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1 1. Stick Man Cognitive Notes: Upside down facing – rock back Upside down away – cartwheel Right side up facing – twist Right side up away – look through 2. Boarder Color, Arrow Color, Arrow direction 3. Then again with rule deduction Tone = rule has changed (must be a NEW rule Get one free mess up per rule change Chant rule in head “Boarder, Direction, Arrow Color 4. 5. 6. 7. Glideslope Wait till it gets in Same / Different GS & Same/Diff Tap in increasing order Numbers Alphabet Alphabet and Number 8. Slider Bar Localizer same opp opp same say rule say rule F-J, U-X F-J, U-X Gets faster the further away from fulcrum Keep it near the center, alternate sides of the fulcrum Then combined with number recall – You want to pick PREVIOUS number 2 FEDEX Pilot Job Knowledge Test Outline “Everything for Professional Pilot" and "Aero for Naval Aviators". Read them over and over. Know it cold. General knowledge test is really really hard. Delta Test goug is decent prep Knowledge/understanding of principles and the application to commercial aircraft operation. Emphasis is on application and problem solving. It is suggested that you invest time studying these areas, up to a level required for an ATP exam, in order to do well on the test. Aerodynamics 1. Airplane nomenclature and terminology Empennage = Vertical and Horiz stabilizer inboard ailerons - low and high speed flight outboard ailerons - low speed flight only (think > 26 alpha) Control Tab - move in event of manual reversion spoilers - reduce lift on landing wing vortex gens: At high speed - delay onset of drag divergence & maintains aileron effectiveness Primary flight controls - outboard ailerons high lift devices - lift at low speeds leading edge flaps in landing config - prevent flow seperation leading edge slot - changes stall AOA - higher angle flaps are more effective on - thick wings Fowler flaps vs. split flaps - generate the most nose down twisting moments split flaps (coming from bottom of wing) as compared to plain flaps - produce only slightly more lift but much more drag 2. Atmosphere: Static pres Density: Static pres, density, temp, humidity, viscosity, relationships to altitude results from the mass of air supported above that level. the mass (quantity of matter) of air per cubic foot of volume, Density varies directly with pressure, inversely with temperature The ratio water vapor at given to the max that could exist at that temp (%) Moist air is lighter than dry air (water vapor is lighter than air) Air is least dense when it contains the maximum amount of water vapor the proportion between the shearing stress and gradient for a fluid flow Humidity: Viscosity: Standard atmosphere: Pressure, temperature and density Standard Pressure = 29.92 in Hg, 1013.2 millibars, or 760 millimeters Hg .01 = 10 feet Standard Press Lapse Rate (1” Hg per 1,000’) Pressure Alt Height above a standard datum plane Standard Temp 15C or 59F F = 9/5 C + 32 (32F = 0C) Standard Temp Lapse Rate - 2C (-3.5F) per 1,000 ft. Density Altitude: Pressure altitude corrected for non-standard Temperature With Alt Increase: Density Humidity Pressure Temp Viscosity 3 Decrease Decrease Decrease Decrease Increase 4 3. Basic aerodynamic principles Aerodynamic properties and relationships to airflow dynamics Bernoulli’s Principle: as velocity of fluid increases, the pressure decreases high pressure above wing, low pressure below Properties of airflow < 260 knots, air can be considered incompressible (density) Given altitude, density remains nearly constant while its pressure varies The effects of viscosity (prevent motion of fluid) are negligible. Subsonic <0.75 Mach Transonic 0.75 Mach – 1.20 Mach Supersonic 1.2-5.0 Boundary layer: layer of air over wing’s surface, which is slowed / stopped by viscosity. Laminar - begins as smooth flow, increases in thickness over wing to TE (less stable) Turbulent - smooth laminar flow breaks down and transitions Pitot-static effects Measures the fluid flow velocity by determining the ram air press (stagnation/total pressure) Total pressure = dynamic pressure + static pressure Static pressure is the pressure of still air When alternate static port used (inside) -- lower pressure = altimeter indicates higher airspeed indicates greater than actual, VSI indicates climb in level flight) “High to low, hot to cold, - look out below”, the alt indicates lower than actual (Cold air is denser) Pitot Static Systems A/S Altimeter Tube blocked, drain open Goes to zero no effect Tube & drain blocked High in climb no effect Static port blocked Low in climb Freeze Alternate static source Faster A/S Higher altitude Both blocked Freeze Freeze Ground speed and effect of wind GS = TAS +/- Wind (GS) x (Time) = Distance Drift (°) = [(Crosswind Component) x 60] / TAS Drift (°) = X-wind (kt) / Miles/minute 35 kt xwind / .7 mach = 5° Degrees off 030 045 060 090 Crosswind 50% 70% 90% 100% 5 Mach #, critical Mach, speed of sound, and effects of change of temperature and altitude Mach Number: the ratio of the TAS to the speed of sound in the same conditions IAS for any given Mach number decreases with an increase in altitude .9 Mach at 10k (500+), .9 Mach at 40k (200+) Speed of sound varies only with temperature (15C- 661 kts, FL400- 574 kts) Critical Mach: free stream mach when airflow over any part reaches (but doesn’t exceed) Mach 1.0 Highest free stream Mach number w/out supersonic flow - local velocity not sonic Free stream Mach # which produces first evidence of local sonic flow Speed of Sound: 661 kts at sea level, STD Think of a climb Increase altitude = Decrease in speed of sound (increase in Mach number) Decrease temperature = decrease speed of sound (increase in Mach number) Constant Mach climb (.88) the KCAS (KTAS or KIAS as well) is falling off (decreasing) Swept Wings: + Critical mach # increases significantly (formation of shock wave delayed) - Disadvantage - wingtip stalls prior to wing root. + Delay the onset of compressibility effects Mach Tuck / Sever moment = Center of Pressure moves aft as shock wave moves aft shock induced sep of airflow symmetrically near root of swept wing 6 4. Aerodynamic forces Airfoil nomenclay, properties of airflow wrt airfoil, properties of aerodynamic forces Camber: the curve of an airfoil’s upper or lower surface Chord line: an imaginary line drawn through an airfoil from the LE to TE Mean Aerodynamic Chord (MAC): the avg distance from the LE to TE Airflow: High pressure below, low pressure above Center of Pressure: Average of pressure variation (for given AOA) Center of gravity, flight path, relative wind Center of Gravity: the point about which an airplane would balance if suspended Flight Path: direction of aircraft movement (climb, level, descent) Relative Wind: the direction of airflow with respect to the wing, parallel to and opposite the flight path of the aircraft Relationship between lift, thrust, relative wind, drag and flight path Lift: acts perpendicular to the flight path through the wing’s center of lift Thrust: opposes or overcomes the force of drag, parallel to the longitudinal axis Drag: rearward, retarding force, opposes thrust, parallel to the relative wind Weight combined load of aircraft, pulls downward because of gravity, opposes lift, acts vertically downward through the CG. Angle of attack, angle of incidence Angle of Attack: chord line and the relative wind Angle of Incidence: chord line and longitudinal axis of the aircraft 7 Generation of net lift force, influence of angle of attack Lift coefficient is ratio between lift pressure and dynamic pressure. Lift (lbs) = ½p*V²*A*Cl p = air density, V = true airspeed, A = wing surf area, Cl = lift coefficient at desired angle of attack Increase in AOA = Increase in lift up to limit Angle of attack is the primary control in steady flight Aerodynamic force, lift, drag, Moment about aerodynamic center and factors affecting Aerodynamic force: Due to the relative motion between the body and the fluid. A Airfoil moving relative to the air generates and aerodynamic force partly parallel to the direction of motion, and partly perpendicular to the direction of relative motion. Drag: the component parallel to the direction of relative motion Lift: the component perpendicular to the direction of relative motion Aerodynamic center: point on the chord at which the pitching moment coefficient for the airfoil does not vary with the lift coefficient (i.e. angle of attack). The aerodynamic center of the airfoil, and not the center of pressure. Pitch: Lateral Axis. (longitudinal stability) Location of CG, Wing, Tail, and surface area of tail Stable = CG forward of the CL Roll: Longitudinal Axis. (Lateral stability) Dihedral: Gust gust shoves