Mountain Flying Basics
Mountain flying represents a real challenge for most flatland pilots. At the same time the rewards are tremendous, offering very spectacular sceneries and views resulting in an amazing flight for the passengers.
It also means that the pilot needs specialized training, develop skills and knowledge to fly safely in such an environment. We provide some basic knowledge on this subject, of course this is no substitute for real training in the actual environment.
Make sure that you receive thorough training with a qualified instructor or experienced mountain pilot. Flying in mountain area's leaves little room for error. The effects of density altitude and degraded performance need to be recognized.
Get a good demonstration of soft, short field take-off and landings. Practice minimum radius turns, just in case you need one. Our first item will be the effects of density altitude, be prepared for a developing and very interesting story here.
Below we describe some fundamentals for mountain flying (in fact you can use them for any type of flying):
- It is absolutely not routine. Expect weather circumstances in the mountains to be different from day to day or even from hour to hour.
- Check the weather beforehand and keep checking enroute. Always have a way out!
- Make sure you are proficient with minimum radius and maximum rate turns (max rates), slow flight and soft/short field take-offs and stabilized landings.
- Get an instructor and do them dreaded crosswind landings and take-offs. They are much easier than you think.
- Airspeed, power and attitude control are important during mountain flying.
- Air above and runway behind you are off no use to us. Use ALL available runway on take-off.
- Understand the effects of density altitude
Before we dive into details we will first discuss density altitude and its effect on aircraft performance.
Density Altitude Chart
For most flatland pilots density altitude is an abstract factor. Mountain pilots are more used to the effects of this. Flying in high terrain (altitude) and in high temperatures will increase the density altitude and decrease the performance of the airplane compared to standard atmosphere. These effects can result in an accident during a landing of take-off if not understood properly.
Density altitude is pressure altitude (pressure altitude is indicated altitude against 1013.25 hPa / 29.92 in HG) corrected for non-standard atmosphere temperature. Density altitude is the altitude the aircraft (and the engine too if no turbo is installed) is performing at. If this altitude is higher than the actual altitude performance is reduced.
Think about: hot, high and humid. These factors create a higher density altitude and decrease aircraft performance, resulting in:
- Increased distance at take-off and landing
- Reduced climb performance
- Higher true (not indicated) air speeds, and ground speeds during approach and landing
In short: aircraft performance depends on air density, which effects lift (drag), engine power and propeller efficiency. And as density decreases aircraft performance decreases. Important to remember.
High temperature and altitude
Check your aircraft performance charts and take note of high temperatures and altitudes (density altitude) and evaluate how they effect the aircraft in terms of runway lengths, take-off roll, rate of climb and if clearance with the terrain can be maintained.
A basic rule of thumb is that for every 10% weight increase the take-off distance increases with 21%. Keep this in mind when flying around and landing at high elevation airports. It is best to keep the weight as low as possible. Plan for a fuel stop at a lower altitude airport.