# Lycoming Service Instruction 1009: Revision BF - Rights: © Avco Corporation. Filed by the FAA in regulations.gov docket FAA-2026-13797; AD 2026-22-13 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Lycoming Service Instruction 1009](https://openairdocs.org/service-documents/lycoming/si-1009.md) - Title as filed: Lycoming Service Instruction 1009BF - Pages: 10 - PDF: https://openairdocs.org/files/sha256/e1/d6/e1d693e6d6c0787c66750c1d6d9410dd49258a8a6cd78f6a8b2589f6baabbf23 - Page: https://openairdocs.org/service-documents/lycoming/si-1009/file/e1d693e6d6c0 ## Text Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 ISSUED REVISED PAGE NO. REVISION MO DAY YEAR MO DAY YEAR 1 of 8 BF 05 27 60 07 20 26 ©2026 by Lycoming. All Rights Reserved” Lycoming Engines is a division of Avco Corporation. 652 Oliver Street Williamsport, PA. 17701 U.S.A. Telephone +1 (877) 839-7878 (U.S. and Canada) Telephone +1 (570) 327-7222 (International) Fax +1 (570) 327-7101 Email Technicalsupport@lycoming.com www.lycoming.com DATE: July 20, 2026 Service Instruction No. 1009BF (Supersedes Service Instruction No. 1009BE) Engineering design data in this service document is FAA approved. SUBJECT: Time Between Overhaul (TBO) Schedules MODELS AFFECTED: Lycoming Engine Models Defined Herein except those affected by and not in compliance with AD 2012-19-01 REASON FOR REVISION: Removed language for Lycoming approved FAA-PMA parts. Removed the NOTICE regarding TBOs for engines used for crop dusting. Added ICA statement and first paragraph to page 1. Added language to subsection b. on page 1. Added CAUTION on page 2. Added language to CAUTION on page 2. Added language to CAUTION on page 3. Added columns to Table 1 and Table 2 for Factory New or Factory Rebuilt engines. Changed hours and notes for some engine models in Table 1 and Table 2. Added footnote for TEO-540-A1A, - C1A to Table 1. Revised Notes 6, 11 and 15. NOTICE: Incomplete review of all the information in this document can cause errors. Read the entire Service Instruction to make sure you have a complete understanding of the requirements. This Service Instruction provides Instructions for Continued Airworthiness (ICA). Engines and crankshafts affected by AD 2012-19-01 are required to have the crankshaft replaced at next overhaul, separation of the crankcase, or no later than 12 years from the time the affected crankshaft entered service in accordance with the current Air worthiness Directive (AD). Any engines that remain in-service and are affected by AD 2012-19-01 and not yet in compliance with AD 2012-19- 01 have the operating hour Time Between Overhaul (TBO) listed in the latest revision of Service Instruction No. 1596 u ntil the crankshaft is replaced. These engines have no TBO extensions until compliance with the AD is accomplished and are not eligible for the TBOs listed in this publication. This Service Instruction identifies the Calendar Time Period in years and the Operating Hour Time Period in hours of engine operation for the Time Between Overhaul for certified Lycoming engine models operated and maintained in compliance with all applicable Lycoming Technical Publications and FAA Airworthiness Directives. The TBOs and TBO Extensions stated in this Service Instruction do not apply to engines that: a. Do not conform to the original engine model type certificate configuration. SERVICE INSTRUCTION ### Page 2 ISSUED REVISED PAGE NO. REVISION S.I. 1009MO DAY YEAR MO DAY YEAR 2 of 8 BF 05 27 60 07 20 26 b. Have been assembled, repaired, or overhauled with parts other than genuine Lycoming parts or parts specifically identified in the type certificate data sheet or applicable Lycoming Service Documents for the engine model. c. Have been maintained or overhauled using methods