one wing down, Bank without turning = sideslip into lower wing Lower wing sees higher AOA = more lift = wing rises Sweepback: Low wing slips into windstreem = more lift Yaw Vertical Axis (Directional or Vertical stability) Area of vertical fin and sides of fuselage AFT of CG Vert tail size and distance to CG Sweepback: when jets yaws, forward wing sees more drag – goes back 8 Effects of changing AOA or true airspeed on moment about aerodynamic center AOA: Must be high to increase lift when airspeed is low. If airspeed is increased, the angle of attack must be decreased. True airspeed: Increase in TAS increases Forces = increases moment Forces in a turn, climb and descent Skid: Slip: Turn: Increase Lift by increasing AOA Increase Thrust to maintain airspeed Excess of centrifugal force over the horizontal component of lift Pulling a / c towards outside of turn. Rate too great for angle of bank Either reduce rate of turn, increase bank, or a combination of the two. Excess of Horizontal Lift (sLip) – Plane not turning at the rate appropriate to bank being used Yawing towards outside of turn due to the horiz comp of lift > centrif force Either decrease bank, increase rate of turn, or combo Angle of Bank (standard rate turn) = 15% of TAS (180 = 27) Turn rad NM (standard rate turn) = TAS / 200 (NM per min x 3 9 Climb: In initial climb + AOA = More lift than weight Decreased airspeed speed b/c Weight acting inline with drag > Thrust Eventually……Decreased airspeed = decreased Drag Steady speed reached (lower) Descent Initially AOA reduced (flight path constant - inertia) Less AOA = Less Lift = Weight > Lift = Descent Airspeed will increase unless power adjusted 5. Lift Lift force—factors affecting p Air Density (+cool, +dry air) V True Airspeed S Wing surface area Cl Coefficient of lift at desired angle of attack Stall smooth flow over airfoil breaks up & separates Abrupt change of flight characteristics Sudden loss of lift Set by Critical AOA Can occur at any pitch attitude or airspeed Factors (increase stall Speed): Load Factor (Level Turns) - Increase AOA Turns (AOA to account for centrifugal force) Weight (1% speed for 2% weight) Forward CG Airfoil - Imperfections, Ice, Frost High density altitude Factors decreasing stall speed High lift devices – reduce AOA for a given lift coefficient Lower density altitudes -Weight increases the stall speed by approximately 1% for every 2% change in weight -High lift devices reduce stall speed by reducing the angle of attack for any given lift coefficient Ground effect Slightly increased air pressure below aircraft wing that increases the amount of lift produced W/in approximately one wing span Reduction in upwash, downwash & wingtip vortices = corresponding decrease in induced drag. Less thrust required Less AOA required 10 6. Drag: types, causes and effects Gross weight is increased - induced drag increases more than parasitie Parasite drag (all but induced drag, not associated with production of Lift): Form drag – Shape - disruption of the streamline flow Interference drag – intersection of airstreams Skin friction – aerodynamic resistance to irregularities Increases with an increase in TAS Induced drag: Created by the production of lift (inc wingtip vortices) Increases with a decrease in TAS (Increase in AOA) 7. Thrust Power curves: Power required to achieve equilibrium in constant-altitude flight at various airspeeds is depicted on a power required curve. Regional on normal command (at Level flight): Higher A/S requires a higher power setting Lower airspeed requires a lower power setting. Region of reverse command (at Level flight): Higher airspeed requires a lower power setting Lower airspeed requires a higher power Max Endurance: As airspeed is increased, power requirements decrease due to aerodynamic factors and fuel flow decreases. Beyond this point increases in airspeed come at a cost. Best endurance speed: lowest power will sustain level flight. 11 AOA Low Speed Flight: Level Flight: Thrust decreases – airspeed decreases – AOA must increase Thrust increases – airspeed increases – AOA must decrease AOA increases with increase in power below best endurance speed to hold altitude, Decreases with increase in power above best endurance Factors affecting Weight: changes induced drag and induced power at any given change. Changes in thrust and power required at high-speed flight are relatively slight Greatest changes are in the low speed range of flight (due to effects of induced drag). Curve moves up. Equivalent parasite area: flaps, gear, etc. will decrease aircraft efficiency. Curve moves left Altitude: aero conditions occur at higher true airspeeds. Increase in altitude will cause the thrust curve to flatten out (to higher TAS) 8. Stability and control Trimmed flight Relieve the need of the pilot to maintain constant pressure on the controls Aerodynamically assisting movement and the position of control surfaces Trim tabs- move in opposite direction of control surfaces Balance tabs – coupled to control surface rods (still move opposite) Antiservo tabs – coupled to control rods, but move with control surface Relationship between controllability and stability Controllability: capability (quality) of an aircraft to respond to a pilot’s control, with respect to flightpath and altitude. Independent of stability. Stability: Inherent quality of an airplane to correct for conditions that may disturb its equilibrium, and to return or continue on the original flightpath. Static – Initial Tendency Dynamic – Overall Tendency 12 Static stability: initial tendency the aircraft displays after its equilibrium is disturbed Tendency to correct in opposite direction Positive: corrects towards original state of equilibrium Neutral: no correction - remains in new condition after being disturbed Negative: Continues away from original state of equilibrium Dynamic stability: overall tendency the aircraft displays after being disturbed Positive: Eventually returns to original state Neutral: corrections do not damp or get worse Negative: Corrections get worse (divergent) Phugoid oscillation: “long period” (> 10 sec) oscillation It is a slow change in pitch & airspeed AOA remains constant Aileron: Right stick = right aileron up = less camber, less lift = wing drops = roll right Proverse roll: Tendency of an airplane to roll in the same direction as it is yawing (Pro,same) Down aileron experiences a large increase in lift and small increase in drag. Up aileron/spoiler experiences a large increase in drag with a small increase in lift. Adverse Yaw: Tendency of an airplane to yaw away of the turn/bank (outside, opposite, Adv). Outside aileron wing produced more Lift in order to roll = higher induced drag It is mostly due to drag, slightly due to velocity differences More pronounced at slower speeds (larger control inputs), long wingspan Elevator: Aft stick – Elevator LE down, Trailing edge up, “dig in” to turn = “up elevator” to go up Decreases camber, Pitches about Center of Gravity Rudder: Sideward lift Flaps: Increase both lift and induced drag for given AOA Leading Edge Slot, Flap, Cuff Spoiler – Spoil lift and increase drag 13 Dutch roll Coupled lateral (YAW) & directional (ROLL) oscillation on swept wing a/c Oscillations are out of phase (roll and yaw our out of phase), dynamically stable Yaw right, Roll right (Left wing sees higher a/s = more lift = rolls right) Increased lift on left wing = increase drag = yaw Left (Nose makes a figure 8) A/C with dutch tendencies usually equipped with gyro-stabilized yaw dampers. Wake turbulence Generated by counter-rotating vortices trailing from wingtips (towards each other at top) Strongest when an aircraft is heavy, clean, and slow. Pressure differential triggers the rollup of the airflow aft of the wing resulting in swirling the wake consists of two counter rotating cylindrical vortices – avoid core by 100’ Land beyond large a/c touchdown point, Rotate prior to rotation point Worst: Quartering tailwind , watch out for drift from parallel rwy w/in 2500’ 3 classes for purposes of wake turbulence: Small: <41k Large: 41k - 255k Heavy: >255k pounds Following (cruise/approach) at same alt or < 1000’ below (no waiver): Heavy behind Heavy 4 miles Heavy/Large behind Heavy 4 miles Behind Small behind 757 5 Small (41) miles Large Small/Large behind Heavy 5 miles Heavy (255) Small - In Front Large (757) 4 (5) 4 (4) 4 (4) Heavy 6 5 4 Small a/c following a/c over landing threshold (no waiver): Small behind Heavy 6 miles Small behind 757 5 miles Small behind Large 4 miles All Takeoff behind Heavy/757: 2 minutes or 4-5 miles (no waiver) - from same threshold - on crossing rwy & flt paths cross - from threshold of parallel rwys < 2500’ 3 minutes (no waiver): - intersection t/o on same rwy or parallel <2500’ (same or opposite direction) - opposite direction t/o same rwy or parallel <2500’ behind Large/Heavy t/o or low/missed appr Small takeoff behind Large: 3 minutes (pilot may waive): - intersection t/o on same rwy or parallel <2500’ (same or opposite direction) - opposite direction t/o same rwy or parallel <2500’ behind Large/Heavy t/o or low/missed appr Behind a/c doing low app/ missed app/ touch and go - wait at least 2 minutes Engine out aerodynamics: 9. Requires rudder input, generating a side slip Flight at high angles of attack Aircraft stall characteristics & Stall and stalling angle of attack (previous) Stall speed and effect of gross weight, load factor and altitude (previous) 14 Fundamental principle of stall recovery: Decrease the angle of attack (to increase airspeed) Aft CG is worst situation (authority to decrease AOA) Purpose of high lift devices and effect of flap extension Purpose: increase the max coeficient of lift (Cl) of the aircraft to reduce stall speed Flap extension: Improve slow speed handling during t/o, climb, landing Increase both lift and induced drag for any given AOA Lower AOA for any given lift coefficient Adding camber aft on the chord – Lower stall speed. 