Forces In Descent Flashcards
What is the descent angle
Angle between ac path through the air and local horizontal
Symbol y (gamma)
Pitch angle + AOA
What is the pitch angle
Angle between longitudinal axis and horizontal (shown on attitude indicator)
Pitch angle is less than the descent angle
Given as a negative value
Forces in descent parallel to flight (power on)
Drag = Thrust + W Siny
Thrust
Drag
Wsiny
Steeper descent will have a
Larger descent angle
Shallowest descent is at
VMD
Engine failure you will fly at…
Vmd for shallowest descent
Vx
Best angle of climb
Steepest climb angle
Operate most efficient at heigh
Slow speed
How do we manage drag
Speed and spoilers
Depressurisation what speed should you fly at
VMO for most excess drag
Drag in a descent formula
T + weight x siny = drag
WSINY =
Drag - Thrust
——————
Weight
In a glide descent forward component is what to drag
Equal as no thrust
Calculating glide range
X lift by the range altitude
Convert ft to nm (6080ft in 1nm)
Gliding with head wind
Range reduces
Gliding with tailwind
Range increases
Mass impact on glide range
Does not affect in still air heavy ac will simply just reach ground quicker in same location
Heavy A/C in headwind glide range
Will be in air less time therefore less effected so slightly better range than a lighter ac
Tailwind and mass
Light a/c will have greater range due to being in air longer
X2 Factors effecting glide range
Flaps - reduce L/D ratio and glide range
Speed - flying faster or slower than vmd
Glide endurance speed is
Vmp (0.76 vmd)
Useful for gliding over sea
Vmp is the minimum speed for power
AOA is always expressed as
A positive number of degrees
Pitch angle is always
Negative
In steady power off descent which force drive ac down descent flight path?
Weight
CDFA Is + advantages
Continuous descent final approach
Certain power setting all the way down the descent saves fuel/reduces engine wear and reduces air and noise pollution