FAA orders · airworthiness directive · current

90-04-06 R1: Propeller Governor External Oil Line

FAA order 90-04-06 R1 is an airworthiness directive in force since May 28, 1991. The FAA's subject line: Propeller Governor External Oil Line. It names the Lycoming AEIO-320-D1B, Lycoming AEIO-320-E1B, Lycoming AEIO-320-E2B, Lycoming AEIO-320 series, Lycoming AEIO-360-A1A, Lycoming AEIO-360-A1B, Lycoming AEIO-360-A1B6, Lycoming AEIO-360-A1D, Lycoming AEIO-360-A1E, Lycoming AEIO-360-A2C, Lycoming AEIO-360-B1B, Lycoming AEIO-360-B1F, Lycoming AEIO-360-B1G6, Lycoming AEIO-360-B2F, Lycoming AEIO-360-B4A, Lycoming AEIO-360-H1A, Lycoming AEIO-360 series, Lycoming GO-435, Lycoming GO-435-C2A, Lycoming GO-435-C2A2, Lycoming GO-435-C2B, Lycoming GO-435-C2B2, Lycoming GO-435C&D series, Lycoming GO-480-B, Lycoming GO-480-B1A6, Lycoming GO-480-B1D, Lycoming GO-480-F4A6, Lycoming GO-480-G1A6, Lycoming GO-480-G1B6, Lycoming GO-480-G1D6, Lycoming GO-480-G2D6, Lycoming GO-480-G2F6, Lycoming GO-480 series, Lycoming GSO-435 SERIE, Lycoming GSO-480-B1B3, Lycoming GSO-480-B1J6, Lycoming HIO-360-A1A, Lycoming HIO-360-B1A, Lycoming HIO-360-B1B, Lycoming HIO-360-C1A, Lycoming HIO-360-C1B, Lycoming HIO-360-D1A, Lycoming HIO-360-E1AD, Lycoming HIO-360-E1BD, Lycoming HIO-360-F1AD, Lycoming HO-360, Lycoming HO-360-B1B, Lycoming IGO-480, Lycoming IGSO-480-A1E6, Lycoming IO-320-A1A, Lycoming IO-320-B1A, Lycoming IO-320-B1C, Lycoming IO-320-B2A, Lycoming IO-320-C1A, Lycoming IO-320-D1A, Lycoming IO-320-D1B, Lycoming IO-320-E1A, Lycoming IO-320-E1B, Lycoming IO-320-E2A, Lycoming IO-320-E2B, Lycoming IO-320 series, Lycoming IO-360-A1A, Lycoming IO-360-A1B, Lycoming IO-360-A1B6, Lycoming IO-360-A1B6D, Lycoming IO-360-A1D, Lycoming IO-360-A1D6, Lycoming IO-360-A1D6D, Lycoming IO-360-A2B, Lycoming IO-360-A3B6D, Lycoming IO-360-A3D6D, Lycoming IO-360-B1A, Lycoming IO-360-B1B, Lycoming IO-360-B1C, Lycoming IO-360-B1D, Lycoming IO-360-B1E, Lycoming IO-360-B1F, Lycoming IO-360-B1F6, Lycoming IO-360-B2E, Lycoming IO-360-B2F, Lycoming IO-360-B4A, Lycoming IO-360-C1A, Lycoming IO-360-C1C, Lycoming IO-360-C1C6, Lycoming IO-360-C1D6, Lycoming IO-360-C1E6, Lycoming IO-360-C1F, Lycoming IO-360-D1A, Lycoming IO-360-E1A, Lycoming IO-360-F1A, Lycoming IO-360 series, Lycoming IVO-360-A1A, Lycoming LIO-320-C1A, Lycoming LIO-360-C1E6, Lycoming LO-360-A1G6D, Lycoming LO-360-A1H6, Lycoming LO-360-E1AD, Lycoming LTO-360-E1A6D, Lycoming O-145-B2, Lycoming O-145B series, Lycoming O-233, Lycoming O-235, Lycoming O-235-C, Lycoming O-235-C1, Lycoming O-235-C1A, Lycoming O-235-C1B, Lycoming O-235-C2C, Lycoming O-235-E1, Lycoming O-235-F2B, Lycoming O-235-J2B, Lycoming O-235-K2C, Lycoming O-235-L2A, Lycoming O-235-L2C, Lycoming O-235-N2A, Lycoming O-235 series, Lycoming O-290, Lycoming O-290-C, Lycoming O-290-D, Lycoming O-290-D2, Lycoming O-290-D2B, Lycoming O-290 series, Lycoming O-320-A1A, Lycoming O-320-A1B, Lycoming O-320-A2A, Lycoming