10. a. Operating strength limitations Maneuvering load factor—effect of Velocity: increase V, flight load is increased Weight: exceed the structural load limitation Level turn requires: 1/(Cos Bank) SAFE FLIGHT ENVELOPE: ------------------------ V-speeds Operation VS0 Power-off stall speed, Landing config min controllable VS1 Power-off stall speed, Specified config min controllable VX Best angle-of-climb (increases with alt, A+ , angle+) VY Best rate-of-climb (decreases with alt, Yaw Rate me down) VLE Landing Gear extended limit speed (extended) VLO Landing Gear Operate speed (extension ongoing) VFE Flaps Extended limit VA Aero Limit - Design maneuvering airspeed. Max speed at which the limit load can be imposed (gust, full deflection in 1 axis) VNO Normal Operation max speed, max structural cruising speed. VNE Never Exceed speed (structural damage / failure) VMO Maximum operating limit speed VMU Minimum unstick speed. 15 16 V-speeds Emergencies (for Transport Category Aircraft – Bold posted in flight deck) VS Stalling speed, minimum controllable steady flight VMC Minimum control speed with Critical engine inoperative VMCG Minimum control ground speed (directional control Critical engine inop, takeoff power on other engine(s) Aero controls only, no nose wheel steer (less than V1) VMCA min control in air speed (above assump, 5° bank into good ) V1 Decision speed / Critical eng failure speed (Abort / Continue) VR Rotation speed. > V1 and > 1.05 times VMC. Must allow engine out acceleration to V2 by 35’ alt at EOR VLOF Lift-off speed V2 Takeoff safety speed (by 35’ at EOR), SETOS Best one-engine operative angle of climb speed Hold until clear or obstacles or at least 400’ AGL VFS Final segment climb speed, 1 engine inop, clean, max continuous power V-speeds Extras V3 Flap retraction speed V4 Steady initial climb speed, until accel to flap retraction speed (NLT 400 feet) VB Blowing Gust - Design speed for maximum gust intensity VC Cruise - Design cruising speed, aka optimum cruise speed VD Diving speed. VDF Flight diving speed VF Flap speed VFC Maximum speed for stability characteristics VH Maximum speed in level flight at maximum continuous power. VLOF Lift-off speed Safe flight envelope (See Vg diagram) 17 11. Takeoff and landing Factors affecting minimum takeoff and landing distances Stall speed or minimum flying speed Acceleration varies directly with the forces & inversely with the mass of an object 2 x the speed = 4 x the distance to stop T/O & Land Performance: (SAWW or SWWAT) Slope / gradient Altitude – Density (Pressure Altitude & Temperature) Weight Wind Effect of Weight, Pressure, Altitude, Temp, Humidity, Wind and Ground Effect (T/O & Land) Weight Effect Higher lift-off speed & Land speed Greater mass to accelerate / decellerate Increased Drag (induced) and ground friction (retarding force) T/O result VAD (increased velocity, decreased accel, increased t/o distance) 0.5 factor -1 factor (min) 2x factor min Land same 1x factor Density Alt (+ temp) (- press) (+ humid) T/O Effect Wind T/O & Land Humidity Increase in humidity - air less dense –same as lower pressure Increase in TAS speeds, Less Thrust Ground effect Land effect Changes TAS speed (same IAS and dynamic press, higher TAS) Decreased thrust and reduced accel force Changes TAS speed (same IAS and dynamic press, higher TAS) No effect on deceleration (just high higher TAS) Changes ground speed (for required IAS) Less AOA required for same C Lift Thrust required is reduced Elevator effectiveness is reduced Floating on Landing Friction and aerodynamic braking effectiveness—factors affecting Friction Normal force on the braking wheel surfaces Affected by surface condition (dry, wet, icy, etc.) Affected by wheel speed - as speed ~0 -- normal force approaches weight Aerobraking Maximum deceleration by creating the greatest possible aerodynamic drag More effective above 60-70 percent of touchdown speed. Hydroplaning Water on the runway reduces the friction between the tires and the runway Dynamic: a/c tires ride on thin sheet of water. Min speed = 9 x √Tire Press. Continues below!! Viscous: surface is damp and provides a very thin film of fluid Reverted Rubber: heat from friction boils the water and reverts the rubber - forms a seal 18 12. Airplane performance Effect of weight, altitude, wind and angle of attack on airplane performance Weight: Shallower climb, increased fuel consump, slower cruise, reduced range Altitude: Increased TAS, reduced stability (dampening), restricted operating speed range, reduced maneuverability, reduction in lift generated Wind: Proportional to groundspeed AOA: Power curve dependent. Additional trust req’d for level flight Read 225 in FAA, bottom left to make sure this makes sense (turbines not affected by alt) Maximum endurance, range, angle of climb, rate of climb, glide range, glide endurance Max Endurance Min Fuel flow (max flying time) Flt hrs / lb = Flt hrs per hr / lb per hour = 1/fuel flow Max Range: At L/D max, certain AOA, AOA does not change with weight (A/S does) Max range per fuel load, min fuel load for a given distance NM / lb = NM per hour / lbs per hour = kts/fuel flow Angle of Climb For a given weight Depends on the dif between thrust and drag, or excess thrust. Maximum angle is at max excess thrust (rocket) Rate of Climb Vertical velocity (speed and i nclination) Maximum rate occurs at greatest difference between power available and power required. 19 Glide Range Range…At min glide angle (L/Dmax), weight determines the best glide speed. A heavy and light aircraft will glide the same distance under this condition. Glide Endurance Time…heavier = higher glide airspeed at same angle = higher fpm The Cl for a heavier aircraft is greater, requiring additional airspeed. Not sure if required: CG position influences the lift and AOA of the wing, the amount and direction of force on the tail, and the degree of deflection of the stabilizer needed to supply the proper tail force for equilibrium. The latter is very important because of its relationship to elevator control force. Forward CG: A/C stalls at a higher speed with a forward CG location. Stalling AOA is reached sooner (at higher speed b/c increased wing loading Higher elevator control forces Increased stabilizer deflection required to balance the aircraft Aircraft cruises slower (increased drag due to higher AOA req’d and more downward deflection of stabilizer required) Aft CG: Less stable - increase in the AOA Wing contribution to the aircraft’s stability is now decreased Tail contribution is still stabilizing. If wing and tail contributions balance, then neutral stability exists. CG movement further aft results in an unstable aircraf 20 Engineering Physical principles of gas turbine engines Air inlet Compressor Combustion chambers Turbine section Exhaust o Principles of gas turbine operation Basic principles Intake air is compressed by the compressors and forced into the combustion chamber. Ignition is initiated and then fuel is continuously sprayed into the combustion chamber, creating exhaust gasses that drive the turbines. The turbines, through shafts, drive the compressors, continuing the process. o Effect of pressure, temperature, altitude and humidity on thrust in a gas turbine engine Pressure increase Thrust Increase Temp increase Thrust Decrease Alt increase Thrust Decrease (even faster than temp affecting) Above trop, density decreases and temp levels/climbs Humidity decrease Thrust Increase (least of 4 factros) o Effect of airspeed and ram effect on