Back to basic: What’s …
Today, it’s already the 7 days after my leave from the last position as a ground agent in HKIA. I come with a new idea to help myself review what I have learnt. Yes – the method is simply asking “What’s…”
In aviation industry, no matter for our own interest as a GA pilot or for the interview of airline cadet pilot. What’s the first step to learn something new as well as answer a question is to explain what is – to describe it.
What’s Airworthiness
Airworthiness is a multi-layered framework as well as system to ensure operational personnel (people) are certified, equipment (and its system) and organization are qualified AND continuous controlled and supervised in suitable status to achieve safe operations – fitness to fly.
What’s the reason for aircraft fly – How planes work?
This is the combination effect of 4 forces, which are Lift, Weight, Thrust and Drag.
In different flight condition should have different magnitude of these 4 forces
What’s the relationship of the 4 forces?
In most case, required thrust is proportional to the weight – next you may ask what’s the reason for this relationship?
If weight increase, more lift is required, and more lift denotes more drag generated (the form drag), and thrust is the force offsetting the drag. So the more the weight, the more thrust required
What’s the condition in which 4 forces will be offset?
In any unaccelerated (i.e steady) straight and level flight.
And actually, the magnitude of lift is usually larger than the thrust and so the magnitude of weight is larger than drag at unaccelerated (steady) straight and level condition.
What’s unaccelerated (i.e steady) condition?
the sum of all upward components offsets the sum of all downward components
plus the sum of all forward components offsets the sum of all rearward components
http://tommykwan.com/abcdxxx/what-does-steady-unaccelerated-flight-mean/
What’s straight and level condition? (FTA)
Straight and level is equilibrium of 4 forces – when Lift offsets the Weight and Thrust offsets Drag, the aircraft are in equilibrium – will not be climbing, descending, accelerating or changing direction
http://tommykwan.com/abcdxxx/whats-straight-and-level/
What’s the expected parameter to show straight and level?
As straight and level is an equilibrium status at which the aircraft don’t climb, descend, accelerate and change direction, so
- altimeter reading no change
- airspeed reading no change
- compass reading no change
What’s the procedure to enter straight and level?
4 steps – 1) select reference point with wing level 2) 4 finger spacing 3) set power 4) select-hold-trim
http://tommykwan.com/abcdxxx/how-to-achieve-straight-and-level-flight/
What’s aircraft stability?
Stability is the inherent ability of an aircraft to go back the original flight path or continue the distrubed flight path
Three type of dynamic stability
Positive – return to original status
Negative – continue intensifying in the new status
Neutral – just maintain in the disturbed status
http://tommykwan.com/abcdxxx/stability-maneuverability-controllability/
What’s the fifth force acting on the aircraft? – What’s 5 forces?
The fifth force is the download on the tailplane.
What’s climbing?
Climbing is a basic maneuver that the aircraft gain height. It require excess thrust and/or power of the engine since there are different climb speed regime. However, if the climbing is not helped by the engine, then the engine need to use airspeed to trade for climb – or so called zoom-climb.
Of course, there is possibility that the aircraft climb at other condition – let’s say updraft – but that is not intended/ controlled climb maneuver.
What’s the 3 common types of climb?
Vx – best angle of climb
Vy – best rate of climb
Vcc – cruise climb
Vx is used to climb as steeply as possible, eg. obstacle climb-out after take off / En-route. The steeper the climb, the more rearward component of weight and so more thrust is required to offset that drag.
Vy is used to climb as quickly as possible, eg. take-off / En-route. As the concept of rate come out. The power is considered for rate of climb. The higher rate of climb you want to make, the more power is needed.
Vcc is used for climbing efficiently, eg. En-route.
Different speed regime are applied for distinguish purposed of climb. The Vx could reach the best height within the least ground distance but the engine cooling is poor and the visibility is reduced and Vcc has opposite features.
What’s the 4 forces in steady climb?
Lift force is acting on center of pressure but tilted backward though it is still perpendicular to the flight path
Weight force is still acting on the center of gravity and downward toward the earth
Thrust is acting forward and parallel along the flight path
Drag is acting backward and opposite to the flight path.
In a steady climb maneuver, the lift should become less than (<) the actual weight!
Be noted that the is part of the rearward weight component acting rearward and opposite to the flight path. Therefore, aircraft need extra thrust to offset the retarded force.
What’s the factors affecting the climb performance?
My notes listed more than 10 factors, let us try to learn some of them. Firstly, the engine performance is the contributory factor which heavily depend on the Density Height/ Altitude. The DA take the air density into consideration – 3H – Humidity, Temperature and Height. Next, the airspeed which is the speed regime should affect the climb performance. After that, the Wind should play role in climb performance. Although the wind don’t affect the rate of climb but headwind should help the aircraft climb to certain height with less ground distance cover and the tailwind in contrast make the aircraft need more ground distance to gain the same height. Then, we should pay attention on the configuration of the aircraft, landing gear and flaps position for instances. Contaminated wings like ice build-up should reduce the climb performance as the ice not only acting weight on the aircraft but also change the aerodynamic property. Last but not least, the IGE – In-Gorund Effect and OGE – out-of -ground effect. However, that’s seems talking about the climb ability and performance within the transition stage from near ground to higher and vice versa.
http://tommykwan.com/abcdxxx/climb/
What’s the method to enter, maintain and level off from a climb?
