Most aircraft accidents occur during the takeoff and landing phase of the flight. Collisions with obstacles during climb out, runway overruns on landing occur every now and then. In 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.
The factors in this table show the variations the pilot needs to account for when determining the takeoff and landing performance of his aircraft under these circumstances.
|Influencing factor||Take-off Distance Increase||Landing Distance Increase|
|10% increase in weight||20%||10%|
|Increase of 1000' in runway altitude (1" MAP)||10%||5%|
|Increase in temperature of 10°C above ISA||10%||5%|
|Dry short grass (under 5")||20%||20%|
|Dry long grass (5 - 10")||25%||30%|
|Wet short / long grass||25% / 30%||30% / 40%|
|2% uphill slope||10%||-10%|
|1% downhill slope||-5%||5%|
|Tailwind component of 10% of liftoff speed||20%||20%|
|Soft ground or snow||at least 25%||at least 25%|
Of course, the pilot must exercise 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.
As you can see, braking action and landing distance are greatly influenced on wet, long grass runways. In winter time try to land on a snow covered grass runway when you have the change, it will be a very interesting experience!
Low tire pressure increases rolling drag and the takeoff run. Landings will be somewhat softer (very helpful on rough terrain) and the ground run is shorter. In both cases the tire will wear sooner and performance will suffer. Just follow the manufacturers recommendation on tire pressure.
Deposits on any aerofoil, wings, tail and propeller reduces the performance. Insect remains eat away at the paint resulting in stains and possibly corrosion on leading edges. Keep the aircraft as clean as possible and performance will be at its peak, don't forget that your aircraft will look great for years to come. Which helps resale value!
Even after you have worked out the numbers for your aircraft landing or takeoff performance, it is wise to add a small contingency factor to allow for any unknown factors you may have overlooked. Think of things as reduced propeller and or engine performance, dragging brakes, wind shifts in direction during takeoff roll or landing approach.
Where ever takeoff or landing distance are marginal, always add 10% to your calculations to be on the safe side.