thrust in a gas turbine engine Incoming air momentum flow is called ram flow Compression of air in an inlet duct is ram effect When moving the ram effect raises the air mass flow to the engine and intake pressure = +Thrust o Engine instrumentation Engine Pressure Ratio (EPR): ratio of turbine discharge to compressor inlet pressure Exhaust Gas Temperature (EGT): monitors the temperature of the turbine section N1 Indicator: Low pressure compressor, % of design RPM N2 Indicator: High pressure compressor, % of design RPM Interstage Turbine Temperature (ITT): High pressure Turbine exit o Function of gas turbine compressor Increase pressure and reduce velocity Centrifugal-Flow compressor: air slowed and centrifugally slung outward into diffuser Axial-Flow Compressor: air remains parallel to the longitudinal, rotor and stators Dual-compressor engines: higher compression ratios The Forward most compressor is the low-pressure compressor (N1) The second compressor is the high-pressure compressor (N2) o Function of turbine section Sustain engine operation by providing rotation of the compressor section (Shaft) 21 Compressor stalls o Characteristics and causes of compressor stalls: airflow distortions, mechanical problems Imbalance between the two vector quantities, inlet velocity and compressor rotational speed. Blades’ angle of attack exceeds the critical angle of attack, interrupting smooth airflow Indications: “Bang” for intermittent stalls as flow reversal takes place “Loud roar and vibration” for while a continuous flow reversal RMP fluctuations and an increase in EGT. Mechanical: Variable inlet guide vanes and variable stator vanes direct the incoming air into the rotor blades at an appropriate angle. o Methods to avoid, reduce or resolve compressor stalls Avoid: Operating within manufacturer’s recommendations Resolve: Reduce throttle setting, lower AOA, and increase airspeed o o Hydraulic systems Basic hydraulic theory Pascal’s Law “pressure exerted anywhere in a confined incompressible fluid is transmitted equally in all directions throughout the fluid such that the pressure ratio remains the same” Powerful, but lightweight transmission method. Basic operation of aircraft hydraulic systems Reservoir, lines Pump Filter Selector valve (flow direction) Relief valve (excess pressure) Actuator (usually short travel) o o Function of basic hydraulic components used on aircraft Pumps: Convert rotary motion to hydraulic pressure Motors: Convert hydraulic power back to mechanical power Actuator: Translate pressure into mechanical movement. Valves: direct the flow of fluid (power) Reservoirs: usually low pressure to minimize foaming Accumulators: store hyd pressure for backup operations normally sealed pressure container w/ diaphragm Electrical systems Basic operation of an aircraft electrical system Engine driven generators supply current to the electrical system and maintain a sufficient electrical charge in the battery Battery provides power for starting (APU, engine) and limited supply of emergency power A bus bar system is used to connect the main electrical system to the equipment Voltage and amps are monitored and regulated, with multiple circuit protection devices. 22 o Methods of producing electricity in aircraft Ground power Battery Generator (Engine driven, APU, ADG) o Function of aircraft electrical components Generators: Generate electricity by moving permanent magnets around a coil of wire, thereby motivating electron flow in the coil. Normally generate AC current (amps) too power all components on the circuits (or load shed) Current = output volume or flow (amps = music volume = flow) Voltage = output of electrical pressure (volts) Generator Control Units (GCU): Voltage regulators, direct current to battery for recharging Provide circuit and generator protection -- disconnect from the system if abnormalities Battery: Power reservoir that stores electrical energy in a chemical form. Must have lower voltage than the system to charge. Rated at amp-hours. Ni-cad: put out sustained voltage over a longer period of time Memory characteristic (low usage limits ability to handle high demand) Thermal runaway (excessive current is drawn & replaced causing overheat) Starter: driven electrically by a battery Relays: remotely control electric circuits carrying large amounts of current Solenoid: electrically powered remote control device, move shaft over a short distance Transformers: used to step aircraft voltage (usually down) Transformer-rectifier units (TRU) convert AC to DC power (ACDC transformed rock) Inverters: convert DC power to AC power Circuit breakers: disconnect individual components that are drawing too much current Fuses: open circuits that are drawing too much current Diodes: one-way check valves Bus ties: switches or relays used to connect / disconnect buses from one another (isolation) o Aircraft electrical distribution system Bus Bar System: organized into separate but interconnected circuits. Important circuits can be isolated from one another and supplied by alternate power sources. Provide redundancy 23 o o Fuel systems Basic operation of an aircraft fuel system Store and deliver in the proper amounts and correct pressures Function of basic fuel system components used on aircraft Collector bays (header tanks): directly continuous supply to engine Fuel pumps (high-pressure pumps, low-pressure pumps, auxiliary pumps, and jet pumps): Move fuel from tank to engines or tank to tank. Engine driven pumps (900-1000 PSI) provide varying pressure and flow capacity Return line back to the tanks for unused fuel. Auxiliary pumps are normally operated from the fuel control panel and have various purposes Transfer fuel, emergency backup Motive flow uses small venturi ports to draw fuel into collection lines Fuel Control Unit: Hydomechanical / Computerized electronic device meters fuel Collects inputs (thrust lever position, air pressure, engine temp) Fuel Valves: manage fuel flow: Direction, recirculation. Fuel Heaters: Fuel-oil or fuel-air (bleed-air) prohibit ice crystals from forming in fuel Fuel Vents: Allows outside air into fuel tanks to prohibit a vacuum from forming as fuel is used Capacitance fuel quantity indicator system: probes measuring electrical capacitance o Fuel flow through basic aircraft fuel system 24 o o Lubrication systems Basic operation of an aircraft lubrication system Function of basic lubrication system components used on aircraft Oil cools and lubricate several parts of the engine. Scavenging system returns oil to the tank for reuse. Oil normally cooled by a heat exchanger. Oil tank & sump are pressurized = constant head pressure to oil pump (prevent cavitation at alt) Pump -- Filter -- Heat exchanger – Engine – Sumps -- Scavenge pumps – Reservoir PFHESSR Pure Fucking Hotness….Engine...sum scavenging raccoon Accessory, starter and ignition systems o Basic operation of an aircraft accessory, starter and ignition system Accessory Drive Gearbox: Engine drive shaft by bevel gears from N2 compressor shaft. Starter and Ignition System: High pressure air (APU, Ground air, cross-bleed) Drives a pneumatic starter motor to rotate the compressor Fuel is added, Igniters begin the combustion process Once combustion starts, igniters turn off. o Types of accessories used on aircraft and how they are driven Oil pump, Hydraulic Pump, Fuel Pump Alternator, Generator (IDG), air turbine starter o Starting sequence for a gas turbine engine Compressor rotation Air Fuel Introduction Fuel Ignition Fire o Types of abnormal starts Hot Start: Fuel is introduced when compressor RMP is too low Pressure inadequate in the combustion chamber Fuel burns too hot with little or no flow aft into the turbine section Hung Start: Normal light-off, RPM steady but no increasing to Idle RPM Due to insufficient power from the starter or a fuel control malfunction 25 o Flap system Types of large aircraft flaps -- Slotted flaps Form a space or “slot” between flap LE and wing – high press air Prevents air separation and increases the lift when flap lowered -- Fowler flaps Move on tracks aft of the wing TE (vice hinging downward Changes camber and increase surface area Initial extension: Increase lift Midrange: Increases both lift and drag Full/Final: Increases drag (Steepen descent w/o increasing A/S) o Effects and methods of actuating flaps Effects: Increased Lift and Drag, change airfoil Coef of lift - Decrease stall airspeed Methods: Drive motor (hyd or mech) and gearbox assembly w/electronic position sensors Actuators via torque tubes and ball screw jacks Landing gear system—brakes, tires Hydraulic pressure with gear position switches to confirm position Squat switch prevents retraction while on the ground Warning systems - Notification in