Metallic Structures — FAA A&P Test Questions (ACS AM.II.A)
Metallic Structures (AM.II.A) is the Airframe subject area covering sheet metal layout, forming, and riveted repair, which is where most Airframe structures questions come from. Expect bend allowance and setback, the neutral axis, rivet selection and driven head dimensions, edge distance and pitch, stop drilling, dimpling versus machine countersinking, and identifying corrosion in aluminum structure. Every AMTprep question tagged to this code carries a rationale and a handbook reference, so the numbers become recall rather than arithmetic you improvise under time pressure.
Written by the AMTprep editorial team · Published · Last reviewed
Written against the FAA primary sources cited at the foot of this page.
What ACS AM.II.A covers
The source is the sheet metal and structural repair material in FAA-H-8083-31, and the questions are written straight from it. Layout and forming come first. Bend allowance is the amount of material consumed in the bend itself, measured along the neutral axis between the bend tangent lines; setback locates those tangent lines back from the mold point and equals K times the sum of the radius and the thickness. The neutral axis is the line in the bend where the metal is neither stretched nor compressed, and it lies closer to the inside of the bend, about 0.445 times the material thickness from the inside surface. Minimum bend radius, grain direction, and the effect of bending across the grain rather than with it all appear. Riveting is the largest cluster. Rivet diameter is normally about three times the thickness of the thickest sheet in the joint. A correctly driven rivet has a formed head about one and a half shank diameters across and about one half a shank diameter high. Minimum edge distance is two rivet diameters, measured from the center of the hole to the edge of the sheet, and two and a half diameters for countersunk rivets, while minimum rivet pitch is three diameters. Machine countersinking needs material thicker than the depth of the rivet head; thinner sheet is dimpled instead. Damage assessment finishes the area: negligible versus repairable damage, stop drilling to blunt a crack tip and remove the stress concentration, patch and doubler work that restores original strength, and spotting corrosion in aluminum by its powdery deposit and pitted surface.
Where this sits on the test
ACS AM.II.A is tested on the FAA Airframe written test, one of 1,739 ACS-tagged questions in the Airframe bank. Every question tagged to this area carries a worked rationale and its FAA handbook reference, so you can drill the code itself rather than the whole test.
FAA handbook references
- FAA-H-8083-31
Three traps candidates fall into
- Bend allowance and setback get swapped. Bend allowance is the material inside the bend, measured along the neutral axis, and it is added into the flat layout length. Setback is K times radius plus thickness, and it locates the bend tangent line from the mold point. Use one where the other belongs and every flat length is wrong.
- Driven head dimensions get flipped. The formed head should be roughly one and a half rivet diameters across and one half a diameter high, not the reverse. A head that is tall and narrow means the rivet was not upset enough; one that is flat and oversized means it was driven too far and the shank may have been damaged.
- A stop drill gets treated as the repair. Drilling at the tip of a crack removes the stress concentration and buys time, but the hole has to capture the actual crack tip or the crack simply runs past it, and the structure still needs a proper repair from approved data before it is considered restored.
50 free sample questions from ACS AM.II.A
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When laying out a sheet metal bend, what is the bend allowance?
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Answer: The length of material in the curved section of the bend
Why: Bend allowance is the length of material actually consumed in the curved portion of a bend. It must be added to the flat dimensions when computing the total developed (flat-pattern) length of a part, because the metal in the radius is neither a straight flange nor part of the setback. Setback is a separate value (the distance from the bend tangent line to the mold-point intersection), and the bend radius is the inside curvature, so those describe different quantities.· FAA-H-8083-31 — Sheet Metal Layout and Forming (bend allowance)
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The neutral axis (neutral line) of a piece of sheet metal that is being bent is the location where the metal
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Answer: is neither compressed nor stretched
Why: During bending, metal on the inside of the radius is compressed and metal on the outside is stretched. Between these zones lies the neutral axis, where the material is neither compressed nor stretched and its length does not change. Bend-allowance formulas are based on the length of this neutral line, which for practical purposes lies near 0.445 of the material thickness from the inside surface.· FAA-H-8083-31 — Sheet Metal Forming (neutral axis)
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What is the primary purpose of an aircraft sheet metal stop drill at the end of a stress crack?
