Introduction
Flying in the mountains is one of the most demanding disciplines in general aviation. It challenges pilots both physically and mentally and requires a deep understanding of the special features of this environment. You can't just fly straight from A to B, you have to take the terrain into account. Emergency situations in particular have to be assessed differently, as it can be difficult to find suitable terrain for landing in case of doubt.
What does flying in the mountains mean? Mountain flying refers to navigating and manoeuvring an aircraft in or over mountainous terrain, often at altitudes of several thousand feet above mountainous terrain such as the Alps. The main difficulties are
- Density height: At high altitudes, the thinner air reduces engine performance, wing lift and propeller efficiency.
- Obstacles: There may be obstacles close to the ground that are specific to mountainous regions and are often difficult to recognise, such as lift cables, cable car cables or high-voltage power lines.
- Complex weather patterns: Typical mountain weather phenomena such as strong winds, sudden weather changes and turbulence.
- Limited performance: Aircraft have to take off, climb and manoeuvre with limited power.
- Special manoeuvres: Flying in narrow passes and safely mastering up- and downwinds requires experience and specific training.
- Emergency landings: In the event of an engine failure or other problems, the terrain often offers hardly any possibilities for a safe landing.
Flying in the mountains requires not only technical understanding, but also comprehensive planning and preparation.
Special features in the mountains and appropriate preparation
Weather in the mountains
Weather plays a central role in mountain flying. Typical challenges are
- Overlying clouds: Clouds clinging to slopes and peaks can suddenly make visual flight conditions (VFR) impossible. This should be taken into account when planning a flight, as it may mean that planned routes cannot be flown. Clouds should also be studied very carefully when it comes to landing, as there is a significant risk of colliding with the terrain in the mountains without ground visibility.
- Lee areas: On the downwind side of mountains, strong downdrafts and turbulence occur, which can endanger aircraft. It is better to fly well clear of such areas.
- Rotor winch: These often occur behind mountain ridges and lead to extreme turbulence.
- Upwind and downwind: Vertical air movements can cause considerable climb or sink rates that need to be controlled.
Oxygen supply
The oxygen content of the air decreases at high altitudes. In accordance with EASA regulations (Regulation (EU) No 965/2012):
- Oxygen is required if more than 30 minutes over 10,000 feet is flown.
- Oxygen is Permanently required from 13,000 feet. Pilots should ensure that sufficient oxygen systems are available and that they are functioning correctly.
Emergency landings in the mountains
Suitable emergency landing sites are rare in the mountains. Pilots should always:
- Identify areas that could be suitable as an emergency landing site.
- Emergency rations and survival equipment have on board. This includes sufficient provisions, a first aid kit, warm clothing, blankets or appropriate sleeping bags.
- An emergency transmitter (ELT or PLB) is required anyway.
Route planning
Well thought-out route planning is essential. The following applies:
- Consider height: Maintain sufficient height above obstacles. It is better to work with generous buffer values here
- Check passages: Pay attention to weather conditions and visibility in mountain passes, especially as the weather can change quickly here.
- Note the influences of the mountain landscapes: For example, the wind blows into rising valleys during the day and out of the valley at night or in the morning. The Venturi effect must also be taken into account, which increases the wind speed in narrow incisions between the mountains. If you fly over a slope with a current upwards, you have to deal with upwinds and downwinds downwind. It is important to note that the air can take a wavy course after descending on the downwind side (rotors), which can be quite dangerous. There are numerous other special features that should be taken into account here. The best thing to do is to attend a special area briefing (see below).
Aircraft and performance analysis
- Calculate density height: The lower air density at altitude leads to reduced engine and wing performance.
- Study performance data: The maximum take-off and climb rate and range must be analysed. This is different due to the low density altitude. During take-off, the required roll distance is longer at high density altitudes, the climb rate is poorer and the roll distance is also longer during landing, as the groundspeed is higher in thin air. The POH provides information on this, but it really needs to be studied in detail.
Manoeuvres in the mountains
- Flying over passesIf you fly over a pass, you may encounter strongly descending air and thus rapidly decreasing altitude. You should therefore approach the passes with extra altitude. In order to be able to turn safely if necessary, mountain passes should also always be approached from the side at an angle of approximately 45 degrees, in order to be able to change direction more quickly, which may be necessary in an emergency.
- Plan flight routes twice: Plan alternatives for emergencies.
Mountain briefing
A special briefing by an experienced flight instructor is highly recommended. This includes:
- Techniques for safe flying in mountain passes.
- Handling up and down winds and turbulence.
- Planning and emergency management.
If you are often travelling in the mountains, you should also consider obtaining a mountain rating.
Mountain Rating
With a mountain flying licence, pilots are authorised to carry out flights in areas for which the respective state requires such a special mountain flying licence. These can be, for example, certain mountain airfields or glacier areas. The authorisation is carried out either on aircraft with wheels (in order to land in corresponding areas where there is no snow and can therefore be landed with wheels) or on aircraft with skis (the latter allows take-off and landing in snow).
Prerequisite: There is no special requirement here, except of course the necessary licence.
ProcedureThe training, which consists of theory and practice, must be completed within a period of 24 months. The theory deals with things such as equipment, take-off techniques, legal regulations, special features of the weather in the mountains, navigation and more. In the practical training, these things are practised while flying in the mountains.
ConclusionAfter training, a test must be successfully completed with an appropriate examiner. The test consists of an oral theory test, in which mountain flying skills are tested, and a practical test, which includes 6 landings on 2 different surfaces that require a mountain flying licence.
The mountain flying licence is always valid for 24 months. It is automatically extended if at least 6 mountain landings have been made in the last 2 years. If this is not the case, the authorisation must be renewed by means of a test flight with an examiner as described above.
Alpine routes for VFR pilots
Popular Alpine crossings
There are several well-known routes from Germany that are suitable for VFR flights. These include
- GAFOR routes: These weather routes indicate which passes can be flown under VFR conditions. Details can be found, for example, in the common navigation apps.
- Inn Valley Route: From Rosenheim via Kufstein and Innsbruck across the Inn Valley to Italy.
- Brenner Pass: A safe and well-marked route that leads from Innsbruck to Italy.
- Tauern motorway route: Over the main Alpine ridge from Salzburg in a southerly direction.
Recommended preparations
- Weather reports from MeteoSwiss, Austro Control and the DWD study.
- Navigation aids such as SkyDemon or ForeFlight utilise.
- Take an alpine briefing from an experienced flight instructor beforehand
Conclusion
Flying in the mountains requires pilots to have in-depth knowledge, meticulous preparation and a high level of experience. Those who master the challenges of this discipline are rewarded with unrivalled views and a deep understanding of the art of aviation. However, it is crucial never to underestimate the risks and always act with due caution.