low-power or alt or flaps extended with the gear retracted o Brakes: Multi-disc rotor-and-stator, Power assist, Antiskid w/computer-controlled hydraulics Automatic braking provides a level of preselected deceleration Sensors are included to monitor brake temperatures and eliminate brake fade o o Tires: Pressure relief valves (overpressure valve) and fFusible plugs Chine design directs water away from the engines Air conditioning and pressurization systems Basic operations Engine bleed air is used to pressurize the cabin (pressure vessel). Pressure relief valves (positive and negative) and dump valves are safety features. Cabin altitude: cabin pressure in terms of equivalent altitude above sea level Cabin rate of climb: shows rate the cabin is climbing or descending Pressure differential: between the cabin and outside atmosphere o Abnormal situations Decompression: lost pressurization indicated by increase of cabin altitude Rapid decompression- sudden decompression of the aircraft Anti-ice/de-ice systems Bleed air thermal LE anti-ice system: Hot, high-pressure bleed air routed under the leading edges 26 Electric heating: Windshield and windows 27 Air Navigation o Introductory air navigation: basic concepts, principles and terminology Chart projections and plotting Great circle and relationship to aircraft navigation Shortest distance between any two points on a sphere measured along a path on the surface Approximates the flight lengths between two airports. Jetstream routes: Eastbound flights in the northern hemisphere take advantage of winds o Heading: Course: Track: Drift Angle: Heading, course, track, bearing and relationships among them Direction nose pointing (magnetic compass or heading indicator) Intended path or direction of flight (measured in degrees from north) Actual path made over the ground in flight Difference between heading and track o Altitudes and airspeeds Relationship among pressure, altitude and airspeed Airspeed measures the differential between ram and static pressure (dynamic pressure) As altitude increases, static pressure decreases o Indicated airspeed, calibrated airspeed, true airspeed, ground speed and Mach number IAS: Shown on the dial, based on pitot static airspeed Standard atmosphere adiabatic compressible flow, sea level, uncorrected for sys errors CAS: IAS corrected for instrument errors, port position error and installation error TAS: Actual airspeed, Correction for Pressure altitude and temperature to the CAS. Add 2% to the calibrated airspeed for each 1,000 feet of altitude GS: Speed over the ground. TAS adjusted for Wind Mach #: Ratio of TAS to speed of sound in the same atmospheric conditions IAS for any given Mach number decreases with an increase in altitude Speed of sound varies only with temperature (15C = 661 kts, 40k = 574 kts) Winds in flight (pg 338) o Evaluating the effect of wind on the path of an aircraft over the ground Drift Angle = Xwind component (kts) / nm per minute o Windshear - Recognition, considerations and actions Sudden, drastic change in wind speed and/or direction in horiz or vert plane Recognition: +/- 15 knots indicated airspeed, 500 fpm vertical speed, Degrees pitch attitude, 1 dot displacement from the glideslope, Abnormal power requirements, aural warning Considerations: Frontal systems, thunderstorms, and temperature inversions Strong upper level winds (>25 knots), convective precipitation Microburst: < 1 mile horizontally and 1,000 feet vertically, 6,000 fpm, (<15 min) Actions: Max Thrust (full if ground contact is imminent) thrust Maintain configuration until clear of windshear, Follow command bars if available. 28 Rate of descent—considerations and computations Considerations: position relative to crossing restriction, airspeed changes, winds Calculations: 3 to 1 rule: altitude to lose (in 1,000s) / 3 = miles to descend Speed change: add 1 NM for every 10 knots of airspeed to lose VVI = (Alt / NM) x (NM / minute) x 1000 15k in 25 NM x 8 nm/min x 1000 = 4800 fpm Angle = Alt / NM x 10 Ex. 15k in 25 NM: 15/25 x 10 = 6° Gradient = Angle x 100 Ex. 6° x 100 = 600 ft/NM VVI (fpm) = Gradient x NM per minute Ex 600 ft/NM * 8 NM/min = 4800fpm GMT and conversion to local time EST = GMT -5 (-4 EDT) CST = GMT -6 (-5 CDT) MST = GMT -7 (-6 MDT) PST = GMT -8 (-7 PDT) Ex. 1400Z into Pacific Standard Time “We are +7 to get to Zulu+ = Local = Zulu – 8 1400Z = 0600L o Electronic navigation (Methods used for electronic navigation) 1. NDB (Ground) / ADF (in Jet): Low or medium frequency radio beacon Transmit non-directional 3 letter code Not limited by line of sight Needle points to station Compass Locator when used in conjunction with an ILS Disturbances such as lightning, precipitation, interference 2. VHF Omni-Directional Range (VOR) 108.0 – 117.95 Mhz, Morse Code VOR, VOR/DME, VORTAC Magnetic bearing to and from station (radials) Line of sight limited (High > 18k = 130 NM) Transmits azimuth info along all directions Terminal, Low Alt, High Alt ±4° for ground checks and ±6° for airborne checks Morse code identifier Radial (magnetic course “FROM” station) or its reciprocal (course “TO” the station) DME Slant range, UHF “paired frequency” RNAV GPS, LORAN-C (Low Frq), VOR/DME. Allow straight line via math on signals 29 Electronic navigation aids and instruments CDI (no compass) RMI (radio stuff & compasss) o HSI (Compass card) Aircraft position and course to navigational aid Given magnetic bearing Mag bearing: direction to or from station measured relative to magnetic north Magnetic Bearing (MB) = Relative Bearing (RB) + Magnetic Heading (MH) 220 = 35 185 (RMI example) True Course + Wind = True Heading. True heading + Variation = Magnetic heading Magnetic heading + Deviation = Compass heading Practice examples?????? o o Charts and chart symbology Airport charts- dependent on charting system used En route charts Min Enroute Alt (MEA): NAVAID coverage & terrain clearance (1k, 2kmts) Omnidirectional unless indicated by an arrow. Min Obstacle Clearance (MOCA): signal coverage w/in 22 nm of VOR and terrain 1k, 2k Min Vector Alt (MVA): terrain clearance only Minimum Reception Alt (MRA): identifies an intersection from an off-course NAVAID Minimum Crossing Altitude (MCA): charted when a higher MEA route segment is approached, climb must be initiated to cross the MCA at the indicated altitude Maximum Authorized Alt (MAA): highest alt without receiving conflicting nav signals MSA: 1,000 feet of obstacle clearance for emergency use within a specified distance VOR Changeover Points (COPs): distance at which to change the VOR frequency 30 o Approach charts- dependent on charting system used o Navigational aids and distance scales Approaches ILS approaches Localizer: Glide slope: Beacons: 108.10 to 111.95 Front and back course aligned with runway centerline 18 NM 1 dot = 1.25 degrees, full scale =2.5 degrees, (700’ at threshold) Intersects MM at 200 feet and OM at 1,400 above runway Nominally 3 degrees 10 NM 3 degree glidepath (FPM) = TAS x 5 1.4 degrees tall = 1 dot = .35 degrees OM (FAF) - Blue, dash dash MM (DH 200’) - Amber, dash dot dash IM – White, dot dot dot Visual information: approach lights, touchdown and centerline lights, runway lights o Non-precision approaches LOC, LOC/BC, VOR, VOR/DME, RNAV, NDB MDA – Above TDZE???? Or Airfield elevation?? Higher minimums than ILS o Visual approaches Must at all times have the preceding aircraft or airport in sight, remaining clear of clouds 31 Advise ATC if unable to continue, follow preceding aircraft, remain clear of clouds, need to climb, or lose sight of the airport. o Final approach segments Glideslope intercept at published altitude, FAF, Procedure turn inbound within 5 degrees of final approach course o Approach minima Visibility is controlling, unless otherwise specified DH for ILS, minimum descent altitude (MDA) for non-precision MAP based off of time or distance from FAF o Landing/missed approach/rejected landing Descent below DH or MDA is not authorized unless: Aircraft continuously in a position from which a descent to landing on the intended runway can be made at a normal descent rate using normal maneuvers Flight visibility is not less than that prescribed for the approach procedure being used Visual reference visual and identifiable: • Approach light system (100’ above runway w/ terminating side row bars) • Threshold, threshold markings, threshold lights, REIL, VASI, • Touchdown zone or markings or lights • Runway or runway markings, runway lights Missed approach is executed when: arrival at MAP or DH with insufficient visual reference to the runway, safe approach or landing is not possible, instructed to do so • Comply with missed approach procedure • If prior to the MAP - fly lateral path to MAP and climb to missed