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Answer: To prevent the crack from spreading farther
Why: A crack acts as a stress concentrator with a very sharp tip. Drilling a small hole precisely at the end (tip) of the crack blunts that sharp point and spreads the load over the larger radius of the hole, which arrests the crack's progress. It is a temporary measure to stop further growth until a proper repair is made; it does not relieve panel-wide stress or serve as a rivet pilot.· FAA-H-8083-31 — Sheet Metal Inspection and Repair (stop drilling)
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The diameter of a rivet shank should generally be about
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Answer: three times the thickness of the thickest sheet being joined
Why: A common rule for selecting rivet diameter is to use a rivet whose shank diameter is approximately three times the thickness of the thickest sheet in the joint. A rivet that is too small will not carry the shear load; one that is too large can cause excessive bearing stress and crack the sheet. This three-times rule produces a rivet sized to develop adequate strength in the joint.· FAA-H-8083-31 — Riveting (rivet selection)
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After a solid rivet is properly driven, the formed (bucked) head should have a height of approximately
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Answer: one-half the shank diameter
Why: Standards for an acceptable driven rivet specify that the formed head should be about one-half the shank diameter in height and about one and one-half times the shank diameter across its width (diameter). These proportions ensure the rivet has been upset enough to fill the hole and clamp the sheets without being over- or under-driven. A formed head that is too thin or too small indicates insufficient driving.· FAA-H-8083-31 — Riveting (formed head dimensions)
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In a riveted lap joint, the minimum edge distance from the center of a rivet to the edge of the sheet is normally
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Answer: two times the rivet diameter
Why: Edge distance is measured from the center of the rivet hole to the nearest edge of the sheet. The minimum acceptable edge distance is generally two times the rivet diameter (2D) for universal-head rivets. Too little edge distance allows the sheet to tear out under load, while excessive edge distance lets the joint buckle. Rivet spacing (pitch) is a separate dimension typically ranging from about 3D to 12D.· FAA-H-8083-31 — Riveting (rivet layout and edge distance)
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Which type of corrosion appears as a powdery deposit and a roughened, pitted surface on aluminum?
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Answer: Surface (uniform) corrosion
Why: Surface, or uniform, corrosion on aluminum shows up as a general roughening, etching, or pitting of the surface, often accompanied by a white or gray powdery oxide deposit. It is the most common form on aluminum structures. Stress corrosion cracking is intergranular cracking under sustained tensile load, and fretting corrosion occurs at the interface of close-fitting parts subject to slight relative motion, so each presents differently.· FAA-H-8083-31 — Aircraft Cleaning and Corrosion Control (forms of corrosion)
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When a countersunk (flush) rivet is to be installed in sheet metal that is too thin to machine countersink safely, the preferred preparation method is to
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Answer: dimple the sheet to receive the rivet head
Why: Machine (countersink) cutting removes material, so on thin sheet it would cut through and leave a knife-edge with no bearing surface for the rivet head. Instead, the sheet is dimpled, which forms a recess by pressing or coining the metal without removing it, preserving the sheet's strength and giving the flush head full support. Machine countersinking is reserved for material thick enough to retain adequate bearing.· FAA-H-8083-31 — Riveting (countersinking and dimpling)
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Alclad aluminum sheet is produced by
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Answer: coating a strong alloy core with pure aluminum on both surfaces
Why: Alclad is a clad aluminum product in which a high-strength alloy core (such as 2024) is metallurgically bonded with a thin layer of nearly pure aluminum (about 5 percent of total thickness per side) on each surface. The pure aluminum cladding resists corrosion and protects the core sacrificially. Anodizing and chemical conversion coating are separate surface treatments applied to existing metal, not the rolled cladding process that defines Alclad.· FAA-H-8083-31 — Aircraft Metals (Alclad aluminum)
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Which major transverse, vertical, load-bearing member of the fuselage can serve as a wall or partial wall that divides sections of the structure?