O-320-A2B, Lycoming O-320-A2C, Lycoming O-320-A2D, Lycoming O-320-A3A, Lycoming O-320-A3B, Lycoming O-320-A3C, Lycoming O-320-B1A, Lycoming O-320-B1B, Lycoming O-320-B2A, Lycoming O-320-B2B, Lycoming O-320-B2C, Lycoming O-320-B3B, Lycoming O-320-C1A, Lycoming O-320-C2A, Lycoming O-320-C3B, Lycoming O-320-D1A, Lycoming O-320-D1D, Lycoming O-320-D1F, Lycoming O-320-D2A, Lycoming O-320-D2B, Lycoming O-320-D2C, Lycoming O-320-D2G, Lycoming O-320-D2J, Lycoming O-320-D3G, Lycoming O-320-E1A, Lycoming O-320-E1F, Lycoming O-320-E2A, Lycoming O-320-E2B, Lycoming O-320-E2C, Lycoming O-320-E2D, Lycoming O-320-E2G, Lycoming O-320-E3D, Lycoming O-320-E3H, Lycoming O-320-H2AD, Lycoming O-320 series, Lycoming O-340-A1A, Lycoming O-340-B1A, Lycoming O-340 series, Lycoming O-350, Lycoming O-350 series, Lycoming O-360-A1A, Lycoming O-360-A1AD, Lycoming O-360-A1D, Lycoming O-360-A1F, Lycoming O-360-A1F6, Lycoming O-360-A1F6D, Lycoming O-360-A1G, Lycoming O-360-A1G6, Lycoming O-360-A1G6D, Lycoming O-360-A1H, Lycoming O-360-A1H6, Lycoming O-360-A1LD, Lycoming O-360-A2A, Lycoming O-360-A2D, Lycoming O-360-A2F, Lycoming O-360-A2G, Lycoming O-360-A3A, Lycoming O-360-A4A, Lycoming O-360-A4G, Lycoming O-360-A4K, Lycoming O-360-A4M, Lycoming O-360-B1A, Lycoming O-360-B1B, Lycoming O-360-B2A, Lycoming O-360-C1A, Lycoming O-360-C1E, Lycoming O-360-C1F, Lycoming O-360-C1G, Lycoming O-360-C2A, Lycoming O-360-C2C, Lycoming O-360-C2D, Lycoming O-360-C2E, Lycoming O-360-D1A, Lycoming O-360-D2A, Lycoming O-360-E1A6D, Lycoming O-360-F1A6, Lycoming O-360-G1A6, Lycoming O-360 series, Lycoming O-435, Lycoming O-435A/O-435C, Lycoming O235N2C, Lycoming R-680E1, Lycoming R680, Lycoming R680E series, Lycoming R680E3A, Lycoming R680E3B, Lycoming TIO-360-C1A6D, Lycoming TIO-360 series, Lycoming TO-360-A1A6D, Lycoming TO-360-C1A6D, Lycoming TO-360-E1A6D, Lycoming TO-360 series, Lycoming TVO-435-A1A, Lycoming TVO-435-D1A, Lycoming TVO-435-F1A, Lycoming TVO-435-G1A, Lycoming TVO-435-GIA, Lycoming VO-435-A1F, Lycoming VO-435-B1A, Lycoming VO-435 series engines: about 58,241 aircraft on the U.S. register today across them, though an order usually covers particular versions or serial numbers rather than every one. System: engine.

What it applies to as the FAA lists it

Kind of product: Engine
Makes: Lycoming Engines; Textron Lycoming, AVCO Corporation
Models: AEIO-320-D1B, AEIO-320-D2B, AEIO-320-E1A, AEIO-320-E1B, AEIO-320-E2A, AEIO-320-E2B, AEIO-360-A1A, AEIO-360-A1B, AEIO-360-A1B6, AEIO-360-A1C, AEIO-360-A1D, AEIO-360-A1E, AEIO-360-A2A, AEIO-360-A2B, AEIO-360-A2C, AEIO-360-B1B, AEIO-360-B1D, AEIO-360-B1F, AEIO-360-B1F6, AEIO-360-B1G6, AEIO-360-B2F, AEIO-360-B2F6, AEIO-360-B4A, AEIO-360-H1A, AIO-320-A1A, AIO-320-A1B, AIO-320-A2A, AIO-320-A2B, AIO-320-B1B, AIO-320-C1B, AIO-360-A1A, AIO-360-A1B, AIO-360-A2A, AIO-360-A2B, AIO-360-B1B, GO-435, GO-435-C2 (O-435-17), GO-435-C2A, GO-435-C2A2, GO-435-C2B, GO-435-C2B1, GO-435-C2B2, GO-435-C2C,...