approach alt Rejected landing: Go around after touchdown of the main landing gear or after bouncing 32 Holding (AIM 5-3-8) ATC controller should issueL • Complete holding instructions (unless pattern is charted) • EFC time and best estimate of any additional en route/terminal delay. “Hold [direction] as published” = Low/high Enroute, and area or STAR charts • If not charted & no instructions -- Pilot should ask for instructions prior to fix. • If unable to obtain instructions prior to fix -- Enter std pattern on the course on which the aircraft approached the fix and request further clearance ASAP Start to slow when 3 minutes or less from a clearance limit to cross at/below max holding speed When no delay is expected, the controller should issue a clearance beyond the fix as soon as possible and, when possible, at least 5 minutes before the aircraft reaches the clearance limit. Pilots should report to ATC the time and altitude/flight level at which the aircraft reaches the clearance limit and report leaving the clearance limit. If holding at altitude above published min holding alt, and subsequently cleared for the approach, the pilot MAY descend to the published minimum holding alt. Climb-in-Hold: Allowed to accel to 310 KIAS (if restricted – use 200/230 for above/below 6K) Holding pattern in lieu of Procedure Turn: Additional circuits of the holding pattern are not necessarily or expected (if at prescribed altitude) Non-charted patterns: • Direction of holding from the fix (eight cardinal compass points) • Holding fix • Radial, course, bearing, airway or route on which the aircraft is to hold. • Leg length in miles if DME or RNAV is to be used (in minutes on pilot request) • Direction of turn if left turns are to be made • Time to expect further clearance (EFC) & pertinent additional delay information. Holding Pattern Make all turns during entry and while holding at the LEAST of: LEAST of: 3 deg/sec; or 30 deg bank; or 25 deg bank if flight director is used Compensate for wind by drift correction on the inbound and outbound legs. • When outbound, triple the inbound drift correction Determine entry turn from aircraft heading upon arrival at the holding fix; • +/-5 degrees in hdg is considered to be w/in allowable good operating limits 33 W/in +/-5 degrees: STANDARD (RIGHT) TURNS TD if hdg Radial to -70 Direct if hdg -70 to -250 Parallel if hdg -250 to Radial LEFT TURNS TD if hdg Direct if hdg Parallel if hdg Hold East Over Tacan 090 radial Outbound = 090 090 to 020: TearDrp 020 to 200: Direct 200 – 090: Parra Radial +0 to +70 Radial +70 to +250 Radial +250 to 0 Parallel Procedure (a) • Turn to a heading to parallel the holding course outbound on the non-holding side • Turn to the holding side for more than 180 degrees • Return to the holding fix or intercept the holding course inbound. Teardrop Procedure (b) • Turn outbound for a 30 degree teardrop. Hdg = radial -30 (right turns), +30 (left) • Stay on the holding side (within the pattern) for a period of one minute • Turn in the direction of the holding pattern to intercept the inbound course Direct Entry Procedure (c) • Fly directly to the fix and turn to follow the holding pattern. Timing. • The initial outbound leg should be flown for 1 minute or 1 1/2 minutes • Subsequent outbound legs should be adjusted, to achieve proper inbound time. • Timing begins over/abeam the fix, whichever occurs later. • If abeam can’t be determined, start timing when turn outbound completed • At VOR station, begin turn outbound at reversal of the to/from indicator •Speed and entry rules Altitude (MSL) MAX (KIAS) Inbound Time MHA - 6000’ 200 1’ 6001’ – 14,000 230* 1’ 14,001’ and above 265 1.5’ *Holding patterns from 6,001' to 14,000' may be restricted to 210 KIAS. USAF airfields only - 310 KIAS maximum, unless otherwise depicted. Navy fields only - 230 KIAS maximum, unless otherwise depicted. NOTE-Non standard max holding airspeed protection - # in or near center of racetrack 34 Endurance speeds and computations Speed: point of minimum fuel flow, or point of minimum power required (Pr min) (Note: range = max of speed per fuel flow, max L/D) Computations: Specific endurance = flight hours / lb of fuel Specific endurance = 1 / fuel flow (pounds per hour) (Note: specific range = nautical miles / lb of fuel or knots / fuel flow) 35 Ground navigation o Runway and taxiway lighting and markings Runway: white markings Designators- whole number closest to magnetic heading Centerline markings- uniformly striped stripes and gaps Aiming point markings- visual aiming point 1,020 feet from the threshold Touchdown zone markers- 500 foot increments (3,2,1 bars) Side stripe markings- continuous white stripes Threshold markings- number of stripes determined by width of runway Displaced threshold - located at a point on the runway other than designated beginning Runway lights o Runway End Identifier Lights (REIL): pair of synchronized omnidirectional flashing lights for the positive identification of the approach end of the runway o Edge Lights: white, except on instrument runways yellow replaces white on the last 2,000 feet. Red lights indicate the end of the runway, green lights visible from the opposite direction o Runway Centerline Lighting System (RLCS): 50 foot spacing, white except last 3,000 feet of runway. White alternates with red for next 2,000 feet, and all red last 1,000 feet o Touchdown zone Lights: indicate the touchdown zone, two rows of transverse light bars o Taxiway Centerline Lead-Off/On Lights: alternate green and yellow o Land and Hold Short Lights: row of pulsating white lights across the runway at the hold short point Taxiway: Continuous yellow centerline and edge markings Runway holding position markings whenever intersecting a runway (double yellow on taxiway side, dashed double yellow on runway side) Taxiway Lights o Edge Lights: blue o Centerline Lights: green o Clearance Bar Lights: installed at holding positions o Runway Guard Lights: installed at taxiway-runway intersections, pair of flashing yellow lights or row of in-pavement lights o Stop Bar Lights: row of red, unidirectional lights o ATC clearances and clearance limits o Clearance: allows an aircraft to proceed under specified traffic conditions within controlled airspace for the purpose of providing separation between know aircraft. o Clearance limit: the fix, point, or location to which an aircraft is cleared when issued an air traffic clearance. 36 37 38 Meteorology http://avstop.com/AC/aviationweather Structure of the atmosphere 78% Nitrogen, 21% Oxygen, and 1% other gases Troposphere 0 to 12 km Contains 75% of the gases in the atmosphere. Where weather occurs. As height increases, temperature decreases. Tropopause (Layer) Separates troposphere from stratosphere (12 km (40-45,000’) Temperature remains fairly constant here. Jet stream -- very strong winds that blow eastward. Stratosphere 12 to 50 km Temp remains fairly constant (-60 degrees Celsius) Ozone Layer (shield for ultraviolet radiation from sun) Atmospheric pressure and temperature Pressure Force per unit area exerted against a surface by the weight of air above Temperature Unequal heating of the surface modifies air density Creates circulation patterns, it also causes changes in pressure Isobars Pressure readings at different station and draw lines in between Measured in millibars and are usually drawn at 4-millibar intervals Resulting pattern reveals the pressure gradient (change over distance_ When isobars are widely scattered, it is considered weak. “High” is a center of pressure surrounded on all sides by lower pressure “Low is an area of low pressure surrounded by a higher pressure “Ridge is a elongated area of high pressure “Trough” is an elongated area of low pressure QFE Field Elevation. Atmospheric pressure at sea level, corrected for temp, Adjusted to a datum such as airfield elevation When set on the altimeter it reads height QNE Atmospheric pressure at sea level in the International Standard Atmosphere (ISA), equal to 1013.25 mbar or hPa and used as reference for measuring the pressure altitude QNH Atmospheric pressure at mean sea level (may be either a local, measured pressure or a regional forecast pressure (RPS)). When set the altimeter reads altitude 29.92 inHg (inches of mercury) = 1013.25 millibars/hectopascal Diurnal Variation – change in temperature from day to night Air moves up – Expands (lower pressure). Air moves down – Compresses (higher press) This causes a change in temperature – adiabatic heating / cooling (dry air) Temperature increasing with altitude is known as temperature inversion. 