other than Lycoming approved procedures. or d. Have been operated outside Lycoming’s published specifications. CAUTION REPAIR OR MODIFICATION OF ENGINES USING PARTS OR PROCEDURES NOT APPROVED BY LYCOMING CAN DAMAGE OR AFFECT THE DURABILITY, SAFETY, AND RELIABILITY OF THE ENGINE. AS A RESULT, SERVICE LIFE CANNOT BE PREDICTED FOR ENGINES THAT HAVE UNDERGONE UNAPPROVED REPAIR OR MODIFICATION. CAUTION THE USE OF PARTS, COMPONENTS, FUELS OR LUBRICANTS THAT ARE NOT APPROVED BY LYCOMING ENGINES IS DONE SOLELY AT YOUR OWN RISK AND MAY RESULT IN YOUR ENGINE’S WARRANTY BEING VOIDED . FAA-PMA PARTS OR FAA-STC FUELS OR LUBRICANTS ARE APPROVED BY THE FEDERAL AVIATION ADMINSTRATION AND NOT BY LYCOMING ENGINES. Engine accessories and propellers can require overhaul prior to engine overhaul. TBO extensions authorized by this Service Instruction do not alter any engine accessory or propeller manufacturer’s recommended overhaul schedule. Overhaul accessories and propellers in accordance with the appropriate manufacturer’s recommendation. The information in this revision of Service Instruction No. SI-1009 is approved by the FAA as an Alternative Method of Compliance (AMOC) for AD-2012-19-01, paragraphs (f)(1)(i) and (f)(2)(i). This Service Instruction is based on the engine being active in a 30-day period. If it is known that an engine is to remain inactive for 30 or more days, refer to the latest revision of Service Letter L180. CALENDAR TIME PERIOD TBO All engine models are to be overhauled within twelve (12) calendar years of the date they first entered service or of last overhaul. This calendar year time period TBO is to mitigate engine deterioration that occurs with age, including corrosion of metallic components and degradation of non -metallic components such as gaskets, seals, flexible hoses and fuel pump diaphragms. CAUTION CALENDAR YEAR TBO IS BASED ON ACCELERATED TESTING AND OVERALL FLEET SERVICE DATA. LOCAL CLIMATE CONDITIONS, STORAGE CONDITIONS, FREQUENT EXTENDED PERIODS OF INACTIVITY, PRESERVATION TECHNIQUES USED DURING INACTIVE PERIODS, AND FREQUENCY OF OIL CHANGES CAN AFFECT CORROSION OF METALS AND DEGRADATION OF NON-METALS AND MAY RESULT IN A REDUCED TBO. ### Page 3 ISSUED REVISED PAGE NO. REVISION S.I. 1009MO DAY YEAR MO DAY YEAR 3 of 8 BF 05 27 60 07 20 26 For FAA Part 91 or EASA Part NCO (non-commercial) or equivalent operations, only an appropriately rated and qualified maintenance person (or international equivalent) can allow the twelve (12) calendar year TBO to be exceeded with concurrence from the controlling civil aviation authority to verify agreement with this provision and after thoroughly examining the engine for corrosion and degradation in accordance with 14 CFR 43 Appendix D (or international equivalent) and determining that the engine remains in an airworthy condition. This inspection is to be repeated annually or as necessary to ensure continued airworthiness. The twelve (12) calendar year TBO must not be exceeded if the engine is affected by AD 2012-19-01 and not in compliance with AD 2012-19-01. WARNING OPERATION OF AN ENGINE IN A NON -AIRWORTHY CONDITION COULD RESULT IN LOSS OF LIFE, SERIOUS INJURY, AND DAMAGE TO PROPERTY. ENGINES ARE NOT TO BE OPERATED BEYOND 12 YEARS UNLESS CERTIFIED AS AIRWORTHY BY QUALIFIED MAINTENANCE PERSONNEL. ENGINES THAT FAIL TO OPERATE WITHIN LYCOMING'S PUBLISHED OPERATING SPECIFICATIONS OR THAT SHOW ANY EVIDENCE OF CORROSION, WEAR, DAMAGE, OR OTHER CONDITION AFFECTING AIRWORTHINESS MUST BE IMMEDIATELY REMOVED FROM SERVICE AND OVERHAUL ED PER LYCOMING TECHNICAL PUBLICATIONS. OPERATING HOUR TIME PERIOD TBO Operating Hour TBOs for fixed wing aircraft are in Table 1 and rotary wing aircraft are in Table 2. These TBOs are to mitigate engine deterioration that occurs