Module 11: Aeroplane Aerodynamics, Structures and Systems

11.1Theory of Flight

11.1(a)Aeroplane Aerodynamics and Flight Controls

• Atmosphere: composition, International Standard Atmosphere (ISA), application to aerodynamics
• Bernoulli's theorem, subsonic airflow
• Boundary layer: laminar and turbulent flow, free stream flow, relative airflow
• Generation of lift: angle of attack, lift coefficient, centre of pressure, aerofoil types
• Drag: parasite drag, induced drag, drag coefficient, ground effect
• Lift/drag ratio, aircraft polar diagram
• Stalling: stall angle, stall speed, stall warning, wing contamination effects
• Aerofoil contamination (ice, frost, rain, insects) — effects on lift and stall characteristics
• Stability: static and dynamic, longitudinal, lateral, and directional
• Wing planforms: aspect ratio, wing sweep, taper, wash out, mean aerodynamic chord
• Control around three axes: roll, pitch, yaw
• Primary flight controls: ailerons, elevators, rudder — operation and effects
• Secondary flight controls: trim tabs, balance tabs, anti-balance tabs, servo tabs, spring tabs, spoilers, leading edge devices (slats, slots), trailing edge devices (flaps — types and effects)
• Drag-inducing devices: spoilers, lift dumpers, speed brakes
• Effects of wing fences and saw-tooth leading edges
• Boundary layer control: vortex generators, stall strips

11.1(b)High Speed Flight and Other Aerodynamic Devices

• Speed of sound, Mach number, critical Mach number
• Compressibility effects: shock waves, aerodynamic heating, Mach tuck, buffet
• Swept wing design: advantages and limitations
• Area rule
• Factors affecting airflow in engine intakes at high speeds

11.2Airframe Structures — General (ATA 51)

11.2(a)General Concepts

• Fuselage: types (truss, monocoque, semi-monocoque), frames, formers, longerons, stringers, skin, doublers
• Structural classification: primary, secondary, tertiary structure
• Fail-safe, safe-life, damage-tolerant concepts
• Zonal and station identification systems
• Stress, strain, bending, compression, shear, tension, torsion, fatigue
• Lightning strike protection and bonding
• Aircraft bonding and earthing

11.2(b)Airworthiness Requirements for Structural Strength

• Structural classification: primary, secondary, tertiary
• Fail-safe, safe-life, damage-tolerant design philosophies
• Aircraft zoning and station numbers

11.2(c)Construction Methods

• Riveted and bolted construction
• Bonded construction (adhesives, honeycomb)
• Surface treatments: alodine, anodising, chromating
• Composite materials: fibre-reinforced plastics, carbon fibre, aramid, glass fibre
• Composite repair techniques
• Woodwork and fabric covering (where applicable)

11.3Airframe Structures — Aeroplanes

11.3.1Fuselage, Doors, Windows (ATA 52/53/56)

• Construction principles: skin panels, frames, longerons, bulkheads, stringers, floor beams
• Pressurised and unpressurised fuselage construction
• Wing-to-fuselage attachment methods
• Structural mountings and stress panels
• Doors: types (passenger, cargo, emergency), construction, operating mechanisms, safety devices, warning systems
• Windows and windshields: construction, heating elements, bird-strike resistance
• Emergency exit design and operation
• Airborne towing devices (glider towing)

11.3.2Wings (ATA 57)

• Wing construction: spar, rib, stringer, skin configuration
• Fuel tank areas (integral, bladder)
• Landing gear attachment points
• Pylon and engine mounting
• Leading edge and trailing edge devices: slats, flaps, spoilers
• Wing tip devices: winglets, wing fences
• Inspection panels and access doors

11.3.3Stabilisers (ATA 55)

• Horizontal stabiliser construction
• Vertical stabiliser (fin) construction
• Tailplane attachment and adjustment
• T-tail and conventional tail configurations

11.3.4Flight Control Surfaces (ATA 55/57)

• Aileron, elevator, rudder construction and attachment
• Tab construction and mechanisms
• Balance panels and mass balance
• Spoiler construction
• Leading edge devices construction
• Trailing edge flap construction and mechanisms

11.3.5Nacelles/Pylons (ATA 54)

