Chapter 1 · Properties of Metals and Aircraft Steels
| Item | Fact / typical value | Topic |
|---|---|---|
| Densities | steel ≈ 7.85 · Ti ≈ 4.5 · Al ≈ 2.7 · Mg ≈ 1.74 g/cm³ | 6.1 |
| Carbon steel | low 0.10–0.30% · medium 0.30–0.50% · high 0.50–1.05% · cast iron > 2% | 6.1 |
| SAE first digit | 1 carbon · 2 Ni · 3 Ni-Cr · 4 Mo (41 Cr-Mo) · 5 Cr · 6 Cr-V · 8 Ni-Cr-Mo · 9 Si-Mn | 6.1 |
| SAE last digits | carbon in hundredths of % (4130 → 0.30% C) | 6.1 |
| Stainless | austenitic 300 (18-8) non-magnetic · martensitic 400 heat-treatable · PH 17-4 | 6.1 |
| Quench speed | brine > water > oil > air | 6.1 |
| Heat treatments | harden: quench · temper: below critical · anneal: furnace cool · normalise: air cool | 6.1 |
| Nitriding | ammonia ≈ 510 °C, no quench | 6.1 |
Chapter 2 · Testing, Inspecting and Repairing Steel Parts
| Item | Fact / typical value | Topic |
|---|---|---|
| Brinell | 10 mm steel ball · 3 000 kg steel (500 kg soft) · impression diameter → BHN | 6.1 |
| Rockwell | 10 kg minor + major · C: diamond cone 150 kg · B: 1/16 in ball 100 kg · depth | 6.1 |
| Vickers | 136° diamond pyramid · diagonals | 6.1 |
| Tensile test | elastic → yield → UTS → necking → fracture · elongation = ductility | 6.1 |
| Impact | Charpy (simple beam) · Izod (cantilever) · energy = toughness | 6.1 |
| Fatigue | S-N curve · steel has an endurance limit, aluminium does not | 6.1 |
| Magnetic particle | ferromagnetic only · surface/near-surface · 2 directions · demagnetise | 6.1 |
| Hydrogen embrittlement | from plating/acid · bake after plating | 6.1 |
Chapter 3 · Aluminium Alloys
| Item | Fact / typical value | Topic |
|---|---|---|
| Al series | 1xxx pure · 2 Cu · 3 Mn · 4 Si · 5 Mg · 6 Mg-Si · 7 Zn · 8 other (Li) | 6.2 |
| Heat-treatable | 2xxx, 6xxx, 7xxx · non-HT 1, 3, 5 (H tempers) | 6.2 |
| Key alloys | 2024 skins/fatigue · 7075 strength · 6061 weldable · 5052 tanks · 2117 rivets | 6.2 |
| Tempers | F · O annealed · H strain hardened · W unstable · T3 · T4 · T6 · T7 · T8 | 6.2 |
| Alclad | pure Al layer ≈ 1.5–5% each side · anodic, sacrificial | 6.2 |
| 2024 heat treatment | solution ≈ 490–500 °C · quench in seconds · age | 6.2 |
| Icebox rivets | 2017 (D) ≈ 1 h · 2024 (DD) ≈ 10–20 min · store ≈ −18 °C | 6.2 |
| Rivet codes | A 1100 · AD 2117 · D 2017 · DD 2024 · B 5056 | 6.2 |
Chapter 4 · Magnesium, Titanium, Copper and Nickel — Testing and Repair
| Item | Fact / typical value | Topic |
|---|---|---|
| Magnesium | 1.74 g/cm³ · most anodic · white powdery corrosion · fire: no water (Class D) | 6.2 |
| Titanium | 4.5 g/cm³ · to ≈ 500 °C · Ti-6Al-4V · no Cd tools, no chlorides · white spark | 6.2 |
| Copper alloys | brass Cu-Zn · bronze Cu-Sn · beryllium copper springs | 6.2 |
| Nickel alloys | Monel Ni-Cu (corrosion) · Inconel Ni-Cr-Fe (heat) | 6.2 |
| Non-ferrous testing | Rockwell B · Brinell 500 kg · Barcol · conductivity % IACS · no MPI | 6.2 |
| Damage classes | negligible · repairable · replace (SRM) | 6.2 |
