft Aisle \n\tStand is in the NORMAL \n\t(IN) position. \n\t4. Make sure there is at \n\tleast 1,000 lbs (500 \n\tkgs) of fuel in the Left \n\tMain Tank. \n\t5. Move APU Selector \n\tswitch on the Overhead \n\tPanel to the ON position \n\tand wait approximately \n\t10 seconds once the APU \n\tselector switch on the \n\toverhead panel is in the \n\tON position. \n\t6. Move the APU Selector \n\tswitch on the Overhead \n\tPanel to the OFF \n\tposition. \n\n((Page 65126)) \n\n\n\n\n\t7. Verify the APU FAULT \n\tlight on the Overhead \n\tPanel illuminates and \n\tthen goes off. \n\t8. If the test fails \n\t(light fails to \n\tilluminate), before \n\tfurther flight requiring \n\tAPU availability, repair \n\tfaults as required \n\t(refer to Boeing AMM 28- \n\t25-02). \n\tNOTE: Dispatch may be \n\tpermitted per MMEL 28-25- \n\t02 if APU is not \n\trequired for flight. ---------------------------------------------------------------------------------------------------------------- \n\n(h) No Alternative Actions or Intervals \n\n\n\tAfter accomplishment of the maintenance or inspection program revision required by paragraph (g) of this AD, no alternative actions (e.g., inspections) or intervals may be used unless the actions or intervals are approved as an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (i)(1) of this AD. \n\n(i) Alternative Methods of Compliance (AMOCs) \n\n\n\t(1) The Manager, Seattle Aircraft Certification Office (ACO) FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the ACO, send it to the attention of the person identified in paragraph (j) of this AD. Information may be emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov. \n\t(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office. \n\n(j) Related Information \n\n\n\tFor more information about this AD, contact Rebel Nichols, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-6509; fax: 425-917-6590; email: rebel.nichols@faa.gov. \n\n(k) Material Incorporated by Reference \n\n\n\tNone.

Discussion \n\n\n\tOn September 7, 2015, we issued AD 2015-19-02, Amendment 39-18265 (80 FR 55512, September 16, 2015), for all The Boeing Company Model 767 airplanes. AD 2015-19-02 required revising the maintenance or inspection program to include new airworthiness limitations. AD 2015- 19-02 resulted from reports of latently failed fuel shutoff valves discovered during fuel filter replacement. We issued AD 2015-19-02 to detect and correct latent failures of the fuel shutoff valve to the engine and APU, which could result in the inability to shut off fuel to the engine and APU and, in case of certain fires, an uncontrollable fire that could lead to structural failure. \n\nActions Since AD 2015-19-02, Amendment 39-18265 (80 FR 55512, September 16, 2015), Was Issued \n\n\n\tSince we issued AD 2015-19-02, Amendment 39-18265 (80 FR 55512, September 16, 2015), we have determined that extraneous language was included in two locations of the text of the airworthiness limitations specified in AD 2015-19-02. In paragraph C.7.a. of the ''Description'' column of figure 1 to paragraph (g) of AD 2015-19-02, the text ''or the APU selector switch on the overhead panel is in the ON position'' is not relevant to the actions specified in that paragraph. In paragraph A.5. of the ''Description'' column of figure 3 to paragraph (g) of AD 2015-19-02, the text ''the FUEL CONTROL switch is in the RUN position or'' is not relevant to the actions specified in that paragraph. \n\tWe have determined that the language must be corrected to avoid any confusion in the paragraphs of the airworthiness limitation. We are issuing this AD to detect and correct latent failures of the fuel shutoff valve to the engine and APU, which could result in the inability to shut off fuel to the engine and APU and, in case of certain fires, an uncontrollable fire that could lead to structural failure. \n\nFAA's Determination \n\n\n\tWe are issuing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design. \n\nAD Requirements \n\n\n\tThis AD requires revising the maintenance or inspection program to include new airworthiness limitations. \n\nInterim Action \n\n\n\tWe consider this AD interim action. The manufacturer is currently developing a modification that will address the unsafe condition identified in this AD. Once this modification is developed, approved, and available, we might consider additional rulemaking. \n\nFAA's Justification and Determination of the Effective Date \n\n\n\tWe are superseding AD 2015-19-02, Amendment 39-18265 (80 FR 55512, September 16, 2015), to correct inaccurate terminology in the \n\n((Page 65122)) \n\n''Description'' column of figure 1 to paragraph (g) of AD 2015-19-02 and figure 3 to paragraph (g) of AD 2015-19-02. We have made no other changes to the requirements published in AD 2015-19-02. We have determinedthat the changes impose no additional burden on any operator. Therefore, we find that notice and opportunity for prior public comment are unnecessary and that good cause exists for making this amendment effective in less than 30 days. \n\nComments Invited \n\n\n\tThis AD is a final rule that involves requirements affecting flight safety, and we did not provide you with notice and an opportunity to provide your comments before it becomes effective. However, we invite you to send any written data, views, or arguments about this AD. Send your comments to an address listed under the ADDRESSES section. Include the Docket Number FAA-2015-4209 and Directorate Identifier 2015-NM-156- AD at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this AD. We will consider all comments received by the closing date and may amend this AD because of those comments. \n\tWe will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this AD. \n\nCosts of Compliance \n\n\n\tWe estimate that this AD affects 450 airplanes of U.S. registry. \n\tWe estimate the following costs to comply with this AD: \n\n\n\tEstimated Costs ---------------------------------------------------------------------------------------------------------------- \n\tCost per Cost on U.S. \n\tAction Labor cost Parts cost product operators ---------------------------------------------------------------------------------------------------------------- Incorporating Airworthiness Limitation 1 work-hour x $85 per $0 $85 $38,250 \n\thour = $85. ---------------------------------------------------------------------------------------------------------------- \n\nAuthority for This Rulemaking \n\n\n\tTitle 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority. \n\tWe are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, ''General requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. \n\nRegulatory Findings \n\n\n\tThis AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. \n\tFor the reasons discussed above, I certify that this AD: \n\t(1) Is not a ''significant regulatory action'' under Executive Order 12866, \n\t(2) Is not a ''significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), \n\t(3) Will not affect intrastate aviation in Alaska, and \n\t(4) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. \n\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.