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Answer: Bulkhead
Why: A bulkhead is a major transverse, vertical, load-bearing member that closes off or divides sections of the fuselage and can act as a wall or partial wall, such as a pressure bulkhead. Frames give shape around the section and stringers run longitudinally, so neither performs the wall function of a bulkhead.· FAA-H-8083-31 — Metallic Structures
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A vertical structural member that forms a partial or full wall across the fuselage is called a
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Answer: Bulkhead
Why: A bulkhead is a vertical structural member that forms a partial or full wall across the fuselage, dividing it into compartments and carrying loads. Longerons run longitudinally along the fuselage, and frames give the fuselage its cross-sectional shape, so neither describes a wall-forming vertical member.· FAA-H-8083-31 — Metallic Structures
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When an antenna opening is cut into a metal skin, structural strength is restored by adding:
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Answer: an internal doubler
Why: Cutting an opening removes load-carrying material and creates a stress concentration. An internal doubler is riveted in to reinforce the skin and redistribute loads around the cutout, restoring strength while keeping the external aerodynamic surface clean and flush.· FAA-H-8083-31 — Metallic Structures
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A semi-monocoque structure is one which has
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Answer: a load-bearing skin supported by an internal load-bearing framework
Why: A semi-monocoque structure carries loads in both the stressed outer skin and an internal framework of frames, formers, and stringers. This differs from a pure monocoque (skin only, no load-bearing internal members) and from a fabric-covered tubular truss design.· FAA-H-8083-31 — Metallic Structures
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A structural member designed primarily to resist a compressive load is called a
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Answer: strut
Why: A strut is a structural member designed primarily to resist compressive (squeezing) loads. A tie carries tension and a beam resists bending, so a member intended to carry compression is correctly called a strut.· FAA-H-8083-31 — Metallic Structures
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A modern large transport aircraft fuselage is normally constructed using
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Answer: semi-monocoque construction
Why: Modern large transport fuselages use semi-monocoque construction, in which a stressed skin is supported by internal frames and stringers to share loads efficiently. Warren-truss and geodetic constructions are older, heavier methods not used for modern pressurized transport fuselages.· FAA-H-8083-31 — Metallic Structures
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An extruded or rolled aluminum channel section that runs lengthwise along the fuselage to stiffen the skin is known as a
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Answer: stringer
Why: A stringer is the light extruded or rolled section that runs lengthwise along the fuselage, stiffening the skin and carrying axial loads between frames. An intercostal runs in short lengths between frames, and a cleat is a small angle bracket used to join members, not a continuous longitudinal member.· FAA-H-8083-31 — Metallic Structures
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A point identified as Fuselage Station +88, Water Line -12 is located
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Answer: 88 inches rearward of the datum and 12 inches below the water line reference
Why: Fuselage station numbers increase rearward from the aircraft datum, so station +88 is 88 inches aft of the datum, and a negative water line value (WL -12) places the point 12 inches below the water line reference. Forward or above-the-line readings would require the opposite signs.· FAA-H-8083-31 — Metallic Structures
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Cantilever construction describes a structure that is supported at
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Answer: one end only
Why: Cantilever construction is fixed and supported at one end only, with the remainder projecting unsupported, so all bending loads are reacted at that single built-in root. Structures held at both ends, or at the ends and the center, are simply supported beams rather than cantilevers.· FAA-H-8083-31 — Metallic Structures
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A fuselage construction in which the skin carries all of the loads is known as
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Answer: monocoque
Why: In a pure monocoque fuselage the skin (shell) carries all of the loads with no internal load-bearing framework. A semi-monocoque shares the loads between the skin and an internal structure of frames and stringers, so it is not a skin-only design.· FAA-H-8083-31 — Metallic Structures
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A part of the airframe whose failure would jeopardize the safety of the aircraft and could cause it to crash is classified as
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Answer: primary structure
Why: Primary structure carries flight, ground, or pressurization loads and is essential to the safety of the aircraft; its failure could result in loss of the aircraft. Secondary structure carries lighter loads, and its failure would not be catastrophic. The term that describes a structure whose failure could cause a crash is therefore primary structure.· FAA-H-8083-31 — Metallic Structures
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The progressive loss of strength and eventual cracking of a metal structure resulting from repeated cyclic loading is called
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Answer: fatigue
Why: Fatigue is the progressive weakening and eventual cracking of a material caused by repeated cyclic loading, even when each individual load remains below the material's static strength. Age hardening is a strengthening heat-treatment process, and fail-safe is a design philosophy, so the failure mechanism produced by cyclic loading is fatigue.· FAA-H-8083-31 — Metallic Structures
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An engine mount is designed to allow for which type of engine movement as the engine heats up and cools down?
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Answer: Longitudinal (fore-and-aft) movement
Why: An engine mount supports the engine and transmits thrust to the airframe while accommodating the lengthwise (fore-and-aft) expansion and contraction of the engine as it heats and cools. The mount allows this longitudinal movement without imposing damaging stresses on the engine or structure (FAA-H-8083-31, Metallic Structures).· FAA-H-8083-31 — Metallic Structures
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What is the purpose of a Dynafocal engine mount?
