By Alan Negrin, CFI, MEI
Many of my transition training clients have been expressed a desire to learn more about mountain flying. So I thought I would put together what I know and share it with you here. I am still learning myself about mountain flying and there is a lot to learn.
I have never attended a mountain flying course like the ones provided in McCall, Idaho by McCall Mountain Canyon Flying Seminars, (http://www.mountaincanyonflying.com/) operated by Lori MacNichol, although, I highly recommend it and I am planning on attending when I can.)
I know they are not used to experimental aircraft but I think I remember someone at the recent Glastar / Sportsman Smiley Creek fly-in tell me they talked Lori into allowing him to come to the course with his Glastar.
Besides attending the Glastar / Sportsman fly-in at Smiley Creek, Idaho for the past three years, I have been airplane camping, mostly in the back country of Idaho near the middle fork of the Salmon River a few times since 2007. Since 2008, I have spent five days and four nights in late September camping and flying out of Johnson Creek with a large group of experienced back country fliers at an event they call the Back Country Safari.
Flying in and among mountainous terrain is very different than simply crossing over and well above it; that is what we are discussing here.
There are many books published on the subject, most notable are the ones written by Sparky Imeson (The Mountain Flying Bible, Mountain Flying and The Shirt Pocket Mountain Flying Guide). I decided to start a series of articles with the Do’s and Don’ts from The Shirt Pocket Mountain Flying Guide:
- DO check all aspects of the weather including weather reports, forecast and PIREPs.
- DON’T go if the weather reports indicated doubtful weather or “bad” conditions.
- DO familiarize yourself with the high-altitude characteristics and performance of your airplane. This includes the takeoff and landing distance and rate of climb under various loading and density altitude conditions.
- DON’T rely on cloud shadows for wind direction unless you are flying near the base of the clouds. Expect strong winds to be constantly changing in direction and velocity.
- DO fly a downdraft. This means that when you encounter a downdraft you will maintain your airspeed by lowering the nose and increasing power. Maintain the airspeed. If the nose has to remain down to keep the airspeed, keep the nose down. Unless the airplane is over a tall stand of trees or near a sheer cliff, the downdraft will not extend through the ground (An exception is the microburst).
- DON’T fly close to rough terrain or sheer cliffs when the wind is 20 knots or more at your altitude. Dangerous and unpredictable turbulence, updrafts and downdrafts may be encountered close to the terrain.
- DO be able to maintain the airspeed within one knot of the desired speed during climbs, descents and approach to landing before venturing to backcountry strips. This is not nearly as hard as it may sound. It requires knowledge of ‘attitude flying’ and a little practice (maybe as little as one-half hour).
- DON’T fly into unimproved mountain strips without being proficient at slow flight maneuvering.
- DO use Sectional Aeronautical Charts instead of World Aeronautical Charts (WAC) because of the greater detail.
- DON’T try to make a go around at a one-way backcountry strip. If your judgment has failed and you get in trouble, it’s much better to make a controlled crash at a slow speed, rather than an uncontrolled crash from flying speed.
- DO plan the fuel load to allow flight from the departure airport to the destination airport with an adequate reserve to counter unexpected winds or weather conditions.
- DON’T execute a cross-country flight into the mountains when the wind at mountain-top level exceeds 30 knots…unless you are experienced with strong downdrafts, updrafts and moderate or greater turbulences. This admonition does not preclude starting on the flight for a “look-see” to check out the conditions. Sometimes the stability of the air will allow the flight.
- DO maintain airspeed when encountering a downdraft after takeoff…even if you have to descend close to the ground.
- DON’T choose a route that prevents a suitable forced-landing area (near civilization, if possible). Flights along roads are a good idea.
- DO study your charts to determine the lowest and highest terrain along the proposed route of flight.
- DON’T leave the airplane without a compelling reason after a precautionary landing or an emergency landing.
- DO approach ridges at a 45-degree angle when within ¼ mile to 1/8 mile of the ridgeline. This allows an escape from unexpected downdrafts and turbulence with less stress on the pilot and airplane than flying perpendicular to the ridge. The angled approach allows an escape with a shallower bank and less g-loading stress on the airplane.
- DON’T become quiescent with weather reports of ceilings of 1000 to 2000 feet. The ceiling is reported above ground level. Often a mountain weather reporting facility will e surrounded by mountains that extend thousands of feet higher than the facility. Clouds may obscure the mountains and passes.
