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Brief explanation on Landing:
If you have read other parts of this site you will know that flaps are used to reduce an aeroplane's stalling speed, allowing for slower take-off and landing speeds, which also means shorter runways being required.
On a B744 there are set flap positions: 1, 5, 10, 20, 25, and 30 degrees of flap. Flap 25 is rarely used. Flap 30 is the normal landing flap setting.
This video clip commences about 8 nm on final for RWY 34L at Sydney in near-perfect conditions. Note the talking radio altimeter calls: 'radio altimeter', '1,000', '500', '100', '50', '30', '20', '10'. These are heights in feet of the main landing gear above terrain. The final approach speed varies with weight (due to stalling speed changing with weight). In this video clip the landing weight is approximately 248 tonne with a final approach speed of 143kts, though we as standard add 5kts above that so in the video the aiming speed is 148 kts when in the final landing configuration of gear down and flap 30. My company requires that its planes are in a stable configuration by 1,000', which is normally 3 nm from the runway.
The landing aiming point is 1500' down the runway. This will put the pilot's eyes 57 feet above the threshold as the plane crosses the end of the runway, and the wheels, which are 90 feet behind and 32 feet below the pilot, will cross the end of the runway at 25 feet. Aiming at 1500 feet means the wheels should touch down somewhere between 1200 feet and 1800 feet from the end of the runway. Flare height varies with "rate of closure" with the runway.
In still air, (I note from this video) the flare height was a bit below 20' wheel height. If we had been landing into a very strong headwind, say 30 kts, the flare height would have been somewhere around 15 feet. Conversely in a 15kt tailwind for landing the flare height would most likely be around 25'. Now these are figures based on the way I land a plane. Ten pilots will each land a different way. Some like long slow flares commencing above 30 feet, some like a "zip flare" closer to the ground.
To those pilots learing to fly note that the approach path is controlled by pitch, ie elevators, and speed by power.
You can tell when the plane has landed by the auto speed brake deploying (short noise). You can see a small white handle lever to the left of the throttles moving aft. This reducs lift causing maximum weight to be loaded onto the wheels, and allows the auto wheel brakes to work more effectively. You can note the small jerk as the auto brakes grab, even though I had reduced to a 1 setting on short final (from 3), this is standard. Some planes grab heavier than others. Reverse thrust is applied once the wheels have touched down by selecting small levers ahead of the thrust levers. Full reveres is held in until about 80 kts and then slowly reduced to idle by about 50 kts.
If you have any questions please email. |
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