To enter – Trim well first, AAI set, bank wing Lookout clear left, center below and above and right, P-A-T
To maintain – ALALP cycle, lowering nose every 500 feet, Engine Temp and Pressure check
To level off -Lookout – A-P-T
http://tommykwan.com/abcdxxx/how-to-enter-maintain-and-exit-climb-maneuver/
What’s descending?
Descending is one of the basic maneuver that the aircraft lose height. It require reduce thrust and/or even idle power of the engine since there are two most common types of descending – powered descend and glide descend.
Of course, there is possibility that the aircraft descend at other condition – let’s say downdraft – but that is not intended/ controlled descending maneuver.
http://tommykwan.com/abcdxxx/descent/
What’s the method to enter, maintain and level off from a descent?
To enter – Trim well first, AAI set, CFM check, bank wing Lookout clear left, center below and above and right, P-A-T
To maintain – ALALP cycle, Engine Temp and Pressure check, increase to cruise power for 3 sec in every 1,000 feet
To level off – Lookout, P-A-T
http://tommykwan.com/abcdxxx/how-to-enter-maintain-and-exit-descending-maneuver/
What’s the flight phases (operation)?
Generally speaking, a flight consists of many parts including:
- Taxi-out
- Takeoff
- Terminal Area Departure (initial climb)
- Climb
- Cruise
- Descent
- Terminal Area Arrival
- Final Approach
- Landing and Rollout
- Taxi-in
However, in real airline operation or even just GA operation, there are far more steps and activities involved.
What’s Runway
Runway is a physical lane used for aircraft rolling in the take-off and landing phase.
What’s take-off
Take-off is one of the phrase at which the parking bake is off and the aircraft start the takeoff run along the runway, after this round roll the aircraft should meet sufficient speed to rotate and then lift off as well as enter to the transitional phrase until meeting the take-off safety speed (TOSS) at certain height
What’s landing
In opposite to take-off, landing is one the phrase at which the aircraft at certain height above threshold transit to the touchdown zone and then start to flare and make a ground roll to reduce speed and then come to a full stop
What’s the factors affecting takeoff performance
- Aircraft
- Weight
- Aircraft Configuration – Flaps
- Thrust regime – derated / Full Thrust
- External factors – WX
- Air density – Density Altitude (Terrain, Diurnal temperature difference, Humidity – 3H)
- Wind (Head/Cross/Tail)
- Runway – Surface condition (dry/wet) / Slope / Length (TODA)
- Regulation – noise abatement provision
- Obstacle height -safety!
What’s flare?
Flare is pitching up the nose to cause the aircraft touchdown and enter the ground roll unaccelerate stage.
What’s runway excursion ?
Runway Excursion is an accident in which aircraft veer off or overrun the runway surface.
What’s Hydroplaning
Hydroplaning is a phenomenon in which the tire skating along a thin film of water is lieu of rotating.
What’s runway incursion ?
Runway incursion is any incorrect presence of 1) aircraft, 2) vehicle or 3) personnel on the protected area designated for take off and landing.
What’s the “sufficient speed to rotate” / “V1 Speed”
There are two way to know the “sufficient speed to/for rotate” – both of them require a well pre-flight planing – but there is a bit different between the assessment regime used in GA application and those aircraft with MTOW exceeding 5700 kg. But the concept are similar – once reaching the calculated/defined speed – that’s the decision speed. Should the rotate speed is reached, pilot in general continue the take off even engine failure.
What’s the take-off safety speed (TOSS)
TOSS is defined airspeed should be reached in order to climb out to sufficient height even in the event of engine failure.
What’s PAPI
PAPI is standing for Precision Approach Path Indication, which is a single wing bar consisting of 4 light units, installed at the side near or adjacent to the touchdown zone and used to assist pilot to check if they are on the correct approach angle.
What’s glide path?
Glide path is the slant track (or in a more professional term trajectory) followed by the pilot at a given gradient (typically 3 º) during approach
What’s go around?
Go around is a maneuver conducted to discontinue an approach and performing a circuit for a new approach
What’s circuit
Circuit is the stand traffic pattern to maintain a form of safe and order flow around the runway, which is consisting of 4 legs – upwind, cross-wind, downwind, base, and final.
What’s Airspace
Airspace is defined 3-D volume of space in which distinguish Air Traffic Service or communication procedure is adopted. In addition, different vertical and horizontal separation between aircraft and could should be comply with.
What’s ISA
ISA is International Standard Atmosphere, which is a list of criteria – temperature 15ºC, 1013 mb (=29.92 inHg), at above meal sea level, air density 1.225 kg/m3 – and the temperature lapse rate should be 2ºC/1000 feet and every 30 feet will have 1 mb dropping.
What’s Pressure Height (PH)
Pressure Height (PH) is also known as the Flight Level (FL) or QFE. The reading of the height take reference to 1013 mb. Or in formula : PH = Height @ certain QNH + (1013- QNH) *30
What’s Density Altitude (DA)
DA is the assumed altitude taking air density into consideration to show the pressure height that the engine performing at. So the density altitude might not be the actual altitude of the aircraft.
http://tommykwan.com/abcdxxx/density-altitude-da/
What’s Altitude
The vertical distance take reference to the mean sea level.
What’s vector/vectoring?
Vector is that heading issued to an aircraft for the purpose of providing navigational guidance
What’s slot?
slot is the assigned time frame for arrival or departure