- DO count on the valley breeze (wind blowing upstream during the morning hours due to convection) to create about a 4 to 6 knot tailwind for landing upstream in the mornings. (Mountain airstrips are usually located next to streams where the landing is made upstream because of the slope of the terrain).
- DON’T fly IFR in the mountains in an unfamiliar or underpowered airplane. Icing is likely to occur even during the summer due to the high minimum en route altitudes.
- DO count on the mountain breeze (wind blowing downstream due to cooling air moving down the mountains during the late afternoon and evening hours) to create an 8 to 12 know tailwind for takeoff downstream (land uphill and take off downhill unless you have a compelling reason to do otherwise).
- DON’T make the landing approach airspeed too slow. “hanging on the prop” is a dangerous operation. Use a stabilized approach for all landings. Maneuver at 1.3 Vso and ‘cross the fence at 1.2 Vso. (For a Glastar or Sportsman that will be 55 knots and 50 knots respectively if you figure a stalling speed of 42 knots. If you can master flying at those low airspeeds on landing, you should be able to land in very short distances).
- DO use horse sense (common sense) when performing takeoffs and landings at mountain strips. If in doubt, don’t. Confirm aircraft performance using the Pilot’s Operating Handbook (We all know the Glastar and Sportsman POH has no performance tables like the certified aircraft have, so we have to know our airplanes and what they can do and cannot do).
- DON’T operate a low-performance aircraft into marginal mountain strips. If in doubt about the takeoff, use the rule of thumb that if 71 percent of the takeoff speed is obtained by the halfway point of the remaining runway, the airplane will takeoff in the remaining distance (but it may not out climb the obstructions).
- Do delay the takeoff or landing during adverse conditions that can compromise the safety of the flight operation.
- DON’T slow down in a downdraft. Maintain or increase the airspeed so that you are under the influence of the downdraft for a lesser period of time. This results in the loss of less altitude overall.
- DO make a stabilized approach for landing to avoid thermal shock to the aircraft engine. This also simplifies the Spot Method for Landing.
- DON’T fly the middle of the canyon. It may feel more comfortable being away form the canyon sides, but this is a poor position to make a turnaround (only half the canyon width is available for the turn) and it is the area of shear (mixing of down air on the lee side and up air on the windward side).
- DO remember that the laws of aerodynamics allow an airplane to be stalled at any airspeed and any attitude, providing you are strong enough to exceed the critical angle of attack and providing the airplane doesn’t break first.
- DON’T fail to visualize the air as water. Although invisible, air will “flow” along the contour of the mountains and valleys; where, with practice, you can visualize areas of updraft, downdraft and turbulence. Ask yourself, “What would water do in this same situation?”
- DO remember the indicated stall speed is the same for all altitudes (if the stall is executed in the same manner each time, for example, from level flight, or from banked turn, or with a slow deterioration of the airspeed, etc.
- DON’T be too vain to check with an experienced mountain pilot concerning operations to and from unfamiliar fields.
- Do have confidence in the magnetic compass. Unless something unusual has happened (leaking fluid, metal next to the compass, or extreme magnetic disturbance in your area), the compass is the most reliable instrument in the cockpit.
- DON’T attempt VFR flight in mountainous terrain without the minimum visibility that you have established as your personal safety standard. Experienced pilots demand at least three miles as a minimum, or they park the airplane.
- DO know the “lay of the land” of the area being flown or have proficient chart reading, pilotage and landmark recognition skills. A good GPS doesn’t hurt either.
- DON’T become complacent about the horizon when flying by outside visual reference. The horizon will be the base of the mountains about 6 to 8 miles away (use peripheral vision if necessary). A gentle up slope may cause a constant climb without your awareness.
- DO maintain situational awareness of the terrain, the weather, the aircraft performance, and the pilot performance.
- DON’T give insufficient attention to the importance of fuel and survival equipment. While it is important to keep the airplane as light as possible to extract all the performance available, do not skimp on these items.
- Do remain alert for clues to potential hazards concerning the weather and terrain.
- DON’T forget the adverse effect of frost. Less than 1/8 inch of frost may increase the takeoff distance by 50 % and reduce the cruise speed by 10%. Remove the frost before flight
- DO know you can make the flight safely or remain on the ground.