during normal operation such as wear and high cycle fatigue of metallic components. CAUTION OPERATING HOUR TBOS ARE BASED ON ACCELERATED TESTING AND OVERALL FLEET SERVICE DATA. BECAUSE OF VARIATIONS IN THE MANNER IN WHICH ENGINES ARE OPERATED AND MAINTAINED, AS WELL AS THE TYPE OR ENVIRONMENT OF OPERATION SUCH AS AEROBATICS OR AGRICULTURAL CROP DUSTING OR OTHER AERIAL CHEMICAL APPLICATION, LYCOMING CANNOT GIVE ASSURANCE THAT ANY INDIVIDUAL OPERATOR WILL ACHIEVE THE OPERATING HOUR TBOS IDENTIFIED HEREIN. ON-CONDITION INSPECTION BY THE OPERATOR IS MANDATORY TO ASSESS AND DETERMINE THE HEALTH AND CONTINUED AIRWORTHINESS OF THE ENGINE. Tables 1-2 have references to the NOTES at the end of this Service Instruction with specific information regarding the engine overhaul intervals. Engine operating hours will be monitored and recorded using the same procedure or method that the airframe manufacturer or operator has chosen to monitor Time in Service for maintenance time records in accordance with 14 CFR 1.1 or its international equivalent. Factory New/Rebuilt – Applies to the first overhaul cycle of engines following delivery of a factory-new or factory-rebuilt Lycoming engine. Overhaul – Applies to all engines overhauled either by Lycoming Engines or by a third -party maintenance provider. ### Page 4 ISSUED REVISED PAGE NO. REVISION S.I. 1009MO DAY YEAR MO DAY YEAR 4 of 8 BF 05 27 60 07 20 26 Table 1 Fixed Wing Aircraft Operating Hour Time Between Overhaul Periods Engine Models/Series Factory New/Rebuilt Overhaul Hours See Note Hours See Note O-235 (except -F, -G, -J) 2400 -------- 2400 12 O-235-F, -G, -J 2000 -------- 2000 13 O-290-D 2000 -------- 2000 -------- O-290-D2 1500 -------- 1500 -------- O-320 (except O-320-H) 2600 10 2000 1,10,11,15,16 O-320-H 2400 -------- 2400 -------- IO-320-A, -E 2600 10 2000 1,10,11,15,16 IO-320-B, -D, -F 2600 4,10 2000 4,10,11,15,16 IO-320-C 1800 2,4,10,11 1800 2,4,10,11 AIO-320 (160 HP) 1600 6 1600 6 AEIO-320 2000 6 2000 6 O-340 2000 --------- 2000 1 O-360 (except O-360-E) 2600 4,10 2000 1,4,10,11,15,16 O-360-E 2000 4,11 2000 4,11 IO-360-L2A 2600 --------- 2000 11,15,16 IO-360-A, -C, -D, -J (200 HP) 2600 4,10 2000 4,5,10,11,15,16 IO-360-B, -E, -F, -M, -N, -P (180 HP) 2600 4,10 2000 1,4,10,11,15,16 TO-360-C, -F; TIO-360-C 1800 3,11 1800 3,11 TO-360-E (180 HP) 1800 3,4,11 1800 3,4,11 AIO-360 (200 HP) 1400 6 1400 6 TIO-360-A 1200 3,11 1200 3,11 AEIO-360 (180 HP) 2000 6 2000 6 AEIO-360 (200 HP) 2000 6 2000 6 IO-390-A, -C, -D 2600 -------- 2000 11,15,16 AEIO-390-A 2000 6 2000 6 O-435; GO-435 1200 -------- 1200 -------- GO, GSO-480; IGSO-480 1400 --------- 1400 1 O-540-A, -B, -E4A5 2600 10 2000 1,10,15 O-540-E4B5, -E4C5 2600 --------- 2000 1,11,15,16 O-540-G, -H, -J 2600 10 2000 10,11,15,16 O-540-L3C5D 2000 2,11 2000 2,11 IO-540-A, -B (290 HP) 1400 10,11 1400 1,10,11 IO-540-AG1A5 1800 -------- 1800 -------- IO-540-C 2600 10 2000 1,10,11,15,16 IO-540-D 2600 10 2000 1,10,15, ### Page 5 ISSUED REVISED PAGE NO. REVISION S.I. 1009 MO DAY YEAR MO DAY YEAR 5 of 8 BF 05 27 60 07 20 26 Table 1 (Cont.) Fixed Wing Aircraft Operating Hour Time Between Overhaul Periods Engine Models/Series Factory New/Rebuilt Overhaul Hours See Note Hours See Note IO-540-E, -G, -P 1600 10,11 1600 1,10,11 IO-540-S, -AA 1800 2,10 1800 2,10 IO-540-J, -R 1800 2,10 1800 2,10 IO-540-J4A5 2000 10 2000 10 IO-540-AB1A5, -AC1A5, -AF1A5 2600 -------- 2000 11,15,16 IO-540-K, -L, -M, -N, -T, -V, -W 2600 10 2000 10,11,15,16 AEIO-540 2000 6 2000 6 IGO & IGSO-540 1200 -------- 1200 -------- TIO-540-V, -W, -AE 2000 3,4,11 2000 3,4,11 TIO-540-C, -AA, -AB, -AF, -AG, -AH, -AJ, -AK 2000 3,4,11 2000 3,4,7,11 TIO-540-A, -F, -J, -N, -R, -S, -U 1800 3,4,11 1800 3,4,11,14 TIO-541-A (320 HP) 1300 3 1300 3 TIO-541-E (380 HP) 1600 3 1600 3,9 