Gust front v.s Microburst?
August 24, 2024
Microburst affect smaller area (say around 2.5 miles), and short-lived (last for 5-10 minutes) Gust front affect wider area (say up to 20 miles) A microburst is a small concentrated downburst that produces an outward burst of strong winds at or near the surface. Microbursts are small — less than 4 km across — and short-lived, lasting
Typical causes of windshear and turbulence at VHHH?
August 24, 2024
Ref: https://www.hko.gov.hk/en/aviat/articles/files/booklet_4th_edition.pdf (6) Six typical causes of windshear and turbulence in Hong Kong: Terrain induced strong winds blowing across the hills over Lantau Island to the south of the airport (account for 75% of reported windshear) Sea breeze account for 15% of reported windshear Gust front (thunderstorm related) Microburst (thunderstorm related) Building induced Low level
Turbulence v.s Wind Shear
August 24, 2024
With reference to HKO publication: Windshear – sustained change (i.e lasting more than a few seconds as experienced by the aircraft) in the wind direction and/or speed, resulting in a change in the headwind or tailwind encountered by an aircraft change in lift (usually decrease lift), and cause the aircraft to go below the intended
Thunderstorm, CB?
August 23, 2024
(4) four main types of thunderstorm Single-cell small, and isolated storm Multi-cell a cluster of single-cell Squall line a line of thunderstorm Super cell very strong thunderstorm, and capable of producting tornadoes Criteria of forming thunderstorm (CB) unstable atmoshpere (warm air) moisture (larage amount) lifting mechanism (trigger action) (5) five types of lifting
DME – Distance Measure Equipment
August 21, 2024
Function of DME? provide distance information (measure the slant distance between the DME station and aircraft) Component of DME? DME ground station (usually combined with VOR) Aircraft DME unit Principle of DME? DME unit onboard the aircraft, that send out interrogation signal to ground DME station Ground DEM station give reply – send
ILS-Z, Y, X?
August 21, 2024
What can be different? ILS frequency Waypoint Descend profile CAT type RNP requirement MAP (miss-approach) procedure
ILS – Instrument Landing System
August 21, 2024
ILS (Instrument Landing System) is used for precision approach, particular useful for low visibility condition and/or bad weather. Component of ILS Localizer Glide slope Distance Measuring Equipment (DME) or Marker Beacons Runway lights 留意飛機方向!!! Function of each components: Localizer Guide the aircraft to the centerline of the runway (lateral guidance) Glide slope Guide the
Endurance? Range?
August 18, 2024
Range is affected by: fuel on board fuel flow (how fast the fuel is burnt)! Fuel flow increase (i.e burn more fuel) –> range will reduce. Range can be said as the distance the aircraft can go per unit of fuel ( Distance NM/ Fuel kg) Range can be translated into specific range
Two spools v.s Triple spools
August 4, 2024
References: Difference between Two Spool Engines and Three Spool Engines – FlyFA Aircraft Maintenance Engineering 3-Spool-Engine Concept | aircraftengineering (wordpress.com) What is triple spool design on the RB211? what are the advantages/disadvantages? A 3 spool engine is one that has three sets of compressors before the combustor and three sets of turbines behind it. A
Cooling Methods in Turbine Blades
August 4, 2024
Reference: Cooling Methods in Turbine Blades | Turbomachinery blog (softinway.com) thermal barrier coating on the turbine blade (Blade Passive Protection) internal cooling – maintains the blade metal temperature below the outside gas temperature by heat transfer to internal cooling air – include convection cooling and impingement cooling, where cooling air runs through channels within the
PUDSUC – 口訣 : pitot static blockages
August 4, 2024
Reference: Instrument failure: the test of trust | Flight Safety Australia PUDSUC A pitot blockage will cause airspeed to underread on descent (vice versa on climb). A static blockage will cause airspeed to underread on climb (vice versa on descent).
[GA piston engine] What’s full throttle height?
August 3, 2024
Full throttle height – Depending on the power setting, as an aircraft climbs (fitted with a fixed-pitch propeller), a height is reached eventually where the throttle will be fully open to maintain that power setting. Important concept: An aicraft can have various power setting! Each power setting has a full-throttle height! Read more
[GA Piston Engine] Effect of Increasing Height on Power Output
August 3, 2024
(On a ‘standard’ day) Aicraft climbs / fly high –> output of the engine decreases for two reasons: decrease in atmospheric pressure – reduces the manifold pressure and thus the flow of air into the cylinders (a similar effect to closing the throttle) – can be compensated for by progressively opening the throttle decrease in
Too lean, Too rich, CCM, Best power, Best economy
August 3, 2024
Notes: The carburettor measures the weight of air passing through the induction manifold and uses this measurement to regulate the amount of fuel discharged into the air stream (according to a predetermined schedule). What’s rich, lean and CCM? Rich: 1:8 Chemically Correct fuel/air Mixture (CCM): 1:15 Lean: 1:20 In theory, the ‘correct’ quantity
