Flying in mountainous terrain presents unique challenges that require specific knowledge and skills to ensure a safe flight. The following do’s and don’ts, based on the principles of mountain flying, are designed to help pilots mitigate risks and make informed decisions.
Do’s and Don’ts of Mountain Flying
| Do’s | Don’ts |
| Pre-flight Planning and Performance | |
| ✓ Check all aspects of the weather, including reports, forecasts, and pilot reports (PIREPs). | ✗ Go if weather reports indicate doubtful or bad conditions. |
| ✓ Familiarize yourself with your aircraft’s high-altitude performance, including takeoff/landing distance and rate of climb. | ✗ Operate a low-performance aircraft into marginal mountain strips. |
| ✓ Plan your fuel load to allow for adequate reserves to handle unexpected winds or weather. | ✗ Fly into unimproved mountain strips without being proficient at slow flight maneuvering. |
| ✓ Use Sectional Aeronautical Charts for their greater detail. | ✗ Try to make a go-around at a one-way backcountry strip. |
| ✓ Study your charts to determine the lowest and highest terrain along your route. | ✗ Leave the airplane without a compelling reason after a landing. |
| ✓ Compute the density altitude for all takeoffs and landings. | ✗ Hurry the preflight. |
| ✓ Compute the weight and balance for any flight where you have doubts. | ✗ Fly at a low altitude that would prevent a safe forced landing. |
| ✓ Develop a plan of action for all takeoffs and landings, including contingency alternatives. | ✗ Give insufficient attention to the importance of fuel and survival equipment. |
| ✓ Check surrounding terrain prior to landing at a backcountry strip to know the best departure path. | |
| ✓ Adjust the mixture when landing to maximize power for a go-around. | ✗ Lean the mixture for takeoff or a go-around in a turbocharged or supercharged engine. |
| ✓ Make PIREPs as there is a lack of reporting stations in the mountains. | |
| ✓ Have confidence in your magnetic compass. | |
| In-flight Procedures | |
| ✓ Maintain airspeed when encountering a downdraft after takeoff, even if you have to descend. | ✗ Slow down in a downdraft. |
| ✓ Approach ridges at a 45-degree angle to allow for an easier escape from unexpected turbulence. | ✗ Fly close to rough terrain or sheer cliffs when the wind is 20 knots or more. |
| ✓ Be able to maintain airspeed within one knot of the desired speed for climbs, descents, and approaches. | ✗ Fly the middle of the canyon. |
| ✓ Maintain situational awareness of terrain, weather, and aircraft performance. | ✗ Fly cross-country in the mountains when mountain-top winds exceed 30 knots unless you’re experienced. |
| ✓ Use horse sense. If in doubt, don’t. | ✗ Ignore the importance of weather reports of ceilings of 1,000 to 2,000 feet. |
| ✓ Know you can make the flight safely, or remain on the ground. | ✗ Fly IFR in the mountains in an unfamiliar or underpowered airplane. |
| ✓ Know the “lay of the land” or have proficient chart reading and pilotage skills. | ✗ Become complacent about the horizon when flying visually. |
| ✓ Remain alert for clues to potential weather and terrain hazards. | ✗ Let a passenger pressure you into a flight you’re uncomfortable with. |
| ✓ Stay out of the mountains when the weather becomes marginal. | ✗ Continue flying if you feel uncomfortable about any aspect of the flight. |
| ✓ Regard terrain clearance after takeoff as a major consideration. | ✗ Takeoff and turn directly on course when terrain requires maneuvering. |
| ✓ Count on the valley breeze (wind blowing upstream) to create a tailwind for morning landings. | ✗ Rely on cloud shadows for wind direction unless near the base of the clouds. |
| ✓ Count on the mountain breeze (wind blowing downstream) to create a tailwind for afternoon/evening takeoffs. | |
| Landing and Takeoff | |
| ✓ Use a stabilized approach for all landings and fly at 1.3 Vso on approach and 1.2 Vso ‘cross the fence’. | ✗ Make the landing approach airspeed too slow. |
| ✓ Delay takeoff or landing during adverse conditions. | ✗ Fail to use the same indicated airspeed at high-altitude airports as at lower elevations. |
| ✓ Use the “spot method” for landing to eliminate visual illusions. | ✗ Forget the adverse effect of frost. |
| ✓ Know that a 10% increase in approach airspeed results in a 21% increase in landing distance. | ✗ Forget that a 10% increase in gross weight causes a 21% increase in takeoff distance. |
| Knowledge and Principles | |
| ✓ Remember that an airplane can be stalled at any airspeed if the critical angle of attack is exceeded. | ✗ Fail to visualize the air as water, flowing over and around terrain. |
| ✓ Know that the indicated stall speed is the same for all altitudes. | ✗ Be too vain to check with an experienced mountain pilot. |
| ✓ Know that a 10% increase in takeoff gross weight will cause a 21% increase in take-off distance. | ✗ Attempt VFR flight in the mountains without your personal minimum visibility. |
Additional Considerations
This guide emphasizes crucial concepts like recognizing the effect of density altitude—the altitude the aircraft “thinks” it’s at, which dictates its performance. It’s important to remember that even a small amount of frost can significantly compromise performance. Additionally, the practice of visualizing air as water is a powerful tool to anticipate updrafts, downdrafts, and turbulence. Always prioritize safety and be prepared to make a go/no-go decision based on all available information, including your own comfort level and proficiency.