Engine series: Lycoming AEIO-320-D1B 2 aircraft
Lycoming AEIO-320-E1B 6 aircraft
Lycoming AEIO-320-E2B 6 aircraft
Lycoming AEIO-320 series 74 aircraft
Lycoming AEIO-360-A1A 3 aircraft
Lycoming AEIO-360-A1B 1 aircraft
Lycoming AEIO-360-A1B6 11 aircraft
Lycoming AEIO-360-A1D 15 aircraft
Lycoming AEIO-360-A1E 11 aircraft
Lycoming AEIO-360-A2C 1 aircraft
Lycoming AEIO-360-B1B 2 aircraft
Lycoming AEIO-360-B1F 4 aircraft
Lycoming AEIO-360-B1G6 22 aircraft
Lycoming AEIO-360-B2F 7 aircraft
Lycoming AEIO-360-B4A 5 aircraft
Lycoming AEIO-360-H1A 8 aircraft
Lycoming AEIO-360 series 883 aircraft
Lycoming GO-435 33 aircraft
Lycoming GO-435-C2A 2 aircraft
Lycoming GO-435-C2A2 5 aircraft
Lycoming GO-435-C2B 1 aircraft
Lycoming GO-435-C2B2 5 aircraft
Lycoming GO-435C&D series 130 aircraft
Lycoming GO-480-B 1 aircraft
Lycoming GO-480-B1A6 10 aircraft
Lycoming GO-480-B1D 1 aircraft
Lycoming GO-480-F4A6 1 aircraft
Lycoming GO-480-G1A6 1 aircraft
Lycoming GO-480-G1B6 1 aircraft
Lycoming GO-480-G1D6 7 aircraft
Lycoming GO-480-G2D6 3 aircraft
Lycoming GO-480-G2F6 1 aircraft
Lycoming GO-480 series 246 aircraft
Lycoming GSO-435 SERIE 7 aircraft
Lycoming GSO-480-B1B3 1 aircraft
Lycoming GSO-480-B1J6 3 aircraft
Lycoming HIO-360-A1A 5 aircraft
Lycoming HIO-360-B1A 16 aircraft
Lycoming HIO-360-B1B 2 aircraft
Lycoming HIO-360-C1A 6 aircraft
Lycoming HIO-360-C1B 1 aircraft
Lycoming HIO-360-D1A 41 aircraft
Lycoming HIO-360-E1AD 9 aircraft
Lycoming HIO-360-E1BD 3 aircraft
Lycoming HIO-360-F1AD 33 aircraft
Lycoming HO-360 74 aircraft
Lycoming HO-360-B1B 2 aircraft
Lycoming IGO-480 1 aircraft
Lycoming IGSO-480-A1E6 1 aircraft
Lycoming IO-320-A1A 2 aircraft
Lycoming IO-320-B1A 55 aircraft
Lycoming IO-320-B1C 2 aircraft
Lycoming IO-320-B2A 1 aircraft
Lycoming IO-320-C1A 7 aircraft
Lycoming IO-320-D1A 57 aircraft
Lycoming IO-320-D1B 6 aircraft
Lycoming IO-320-E1A 3 aircraft
Lycoming IO-320-E1B 3 aircraft
Lycoming IO-320-E2A 11 aircraft
Lycoming IO-320-E2B 4 aircraft
Lycoming IO-320 series 1,707 aircraft
Lycoming IO-360-A1A 195 aircraft
Lycoming IO-360-A1B 52 aircraft
Lycoming IO-360-A1B6 141 aircraft
Lycoming IO-360-A1B6D 844 aircraft
Lycoming IO-360-A1D 15 aircraft
Lycoming IO-360-A1D6 191 aircraft
Lycoming IO-360-A1D6D 3 aircraft
Lycoming IO-360-A2B 2 aircraft
Lycoming IO-360-A3B6D 74 aircraft
Lycoming IO-360-A3D6D 1 aircraft
Lycoming IO-360-B1A 49 aircraft
Lycoming IO-360-B1B 67 aircraft
Lycoming IO-360-B1C 6 aircraft
Lycoming IO-360-B1D 2 aircraft
Lycoming IO-360-B1E 184 aircraft
Lycoming IO-360-B1F 8 aircraft
Lycoming IO-360-B1F6 3 aircraft
Lycoming IO-360-B2E 3 aircraft
Lycoming IO-360-B2F 1 aircraft
Lycoming IO-360-B4A 969 aircraft
Lycoming IO-360-C1A 7 aircraft
Lycoming IO-360-C1C 45 aircraft
Lycoming IO-360-C1C6 64 aircraft
Lycoming IO-360-C1D6 14 aircraft
Lycoming IO-360-C1E6 43 aircraft
Lycoming IO-360-C1F 2 aircraft
Lycoming IO-360-D1A 4 aircraft
Lycoming IO-360-E1A 3 aircraft
Lycoming IO-360-F1A 3 aircraft
Lycoming IO-360 series 8,560 aircraft
Lycoming IVO-360-A1A 2 aircraft
Lycoming LIO-320-C1A 1 aircraft
Lycoming LIO-360-C1E6 6 aircraft
Lycoming LO-360-A1G6D 3 aircraft
Lycoming LO-360-A1H6 9 aircraft
