Aircraft Hardware Part I (A.N Bolt & Nut Guide Listing) PDF

Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City...

Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT AIRCRAFT HARDWARE Part I (A.N BOLT & NUT GUIDE LISTING) TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 1 of 2  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT AN3 – AN20 HEX HD. BOLT (Aircraft) AN341 HEX. BRASS NUT HEX. MACHINED SCREW AN 21 – AN36 CLEVIS BOLT AN345 NUT (NF) AN42 - AN49 EYE BOLT AN350 WING NUT DRILLED HD BOLT AN73 – AN81 (Engine) AN355 SLOTTED NUT (Engine) SELF-LOCKING NUT (Right AN256 Angle Plate) AN360 PLAIN NUT (Engine) HIGH TEMP. SELF- AN310 CASTLE NUT (Airframe) AN362 LOCKING NUT (Plated) HIGH TEMP. SELF- AN315 PLAIN NUT (Airframe) AN363 LOCKING NUT (Hex) LOW TEMP. SELF- AN316 CHECK NUT AN364 LOCKING NUT (Hex) AN320 CASTLE NUT (Shear) AN365 SELF-LOCKING NUT (Hex) PLAIN HEX (NC) (Semi- SELF-LOCKING NUT AN335 Fin) AN366 (Plated) PLAIN HEX MACHINED SELF-LOCKING NUT AN340 SCREW NUTS (NC) AN373 (Plated for 100 ctsk screw) TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 2 of 2  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT AIRCRAFT SAFETY WIRING 1|Page  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT The word “safetying” is a term universally used in the aircraft industry. It is defined as: “Securing by various means any nut, bolt, turnbuckle etc., on the aircraft so that vibration will not cause it to loosen during operation.” These practices are not a means of obtaining or maintaining torque, rather a safety device to prevent the disengagement of screws, nuts, bolts, snap rings, oil caps, drain cocks, valves, and parts. Three basic methods are used in safetying; safety-wire, cotter pins, and self-locking nuts. 2|Page  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT a. Wire, either soft brass or steel is used on cylinder studs, landing gears, control cable turnbuckles, and engine accessory attaching bolts. b. Cotter pins are used on aircraft and engine controls, landing gear, and tailwheel assemblies, or any other point where a turning or actuating movement takes place. c. Self-locking nuts are used in applications where they will not be removed often. Repeated removal and installation will cause the self- locking nut to lose its locking feature. They should be replaced when they are no longer capable of maintaining the minimum prevailing torque. 3|Page  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT TWO METHODS OF SAFETY WIRING Double-twist method - most commonly used method 4|Page  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Single-wire method - used on screws, bolts, and/or nuts in a closely-spaced or closed-geometrical pattern such as a triangle, square, rectangle, or circle. The single-wire method may also be used on parts in electrical systems and in places that are difficult to reach. 5|Page  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT 6|Page  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT 7|Page  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Procedures for installing safety wire include the following (with quotations from AC 43.13): 1. Safety wire must be new upon each application. (This seems fairly obvious until you catch yourself trying to redo a short run using the same wire.) 2. All safety wires "must be tight after installation, but not under such tension that normal handling or vibration will break the wire." 3. Twists should be "tight and even, and the wire between nuts as taut as possible without over-twisting." (Six to eight turns per inch.) 4. A "pigtail" of 1/4- to 1/2-inch (three to six twists) should be made at the end of the wire run. This pigtail "must be bent back or under to prevent it from becoming a snag." 5. When castle nuts are safetied, "tighten the nut to the low side of the selected torque range, unless otherwise specified, and if necessary, continue tightening until a slot aligns with the hole." 6. The wire must be applied "so that all pull exerted by the wire tends to tighten the nut." 7. The wire should always "be installed and twisted so that the loop around the (bolt) head stays down and does not tend to come up causing a slack loop." 8|Page  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT COMMON APPLICATIONS 9|Page  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Wing Landing Gear Downlock Actuator 10 | P a g e  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT OIL FILTER 11 | P a g e  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT FUEL STRAINER 12 | P a g e  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT TURNBUCKLES 13 | P a g e  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT SAFETY WIRING GONE WRONG (Identify the mistakes) 14 | P a g e  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT 15 | P a g e  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT 16 | P a g e  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS INSTITUTE OF ENGINEERING AND TECHNOLOGY ATOC. No.: Acc. No.: M2700903PM 86-06 Certificate Number: AJA16.0920 AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT 17 | P a g e AIRCRAFT HARDWARE PART I (CONTROL CABLE) CONTROL CABLE Carbon Steel or Stainless Steel cables are used in most aircraft mechanical transmissions. Small aircraft such as C150 uses control cables while commercial aircraft such as B747 uses jackscrew transmissions. The changes in control cables are accomplished using “pulleys” and “quadrants”. Excessive wear on both of the sides of a control cable pulley groove is evidence of “pulley misalignment”. CONTROL CABLE All cables consist of 7 strands, which are helically twisted. The strands consist of a number of wires, which are also helically twisted. Some strands have 7 wires and some have 19 wires. The greater the number of wires in a strand, the more flexible the cable is. The diameter of a cable is the diameter of the circumscribed circle. CONTROL CABLE Cable Fittings - Terminal Fittings are generally of swaged type. Turnbuckles - Mechanical screw device consisting of two threaded terminals and a threaded barrel. - Are fitted in the cable assembly for the purpose of making minor adjustment in cable length, and for adjusting cable tension. CONTROL CABLE CONTROL CABLE A cable is identified by: the diameter, the number of strands, and the number of wires in each strand. CONTROL CABLE CONTROL CABLE CROSS SECTION CONTROL CABLE FITTINGS TURNBUCKLES TURNBUCKLES TURNBUCKLES (SAFETY WIRED) CONTROL CABLE FITTINGS CONTROL CABLE FITTINGS CONTROL CABLE FITTINGS CONTROL CABLE ROUTING CONTROL CABLE VS ROD TRANSMISSION  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT AIRCRAFT HARDWARE Part I (BOLTS & THREADED FASTENERS) TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 1 of 14  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT INTRODUCTION The term aircraft hardware describes the various types of fasteners and miscellaneous small items used in the manufacture and repair of aircraft. The importance of aircraft hardware is often overlooked because of its small size; however, the safe and efficient operation of all aircraft depends on the correct selection and use of aircraft hardware. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 2 of 14  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT SPECIFICATION AND STANDARDS Before the Federal Aviation Administration issues a Type Certificate for an aircraft, the manufacturer must demonstrate that the aircraft conforms to all airworthiness requirements. These requirements pertain not only to performance, but to structural strength and integrity as well. To meet these requirements, each individual aircraft produced from a given design must meet the same standards. To accomplish this, all materials and hardware must be manufactured to a standard of quality. Specifications and standards for aircraft hardware are generally identified by the organization originating them. Some of the most common are: AMS Aeronautical Material Specifications AN Air Force-Navy AND Air Force-Navy Design When an “MS20470-AD4-4” rivet is required, specifi- AS Aeronautical Standard cations have already been written for it and are available ASA American Standards Association to both the aircraft manufacturer and rivet producer. ASTM American Society for Testing and Materials MS Military Standard These specifications stipulate the material to be used as NAF Naval Aircraft Factory well as the rivet dimensions. NAS National Aerospace Standard SAE Society of Automotive Engineers TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 3 of 14  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT BOLTS AND THREADED FASTENERS Various types of fastening devices allow quick dismantling or replacement of aircraft parts that must be taken apart and put back together at frequent intervals. Bolts and Screws are two types of fastening devices that gives the required security of attachment and rigidity. Generally, bolts are used where great strength is required, and screws are used where strength is not the deciding factor. Threaded fasteners allow parts to be fastened together with all of the strength unthreaded fasteners provide. However, unlike rivets and pins, threaded fasteners may be disassembled and reassembled an almost infinite number of times. Aircraft bolts, screws, and nuts are threaded in either American National Coarse (NC), the American National Fine (NF), the American Standard Unified Coarse (UNC), or the American Standard Unified Fine (UNF) series. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 4 of 14  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT BOLTS AND THREADED FASTENERS The difference between the American National series and the American Standard Unified series is the American National series has more threads per inch than the American Standard Unified series. For example, on a one inch diameter bolt, the NF thread specifies 14 threads per inch (1-14NF), while the UNF thread specifies 12 threads per inch (1-12 UNF). Both thread types are designated by the number of times the threads rotate (number of turns) around a 1-inch length of a given diameter bolt or screw. In addition to being identified as either coarse or fine, threads are also designated by class of fit from one to five. A Class 1 thread is a loose fit, a Class 2 is a free fit, a Class 3 is a medium fit, a Class 4 is a close fit, and a Class 5 fit is a tight fit. A Class 1 fit allows you to turn the nut all the way down using only your fingers. Wing nuts are a good example of a Class 1 fit. A Class 4 and 5 fit requires a wrench to turn a nut down from start to finish. Aircraft bolts are usually fine threaded with a Class 3 fit, whereas screws are typically a Class 2 or 3 fit. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 5 of 14  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 6 of 14  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT BOLTS AND THREADED FASTENERS A bolt is designed to hold two or more items together. Bolts that are typically used for airframe structural applications have hex heads and range in size from AN3 to AN20. Bolts are identified by their diameter and length. A diameter represents the shank diameter while the length represents the distance from the bottom of the head to the end of the bolt. A bolt's grip length is the length of the unthreaded portion. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 7 of 14  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT BOLTS AND THREADED FASTENERS IDENTIFICATION Aircraft bolts can be identified by the code marking on the bolt head. The markings according to US standards denote the bolt manufacturer, the material from which the bolt is made and whether the bolt is a standard type or a special purpose bolt. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 8 of 14  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT AN 4 DD 6 LENGTH (1/8”) MATERIAL DESIGNATION MATERIAL CONSTRUCTION DIAMETER (1/16”) Aircraft bolts are available in cadmium-plated nickel steel, corrosion resistant steel, and in 2024 aluminum alloy. Unless specified, a bolt is made of cadmium-plated nickel steel. A corrosion resistant bolt, on the other hand, is identified by the letter "C" inserted between the diameter and length designations. Aluminum alloy bolts are identified by the letters "DD." For example, a bolt that is 1/4 inch in diameter, 3/4 inch long, and made of cadmium-plated nickel steel is identified by the code AN4-6. However, if the same bolt is made of corrosion resistant steel it carries the code AN4C6, whereas an aluminum alloy bolt would be AN4DD6. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 9 of 14  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Aircraft bolts are available in cadmium-plated nickel steel, corrosion resistant steel, and in 2024 aluminum alloy. Unless specified, a bolt is made of cadmium-plated nickel steel. A corrosion resistant bolt, on the other hand, is identified by the letter "C" inserted between the diameter and length designations. Aluminum alloy bolts are identified by the letters "DD" most aircraft bolts have a marking on their head identifying what the bolt is made of and, in many cases, the manufacturer. For example, a standard AN bolt has an asterisk in the center of its manufactured head. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 10 of 14  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 11 of 14  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 12 of 14  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT The FAA forbids the use of aluminum alloy bolts and alloy steel bolts smaller than AN3 on structural components. Furthermore, since repeated tightening and loosening of aluminum alloy bolts eventually ruins their threads, they are not used in areas where they must be removed and installed frequently. Aluminum alloy nuts can be used with cadmium-plated steel bolts loaded in shear, but only on land aircraft. However, since exposure to moist air increases the possibility of dissimilar-metal corrosion, they cannot be used on seaplanes. When hardware was first standardized, almost all nuts were locked onto a bolt with a cotter pin and, therefore, all bolts had holes drilled near the end of their shank to accommodate a cotter pin. However, when self-locking nuts became popular, many standard AN bolts were made without a drilled shank. To help you identify whether or not a bolt has a hole drilled through it, the letter A is used in the part code. For example, if an "A" appears immediately after the dash number the bolt does not have a hole. However, the absence of an "A" indicates a hole exists in the shank. As an example, an AN6C-12A bolt is 3/8 inch in diameter, made of corrosion-resistant steel, 1 1/4 inches long, and has an undrilled shank. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 13 of 14  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Some AN bolts, such as those used to fasten a propeller into a flanged shaft, must be safetied by passing safety wire through holes drilled through the bolt's head. A bolt drilled for this type of safetying has the letter H following the number indicating its diameter. For example, the part number AN6H34A identifies a bolt that is 3/8 inch in diameter, made of nickel-steel, has a drilled head, is 3 1/2 inches long, and has an undrilled shank. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 14 of 14  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT AIRCRAFT HARDWARE Part I (NUTS) TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 1 of 11  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT General Nuts for aircraft bolts and screws are manufactured in many sizes and shapes. - non−self−locking nuts; - locking nuts; - high−temperature self−locking nuts; - low−temperature self−locking nuts TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 2 of 11  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT NON−SELF−LOCKING NUTS These are used with drilled−shank or hex−head bolts, clevis bolts, eye bolts or struts and is designed to accommodate a cotter pin or wire-locking as a means of safetying. Shear Castle Nut Used only for shear load on clevis bolts. These nuts are available in cadmium−plated nickel steel, corrosion−resistant steel and in 2024 aluminium alloy. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 3 of 11  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Castle Nut These nuts are designed to fit on standard airframe bolts and may be used when the bolt is subjected to either shear or tensile loads. They are made from the same material as the shear castle nut. Slotted Engine Nut This nut is designed for use on an aircraft engine and is not approved for airframe use. It is made of heat−treated steel. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 4 of 11  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Wing Nut Wing nuts are intended for use on hose clamps and battery connections, etc, where the desired tightness is ordinarily obtained by the use of fingers. They are made of either cadmium-plated steel or brass. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 5 of 11  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT LOCKING NUTS Lock Nut A lock nut is a thin, plain nut which is tightened down firmly onto the main, plain nut. This friction wedges the threads to prevent them both slackening. Nyloc Stiffnuts This nut has an unthreaded nylon insert permanently housed at the outer end. As the bolt threads engage the insert, the nylon is compressed into them, setting up a friction which prevents the nut unscrewing. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 6 of 11  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Oddie Stiffnuts Oddie stiffnuts have six tongues at their outer end which are bent inwards to form a circle slightly less in diameter than the root of the bolt thread. As the bolt passes through the nut the tongues are pushed upwards, applying a locking load onto the bolt thread. Aerotight and Philidas Stiffnuts These nuts have slotted locking extensions which are closed during manufacture to put the screw-thread out of alignment. As the bolt engages and realigns the extension thread, a grip is produced which provides a friction lock. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 7 of 11  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Anchor Nuts A floating type anchor nut is used when a slight range of movement is necessary to ensure the bolt can locate. A strip nut is used when a row of anchor stiffnuts is required. In this arrangement, the stiffnuts are fitted at equal intervals along a channel strip which itself is riveted to the blind side of the structure. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 8 of 11  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT HIGH−TEMPERATURE SELF−LOCKING NUTS In applications where temperatures exceed 120 C (25O F), all-metal locknuts are used. All−metal locknuts are constructed with either the threads in the locking insert out−of−phase with the load−carrying section, or with a saw−cut insert with a pinched−in thread in the locking section. The locking action of the all−metal nut depends upon the resiliency of the metal when the locking section and load-carrying section are engaged by screw threads. They are made out of steel alloy, CRES or CRES silver-plated. Silver-plated nuts should not be used in contact with titanium. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 9 of 11  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT LOW−TEMPERATURE SELF−LOCKING NUTS These should not be used in any location where the temperature will exceed 121 C (250 F). Fibre- or nylon-locknuts are constructed with an unthreaded fibre−locking insert held securely in place. The fibre or nylon has a smaller diameter than the nut, and when a bolt or screw is entered, it taps into the insert, producing a locking action. After the nut has been tightened, ensure the rounded or chamfered end bolts, studs or screws extend at least one thread or chamfer through the nut. Flat end bolts, studs or screws should extend at least 1/32 inch through the nut. If fibre−type self−locking nuts are reused, inspect the fibre carefully to ensure it has not lost its locking friction or become brittle. Do not reuse locknuts if they can be run up fingertight. Bolts 5/16 inch diameter and over with cotter-pin holes may be used with self− locking nuts but only if free from burrs around the holes. Bolts with damaged threads and rough ends are not acceptable. Do not tap the fibrelocking insert. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 10 of 11  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT NUT DESIGNATION AN310DD5 AN310 – AIRFORCE NAVY/CASTLE NUT DD – MATERIAL CONSTRUCTION 5 – Diameter (1/16”) TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 11 of 11  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT AIRCRAFT HARDWARE Part I (MISCELLANEOUS) TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 1 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT AN21-AN36 CLEVIS BOLT AN23 The Clevis Bolt is used for SHEAR LOADS ONLY and DASH NO. GRIP LENGTH requires a shear nut AN320 (for use with cotter pin) or 8 3/16” 17/32” AN364 (self-locking nut). The head of a clevis bolt is round 9 ¼” 19/32” and is either slotted to receive a common screwdriver or 10 5/16” 21/32” recessed to receive a crosspoint screwdriver. It is often 11 3/8” 23/32” inserted as a mechanical pin in a control system. 12 7/16” 25/32” 13 ½” 27/32” TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 2 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT AN42- AN 49 EYEBOLT An EYEBOLT is a bolt with a loop at one end. They are used to firmly attach a securing eye to a structure, so that ropes or cables may then be tied to it.This type of special purpose bolt is used where external tension loads are to be applied. The eyebolt is designed for the attachment of such devices as the fork of a turnbuckle, a clevis, or a cable shackle. The threaded end may or may not be drilled for safetying. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 3 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT SAFETY WIRE MS20995C32 MS =Specification (Military Standard) 20995 = Standard No. (Lockwire) C = Letter Code 32 = Diameter (1/1000”) Letter Code Material C CRES F Carbon Steel (Zinc Plated) N Ni Cr Fe Alloy NC Ni Cu (Monel) AB Aluminium CY Copper TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 4 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT STUDS A stud is a piece of rod, threaded at each end with a plain portion in the middle. It should be a tight fit in the thread tapped to receive it. Unlike a bolt, a stud has no head. Therefore, its fitting (and removal) requires special tools or techniques. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 5 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Fitting Various methods are employed to fit studs. Amongst these methods are: Stud Box This is simply a piece of hexagonal metal bar, drilled and tapped through its axial centre-line. 1. The stud is screwed into one end and a standard set screw into the other. 2. The end of the screw is brought firmly into contact with the end of the stud to lock the items into one unit. 3. The stud can now be screwed tightly into its housing by using a spanner on the hexagon. Once fitted, the stud box is removed by undoing the locking set screw to free the box, which can then be unscrewed from the stud. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 6 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Stud Insertion/Removal Tool The stud is started into its thread by hand and then the inserting tool is placed over the protruding end until the plain shank of the stud enters the tool. A locating screw on the outer end of the tool is adjusted to position the tool correctly, and a cage and cam arrangement grips the shank of the stud when the tool is turned. The stud and tool can now turn together. Lock Nuts Two nuts are screwed onto the outer thread of the stud and locked firmly together by using two spanners. The stud is then screwed firmly into its housing by using a single spanner on the outer nut. A spanner used on the lower nut will remove the stud. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 7 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 8 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Stud Removal (Damaged) The state of the stud dictates the method of removal. If it is undamaged, the stud can be removed as described previously. However, if the stud is damaged, removal should be carried out using one of the following methods. Filed Flats Providing there is sufficient stud protruding, flats are filed and a spanner or tapwrench used to unscrew the stud. Ezi-Out If the stud is broken level with or below the surface, drill as large a hole in the stud as possible (without encroaching on the stud threads) and remove the stud using an Ezi-Out screw- extractor. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 9 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 10 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT WASHERS Various methods exist, depending on their application and the whim of the design authority, for locking nuts and bolts with washers. Spring Washer This is either a single coil or square section spring with sharp corners or a double-coil spring. It is fitted beneath the nut so that when the nut is tightened the spring is compressed, setting up a friction and thus preventing the nut from vibrating loose. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 11 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Tab Washer This is a metal washer with two or more tabs, suitable for use with plain nuts. One tab is bent against one of the flats of the nut and the other is bent over an edge of the component or fitted into a slot or hole machined in the component. It is not permissable to straighten the tabs and re-use the washer. Shakeproof Washer This is a spring steel washer with slanting serrations on its internal or external circumferences. The angle of the serrations is such that the nut is able to ride over them whilst being tightened, but any tendency to unscrew will be resisted by the sharp edges of the serrations biting into the underside of the nut (similar to a ratchet). TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 12 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT QUICK-RELEASE FASTENERS Pip Pin This is a simple and secure, non-threaded fastener, allowing the rapid installation and removal of parts without tooling. Available as a simple locating pin (detent pin) and a locking version (double-acting). 1. Ring pull detent pin. A single ball locates the pin, no positive lock. The simplest option for location purposes. Simply push to insert, and pull to remove. Fitted with a ’keyring’ loop. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 13 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT 2. Double acting steel pin. To release the ball lock mechanism, the ring handle can be pushed in or pulled out (double acting), moving a centre core, thus releasing the two balls, allowing the pin to be extracted. Instantaneous self locking, Vibration resistant, easy application. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 14 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Camloc The Camloc fastener consists of four principal parts: - Receptacle - Grommet - retaining ring and - stud assembly. The receptacle consists of an aluminium alloy forging mounted in a stamped sheet metal base. The receptacle assembly is riveted to the access door frame, which is attached to the structure of the aircraft. The grommet is a sheet metal ring held in the access panel by the retaining ring. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 15 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Grommets are available in two types; the flush type and the protruding type. In addition to serving as the grommet for the hole in the access panel, it also holds the stud assembly. The stud assembly consists of a - Stud - cross pin - spring, and - spring cup. The assembly is designed so that it can be quickly inserted into the grommet by compression of the spring. Once installed in the grommet, the stud assembly cannot be removed unless the spring is again compressed. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 16 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 17 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Dzus Dzus fasteners are available in two types: - One is the light−duty type, used on box covers, access hole covers, and lightweight fairing. - The second is the heavy−duty type, which is used on cowlings and heavy fairings. The main difference between the two types of Dzus fastener is a grommet, used with the heavy−duty fasteners. Otherwise their construction features are about the same. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 18 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 19 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT Airloc Airloc fastener consists of a receptacle, stud, and cross pin. The stud is attached to the access panel and is held in place by the cross pin. The receptacle is riveted to the access panel frame. Two types of Airloc receptacles are available: - the fixed type and - the floating type. The floating type makes for easier alignment of the stud in the receptacle. Several types of studs are also available. In each instance the stud and cross pin come as separate units so that the stud may be easily installed in the access panel. TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 20 of 21  Republic of the Philippines PHILIPPINE STATE COLLEGE OF AERONAUTICS Institute of Engineering and Technology Piccio Garden, Villamor, Pasay City AIRCRAFT MAINTENANCE TECHNOLOGY DEPARTMENT TOPIC: AIRCRAFT HARDWARE I | Ver. 1 Rev. June 2018 Page 21 of 21