We have discovered the tolerance or accuracy of Take-off Performance Charts is as little as 15m for CASA exams (which is ridiculous).
This equates to a final TODR accuracy of 0.66mm on the right side of the chart, which is 1/3rd of one box.
So here's what you MUST do.
Buy a pair of cheap strong reading glasses from the chemist or eBay for $5.50 delivered.
Use a sharp mechanical pencil and mark both ends of each line then check with the magnifier. If accurate draw the line. If not remark. Repeat this for every line.
Where lines follow curves, use 2-3 segments to follow the curve and the above process.
Check each step for deadly accuracy.
Deliberately make a mistake and ask for a second work booklet. Redraw it and compare.
Do this in two work booklets. If your decision is a line ball, double check everything and adjust.
Note: if you get 3 TO chart questions at 2 marks each out of your 56 questions. That right there is 12% lost if you get them wrong. That’s 40% of your possible lost marks on one topic. So it is vital you practice these over and over with precision accuracy.
Important - Runway Slope Of 1%
Wording From CAO 20.7.4 4.1
Example when to use the CAO and ignore any slope that is NOT in excess of 1%.
Question would say: Aerodrome alpha has 1% slope, OAT 10°C, QNH 1016, surface long dry grass etc....calculate TODR.
In this case use a slope of 0%
Example when NOT to use the CAO and to include a slope NOT in excess of 1%. .
Question would say: Given 1% slope, OAT 10°C, QNH 1016, surface long dry grass etc....calculate TODR... or
Give n the following: 1% slope, OAT 10°C, QNH 1016, surface long dry grass etc....calculate TODR...
In this case use a slope of 1%
Safe endurance is what remains after all the reserves have been subtracted from the fuel available. Safe endurance is the amount of fuel that you can plan to burn safely in flight and still have the required reserves in tact.
Consider a CHTR flight to an airfield which requires INTER holding in a small, piston engine aeroplane.