Lycoming LO-360-E1AD 1 aircraft
Lycoming LTO-360-E1A6D 1 aircraft
Lycoming O-145-B2 5 aircraft
Lycoming O-145B series 538 aircraft
Lycoming O-233 6 aircraft
Lycoming O-235 14 aircraft
Lycoming O-235-C 31 aircraft
Lycoming O-235-C1 49 aircraft
Lycoming O-235-C1A 2 aircraft
Lycoming O-235-C1B 20 aircraft
Lycoming O-235-C2C 29 aircraft
Lycoming O-235-E1 1 aircraft
Lycoming O-235-F2B 1 aircraft
Lycoming O-235-J2B 1 aircraft
Lycoming O-235-K2C 13 aircraft
Lycoming O-235-L2A 2 aircraft
Lycoming O-235-L2C 84 aircraft
Lycoming O-235-N2A 2 aircraft
Lycoming O-235 series 6,134 aircraft
Lycoming O-290 46 aircraft
Lycoming O-290-C 1 aircraft
Lycoming O-290-D 45 aircraft
Lycoming O-290-D2 59 aircraft
Lycoming O-290-D2B 6 aircraft
Lycoming O-290 series 2,125 aircraft
Lycoming O-320-A1A 20 aircraft
Lycoming O-320-A1B 2 aircraft
Lycoming O-320-A2A 9 aircraft
Lycoming O-320-A2B 180 aircraft
Lycoming O-320-A2C 1 aircraft
Lycoming O-320-A2D 13 aircraft
Lycoming O-320-A3A 5 aircraft
Lycoming O-320-A3B 12 aircraft
Lycoming O-320-A3C 1 aircraft
Lycoming O-320-B1A 17 aircraft
Lycoming O-320-B1B 3 aircraft
Lycoming O-320-B2A 11 aircraft
Lycoming O-320-B2B 92 aircraft
Lycoming O-320-B2C 55 aircraft
Lycoming O-320-B3B 22 aircraft
Lycoming O-320-C1A 1 aircraft
Lycoming O-320-C2A 2 aircraft
Lycoming O-320-C3B 1 aircraft
Lycoming O-320-D1A 116 aircraft
Lycoming O-320-D1D 4 aircraft
Lycoming O-320-D1F 7 aircraft
Lycoming O-320-D2A 72 aircraft
Lycoming O-320-D2B 18 aircraft
Lycoming O-320-D2C 1 aircraft
Lycoming O-320-D2G 21 aircraft
Lycoming O-320-D2J 96 aircraft
Lycoming O-320-D3G 134 aircraft
Lycoming O-320-E1A 3 aircraft
Lycoming O-320-E1F 5 aircraft
Lycoming O-320-E2A 98 aircraft
Lycoming O-320-E2B 4 aircraft
Lycoming O-320-E2C 11 aircraft
Lycoming O-320-E2D 257 aircraft
Lycoming O-320-E2G 32 aircraft
Lycoming O-320-E3D 65 aircraft
Lycoming O-320-E3H 2 aircraft
Lycoming O-320-H2AD 83 aircraft
Lycoming O-320 series 27,316 aircraft
Lycoming O-340-A1A 5 aircraft
Lycoming O-340-B1A 1 aircraft
Lycoming O-340 series 60 aircraft
Lycoming O-350 1 aircraft
Lycoming O-350 series 17 aircraft
Lycoming O-360-A1A 600 aircraft
Lycoming O-360-A1AD 29 aircraft
Lycoming O-360-A1D 1,057 aircraft
Lycoming O-360-A1F 4 aircraft
Lycoming O-360-A1F6 13 aircraft
Lycoming O-360-A1F6D 18 aircraft
Lycoming O-360-A1G 1 aircraft
Lycoming O-360-A1G6 1 aircraft
Lycoming O-360-A1G6D 11 aircraft
Lycoming O-360-A1H 8 aircraft
Lycoming O-360-A1H6 106 aircraft
Lycoming O-360-A1LD 1 aircraft
Lycoming O-360-A2A 38 aircraft
Lycoming O-360-A2D 5 aircraft
Lycoming O-360-A2F 13 aircraft
Lycoming O-360-A2G 3 aircraft
Lycoming O-360-A3A 50 aircraft
Lycoming O-360-A4A 63 aircraft
Lycoming O-360-A4G 2 aircraft
Lycoming O-360-A4K 44 aircraft
Lycoming O-360-A4M 418 aircraft
Lycoming O-360-B1A 13 aircraft
Lycoming O-360-B1B 2 aircraft
Lycoming O-360-B2A 3 aircraft
Lycoming O-360-C1A 7 aircraft
Lycoming O-360-C1E 5 aircraft
Lycoming O-360-C1F 102 aircraft
Lycoming O-360-C1G 142 aircraft
Lycoming O-360-C2A 19 aircraft
Lycoming O-360-C2C 6 aircraft
Lycoming O-360-C2D 2 aircraft
Lycoming O-360-C2E 5 aircraft
Lycoming O-360-D1A 6 aircraft
Lycoming O-360-D2A 4 aircraft
