BTS Aéronautique cheat sheet

Thèse, arguments, exemples : la thèse est l'idée défendue, l'argument la justifie, l'exemple l'illustre concrètement.

Connecteurs logiques et leurs valeurs : 'donc' (conséquence), 'or' (opposition/addition décisive), 'en revanche' (opposition), 'par conséquent' (conclusion).

Types de textes : narratif (raconte), descriptif (décrit), explicatif (fait comprendre), argumentatif (convainc, persuade, délibère).

Registres de langue : soutenu, courant, familier ; le registre d'un texte se repère au lexique, à la syntaxe et aux marques de modalisation.

Figures de style fréquentes : métaphore (analogie implicite), comparaison (outil 'comme'), hyperbole (exagération), ironie (dire le contraire), litote (dire moins pour suggérer plus).

Synthèse de documents : reformuler avec ses propres mots, citer entre guillemets avec référence, confronter les documents (convergences/divergences) sans juxtaposer.

Écrit professionnel : la lettre formelle comporte objet, formule d'appel, corps, formule de politesse ; le compte rendu est objectif et chronologique.

Accord du participe passé : avec 'être' s'accorde avec le sujet ; avec 'avoir' s'accorde avec le COD placé avant le verbe.

Aircraft anatomy terms: fuselage (body), wing, empennage (tail), landing gear, engine nacelle, cockpit, cargo hold.

Maintenance vocabulary: scheduled maintenance, unscheduled/unscheduled defect, AOG (Aircraft On Ground), MEL (Minimum Equipment List), troubleshooting, rectification.

Passive voice for technical writing: 'The panel is inspected every 500 flight hours' - form be + past participle.

Modals of obligation and permission: 'must' (obligation), 'should' (recommendation), 'may/might' (possibility), 'can' (capability/authorisation).

Conditional type 1 for procedures: 'If the warning light remains on, the crew must return to the gate.'

Numbers and units: read 'FL350' as flight level three five zero; '12 000 ft' as twelve thousand feet; units are not pluralised (5 kg, 3 m).

Reported speech shift: present becomes past, 'today' becomes 'that day', 'will' becomes 'would'.

Email conventions: subject line with reference (e.g., 'RFQ – P/N 12345'), salutation 'Dear Mr Smith', closing 'Best regards' or 'Yours sincerely'.

Trigonometry: in a right triangle sin = opposite/hypotenuse, cos = adjacent/hypotenuse, tan = opposite/adjacent; SOH-CAH-TOA.

Pythagorean theorem: a² + b² = c² for the hypotenuse c; used for distance and vector magnitude calculations.

Derivative rules: (xⁿ)' = n·xⁿ⁻¹, (sin x)' = cos x, (cos x)' = −sin x, (eˣ)' = eˣ, (ln x)' = 1/x.

Exponential and logarithm: ln(a·b) = ln a + ln b; ln(a/b) = ln a − ln b; ln(aⁿ) = n·ln a; e^(ln x) = x.

Statistics: mean = Σxᵢ/n; variance = Σ(xᵢ − mean)²/n; standard deviation = √variance; median splits the sorted series in two.

Linear regression: y = ax + b with a = Cov(x,y)/Var(x); correlation coefficient r between −1 and 1, |r| close to 1 means strong linear link.

Units and conversions: 1 inch = 25.4 mm; 1 knot = 1.852 km/h; 1 bar = 10⁵ Pa; 1 psi ≈ 6 895 Pa; 1 kgf ≈ 9.81 N.

Geometry: circle area = πr², circumference = 2πr; cylinder volume = πr²h; sphere volume = (4/3)πr³.

Pressure: p = F/S in pascals (N/m²); hydrostatic pressure p = ρ·g·h with ρ in kg/m³, g ≈ 9.81 m/s², h in m.

Ideal gas law: p·V = n·R·T with R = 8.314 J/(mol·K); T must be in kelvin (T(K) = θ(°C) + 273.15).

Bernoulli (incompressible, steady flow): p + ½ρv² + ρgz = constant; higher velocity means lower static pressure.

Lift formula: L = ½·ρ·v²·S·C_L; drag D = ½·ρ·v²·S·C_D; increasing speed increases lift as the square of velocity.

Ohm's law and power: U = R·I; P = U·I = R·I² = U²/R; energy W = P·t in joules (or kWh).

pH and acids/bases: pH = −log[H₃O⁺]; pH < 7 acidic, pH = 7 neutral, pH > 7 basic; dilution moves pH toward 7.

Corrosion: oxidation of a metal (aluminium, steel) by oxygen and moisture; protection by paint, anodising, or sacrificial anode (cathodic protection).

Thermal expansion: ΔL = L₀·α·ΔT; α is the linear expansion coefficient (per kelvin).

