Metallic Structures
Metallic Structures is a core knowledge area on the AMT — Airframe FAA written exam. This hub collects our 16 in-depth, ACS-aligned metallic structures articles — each written in plain English and grounded in the official FAA handbooks. Work through them below, then drill the topic with practice questions.
Aircraft Aluminum Alloy Designations and Temper Codes
Aircraft aluminum alloys are identified by a four-digit designation system paired with temper codes that define both composition and mechanical properties — knowledge essential for selecting correct repair materials.
Solid Shank Rivet Types and Head Styles in Aircraft Construction
Aircraft solid shank rivets are permanent fasteners classified by alloy, head style, and marking; choosing the correct type and installation method is critical to airframe structural integrity.
Rivet Hole Preparation and Dimpling Methods
Proper rivet hole preparation and dimpling are critical steps in aircraft sheet metal work — wrong techniques cause cracks, improper flush fits, and structural weakness that compromise airworthiness.
Cleco Fasteners and Temporary Fastening Techniques
Cleco fasteners are spring-loaded temporary fasteners used to align and hold sheet metal parts during assembly before final riveting, ensuring proper fit-up and hole alignment throughout the metalworking process.
Sheet Metal Layout and Bend Allowance Calculations
Sheet metal layout and bend allowance calculations are foundational AMT skills that ensure accurate, stress-free bends in aircraft structural repairs by accounting for material stretch during forming.
Hi-Lok and Lockbolt Fastener Systems
Hi-Lok and lockbolt fasteners are high-strength, two-piece aerospace fasteners used where standard rivets fall short — understanding their installation, inspection, and removal is essential for AMT airframe certification.
Aircraft Steel Alloy Identification and Heat Treatment
Steel alloys used in aircraft structures are identified by SAE/AISI numbering systems and require precise heat treatment processes to achieve the mechanical properties needed for safe, airworthy structures.
Alclad and Surface Treatment Processes for Aluminum
Alclad aluminum combines a high-strength alloy core with a pure-aluminum cladding layer for corrosion protection, and proper surface treatment processes are essential before any repair or finish application on aircraft structures.
Corrosion Types and Identification on Aircraft Metal Structures
Aircraft corrosion takes many distinct forms—each with unique causes, appearances, and danger levels. Recognizing each type early is essential for airframe safety and FAA airworthiness standards.
K-Factor and Setback in Sheet Metal Bending
K-factor and setback are critical sheet metal layout calculations that determine where to place bend lines so finished parts have accurate dimensions after bending.
Joggle Joints and Flanged Lightening Holes in Sheet Metal
Joggle joints and flanged lightening holes are two essential sheet metal forming techniques that AMT airframe technicians use to maintain structural integrity while reducing weight and allowing parts to nest flush.
Stressed-Skin Monocoque and Semi-Monocoque Airframe Construction
Monocoque and semi-monocoque construction are the dominant airframe designs in modern aircraft, transferring flight loads through the skin and internal framework rather than a separate truss structure.
Repair Patch Design and Rivet Pattern Layout for Sheet Metal
Proper repair patch design and rivet pattern layout are foundational AMT skills that restore structural integrity to damaged sheet metal airframes while meeting FAA-accepted engineering standards.
Fretting Corrosion and Dissimilar Metal Contact Prevention
Fretting corrosion occurs at metal contact points experiencing micro-motion, and dissimilar metal contact accelerates galvanic attack — understanding both hazards is essential for airframe structural integrity.
Non-Destructive Testing Methods for Metallic Airframe Structures
Non-destructive testing (NDT) methods allow AMTs to detect hidden cracks, corrosion, and flaws in metallic airframe structures without damaging the part, ensuring continued airworthiness.
Driven Rivet Inspection and Rejection Criteria
Learn how to inspect driven rivets on aircraft structures, identify defects using FAA-approved criteria, and determine when a rivet must be removed and replaced to maintain airworthiness.
More AMT — Airframe subjects
Articles are original summaries grounded in the public-domain FAA handbooks and cite their source. ACS-aligned study aids — not a substitute for the official handbooks or regulations.