Chapter 5 · Composites, Plastics, Rubber and Sealants
| Item | Fact / typical value | Topic |
|---|---|---|
| Composite | fibres carry load · matrix binds and transfers | 6.3.1 |
| Fibres | glass white (radar-transparent) · aramid yellow (tough, poor compression) · carbon black (stiff, conductive) | 6.3.1 |
| Resins | thermoset: epoxy, polyester, phenolic, BMI · thermoplastic: PEEK | 6.3.1 |
| Prepreg | stored frozen ≈ −18 °C · out-time · shelf life | 6.3.1 |
| Directions | warp 0° · fill/weft 90° · bias 45° | 6.3.1 |
| Cores | Nomex · aluminium · glass honeycomb · foam · balsa | 6.3.1 |
| Rubbers | Buna-N fuel/oil · butyl Skydrol · neoprene weather · silicone temperature · Viton heat/fuel | 6.3.1 |
| Sealant | polysulphide two-part · pot life, tack-free, cure | 6.3.1 |
Chapter 6 · Composite Damage: Detection and Repair
| Item | Fact / typical value | Topic |
|---|---|---|
| Composite defects | delamination · disbond · voids · BVID · moisture · heat · lightning · erosion | 6.3.1 |
| Tap test | sharp ring = sound · dull thud = delamination/disbond | 6.3.1 |
| NDI | ultrasonic maps damage · thermography & X-ray find water · Barcol checks cure | 6.3.1 |
| Scarf ratio | shallow taper, often 30:1–50:1 (per SRM) | 6.3.1 |
| Bag lay-up | peel ply · release film · bleeder · breather · bag · sealant tape | 6.3.1 |
| Cure | heat blanket + hot bonder + thermocouples · ≈ 120 °C or 180 °C prepregs | 6.3.1 |
Chapter 7 · Wooden Structures and Fabric Covering
| Item | Fact / typical value | Topic |
|---|---|---|
| Aircraft woods | Sitka spruce reference · Douglas fir, Noble fir, Western hemlock substitutes | 6.3.2 |
| Grain slope | ≤ 1 in 15 | 6.3.2 |
| Never acceptable | decay · compression wood · compression failures | 6.3.2 |
| Wood glues | resorcinol, epoxy (casein deteriorates) | 6.3.2 |
| Spar scarf | ≈ 1 in 10 to 1 in 12 | 6.3.2 |
| Fabrics | cotton, linen (doped) · polyester (heat-shrunk) · glass | 6.3.3 |
| Dopes | nitrate: adhesion, flammable · butyrate: fire-resistant, tautens | 6.3.3 |
| Fabric strength | ≥ 70% of new-fabric requirement | 6.3.3 |
Chapter 8 · Corrosion
| Item | Fact / typical value | Topic |
|---|---|---|
| Corrosion cell | anode (corrodes) · cathode · electrolyte · electrical path | 6.4 |
| Galvanic order | Mg · Zn · Cd · Al · steel · Pb/Sn · Cu alloys · Ni/Monel · stainless · Ag · Ti · graphite · Au | 6.4 |
| Worst pairing | small anode + large cathode | 6.4 |
| Products | Al white/grey · Mg white snow-like · steel red rust · Cu blue-green · Cd white | 6.4 |
| Hidden forms | intergranular · exfoliation · SCC (sustained tension) · corrosion fatigue | 6.4 |
| Fretting | 'smoking rivets' — loose fasteners | 6.4 |
| Concentration cell | low-oxygen areas corrode (crevices, under seals) | 6.4 |
| Removal on Al | aluminium oxide paper, nylon pads — never steel wool | 6.4 |
| CPCP levels | 1 within limits · 2 beyond limits · 3 urgent airworthiness concern | 6.4 |