39 Winds and circulations o Equator is warm – zone of thermal lows -- intertropical convergence zone (ITCZ) o ITCZ draws in surface air from the subtropics o This air rises into the upper atmosphere due to convergence and convection o Hits 14 km (top of the troposphere), and flows horizontally to the N/S poles o Coriolis force causes the deflection of this moving air in the upper atmosphere o By 30° Lat - air begins to flow zonally from west to east = Subtropical jet stream o Also causes the accumulation of air in the upper atmosphere o Some of the air in the upper atmosphere sinks back to the surface o = Subtropical high pressure zone. o From this zone, the surface air travels in two directions o 1. Some moves back toward the equator completing the Hadley cell. o This moving air is also deflected by the Coriolis effect to create the Northeast Trades (right deflection) and Southeast Trades (left deflection). o 2. Some moves towards the poles o Deflected by Coriolis acceleration producing the Westerlies o 30 to 60° North and South o Upper air winds blow generally towards the poles. o Coriolis force deflects this to flow west to east forming the polar jet stream o o o o o 60° North and South. Subtropical Westerlies collide with cold air traveling from the poles Frontal uplift and the creation of the subpolar lows or mid-latitude cyclones Small portion of this lifted air is sent back into the Ferrel cell at top of the trop. Most is directed to the polar vortex where it moves down to create the polar high Hadley Cell: 0 to 30° N/S, Rising air (intertropical convergence zone) at the equator and descending air (subtropical highs) at 30° North and South. Ferrel Cell 30 to 60° Circulation cell Polar Cell 60 to 90°. Vertical air flow in the Polar cell consists of rising air at the polar font and descending air at the polar vortex 40 o Wind is caused by air flowing from high pressure to low pressure o Since the Earth is rotating, air is deflected to the right (in the Northern hemi) o Wind flows mostly around the high and low pressure areas o Wind "feeling the Earth turn underneath it" is important for very large and long-lived pressure systems. o For small, short-lived systems - the wind will flow directly high to low o The closer the high and low pressure areas, the stronger the "pressure gradient" o Stronger the gradient – Stronger winds o The closer the isobars – Stronger winds o Curved around High – Stronger winds (anticyclonically) o Friction from the ground slows the wind down o Most pronounced at night o Convective mixing has stopped o Wind allows atmosphere to move excess heat around o Away from the surface of the Earth Sunlight causes an excess buildup o Away from warm regions (usually the tropics) o In tropics – trade winds, monsoons, and hurricanes transport heat o Outside tropics - Extratropical cyclones transport heat THE WIND AFFECTS THE EARTH'S ROTATION Winter, the stronger westerly winds in the Northern Hemisphere, combined with frictional drag at surface, produce a very small increase in the rotation Clouds and moisture; fog and low clouds o Moisture accounts for a small percentage of the total volume of the atmosphere o Generally if air is moist, then poor or severe weather can occur o Clouds are formed when air is cooled to its saturation point o Very small droplets of water or, if cold enough, ice crystals o The droplets condense (subliminate) on small particles of matter Dust, salt from sea spray, or products of combustion. o Low to the ground = fog o o o o Nimbus Stratus Cumulus Cirrus Produce rain Sheet-like (layer) (wide) Puffy Whispy 41 Low Clouds Stratus Stable air near the surface due to cooling from below Nimbostratus Gray or black clouds that can be more than several thousand of feet thick, Widespread areas of rain or snow Stratocumulus White, puffy clouds that form as stable air is lifted Middle Clouds Altostratus clouds are flat, dense could that cover a wide area. Altocumulus Patchy clouds of uniform appearance that often, when altostratus break up High Clouds (>20k AGL) Ice crystals, and seldom pose a serious turbulence or icing hazard Cirrus Stable air at high altitudes Cirrostratus Thin, white clouds that often form in long bands or sheets Cirrocumulus White patchy clouds that look like cotton Fog Base within 50 feet of the ground. Ground fog – less than 20 feet deep Radiation fog - over low-lying, fairly flat surfaces on clear, calm, humid nights. Advection fog - when a lower layer of warm, moist air moves over a cooler surface Upslope fog - moist, stable air is forced up a sloping land mass Steam fog – (sea smoke) cold, dry air moves over comparatively warmer water Atmospheric stability and turbulence o Stability o Stability is the atmosphere’s resistance to vertical motion o A stable atmosphere makes it more difficult to move vertically o An unstable atmosphere, convection is the rule. o Stability of an air mass is decreased my warming from below. o Turbulence 1. Near thunderstorms 2. Low Level (<15k): surface heating or friction. a. Mechanical turbulence (buildings or rough terrain) b. Convective turbulence / Thermal turbulence, typically in the daytime happens when air is heated by the ground. c. Frontal turbulence occurs in the narrow zone just ahead of a fast-moving cold front where updrafts can reach 1,000 fpm. d. Wake turbulence is caused by other a/c. 3. Clear Air Turbulence a. Interaction of layers of air with differing wind speeds, convective currents, or obstructions to normal wind flow. It develops near the jet stream. 4. Mountain Wave Turbulence - Stable air crosses a mountain barrier 42 a. Air moving across this surface causes circulation or a rotor. 43 Air Masses and Frontal systems Airmass: Large body of air with fairly uniform temperature and moisture content o Polar or tropical to identify their temperature characteristics o Continental or maritime to identify their moisture content o Modification – as an airmass moves out of its source region, it is modified by the temperature and moisture of the area over which it moves. o Depends on speed, nature of the region depth of the airmass, and temperature difference between the airmass and the new surface. o Warming from below – As an airmass mover over a warmer surface, its lower layers are heated and vertical movement of the air develops. o Fronts: Boundary between the airmasses is called a front o Cold front: Cold air is moving to displace warmer air o Warm front: Warm air is replacing cold air o Stationary front: No movement o Occluded front: Cold air and warm air front merge o Most easily recognized discontinuities across a front is the change in temperature o When flying across a front, you will notice a change in wind direction and windspeed. Thunderstorms and Windshear Thunderstorms: 3 conditions must be present o Instability - air that has a tendency to toward instability o Lifting action - some type of lifting action o Relatively high moisture content. 2 types o Airmass TS – scattered, summer afternoons, coastal nights o Severe TS – Gusts of 50+ kts, Hail ¾”, Tornadoes. Single-cell – lasts less than 1 hour Super-cell – lasts about 2 hours Multi-cell – a compact cluster of TS cells in different stages of development Cause the duration to be much longer than any individual cell o Squall line: Multicells form a line, 50 to 300 miles ahead of a fast-moving cold front, Hail, destructive winds, tornadoes, etc. o Life Cycle o Cumulus Stage - Initial stage - updraft air reaches condensation point. Expand vertically (30k) and laterallu (5-10 mi). Continuous updrafts. o Mature Stage - First drop of precipitation reaches the ground. Cloud tops Exceed 60,000 feet, Anvil shape from strong winds. TS is strongest toward the end of the mature stage. Rain will be the heaviest Lightning abundant Hail, strong winds, tornadoes may form. o Dissipating Stage - End of a TS. Precipitation falls through and breaks it up, Humidity in the air drops and the precipitation ends -- Downdrafts. 