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Answer: It reduces engine vibration transmitted to the airframe
Why: A Dynafocal engine mount uses resilient rubber isolators arranged about the engine's center of gravity to absorb and damp engine vibration before it reaches the airframe. It reduces the vibration transmitted to the structure but cannot eliminate it entirely, and it is not made of plastic (FAA-H-8083-31, Metallic Structures).· FAA-H-8083-31 — Metallic Structures
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Tension is the stress that tends to
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Answer: elongate or stretch the material
Why: Tension is the stress that tends to pull a material apart, stretching or elongating it along the line of the applied load. Compression crushes the material and torsion twists it; the stress that stretches is tension (FAA-H-8083-31, Metallic Structures).· FAA-H-8083-31 — Metallic Structures
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A fuselage station identifies a
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Answer: longitudinal (fore-and-aft) point on the fuselage
Why: Fuselage stations are measured fore-and-aft in inches from a reference datum, locating a point along the longitudinal axis of the fuselage. Lateral positions across the fuselage or wing are defined instead by buttock lines and wing stations (FAA-H-8083-31, Metallic Structures).· FAA-H-8083-31 — Metallic Structures
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In the ATA 100 zonal numbering system, major zone 100 designates the
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Answer: lower half of the fuselage
Why: In the ATA 100 zonal system, major zone 100 designates the lower half of the fuselage while zone 200 covers the upper fuselage. The left and right wings are zones 500 and 600, so zone 100 is the lower fuselage (FAA-H-8083-31, Metallic Structures).· FAA-H-8083-31 — Metallic Structures
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What force is an I-beam primarily designed to resist?
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Answer: Bending
Why: An I-beam is shaped to resist bending: its top and bottom flanges carry the tension and compression produced by a bending moment while the web carries the shear. The geometry concentrates material where bending stresses are greatest, so it is designed primarily to resist bending (FAA-H-8083-31, Metallic Structures).· FAA-H-8083-31 — Metallic Structures
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Precise locations on an aircraft structure are defined by a system of
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Answer: fuselage stations, water lines, and buttock lines
Why: Aircraft locations are defined by three orthogonal references: fuselage stations measured fore-and-aft, water lines measured vertically, and buttock lines measured laterally from the centerline. Together these three systems pinpoint any precise location on the structure (FAA-H-8083-31, Metallic Structures).· FAA-H-8083-31 — Metallic Structures
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Which of the following is an example of a fail-safe (multiple-load-path) structural member?
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Answer: A stringer
Why: A fail-safe structure relies on multiple load paths so that if one member fails the load is redistributed to others. Stringers are numerous and share skin loads, so the failure of one is carried by adjacent members. A spar or longeron is a primary single load path whose failure is more critical (FAA-H-8083-31, Metallic Structures).· FAA-H-8083-31 — Metallic Structures
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Damage-tolerant structural design
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Answer: allows certain damage to remain un-repaired between scheduled inspections
Why: Damage-tolerant design assumes that flaws or cracks may exist and ensures the structure retains adequate residual strength so the damage can be found at scheduled inspections before it becomes critical. It therefore permits certain damage to remain between inspections and applies to primary structure, not only secondary (FAA-H-8083-31, Metallic Structures).· FAA-H-8083-31 — Metallic Structures
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In the ATA 100 zonal system, a passenger entry door is identified by which major zone designation?
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Answer: 800
Why: In the ATA 100 zonal system, zone 800 is allocated to the doors, including passenger entry doors. The 400 and 600 series designate other major zones (powerplant and right wing), so a passenger entry door carries an 800-series designation (FAA-H-8083-31, Metallic Structures).· FAA-H-8083-31 — Metallic Structures
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Which area of an aircraft is subject to hoop stress?