Chapter 9 · Screw Threads, Bolts, Studs, Screws and Nuts
| Item | Fact / typical value | Topic |
|---|---|---|
| Thread angles | Unified/metric 60° · Whitworth 55° · BA 47.5° · Acme 29° | 6.5.1 |
| Pitch / lead | TPI = 1 ÷ pitch · lead = pitch × starts | 6.5.1 |
| Fits | 1 loose · 2 general · 3 close · A external · B internal | 6.5.1 |
| AN bolt diameter | AN number in 1/16 in (AN4 = 1/4 in) | 6.5.2 |
| AN grip dash number | 1st digit inches, 2nd eighths (-12 = 1¼ in) | 6.5.2 |
| AN letters | C stainless · DD 2024 · none Cd steel · H drilled head · A undrilled shank | 6.5.2 |
| Head marks | cross steel · 1 dash stainless · 2 dashes Al · triangle close tolerance | 6.5.2 |
| Torque extension | setting = T × L ÷ (L + E) | 6.5.2 |
| Nuts | AN310 castellated · AN320 shear · AN315 plain · AN316 check · AN350 wing · AN365 nylon ≤ 120 °C | 6.5.2 |
Chapter 10 · Locking Devices and Aircraft Rivets
| Item | Fact / typical value | Topic |
|---|---|---|
| Lockwire pigtail | ≈ ½ in, bent back · usually ≤ 3 fasteners per run | 6.5.3 |
| Rivet codes | A 1100 · AD 2117 dimple · D 2017 dot · DD 2024 double dash · B 5056 cross | 6.5.4 |
| Rivet part number | MS20470AD4-6: Ø 4/32 in · length 6/16 in | 6.5.4 |
| Icebox time | 2024-DD: drive within ≈ 10–20 min | 6.5.4 |
| Rivet length | grip + 1.5 D | 6.5.4 |
| Shop head | 1.5 D wide · 0.5 D high | 6.5.4 |
| Layout | edge ≥ 2 D (2.5 D csk) · pitch 3–4 D · transverse ≈ 75 % of pitch | 6.5.4 |
Chapter 11 · Pipes, Hoses, Unions and Springs
| Item | Fact / typical value | Topic |
|---|---|---|
| Flare angle | AN 35–37° · automotive 45° not permitted | 6.6 |
| Sizes | tube OD in 1/16 in · hose ID in 1/16 in | 6.6 |
| Bend flattening | ≥ 75 % of OD | 6.6 |
| Double flare | soft Al ≤ 3/8 in OD | 6.6 |
| Hose slack | 5–8 % · support ≈ every 24 in | 6.6 |
| Hose pressure | low < 250 psi · high ≥ 3000 psi | 6.6 |
| Spring rate | k = F ÷ x | 6.7 |
Chapter 12 · Bearings and Transmissions
| Item | Fact / typical value | Topic |
|---|---|---|
| Gear ratio | driven teeth ÷ driver teeth = driver speed ÷ driven speed | 6.9 |
| Belt ratio | driven pulley Ø ÷ driver pulley Ø | 6.9 |
| Lever MA | effort arm ÷ load arm | 6.9 |
Chapter 13 · Control Cables and Fittings
| Item | Fact / typical value | Topic |
|---|---|---|
| Cable types | 1×19 non-flexible · 7×7 flexible · 7×19 extra-flexible | 6.10 |
| Turnbuckle | ≤ 3 threads exposed each end | 6.10 |
| Fairlead | ≤ ≈ 3° deflection | 6.10 |
Chapter 14 · Electrical Cables and Connectors
| Item | Fact / typical value | Topic |
|---|---|---|
| Plating | tin ≈ 150 °C · silver ≈ 200 °C · nickel ≈ 260 °C | 6.11 |
| Aluminium wire | ≥ 8 AWG · not on engines · not runs < 3 ft | 6.11 |
| Terminal colours | red 22–18 · blue 16–14 · yellow 12–10 AWG | 6.11 |
| Marking | ≤ 15 in intervals · within 3 in of ends | 6.11 |
| Bend radius | ≥ 10 × OD (3 × at supported terminals) | 6.11 |
| Supports | ≤ 24 in · ≈ ½ in slack deflection | 6.11 |
| Coax | 50 Ω or 75 Ω | 6.11 |