× Welcome to the CPL Performance question and answer forum. Please feel free to post your questions but more importantly also suggest answers for your forum colleagues. Bob himself or one of the other tutors will get to your question as soon as we can.

## TODR/LDR and applying CAO 20.7.4

• Wong
• Topic Author

### Wong created the topic: TODR/LDR and applying CAO 20.7.4

Hello everyone...again!

So im doing revision on the take-off and landing charts. When re-doing the exercises, just wondering after you get the TODR or LDR figure, do we then have to apply the factors stated in CAO 20.7.4? Because in the answers of the book there was no mention of multiplying the factors.

So say if i have an aircraft less than 2000kg, my TODR is 1000m, after multiplying the 1.15 figure, my TODR would be 1150m. And for that same aircraft if my LDR, was 700m, after multiplying by 1.15, LDR should be 805m.

Another example is say ive got aircraft ECHO, and i calculate my TODR and LDR, what factor should i be multiplying by?

Pretty much i just want to know when it comes to answering the questions in the exam do i have to multiply using the factors given in CAO 20.7.4?

Cheers!

• Posts: 1169

### Richard replied the topic: Re: TODR/LDR and applying CAO 20.7.4

Hi Wong,

No, you don't need to multiply by anything; the manufacturer has already done that when they generated the data in the charts.

In the VFR (Day) booklet (a copy of which will be supplied in the exam), you will see an information box with each of the different TO/L charts. In these information boxes, there are entries for the safety factor used when the charts were created.

For the Type 1 and Linear take-off and landing charts they have used a factor of 1.15. For the Echo take-off chart they use 1.22 and for the Echo landing chart they have applied a distance factor of 1.26.

So, in real life, you simply read your answers off the charts, safe in the knowledge that the relevant safety factor has already been applied.

Cheers,

Rich

• Wong
• Topic Author

### Wong replied the topic: Re: TODR/LDR and applying CAO 20.7.4

Richard, thank you so much for your help! You are amazing!!

It seems as if after each study session i always have questions to ask!

Cheers!!

• Posts: 1169