TIGO-541 (425 HP) 1200 3 1200 3 IO-580-B1A 2600 -------- 2000 11,15,16 AEIO-580-B1A 2000 6 2000 6 IO-720 1800 11 1800 11 TEO-540-A1A, -C1A* 2000 3,4,11 2000 3,4,11 * ECU, APU, and ADL installed on TEO-540-A1A, -C1A engines are On-Condition units. Table 2 Rotary Wing Aircraft Operating Hour Time Between Overhaul Periods Engine Models/Series Factory New/Rebuilt Overhaul Hours See Note Hours See Note O-320-A2C, -B2C 2500 -------- 2000 11,15,16 HO-360-C1A 2000 11 2000 11 O-360-C2B,-C2D; HO-360 (except –C1A); HIO-360-B 1500 -------- 1500 -------- O-360-J2A 2500 -------- 2000 11,15,16 HIO-360-A, -C, -D, -E, -F 1500 -------- 1500 -------- HIO-360-G1A 2000 11 2000 11 VO-360-A 600 -------- 600 -------- VO-360-B; IVO-360 1000 -------- 1000 -------- HIO-390-A1A 2500 -------- 2000 11,15,16 VO-435-A 1200 -------- 1200 -------- ### Page 6 ISSUED REVISED PAGE NO. REVISION S.I. 1009 MO DAY YEAR MO DAY YEAR 6 of 8 BF 05 27 60 07 20 26 Table 2 (Cont.) Rotary Wing Aircraft Operating Hour Time Between Overhaul Periods Engine Models/Series Factory New/Rebuilt Overhaul Hours See Note Hours See Note VO-435-B 1200 -------- 1200 -------- TVO-435 1000 3 1000 3 O-540-F1B5 (Robinson R44) 2500 -------- 2000 11,15,16 O-540-F1B5 (Robinson R44 CADET) 2500 -------- 2200 15 IO-540-AE1A5 2500 -------- 2000 11,15,16 VO-540 1200 -------- 1200 8 IVO-540 600 -------- 600 -------- TVO, TIVO-540 1200 3 1200 3,8 NOTES 1. Only engines built with 1/2 in. (12.7 mm) dia. exhaust valve stems. Engines of this series with 7/16 in. (11.1 mm) dia. exhaust valves must not exceed 1200 hours between overhauls regardless of the type of operation. New and rebuilt engines built with 1/2 in. (12.7 mm) dia. exhaust valve stems are identified, respectively, by serial numbers and date in the latest revision of Service Instruction No. 1136. 2. These engines are designed to incorporate exhaust turbocharging. 3. Turbochargers could require removal, prior to engine overhaul, for carbon removal and repair. 4. Engines with reverse rotation have same overhaul times as corresponding normal rotation engines. 5. 1200 HOURS: Engines that do not have large main bearing dowels must not be operated more than 1200 hours between overhauls. 1400 HOURS: Engines that have large main bearing dowels can be operated to 1400 hours between overhauls. These include engines with serial numbers L -7100-51A and up, and L -101-67A and up; engines which are in compliance with the latest revision of Service Bulletin No. 326; and remanufactured engines shipped after January 26, 1970. 2000 HOURS: Engines that have large main bearing dowels and redesigned camshafts can be operated to 2000 hours between overhauls. These include engines with serial numbers L -9762-51A and up; IO-360-C1E6 engines with serial numbers L-9723-51A and up; LIO-360-C1E6 engines with serial numbers L-524-67A and up; engines that are in compliance with the latest revision of Service Bulletin No. 326 and Service Instruction No. 1263. Rebuilt engines shipped after October 1, 1972, can be operated to 2000 hours between overhauls except those with serial numbers L -2349-51A and L - 7852-51A which do not have the redesigned camshaft and must not exceed 1400 hours of operating time between overhauls. ### Page 7 ISSUED REVISED PAGE NO. REVISION S.I. 1009 MO DAY YEAR MO DAY YEAR 7 of 8 BF 05 27 60 07 20 26 6. The reliability and service life of engines can be detrimentally affected if they are repeatedly operated at alternating high and low power applications which cause extreme changes in cylinder temperatures. Flight maneuvers which cause engine overspeed and/or significant fluctuations in oil pressure also contribute to abnormal wear characteristics that tend to shorten engine life. These factors must be considered to establish TBO of aerobatic engines; therefore, it is the responsibility of the operator to determine the percentage of time their engine is used for aerobatics and establish TBO for their engine. On-condition inspection is mandatory to assess and determine the health and continued airworthiness of the engine. The maximum TBO is the time specified in this instruction. 