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Answer: The pressurized cabin
Why: Hoop stress is the circumferential tension that acts to split a pressurized cylinder along its length. The pressurized fuselage cabin behaves like such a cylinder, so cabin pressurization loads the skin in hoop tension. Wings and control surfaces are loaded mainly in bending and shear, not hoop stress (FAA-H-8083-31, Metallic Structures).· FAA-H-8083-31 — Metallic Structures
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Shear stress is best described as a stress that tends to make adjacent layers of material
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Answer: slide or slip past one another
Why: Shear stress arises when two opposing forces act parallel to a section, tending to make one layer of material slide or slip relative to the adjacent one. Compression pushes material together and tension pulls it apart; the stress that makes parts slide past each other is shear (FAA-H-8083-31, Metallic Structures).· FAA-H-8083-31 — Metallic Structures
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An aircraft location given as FS 245, RWS 45 refers to a point that is
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Answer: 245 inches aft of the datum and 45 inches outboard from the right wing centerline
Why: Fuselage stations are measured from the aircraft reference datum, not from the nose, so FS 245 means 245 inches aft of that datum. RWS 45 means 45 inches outboard along the right wing from the wing centerline, so the position is referenced to the datum and the wing centerline (FAA-H-8083-31, Metallic Structures).· FAA-H-8083-31 — Metallic Structures
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The permanent deformation a material undergoes after being loaded beyond its elastic limit is described in terms of
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Answer: strain
Why: Strain is the deformation a material experiences under load. When a material is stressed beyond its elastic limit, the strain becomes permanent. Shear and bending describe types of loading, not the resulting deformation itself.· FAA-H-8083-31 — Metallic Structures
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A characteristic of semi-monocoque fuselage construction is that it
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Answer: offers good damage resistance
Why: Semi-monocoque construction carries loads through a stressed skin supported by formers, frames, bulkheads, and stringers, providing multiple load paths. If one member is damaged, adjacent members can carry the load, giving it good damage resistance. It is used for more than just the fuselage.· FAA-H-8083-31 — Metallic Structures
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Most radio antennas on an aircraft are
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Answer: bonded to the airframe
Why: Radio antennas are electrically bonded to the airframe so they share a common ground potential and have a low-resistance path that protects the antenna and radio equipment from static buildup and lightning. An unbonded or insulated antenna would allow charge accumulation and degrade radio performance.· FAA-H-8083-31 — Metallic Structures
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Water lines (WL) are measured reference points located along a
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Answer: vertical line
Why: Water lines measure height, locating points along a vertical reference above (or below) a horizontal datum plane. They form the vertical leg of the station system, complementing fuselage stations (fore-and-aft) and buttock lines (lateral).· FAA-H-8083-31 — Metallic Structures
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The separate parts of an aircraft airframe are maintained at the same electrical potential by
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Answer: bonding
Why: Bonding connects the separate parts of the airframe together with low-resistance straps so they are held at the same electrical potential, preventing dangerous voltage differences and providing a path for static and lightning currents. Static wicks discharge accumulated charge to the atmosphere; equalizing potential between structural parts is bonding.· FAA-H-8083-31 — Metallic Structures
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Which grouping lists only basic stresses that act on an aircraft structure?
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Answer: tension, compression, torsion, and shear
Why: FAA-H-8083-31 lists five stresses that act on an aircraft structure: tension (stretching), compression (crushing), torsion (twisting), shear (sliding), and bending (a combination of tension and compression). Of the groupings offered, only tension, compression, torsion, and shear are all basic stresses. Fatigue and creep are failure mechanisms caused by stress applied over time, not stresses themselves.· FAA-H-8083-31 — Metallic Structures
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A structural member designed to carry a compression load is called a
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Answer: strut
Why: A strut is a structural member designed to carry compression (push) loads along its length. A cable can only take tension, and a beam is designed to resist bending, so the member that takes a compression load is a strut.· FAA-H-8083-31 — Metallic Structures
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Stringers are longitudinal stiffeners used in which type of fuselage construction?
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Answer: semi-monocoque
Why: Stringers are longitudinal stiffeners fitted in semi-monocoque construction, where the skin, frames, and stringers share the loads. Pure monocoque relies on the skin alone with no stringers, and truss-type fuselages use welded tube members, so stringers belong to semi-monocoque design.· FAA-H-8083-31 — Metallic Structures
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Wing station numbers are measured
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Answer: outboard from the fuselage centerline
Why: Wing station numbers increase outboard from the aircraft's longitudinal centerline, giving a spanwise coordinate. They are not taken from the upper surface, which is a vertical reference, so wing stations are measured outboard from the fuselage centerline.· FAA-H-8083-31 — Metallic Structures
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What type of load is a tie rod designed to accept?
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Answer: tensile
Why: A tie rod is a slender member that carries only tensile (pulling) loads, holding two points together. It is not designed for bending or torsion, which require stiffer sections, so a tie rod is intended to accept a tensile load.· FAA-H-8083-31 — Metallic Structures
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Primary structure carries the principal flight, ground, and pressurization loads. Which of the following is classified as primary structure?