Lycoming O-360-E1A6D 7 aircraft
Lycoming O-360-F1A6 23 aircraft
Lycoming O-360-G1A6 3 aircraft
Lycoming O-360 series 1,066 aircraft
Lycoming O-435 88 aircraft
Lycoming O-435A/O-435C 135 aircraft
Lycoming O235N2C 18 aircraft
Lycoming R-680E1 1 aircraft
Lycoming R680 218 aircraft
Lycoming R680E series 225 aircraft
Lycoming R680E3A 1 aircraft
Lycoming R680E3B 13 aircraft
Lycoming TIO-360-C1A6D 3 aircraft
Lycoming TIO-360 series 15 aircraft
Lycoming TO-360-A1A6D 1 aircraft
Lycoming TO-360-C1A6D 4 aircraft
Lycoming TO-360-E1A6D 1 aircraft
Lycoming TO-360 series 74 aircraft
Lycoming TVO-435-A1A 1 aircraft
Lycoming TVO-435-D1A 2 aircraft
Lycoming TVO-435-F1A 1 aircraft
Lycoming TVO-435-G1A 1 aircraft
Lycoming TVO-435-GIA 88 aircraft
Lycoming VO-435-A1F 15 aircraft
Lycoming VO-435-B1A 6 aircraft
Lycoming VO-435 series 190 aircraft

Dates and paperwork

In force since: May 28, 1991
Docket: 89-ANE-21
Status: Current
The FAA's document: Read the order on the FAA's site

The order itself the regulatory text, as published

Show the full text (4,969 characters)

90-04-06 R1  TEXTRON LYCOMING:   Amendment  39-6427  as  revised by Amendment 39-6915.  Docket No. 89-ANE-21. \n\n\tApplicability:  All Textron Lycoming four cylinder piston engines equipped with a rear mounted propeller governor and external oil line, manufactured prior to  January 1, 1990. \n\n\tCompliance:  Required as indicated, unless already  accomplished. \n\n\tTo prevent oil line fracture and loss of engine oil,  accomplish the following:\n \n\t(a)\tWithin the next 25 hours time in service or whenever the propeller governor oil line is removed, whichever occurs first, accomplish the following: \n\n\t\t(1)\tInspect the propeller governor external oil line for abrasions, cracks, and oil leaks along the length of the line and at the end attachment fittings.  Inspect to determine that the two cushion type support clamps or clips are properly installed as shown in Figure 1 of Appendix 1 to this AD, and assure that sufficient clearances exist between the oil line and adjacent components.(2)\tIf any leaks, chafing, or interference condition exists or if the two support clamps or clips are not properly installed, replace the governor oil line and its attachment end fittings with new parts even though the parts show no visible damage.  Refer to Figure 1 in Appendix 1 to this AD, for parts identification, line routing, and location of support clamps or clips.  The fittings in the engine case and governor must be replaced if they are damaged or are made of aluminum.\n \n\t(b)\tAt the next engine overhaul or anytime the governor oil line is removed for any reason, whichever occurs first, but no later than May 1, 1992, remove any governor oil line assembly having integral aluminum connecting nuts and reinstall an oil line assembly with corresponding steel connecting nuts. Replace any engine case/governor aluminum fittings with corresponding steel fittings as shown in Figure 1 of Appendix 1 to this AD. \n\n\tNOTE:  The attachment nuts are components of the governor oil line tube assembly and have been changed by Textron Lycoming from aluminum to steel without changing the oil line part number.  