• Nacelle construction and cowlings
• Engine pylon structure and attachment
• Firewall construction
• Engine mounting systems and vibration isolation

11.4Air Conditioning and Cabin Pressurisation (ATA 21)

11.4(a)Pressurisation

• Pressurisation systems: need, principles, operation
• Cabin pressure controllers, outflow valves, safety valves
• Pressure differential, maximum differential
• Cabin altitude and rate of climb/descent
• Sources of pressure: engine bleed, APU, ground cart

11.4(b)Air Supply

• Air supply sources: engine bleed, APU bleed, pneumatic ground supply
• Flow control and shut-off valves
• Cross bleed systems
• Ram air ventilation

11.4(c)Air Conditioning

• Air cycle machines (bootstrap, reverse bootstrap)
• Vapour cycle systems
• Pack valves and flow control
• Temperature control systems
• Distribution ducting and mixing chambers
• Recirculation fans and filters

11.4(d)Safety and Warning Devices

• Cabin altitude warning systems
• Over-pressure and negative pressure relief
• Excessive cabin rate of change warnings
• Duct overheat detection

11.4(e)Heating and Ventilation System

• Combustion heaters
• Exhaust heat exchangers
• Electric heaters
• Ventilation and defog/demist systems

11.5Instruments/Avionics Systems

11.5.1Instrument Systems (ATA 31)

• Pitot-static systems: pitot tube, static ports, alternate static
• Airspeed indicator (ASI): IAS, CAS, TAS, Mach
• Altimeter: operation, subscale settings, encoding altimeter
• Vertical speed indicator (VSI, IVSI)
• Gyroscopic instruments: attitude indicator, heading indicator, turn coordinator
• Compass systems: direct reading, remote reading (flux valve)
• Engine instruments: RPM, temperature (EGT, CHT), pressure (manifold, oil, fuel), fuel flow, torque
• Alerting/warning systems: master caution, master warning, annunciator panels
• Glass cockpit: EFIS, EICAS/ECAM, PFD, MFD
• Standby instruments

11.5.2Avionics Systems

• Autoflight systems (ATA 22): autopilot, flight director, yaw damper, trim systems
• Communication systems (ATA 23): VHF, HF, SATCOM, intercom, CVR, ELT
• Navigation systems (ATA 34): VOR, ILS, ADF, DME, GPS, RNAV, inertial navigation, FMS
• Radar systems: weather radar, radio altimeter
• TCAS/ACAS, transponder (Mode A/C/S, ADS-B)
• TAWS/EGPWS (Terrain Awareness Warning System)
• FDR (Flight Data Recorder)

11.6Electrical Power (ATA 24)

• Batteries: installation, operation (lead-acid, NiCd, Li-ion)
• DC generation: generators, starter-generators, alternators
• AC generation: alternators, frequency-wild and constant-frequency systems
• Integrated Drive Generators (IDGs)
• Emergency generation: RAT (Ram Air Turbine), standby generators
• Voltage regulation and current limiting
• Power distribution: bus systems, split bus, essential bus, battery bus
• Circuit protection: circuit breakers, fuses, current limiters
• External/ground power connections and interlocks
• Inverters, transformer rectifier units (TRUs)
• Load management and shedding
• Electrical system monitoring and indicating

11.7Equipment and Furnishings (ATA 25)

11.7(a)Emergency Equipment

• Oxygen masks (crew, passenger), life vests, life rafts
• Emergency exits, slides, slide/rafts
• ELT (Emergency Locator Transmitter)
• Portable fire extinguishers
• Crash axes, megaphones
• Emergency lighting systems

11.7(b)Cabin and Cargo Layout

• Passenger seats and seat belts
• Cabin interior panels, overhead bins, partitions
• Galley installation and equipment
• Lavatory installation
• Cargo compartment: liners, nets, restraints
• Cargo loading systems

11.8Fire Protection (ATA 26)

11.8(a)Fire and Smoke Detection and Extinguishing Systems

• Fire detection systems: thermocouple, resistance loop, continuous loop (pneumatic, electrical)
• Smoke detection: ionisation, photoelectric, CO detection
• Fire zones: engine, APU, cargo, wheel well, lavatory
• Fire extinguishing: fixed systems (HRD bottles), agents (Halon alternatives, inert gas)
• Fire shut-off valves and engine fire switches
• System testing and maintenance