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Answer: the stressed skin
Why: Primary structure carries the principal flight, ground, and pressurization loads, and its failure would endanger the aircraft. The stressed skin of a semi-monocoque airframe carries a major share of these loads and is therefore classified as primary structure.· FAA-H-8083-31 — Metallic Structures
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Fuselage station numbers are measured aft from a forward datum and are conventionally expressed in
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Answer: inches
Why: Fuselage station numbers are linear distances measured aft from a forward datum and, by convention, are expressed in inches. Using a single consistent unit of inches keeps station, water-line, and buttock-line coordinates uniform.· FAA-H-8083-31 — Metallic Structures
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A structure built with redundancy so that more than one member shares a load is described as
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Answer: fail-safe
Why: A fail-safe structure has built-in redundancy: multiple load paths so that if one member fails, the remaining members carry the load until the defect is found and repaired. Safe-life relies on retiring a part before failure rather than on redundancy, so a redundant design is termed fail-safe.· FAA-H-8083-31 — Metallic Structures
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A structural component that must be replaced at a specified number of cycles, flight hours, or calendar years regardless of its physical condition is what type of item?
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Answer: Safe-life
Why: A safe-life item is removed from service at a predetermined number of cycles, flight hours, or calendar time regardless of apparent condition, because fatigue failure cannot be reliably detected before it occurs. Fail-safe and condition-monitored items remain in service as long as inspections show them serviceable.· FAA-H-8083-31 — Metallic Structures
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The safe-life of a structural component is best described as
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Answer: the minimum number of flight hours that should elapse before a major structural failure occurs
Why: Safe-life is the conservatively established minimum service life, in flight hours or cycles, that should elapse before fatigue could cause a major structural failure; the part is retired before that point with a safety margin. Loads shared between members describe redundancy, not safe-life.· FAA-H-8083-31 — Metallic Structures
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Bending stress in a structural member is a combination of
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Answer: tension and compression stresses
Why: When a member bends, the fibers on the convex side are stretched in tension while those on the concave side are squeezed in compression, with a neutral axis between them. Bending stress is therefore the combination of tension and compression, not torsion or shear.· FAA-H-8083-31 — Metallic Structures
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The areas that share the most ground with AM.II.A — study them alongside it.
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Frequently asked questions
- How do you calculate bend allowance?
- Bend allowance is the length of material in the bend, measured along the neutral axis from one bend tangent line to the other. You get it from a bend allowance chart for the material thickness, bend radius, and angle, or from the standard formula that combines the radius, the thickness, and the number of degrees of bend. Add it to the flat portions for total developed length.
- What is the minimum edge distance for a rivet?
- Two rivet diameters, measured from the center of the rivet hole to the edge of the sheet, and two and a half diameters when the rivet is countersunk. Any less and the sheet can tear out at the edge. Common practice keeps edge distance between two and four diameters, with minimum rivet pitch of three diameters along the row.
- What size rivet do I use for a given sheet thickness?
- The rule of thumb is a shank diameter about three times the thickness of the thickest sheet in the joint, then rounded to the nearest standard size. Rivet length is the total grip length of the sheets plus roughly one and a half diameters of extra shank, which supplies the material needed to form the head.
- When do you dimple instead of machine countersinking?
- Machine countersinking cuts material away, so it needs sheet thicker than the depth of the countersunk rivet head. On thinner material the cut breaks through and leaves a knife edge with no bearing surface, so the sheet is dimpled instead, forming the recess by pressing the metal rather than removing it. As a rule of thumb, thin sheet around 0.040 inch and under is dimpled.
- Is stop drilling a permanent crack repair?
- No. Stop drilling removes the sharp tip where stress concentrates and keeps the crack from growing in the short term, but it restores no strength. The area still needs a repair sized from approved data, typically a patch or doubler, and the reason the crack started has to be addressed or the same damage returns nearby.
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- Airframe Inspection
- Landing Gear Systems
- Hydraulic and Pneumatic Systems
- Environmental Systems
- Aircraft Instrument Systems
- Communications, Light Signals, and Runway Lighting Systems
- Aircraft Fuel Systems
- Aircraft Electrical Systems
- Ice and Rain Control Systems
- Airframe Fire Protection Systems
- Rotorcraft Fundamentals
- Water and Waste Systems
Powerplant
- Reciprocating Engines
- Turbine Engines
- Engine Inspection
- Engine Instrument Systems
- Engine Fire Protection Systems
- Engine Electrical Systems
- Engine Lubrication Systems
- Ignition and Starting Systems
- Engine Fuel and Fuel Metering Systems
- Reciprocating Engine Induction and Cooling Systems
- Turbine Engine Air Systems
- Engine Exhaust and Reverser Systems
- Propellers
Primary sources
Drill ACS AM.II.A inside the full Airframe bank
Adaptive engine, timed exam simulator, ACS-code remediation, and oral prep — everything you need to pass.