7. TIO-540-C Series engines with serial numbers L-1754-61 and up, TIO-540-C Series engines that were rebuilt or overhauled at Lycoming Engines, Williamsport, PA after March 1, 1971 , and TIO-540-C series engines that have been modified to incorporate large main bearing dowels as described in the latest revision of Service Instruction No. 1225 can be operated to 2000 hours. Engines that do not incorporate this modification must not exceed 1500 hours between overhauls. 8. VO, TVO and TIVO -540 engines built with P/N 77450 connecting rods as described in the latest revision of Service Bulletin No. 371 can be continued in service to 1200 hours. Engines that do not incorporate this new connecting rod are restricted to 1000 hours for VO-540 models and 900 hours for TVO and TIVO-540. See the latest revision of Service Bulletin No. 371 for improved connecting rod assembly. 9. TIO-541-E series engines with serial numbers L -804-59 and up, rebuilt engines shipped after March 1, 1976, and all engines that incorporate the improved crankcases and cylinder assemblies described in the latest revision to Service Bulletin Nos. 334 and 353 can be operated for 1600 hours before overhaul. Engines not in compliance with these requirements are limited to a 1200-hour TBO. 10. Some engines in the field have been altered to incorporate an inverted oil system in order to perform aerobatic maneuvers. Whenever this modification is done to an engine, the TBO of the engine must be determined in the same manner listed for AEIO engines of the same model series. See Note 6. 11. If an engine is being used in “frequent” type service, by accumulating a minimum total of 120 hours in every rolling 90-day period since being placed into service, with no individual 30-day period having less than 20 hours of operation, add 200 hours to TBO time. 12. To qualify for the 2400 hour TBO, high-compression, O-235 engines must have the increased strength pistons (P/N LW-18729). See the latest revision of Service Letter No. L213. 13. The high-compression O-235-F, -G and -J series do not have the increased-strength pistons (P/N LW- 18729); therefore, they do not qualify for the 2400 hour TBO. 14. TIO-540-A series engines with serial numbers L-1880-61 and up, TIO-540-A series engines that were rebuilt or overhauled at Lycoming Engines, Williamsport, PA after March 1, 1971 , and TIO-540-A series engines that have been modified to incorporate large main bearing dowels as described in the latest revision of Service Instruction No. 1225 can be operated to 1800 hours. Engines that do not incorporate this modification must not exceed 1500 hours between overhauls. ### Page 8 ISSUED REVISED PAGE NO. REVISION S.I. 1009 MO DAY YEAR MO DAY YEAR 8 of 8 BF 05 27 60 07 20 26 15. A 200-hour extension to the listed TBO can be applied to Lycoming Factory Overhauled engine models. Engine repairs or field overhauls that are performed by any entity other than the Lycoming Factory in Williamsport PA must meet all of the following requirements to be eligible for this 200 - hour TBO extension: a. Be performed using ONLY Lycoming genuine parts and parts expressly listed in the engine type certificate data sheet or applicable Lycoming Service Documents. b. Be performed using ONLY Lycoming approved procedures. c. Block 12 of FAA form 8130 -3 or international equivalent must indicate the repair or overhaul was performed using ONLY Lycoming