Aircraft Approach and Landing PDF

Landing Performance - During take-off and landing, the CL and CD are determined by 2 things: 1. The AOA 2. The configuration of the aircraft (flap, slats, spoiler and gear extension) - AOA is not considered from the start of the flow seperation up to and inclusing th...

Landing Performance - During take-off and landing, the CL and CD are determined by 2 things: 1. The AOA 2. The configuration of the aircraft (flap, slats, spoiler and gear extension) - AOA is not considered from the start of the flow seperation up to and inclusing the stall - The parasitic drag (CDO) is independent of the AOA - The parabolic characteristics equation is valid Approach Distance - Due to the landing configuration (flaps, slats and gear activated) an idle descent is not possible during a ILS approach, so we have to use thrust This is known as powered descent - Flaps configurations are only be used during landing and take-off, because of it’s increase in drag. - The flaps will be retracted as soon after the take-off to reduce noise for citizens and to save fuel consumption - When the plane is in landing configuration, the CD0 will increase, which means the parasitic drag will increase - The brown(CD0), green (CDi) and dark green (Total Drag), line shows the airplane in clean configuration - The pink line shows the parasitic drag (CD0) increasing when the plane is in the landing configuration - The induced drag (CDi) will increase because of its increasing CL and the Oswald factor decreases slightly because of its changing wind shape These 2 won’t change so much/significant so we can assume that the green line will not change - The dark green line is the clean configuration and will change to the blue line (D) which is the landing configuration - The minimum happens at the lowest speed Flare Distance - Sum of the forces parallel to the TAS are equal to zero because the TAS is constant Y = (D-T)/W - Sum of the force prependicular to the TAS ae equal to the centripetal force r= radius of the arc The formula is limited of use because: - The radius needs to be constant throughout the arc - While the flight angle Y decreases during the flare arc - So the lift has to increase during the flare arc and so does the AOA because the speed is kept constant