11.8(b)Portable Fire Extinguisher

• Types of extinguishers: water, CO₂, dry chemical, Halon/clean agent
• Selection for fire class (A, B, C, D)
• Inspection and maintenance requirements

11.9Flight Controls (ATA 27)

11.9(a)Primary and Secondary Flight Controls

• Ailerons, elevators, rudder: operation and function
• Spoilers: flight spoilers, ground spoilers/lift dumpers
• Trim systems: trim tabs, trimmable horizontal stabiliser, electric trim
• Flaps: types (plain, split, slotted, Fowler), operation
• Slats and leading edge devices
• Speed brakes

11.9(b)Actuation and Protection

• Manual control: cables, rods, bellcranks, pulleys, torque tubes
• Hydraulic actuators: linear, rotary
• Electrical actuators
• Fly-by-wire (FBW) systems: principles, redundancy, normal/alternate/direct law
• Artificial feel and Q-feel systems
• Stall protection: stick shaker, stick pusher
• Mach trim systems
• Rudder limiters and yaw dampers

11.9(c)System Operation

• Control system architecture: mechanical, hydro-mechanical, FBW
• Power control units (PCUs)
• Autopilot servo actuators
• Gust lock systems
• Control surface flutter damping
• Flap and slat asymmetry protection
• Control system redundancy and monitoring

11.9(d)Balancing and Rigging

• Cable tension adjustment and measurement
• Control surface travel measurement
• Rigging pins and fixtures
• Mass balance and static balance
• Control surface free play checks

11.10Fuel Systems (ATA 28, ATA 47)

11.10(a)Systems Layout

• Tank types: integral, bladder (flexible), rigid removable
• Tank locations: wing, centre section, fuselage, auxiliary, trim tanks
• Tank venting and pressurisation
• Tank drainage and sump drains
• Baffles and anti-surge provisions

11.10(b)Fuel Handling

• Boost pumps: AC motor-driven, DC, jet pump (ejector)
• Transfer and crossfeed systems
• Refuelling: overwing, pressure (single-point)
• Defuelling and fuel jettison systems
• Fuel heating (anti-icing)
• Fuel filtration and water separation

11.10(c)Indication and Warnings

• Fuel quantity indication: capacitance type, drip sticks
• Fuel flow measurement
• Fuel temperature indication
• Low fuel pressure and low fuel level warnings
• Fuel used and fuel remaining computation

11.10(d)Special Systems

• Auxiliary and ferry tank systems
• Fuel jettison (dump) systems
• Inert gas generation systems (OBIGGS)

11.10(e)Balancing

• CG management through fuel transfer
• Automatic fuel sequencing and scheduling
• Trim tank operation

11.11Hydraulic Power (ATA 29)

11.11(a)System Description

• Hydraulic system layout and architecture
• Fluids: types (mineral, synthetic, phosphate-ester), properties, compatibility
• Reservoirs: types, pressurisation, level indication
• Accumulators: types, pre-charge, functions

11.11(b)System Operation (1)

• Pumps: engine-driven (EDP), electric motor-driven (EMDP), hand pumps
• Pressure regulation, relief valves, priority valves
• Filters and filter bypass indicators
• Actuators: linear (single and double-acting), rotary
• Seals and gaskets: types and materials

11.11(c)System Operation (2)

• Power transfer units (PTUs)
• Ram air turbine (RAT) — hydraulic emergency power
• System monitoring: pressure, temperature, quantity indications
• Leak classification and management
• Multiple hydraulic system architecture and redundancy

11.12Ice and Rain Protection (ATA 30)

11.12(a)Principles

• Ice formation: conditions, types (rime, glaze, mixed)
• Effects of icing on aircraft performance and systems
• Ice detection systems

11.12(b)De-icing

• Pneumatic de-icing boots: construction, operation, timer systems
• Electro-thermal de-icing: heated elements in leading edges
• Windshield de-icing: electric heating elements

11.12(c)Anti-icing

• Hot air anti-icing: engine bleed air systems for wing and engine intake
• Electro-thermal anti-icing: continuously heated surfaces
• Fluid (TKS) anti-icing systems