approved procedures and Lycoming genuine parts and/or parts expressly listed on the type certificate data sheet or applicable Lycoming Service Documents. A repair or overhaul performed using any FAA approved local shop procedures or using FAA-PMA parts not approved by Lycoming is not eligible for this 200-hour TBO. 16. When NOTE 15 is referenced with NOTE 11 for engine models in Tables 1 and 2, and the conditions of both NOTES are met, the sum of the extended TBO hours in both NOTES 11 and 15 can be added to the required TBO, thus extending the TBO a total of 400 hours. ### Page 9 Aviation Safety Date: May 29, 2026 Letter Number: 755-26-00281 Ms. Marian Folk Lycoming TC ODA Administrator Lycoming Principal Engineering Consultant Lycoming Engines 652 Oliver Street Williamsport, PA 17701 Subject: Request for Global Alternate Means of Compliance (AMOC), Against FAA AD 2012-19-01 (AMOC Log # 26-15, WTS # 26-DOC-06422) References: 1 – FAA AD 2012-19-01 2 – SI No. 1009BF, Time Between Overhaul (TBO) Schedules, dated July 20, 2026 3 – SI No. 1596, Rev --, Recommended Time Between Overhaul Periods for Engines Affected by and Not in Compliance with AD 2012-19-01, dated July 20, 2026 Dear Ms. Folk: The Federal Aviation Administration (FAA) has received your proposal for a global AMOC to AD 2012-19-01, dated April 28, 2026, to allow the use of Lycoming Service Instruction (SI) 1596, Rev --, dated July 20, 2026, in place of paragraphs (f)(1)(i) and (f)(2)(i). Paragraphs (f)(1)(i) and (f)(2)(i) of AD 2012-19-01 require replacing an affected crankshaft at the time of the next overhaul as specified in Lycoming Service Instruction No. 1009AU, dated November 18, 2009. Lycoming Engines SI 1596, dated July 20, 2026, lists the operating hour time before overhaul (TBO) for engines affected by and not in compliance with AD 2012-19-01. These engines have no TBO extensions until compliance with the AD is accomplished and are not eligible for the TBOs listed in Lycoming Engines SI 1009BF, dated July 20, 2026. There are notes in each SI making this clear to operators. The East Certification Branch approves Lycoming Engines SI 1596, Revision --, dated July 20, 2026, as an AMOC to paragraphs (f)(1)(i) and (f)(2)(i), of AD 2012-19-01. In accordance with FAA Order 8110.103C, dated May 11, 2026, the following conditions apply: East Certification Branch 1701 Columbia Ave. College Park, Georgia 30337 ### Page 10 2 1. All provisions of AD 2012-19-01 that have not been specifically referenced above remain fully applicable and must be complied with accordingly. 2. This approval is transferable with engine(s) to other operators. 3. Before using this AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office. The preceding paragraph also applies to any applicable foreign-registered aircraft upon transfer of the aircraft to the U.S. registry if compliance with the AMOC has not been accomplished. 4. This AMOC only applies to the FAA AD listed above. The FAA does not have the authority to approve this as an AMOC to any AD issued by another civil aviation authority (CAA). Approval of an AMOC to another CAA’s AD must come from that CAA. If you have any questions or need additional information, please contact Mr. David Bergeron, Aerospace Engineer, AIR-755, by telephone at 860-386-1805 or electronic mail at david.j.bergeron@faa.gov. Sincerely, KRISTOPHER GREER for: Michael Linegang Digitally signed by KRISTOPHER GREER Date: 2026.06.03 09:34:04 -04'00' Manager, East Certification Branch Compliance & Airworthiness Division Aircraft Certification Service cc: Ron Coleman, AFS-150, Propulsion Systems Branch --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain, except the copies of manufacturers’ service documents, which belong to their rights holders.