CAAB AME B1.1 Exam cheat sheet

Aircraft Maintenance Engineering (B1.1) - Core Knowledge Reference

• Mass and balance: moment = mass × arm; CG position = total moment ÷ total mass; adding mass aft of the datum moves the CG aft, adding mass forward moves it forward.

• Bernoulli and continuity: for steady incompressible flow, A₁V₁ = A₂V₂ and total pressure = static pressure + dynamic pressure (q = ½ρV²); a venturi throat shows lower static pressure and higher velocity.

• Gas laws for B1.1 systems: Boyle pV = constant at constant temperature; Charles V/T = constant at constant pressure; the combined gas law pV/T = constant applies to pressurised cabins and gas-charged accumulators.

• Hydraulic power: pressure p = F/A; flow rate Q = area × velocity; hydraulic power = p × Q. A smaller piston area gives higher output pressure for the same input force (force multiplier).

• Electrical essentials: Ohm's law V = IR; power P = VI = I²R = V²/R; series resistances add, parallel resistances give 1/R_total = Σ(1/Rᵢ); two equal resistors in parallel halve the value.

• Torque and stress: torque = force × perpendicular distance; stress σ = load/area; strain ε = extension/original length; Young's modulus E = σ/ε applies in the elastic region only.

• Materials decision rule: 2024 aluminium alloy has good fatigue resistance but low corrosion resistance (clad or protected); 7075 has high strength with poor corrosion resistance; 6061 is weldable and corrosion resistant but lower strength.

• Corrosion rule: galvanic corrosion needs two dissimilar metals, an electrolyte and electrical contact; the more anodic metal corrodes. Cadmium-plated steel fasteners in aluminium structure are a classic couple to avoid or seal.

• Inspection intervals: 'A' checks are typically light, frequent line checks; 'C' checks are heavier and less frequent; 'D' checks are the heaviest structural checks. Actual intervals and content are set by the approved maintenance programme, not by the letter alone.