11.12(d)Wipers

• Windshield wiper systems: electric motor-driven

11.12(e)Rain Repellent Systems

• Chemical rain repellent
• Hydrophobic coatings

11.13Landing Gear (ATA 32)

11.13(a)Description

• Landing gear types: tricycle, tailwheel, tandem
• Fixed and retractable gear
• Landing gear construction: struts, side braces, drag struts, trunnions
• Shock absorbers: oleo-pneumatic, spring, rubber
• Tyres: construction, ply rating, speed rating, creep marks, fusible plugs
• Wheels: construction, bearings, thermal plugs
• Nose wheel steering systems
• Brake systems: disc, multi-disc, carbon brakes
• Anti-skid and autobrake systems

11.13(b)System Operation

• Extension and retraction systems: hydraulic, electric, mechanical
• Uplocks, downlocks, overcenter mechanisms
• Gear doors and sequencing
• Warning systems: gear unsafe, gear in transit
• Emergency extension: free-fall, manual, pneumatic blow-down

11.13(c)Air-Ground Sensing

• Weight-on-wheels (WOW) switches: proximity, mechanical
• Squat switch functions: ground spoilers, brakes, thrust reversers, pressurisation

11.13(d)Tail Protection

• Tail bumper/skid: purpose, construction
• Tail strike indication systems

11.14Lights (ATA 33)

• External lights: navigation (red, green, white), anti-collision (beacon, strobe), landing, taxi, runway turnoff, wing inspection, logo
• Internal lights: cockpit, cabin, cargo, emergency
• Emergency lighting: floor path, exit signs
• Light switching and dimming controls

11.15Oxygen (ATA 35)

• Oxygen system requirements and regulatory basis
• Sources: gaseous (high-pressure cylinders), liquid, chemical generators
• Crew oxygen systems: diluter-demand, pressure-demand masks
• Passenger oxygen: continuous flow masks, chemical generators, drop-out systems
• Portable oxygen bottles
• Oxygen system components: regulators, valves, distribution lines, indicators
• Oxygen system safety: servicing, contamination prevention, fire hazards

11.16Pneumatic/Vacuum (ATA 36)

11.16(a)Systems

• Pneumatic system layout: low pressure, medium pressure, high pressure
• Air sources: engine bleed, APU bleed, ground pneumatic
• System components: valves, regulators, filters, moisture separators
• Pneumatic system uses: engine starting, hydraulic reservoir pressurisation, de-icing, door seals

11.16(b)Pumps

• Vacuum pump systems: engine-driven, electric
• Vacuum system instruments: attitude, heading indicators
• Vacuum system regulators, filters, relief valves

11.17Water/Waste (ATA 38)

11.17(a)Systems

• Potable water system: tanks, pumps, distribution, heaters
• Waste water and toilet systems: vacuum waste, chemical waste, flush systems
• Drain mast heaters
• Servicing connections and procedures

11.17(b)Corrosion

• Corrosion aspects of water and waste system installations
• Drain and leak prevention
• Inspection and maintenance of waste areas

11.18On-Board Maintenance Systems (ATA 45)

• Central maintenance computers (CMC)
• Built-in test equipment (BITE)
• Centralised fault display system (CFDS)
• Data loading systems
• Electronic Flight Bag (EFB) integration
• Maintenance data recording and retrieval

11.19Integrated Modular Avionics (ATA 42)

11.19(a)Overall System Description and Theory

• IMA concept and architecture
• Common computing resources and shared modules
• ARINC 653 partitioning
• Advantages over federated avionics

11.19(b)Typical System Layouts

• Core processing and I/O modules
• Line Replaceable Modules (LRMs)
• Data buses and network topologies (ARINC 429, ARINC 664/AFDX)
• IMA configuration and software loading

11.20Cabin Systems (ATA 44)

• Cabin management systems
• In-flight entertainment systems (IFE)
• External and internal communications for passengers
• Cabin lighting control systems
• Cabin monitoring systems

11.21Information Systems (ATA 46)

• Aircraft communications addressing and reporting system (ACARS)
• Data network systems: Ethernet, AFDX, wireless LAN
• Electronic Flight Bag (EFB)
• Software configuration management
• Database loading and management
• Server and network security considerations