Take Off Optimisation Flashcards
What are the sustained and free parameters for a T/O?
Sustained: RWY, CWY, SWY, ELE, slope, obstacles, temp, px, wind, RWY conditions, anti ice, a/c (MEL)
Free: V1, V2, T/O configuration, air con
How does air con affect T/O performance?
Decreases power available and therefore reduces performance.
What is the range for V1/Vr?
V1/Vr ratio lie between 0.84 and 1
How will an increase in V2 affect TODR?
What range should V2/Vs lie? Draw graph to show this
Increase V2 increases TODR, any increase in V2/Vr has same effect as increasing V2.
Lie between the min and max. Also, y axis is 2nd segment climb gradient.
Draw a graph showing RWY MTOW limits with variable V1/Vr and constant V2/Vs.
What are the limiting factors as V1/Vr increases?
Refer notes.
Draw a graph showing climb/obstacle limits with variable V1/Vr and set V2/Vs.
What are the limiting factors?
V1 has no influence on climb gradients/MTOW, are constant.
It has an effect on obstacle limited weight as increased V1 will reduce TODR so start of flight path is earlier, therefore a greater clearance/reduced gradient to clear obstacles… increasing MTOW.
Increasing V1 reduces TODR as assuming an EF with a higher V1, the one engine acceleration to reach V2 at 35ft is less so decreases TODR
Draw a graph showing brake energy/tyre speed with increasing V1/Vr affecting MTOW?
Max V1 is limited by tyre speed, has no effect on MTOW.
A lesser MTOW is required for an increase in V1/Vr
What occurs if you combine all 3 graphs?
Find the best ratio of V1/Vr that allows the greatest MTOW.
How does increasing V2/Vs affect MTOW for RWY limitations?
Draw a graph to show this.
An increased V2/Vs means a longer acceleration run so causes all distances along the ground to increase. This required a decrease of all MTOW.
No direct impact on ASD but a higher V2 required a higher Vr and therefore V1 so need to reduce MTOW.
Draw a graph showing how an increase in V2/Vs affects MTOW due to climb/obstacle gradients
Nil for final T/O as flown GD.
Increases all others to increase MTOW as better gradients can be achieved.
Draw a graph showing effect of MTOW due to brake energy/tyre speed of a higher V2/Vs
Decreases both.
A higher V2 means higher speed on ground so limits the brake energy speed.
As tyre speed is limited by Vlof, an increase in V2/Vs (assuming V2 max) means a reduction in Vs so a lower MTOW is required.
What is the result of the optimisation process?
Achieves the highest MTOW, optimum V1/Vr and optimum V2/Vs ratio.
There could be 1/2/3 MTOW limitation that give a (or range) of V1/Vr speeds.