Tightening torque: C = F·r (torque = force × lever arm); a torque wrench applies a controlled tightening moment in N·m.

Mechanical assemblies: bolted joint (démontable), riveted joint (permanent), welded joint (permanent), bonded joint (adhesive).

Bearings and friction: ball/roller bearings reduce friction and carry radial and/or axial loads; plain bearings rely on a lubricant film.

Tolerances and fits: ISO fits (H7/g6) define clearance or interference; the shaft and hole tolerance classes determine assembly type.

Gear ratio: r = Z_driven / Z_driver; output speed N_out = N_in / r; torque increases as speed decreases (ideal case).

Belt and chain drives transmit motion between parallel shafts; slip is possible with belts but not with chains.

Stress and strain: σ = F/S (normal stress in MPa), ε = ΔL/L₀ (strain, dimensionless); Hooke's law σ = E·ε in the elastic domain.

Free-body diagram (bilan des actions mécaniques): identify external forces, their points of application, direction, sense, and magnitude before solving equilibrium.

Series circuit: R_eq = R₁ + R₂ + …; current is the same everywhere; voltages add. Parallel circuit: 1/R_eq = 1/R₁ + 1/R₂ + …; voltage is the same; currents add.

Voltage divider: V_out = V_in · R₂/(R₁ + R₂) for two resistors in series.

Power in DC: P = U·I; in AC single-phase: P = U·I·cos φ (cos φ = power factor).

Three-phase: P = √3 · U · I · cos φ; line voltage vs phase voltage depends on star (Y) or delta (Δ) connection.

Diode: conducts in forward bias above ~0.7 V (silicon), blocks in reverse bias; used for rectification.

Logic gates: AND (output 1 only if all inputs 1), OR (output 1 if at least one input 1), NOT (inverter), NAND and NOR (universal gates).

Relay/contactor: an electromagnet coil controls isolated contacts; used to switch high-current loads from a low-current control circuit.

Sensors and signals: 4–20 mA current loop and 0–10 V voltage signals are standard industrial interfaces; a PLC reads inputs, executes the program, drives outputs.

Maintenance types: line maintenance (before flight, daily, transit), base maintenance (heavy checks, C/D checks), shop maintenance (components).

ATA 100 chapters classify systems: ATA 21 air conditioning, ATA 24 electrical power, ATA 27 flight controls, ATA 32 landing gear, ATA 71 power plant.

MEL (Minimum Equipment List): allows dispatch with specified inoperative items under defined conditions; deferral must be recorded.

Technical logbook: records defects, rectifications, and release to service; a Certificate of Release to Service (CRS) is signed by authorised staff.

FOD (Foreign Object Debris) prevention: tool control, FOD walk, shadow boards, and area inspection before engine start.

Safety around aircraft: never approach an engine intake; respect propeller/rotor danger zones; use lockout/tagout before working on systems.

Corrosion inspection: look for exfoliation, pitting, and galvanic corrosion at dissimilar-metal joints; treat per structural repair manual (SRM).

Torque and safetying: use calibrated torque wrench; apply lockwire or cotter pins where specified after tightening.

PDCA cycle: Plan (define objectives), Do (implement), Check (measure results), Act (standardise or correct).

Quality tools: Ishikawa (cause-effect diagram), Pareto (80/20 priority), 5 Whys (root cause), control chart (process stability).

Lean principles: eliminate waste (muda), just-in-time, kanban, 5S (sort, set in order, shine, standardise, sustain), continuous improvement (kaizen).

KPI examples: OEE (Overall Equipment Effectiveness = availability × performance × quality), on-time delivery rate, defect rate (PPM).

Safety: risk assessment = severity × probability; hierarchy of controls (eliminate, substitute, engineering, administrative, PPE).

Non-conformity handling: identify, contain, root-cause analysis, corrective action, verify effectiveness, close the record.

Traceability: batch/lot numbers, serial numbers, and records allow tracking a part from raw material to delivery.

Documentation: work instruction, procedure, quality manual; version control and approval before use.

Project phases: initiation, planning, execution, monitoring/control, closure; deliverables and milestones mark progress.

Gantt chart: horizontal bars show tasks over time and dependencies; critical path is the longest sequence of dependent tasks.

Cahier des charges (specification): functional requirements (what the system must do) and technical constraints (performance, standards, cost, safety).

Communication: adapt the message to the audience (technician, customer, manager); use clear structure: context, facts, proposal, action.

Meeting minutes: date, attendees, agenda items, decisions, action items with owner and deadline.

Technical report structure: title, summary, context, method, results, analysis, conclusion, recommendations, appendices.

Risk register: list risks with probability, impact, mitigation plan, owner; review regularly.

Change management: any change to a technical baseline must be documented, approved, and communicated to affected parties.