Aluminum nuts may be identified by their blue colored anodized surface.  The attachment nuts as well as the elbow/nipple end fittings may also be identified by using a magnet to differentiate aluminum from steel.\n \n\t(c)\tAn optional method of compliance with paragraph (a)(2) and (b) is the installation of steel fittings and a fire resistant flexible hose assembly which meets the standards in FAA Technical Standard Order TSO- C53a Type D, and is installed in accordance with Appendix 2 of this AD. \n\n\tNOTE:  Further guidance pertaining to installation can be obtained from FAA Advisory Circular 43.13-1A, Chapter 10, Maintenance Standards. \n\n\t(d)\tAircraft may be ferried in accordance with the  provisions of FAR 21.197 and 21.199 to a base where the AD can be accomplished. \n\n\t(e)\tUpon submission of substantiating data by an owner or  operator through an FAA Inspector(maintenance, avionics, or operations, as appropriate), an alternate method of compliance with the requirements of this AD or adjustments to the compliance times specified in this AD, may be approved by the Manager, New York Aircraft Certification Office, Engine and Propeller Directorate, Aircraft Certification Service, FAA, 181 South Franklin Avenue, Room 202, Valley Stream, New York 11581.\n \n\tThis amendment revises Amendment 39-6427 (55 FR 3577, February 2, 1990) AD 90-04-06. \n\n\tThis amendment (39-6915, AD 90-04-06 R1) becomes effective on May 28, 1991. \n\n\n\nAD 90-04-06 R1 \n\n\n\nAPPENDIX 2 \n\nIf -5 (5/16") fittings have been installed on some standard cylinder flange crankcase model engines, the propeller governor drive fitting and front crankcase fitting must be changed to the appropriate steel fitting to accommodate the new -6 (3/8") line.  When re-installing new stainless steel tube assembly, appropriate -5 steel fittings must be re-installed. \n\nCAUTION \n\n\tIT IS MANDATORY THAT THIS FLEXIBLE HOSE BE REPLACED \n\tAT EACH OVERHAUL. \n\nWhen this engine modification is accomplished, Textron Lycoming recommends that a copy of the approved FAA Form 337 - plus the proper logbook entry become a permanent part of the aircraft records. \n\n\n\nInstallation is as follows: \n\t\ta.\tDetermine proper hose length as required for your particular installation. \n\n\t\tb.\tNo sharp bends are permissible.  Ascertain that no "kinks" exist while routing and clamping hose. \n\n\t\tc.\tHose must not be routed near a heat source, such as any portion of the exhaust system. \n\n\t\td.\tHose is to be clamp supported to the engine (not to an airframe component) at a minimum of two locations.\n \n\t\te.\tNo clamping to cylinder head drain back tubes is allowed. \n\n\t\tf.\tAfter installation is complete, ensure that hose is not pinched.  Make certain that engine motion during startup and shutdown does not pull or pinch the hose.

Source: FAA Dynamic Regulatory System, airworthiness directives. The FAA's document is the authority; the register counts are this site's, from the FAA register of October 5, 2026. Connections as data: /graph/directive/90-04-06 R1.json · aircraft systems.