44 o o o o o o o Ice & Icing Takeoff Clean Wing (no Ice, Snow, Frost) Found in Visible moisture between +5° and -20° C or colder (usually +2 to -10) Stay 3k below or 8k above freezing level Climb through Rime, Descend with Clear. AIMET – Moderate Ice. SIGMTE – Severe Ice. Freezing rain usually produces the highest rate of ice accumulation Thrust and lift are reduced, drag and weight is increased Rime – Opaque - Instantaneous freezing of small super cooled droplets (-15 to 20C) Clear – Most serious. Adheres to jet and difficult to remove. (0 to -10C) Large super cooled water droplets which are in cumulus clouds / frzng rain 4 Levels: Trace, Light, Moderate, Severe WX depiction charts, radr summary, maps, winds aloft, prog, constant pressure charts o Weather depiction chart o Computer-human generated - METAR reports (01 Zulu each day, 3-hour intervals) o Observation used is the latest METAR (not the one closest to the stated time) o Some observation info may be omitted, but all info is to determine IFR/Mvfr/VFR o Broad overview of the observed flying category conditions o Right bracket ( ] ) indicates obtained by automated system only o Total sky cover, cloud height (AGL, hundreds of ft) or ceiling o Weather and obstructions to vision, and visibility (left of station) o Visibility of 5nm or less (sm and fractions) o Fronts and Troughs analysis from preceding hour (except 10Z and 23Z) IFR <1,000 feet & 3 miles Hatched (lined through) area outlined by a smooth line. MVFR (Marginal VFR) 1 - 3,000 feet, 3-5 miles Non-hatched outlined by a smooth line. VFR 3,000’ or higher, vis > 5 miles Not outlined 45 o Radar Summary Chart o Computer-generated graphic of automated radar weather reports (SDs) o Areas of precipitation: Type, intensity, configuration, coverage, echo top, cell movement o Severe weather watches are plotted if they are in effect o Hourly 35 minutes past each hour o Echo Type (Precipitation) – Determined by computer model (not from METAR) o Echo Intensity (radar return) – Contours o Six precipitation intensity levels are reduced into three contour intervals o Grouped like: Light to Moderate intensity (can’t determine which one) o Intensity is coded for frozen precipitation (i.e., snow or snow showers). Trend not coded o Echo Configuration (arrangement) & Coverage (area) o 3 designated arrangements: LINE, AREA, CELL of echoes o Coverage depicted by Hatched area inside the contours If 8/10 coverage or more, the line solid (SLD) at both ends o Echo Tops (from radar and satellite data) o Approximate max height of the precipitation in hundreds of feet MSL o Tops are entered above a short line, with the top height displayed o Assumed that all precipitation displayed on the chart is reaching the surface o Echo movement o Arrow with the speed in knots entered as a number at the top of the arrow head. o Line or area movement is no longer indicated on the chart. o Severe WX Watch Areas o Outlined by heavy dashed lines, usually in the form of a large rectangular box. o Tornado watches and Severe TS watches = Type and Watch number depicted “WS0005” = The 5th severe thunderstorm watch issued in the year 46 Winds and Temperatures Aloft 6k -18k every 3,000 24, 30, 34, 39k (see const press) Temp in degrees C (on right) Wind in knots Direction – Arrow with 1 digit Ex. Arrow to E with a 6 = 060 60 kts of wind, 060° -31 Celcius Significant Wx (Prognostic Charts) Manually and computer-prepared 12 and 24 hour Sfc, Low and High level charts (24k) CLOUDS ISO Less than 1/8th Coverage 420 – Max tops at 42k th th OCNL 1/8 to 4/8 Coverage XXX – bottoms below 24k th th FRQ 5/8 to 8/8 Coverage EMBD Embedded CB Implies thunderstorm – implies hail, moderate or greater turbulence, and icing TURBULENCE ^ Mod Dbl Severe SQUALL Line 33k down to below 24k 47 Constant Pressure Charts Approximate temp, wind, dew point All info depicted is at the specified pressure millibar (mb) / hectoPascal (hPa) charts Twice daily 850 mb/hPa, 700 mb/hPa, 500 mb/hPa, 300 mb/hPa, 250 mb/hPa, and 200 mb/hPa 700 mb/hPa = approx 10,000 feet MSL 300 mb/hPa = approx. 30,000 feet 250 mb/hPa = approx. 34,000 feet 200 mb/hPa = approx.. 39,000 feet TT = Temp T-D =Temp Dew spread HGT = Actual heigh (mtrs) Of pressure surface Hc Height Change in Thens of meters BC - patches BL - blowing DR - low drifting FZ - freezing MI - shallow SH - shower(s) TS - thunderstorm Aviation weather reports (PDF Guide) o Terminal forecasts, area forecasting (ATIS, METAR, etc.) RA - rain FG - fog (< 5/8 mi) o METAR - ROUTINE WEATHER REPORT GR - hail (> 1/4") BR - mist (5/8 - 6 mi) Type of report SPECI or routine DZ - drizzle PY - spray 2. Station designator GS - small hail SA - sand SN - snow FU - smoke 3. Time of report Zulu (UTC) PE ice pellets DU - dust 4. Wind kts, variable if 60 deg + SG - snow grains HZ - haze 5. Visibility Statute miles (5SM) IC - ice crystals VA - volcanic ash RVR (R32L/1200FT) SQ - squall 6. Weather and obstructions to visibility SS - sandstorm Intensity (-+)/ Proximity / Descriptor / Precip / DS - duststorm Visibility obstruction / Other PO - dust/sand whirls 7. Sky condition (bases in hundreds of ft) FC – funnel cloud /tornado/waterspout o SCT 1/8 – 4/8 o BKN 5/8 – 7/8 Ceiling o OVC 8/8 Ceiling o CB or TCU (Towering Cumulus) o VV006 Vertical visibility 600’ 8. Temperature and dew point (Celcius) o M04 -4 C 9. Altimeter setting (in Hg) 10. Remarks RMK REFZDZB45 WS TKO RW04R Remarks, REcent wx, FZDZ Began 45’ after the hour Wind Shear during TaKe Off RunWay 04 Right 48 o o o o TAF 4 times a day TYPE / LOCATION / ISSUANCE TIME / VALID TIME / FORECAST TYPE: Routine or Amended AMD, Corrected COR, Delayed RTD PROB40 (40% probably) TEMPO HHHH Start hour to finish hour FM HH From hour BECMG HHHH Becoming (gradual change) between hours of HH and HH o TIME: DDHHMM o WIND / VISIBILITY / WEATHER / SKY CONDITION TAF KMEM 121720Z 1818 - TAF issued for Memphis, TN on the 12th at 1720Z and valid for a 24 hour period from 1800Z to 1800Z. o AREA Forecast (FA) • Over several states (6 areas in CONUS) • 3 times a day for a 12-hour forecast and 6 hour outlook (18 total hours) • No annotation on Alt = MSL. Else CIG = ceiling and AGL = AGL o Flight weather advisories, pilot reports Convective SIGMET (WST) SIGMET (WS) AIRMET (WA). Pilot reports can generate Urgent Center Weather Advisory (UCWA) Center Weather Advisory (CWA) KC3 CWA 032140 3rd CWA form K.City DDHHMM ZKC CWA 301 VALID UNTIL 032340 301 – 3rd phonemoneal, 1st issuance SIGMETS and AIRMETS o AIRMET (Airmen's Meteorological Information) -- Of Interest to ALL Hazardous to limited capability a/c orr non-instrument rated pilots Every 6 hours & valid for 6 hours: Mod icing, turbulence, 30+ sfc winds, IFR (S) Sierra – Mountain Obscuration or IFR) less than 1000 or 3 50% of an area at one time. Extensive mountain obscuration (T) Tango – (Turbulence) Mod turbulence, sustained winds of 30 kts+ at SFC (Z) Zulu – (Icing) Moderate icing, freezing levels o SIGMET (Significant Meteorological Information) -- Of Interest to ALL Safety of all aircraft -- issued in alphabetic order from N to Y, (not S or T) Non-Convective – Severe or greater icing, IMC, dust, sand, volc ash, valid for 4 hr (WST) Convective – TS over 3,000 sq mi, line of storms >60nm and/or embedded storms affecting any area for >30min. (valid 2 hours) 49 Weather radar o Precipitation, wind, and weather systems o 3 Types o WSR-88D NEXRAD Doppler radar • Surrounding communities of impending weather o FAA terminal doppler weather radar (TDWR) - severe weather alerts and warnings • Wind shear, gust fronts, and heavy precipitation, o Airport surveillance radar • Primary to detect aircraft • Also detects the location and intensity of precipitation around an airport Climb Segments: o First segment- from the point which the aircraft becomes airborne until it reaches the 35-foot height at the end of the runway distance required, speed V2 o Second segment- (most restrictive) from the 35-foot height to 400 AGL, V2 speed, flaps set for takeoff, gear retracted. Provides 2.4% climb gradient o Acceleration segment- begins at 400 AGL and accelerating from V2 to the Vfs speed before climb is continued. Flaps are raised, takeoff power o Final segment- 400 to 1,500 AGL with maximum continuous power. 1.2% climb gradient -------------FROM ATP Study Icing increases stall speed, decreases stall AOA reduce lift by 30%, increase drag by 40% (worse on drag) Clear Air Turbulence Most likely – const press charts show 20 kt isotachs less than 150 nm apart Moderate CAT = 40 kts per 150 miles (double) CAT from mnt wave – 5000’ above tropopause Likely location – upper trough on polar side of jetstream In TS – maintain const Attitude (don’t change altitude) Microbursts Max downdrafts – 600 fpm / Peak intensity windspeed change – 45 knots “Severe” wind shear – Rapid change of wind direct 15 knots a/s, or 500 fpm vvi Precipitation = light, mod, heave, extreme (no severe…that’s for TS) Ground based inversion – poor visibility Temperature inversion – A stable layer of air (if it were unstable, it wouldn’t exist) Freezing rain – a layer of warmer air exists above Common location for inversion - Stratosphere Temp of air changes by compression or expansion - Adiabatic Station pressure = actual pressure at field elevation What causes Adiabatic cooling – Expansion of air as it rises Very strong turbulence clouds – standing lenticular What happens when passing through a front into colder air – Press increases Stability of atmosphere determined – ambient temp lapse rate What signals mature stage of TS – Start of rain at surface Most likely to produce funnel clouds/tornadoes – Cold Front/Squall line TS Only cloud types in a TAF - CB 50 51