Aircraft Performance, Takeoff and Landing distance factors
Most aircraft accidents occur during the takeoff and landing phase of the flight. Collisions with obstacles during climb out, runway overruns on landing occur too often. On this part of the site we will take a look at the various factors contributing to the performance of the aircraft in this part of the flight. Hopefully we help the pilot ensuring safe operation during these phases of the flight as the rules require that of the pilot in command.
A number of external factors have a big difference on aircraft performance during takeoff or landing, and the pilot in command should be aware of these. The previous articles described some of them here we list them all together for a good review.
Takeoff distance factors
The factors in this table show the variations the pilot needs to account for when determining the takeoff performance of his aircraft under these circumstances.
| Influencing factor | Increase in Takeoff Distance |
| 10% increase in weight | 20% |
| Increase of 1000' in runway altitude | 10% |
| Increase in temperature of 10 gr C | 10% |
| Dry short grass (under 5 ") | 20% |
| Dry long grass (5 - 10 ") | 25% |
| Wet short / long grass | 25% / 30% |
| 2% uphill slope | 10% |
| Tailwind component of 10% of liftoff speed | 20% |
| Soft ground or snow | at least 25% |
Off course, the pilot must excercise the correct technique for short and soft runways to obtain these numbers. When not proficient, have an instructor onboard for some quality time under these circumstances.
Landing distance factors
And in this table we show the variations the pilot needs to account for when determining the landing performance of his aircraft under these circumstances. There is not much difference, but when landing the surface has influence on the braking action.
| Influencing factor | Increase in Landing Distance |
| 10% increase in weight | 10% |
| Increase of 1000' in runway altitude | 5% |
| Increase in temperature of 10 gr C | 5% |
| Dry short grass (under 5 ") | 20% |
| Dry long grass (5 - 10 ") | 30% |
| Wet short / long grass | 30% / 40% |
| 2% uphill slope | 10% |
| Tailwind component of 10% of liftoff speed | 20% |
| Soft ground or snow | at least 25% |
As you can see, braking action and landing distance are greatly influenced on wet long grass runways. Try to land on a snow covered grass runway someday when you have the change, very interesting!
Runway contamination
At some point in time runways will be contaminated with rain, snow or slush. You will have to allow for these circumstances as the result can be directional control problems, reduced braking action (or hydroplaning) and more drag on takeoff. When show depth is more than 2", or if water, slush or wet snow covers the runway to more than 1/2", takeoff is not recommended. And operating from a slippery runway with a crosswind more than 10Kts or with a tailwind takeoff should also not be attempted.
Accelerated Stop Distance Available (ASDA)
When calculating the takeoff distance with all known factors one should also account for the accelerated stop distance available, this should be at least twice the takeoff distance on a paved runway and 2.6 times the takeoff distance on a grass runway.
Landing performance
Any water (heavy rain showers), snow or slush can and will have a very adverse effect on the landing distance and the danger of hydroplaning (with no wheel braking and loss of directional control) is very real and has led to loss of life in the past already.