- DON’T fail to use the same indicated airspeed at high-altitude airports that you use at lower-elevation airports. It is not necessary to increase the indicated airspeed for high-altitude operations. There is a “built-in” airspeed error that automatically compensates for altitude. (The true airspeed is about two percent faster than indicated for each 1000 feet increase in altitude).
- DO compute the density altitude for takeoff and landings. If there is any doubt about the operation, apply this information to the aircraft performance at sea level.
- DON’T hurry the preflight.
- Do compute the weight and balance and apply this information to the aircraft performance for any flight where there is doubt about the operation.
- DON’T fly at a low altitude that would prevent a safe forced landing.
- DO learn the “spot method for landing.” This will eliminate visual illusions associated with up sloping and down sloping runways.
- DON’T venture into the mountains unless you are proficient at “slow flight”. You must be able to maintain the desired airspeed exactly (within one knot) during climbs, descents, level flight and for the approach to landing.
- 49. Do know the general direction of the wind at all times for visualization of updrafts, downdrafts and turbulence.
- DON’T leave the fuel selector valve “on” when parked on a slope. The fuel may siphon to the low tank
- DO make PIREPs. There is a lack of reporting stations in the mountains and your pilot report is valuable information.
- DON’T continue flying if you feel uncomfortable about any aspect of the flight.
- DO adjust the mixture when landing to maximize the power available in the event of a go-around.
- DON’T lean the mixture for takeoff or go-around with a turbocharged or supercharged engine. These engines provide sea level power and must have sea level fuel flow to operate properly.
- DO stay out of the mountains when the weather becomes marginal.
- DON’T try to takeoff and turn directly on course when the terrain or obstructions require maneuvering or a shuttle climb for avoidance.
- DO make your GO / NO-GO decision for flight based on all available weather information and the aircraft’s performance capabilities.
- DON’T let a passenger pressure you into initiating the flight if you are uncomfortable about weather conditions or the aircraft performance based on current conditions.
- DO develop a plan of action for all landings, considering contingency alternatives.
- DO establish a go-around point for all airports (except one-way strips).
- DON’T fail to check surrounding terrain prior to landing at a back country strip so that you know the best departure path.
- DO make ferry flights carrying partial loads or passengers and baggage to a longer airstrip when conditions become marginal. Then the total load may be safely flown from the longer strip.
- DON’T land at a back country airport without verifying the strip is the actual one you want. The airport you see may be unsuitable for your operation.
- DO develop a plan of action for all takeoffs by developing a “what if” scenario. “What if the engine fails?” “What if I experience a downdraft immediately after takeoff?” “What if the airplane is not accelerating normally?” Play this game before each takeoff to be prepared.
- 65. DON’T fly up sloping canyons until you have received dual instruction from a knowledgeable mountain pilot. If there is something you want to see in the canyon, gain altitude, fly to the head of the canyon and fly down the canyon.
- DO lean the mixture for takeoff at density altitudes of 3000 feet or higher in accordance with the manufacture’s recommendation (Do NOT lean turbocharged or supercharged engines).
- DON’T fail to maintain the exact and proper airspeed during approach for landing. If you are unable to fly an exact airspeed, stay out of mountain airstrips until you have greater proficiency.
- DO allow a minimum of an extra one-half hour to one hour of daylight when your destination is a mountain airstrip without runway lighting. Late afternoon shadows can place the airstrip in darkness when sufficient light remains for cross-country flight.
- DON’T become complacent…about any aspect of the flight.
- DO regard terrain clearance after takeoff as a major consideration of the flight.
- DON’T ignore density altitude, the altitude the airplane thinks it is at and performs in accordance with. (It is the pressure altitude corrected for non-standard temperature variations).
- DO remember that a 10 % increase in approach airspeed results in a 21 % increase in landing distance.
- DON’T forget that the takeoff distance varies with the gross weight. A 10 % increase in the takeoff gross weight 9while not exceeding the maximum allowable gross weight (will cause a 21 % increase in take off distance.
Alan Negrin is CFI,MEI and former factory demo, flight test and transition training pilot. He owns a Sportsman tail dragger and provides transition training for Glasair, GlaStar and Sportsman owners, including those who are about to commit first flight and those who have purchased flying aircraft.
He can be reached at firstname.lastname@example.org or 425-466-8472