Learn — Paragliding knowledge base

Knowledge specific to hike-and-fly (H&F) paragliding — the format most Wingtrail sites are built around.

1. Pre-launch: the 5-point check

The standard pre-flight check, applied to every launch. Radiates from the pilot outward:

Equipment — harness (especially leg straps), helmet, risers clipped to carabiners, radio, speed bar.
Risers & Lines — brake lines below other lines, stabilizer lines clear and outside, no snags or loops.
Wing — symmetrical arc layout, no tangles, leading edge clean.
Wind — speed and direction re-checked at the last moment.
Airspace — nothing else in the air in front of or above launch.

Order: always the same sequence. Any consistent order is fine, but it must be routine so you never skip one. Last thing before takeoff = check wind + airspace again.

Implication for H&F fatigue: after a 3-hour hike, shortcut habits are the risk. The check is more important when you're tired, not less. If the app ever adds a pre-launch checklist feature, this list is canonical.

2. Site evaluation for unfamiliar sites

When arriving at an unknown launch, the pilot should inspect:

Takeoff slope — open, regular, moderately inclined. Hidden obstacles, uneven ground, terrain beyond line of sight all need active inspection before unpacking.
Decision line — the point beyond which abort is no longer safe. Roughly <10 m in front of where the wing is laid out, but depends on wind + wing loading. Weaker headwind + higher loading → decision line farther out.
Point of no return — the limit beyond which the pilot must already be airborne to clear obstacles.
Behind launch — especially important in winds >20 km/h where the glider can move backward on inflation. The area behind must be wide, open, obstacle-free, no cliffs downwind.
Landing zone — wind direction options, obstacles on approach. Inspect before flying.

Four factors to know in advance:

Weather — general + local expected during the flight window.
Legal — airspace, temporary restrictions.
Obstacles — cables, towers, cliffs, trees on approach.
Wildlife — eagle nesting (March–May, cliffs below forest line), chamois/ibex on south slopes.

3. High-altitude H&F (3000 m+ launches)

Several of Wingtrail's featured sites are high alpine: Weissmies (3991 m), Klein Matterhorn (3792 m), Jungfraujoch (3471 m), Piz Nair (2991 m), Titlis (3061 m), Corvatsch (3251 m), Gemsfairenstock (2940 m).

Physiological effects to respect:

Hypoxia

Kicks in from ~4000 m (mild euphoria, slowing motor + sensory skills).
Acute mountain sickness (AMS) possible from 2800–3500 m after 5–10 h exposure — severe headache, breathlessness. Short flight duration makes AMS rare for pilots but the multi-hour hike before launch adds exposure.
Pre-existing fatigue, lack of sleep, alcohol, tobacco all increase sensitivity.
Treatment: rapid altitude loss (easy for a pilot — just fly down).

Thin-air performance

Lower air density → glider needs higher true airspeed to maintain lift.
Launch run is longer and more exhausting.
Sink rate over ground is higher.
Stall speed in true airspeed is unchanged but the margin feels tighter.

Cold + wind chill

Glider flying at 32 km/h in 2 °C air feels like −11 °C.
Heat loss increases oxygen demand and reduces performance. Dress for cruise temp, not launch temp.

Ears / sinuses

Altitude changes pressurize sinus cavities. A cold, sinus infection, or ear infection can cause severe pain during climb-out or descent. Don't fly with congestion.

4. Wind & conditions specific to H&F

Headwind on launch

Ideal: ~15 km/h headwind — reduces ground run, ideal for heavier H&F-loaded wings.
Zero/tailwind: longer runway needed, running speed higher.
>5 km/h tailwind: abort — insufficient airspeed at takeoff, reduced glide ratio, high accident risk.
>20 km/h headwind: risk of backward inflation — reverse launch mandatory, watch the area behind.

Cross-wind technique

If wind is off-axis to the slope (e.g. 120° wind on a south-facing slope), inflate into wind, then pivot toward the slope during the control phase, then accelerate. Don't inflate directly down the slope in a crosswind.

Wet wing

A wet wing adds several kg, needs higher airspeed, inflates poorly, and has higher stall risk. H&F with any morning rain / heavy dew = check the wing before packing and dry it if possible.

5. Walk-out vs fly-down — the core H&F decision

The decision to abandon the fly-down is as important as the decision to launch. If in doubt, don't fly. Applied to H&F:

Ascent took longer than planned → less daylight → higher OD risk.
Conditions deteriorate during the ascent → the walk-down is always available and always safer.
The wing weighs ~4 kg in the pack — walking out with it is not a failure, it's a legitimate outcome.

Signals to walk down instead of fly:

Cu congestus already present by early afternoon.
Wind on launch >70% of site maxWind and gusting.
Föhn gradient rose during the ascent.
Sunset within 1 h — post-sunset conditions become cold, shadow-triggered katabatic flow starts, and emergency landing options shrink in low light.

6. Emergency descent maneuvers

If caught in stronger-than-expected lift (e.g. under Cb suction, powerful thermal) and needing to descend fast, three options:

Big ears — pull outer A risers to fold wingtips. Modest sink rate increase, maintained direction, safe.
B-stall — pull B risers symmetrically to distort profile. Strong descent. Risk: parachutal stall on exit — release B risers quickly and decisively to recover flight speed.
Spiral dive — tight 360° turns. Highest descent rate. High G-forces; requires mastery especially in turbulent air.

Normal paraglider sink rate is ~1 m/s. These maneuvers reach 5–10 m/s. Necessary tool if caught under a developing Cb — but the better rule is not to be there: don't launch into a day with Cb already forming.

7. Landing — slope landings

H&F pilots more often land in non-standard terrain than park pilots.

Against vs with the slope

Against the slope (up-slope approach): easy to be precise, but ground contact is rougher.
With the slope (down-slope approach): gentle contact but precision is difficult — wing keeps flying.

Neither is inherently wrong — terrain and obstacles dictate.

Turbulence barriers

Any obstacle upwind of the landing (trees, buildings, rocks) creates turbulence downwind extending up to 10× its height. Pick landing approaches with clear upwind air.

Emergency landing (parachute)

If a reserve parachute is deployed, pilot should:

Pull B or C lines on the main wing to prevent it re-flying and interfering with the reserve.
Sit up, knees slightly bent and together.
Prepare for ground contact at 5–6 m/s (equivalent to a 1.5 m free fall).

This is a last-resort; pilots should train the posture before needing it.

8. Wildlife-aware H&F

Paragliding clubs have agreements with Swiss game wardens. Three species to respect:

Golden eagle — nests March–May on cliffs just below the forest line. Flying near nests causes adults to abandon eggs. Territory ~100 km². Avoid close passes to cliff nest sites in spring.
Chamois and ibex — winter/spring on south-facing slopes. Females give birth May (chamois) and June (ibex). Summer: they retreat to shaded cliffs and ridges to rest. Low passes on slopes in uninhabited alpine regions disturb them most.

A future feature could flag sites with seasonal wildlife protection zones during breeding season.

9. Skill-level gating

Wingtrail sites include Easy / Medium / Hard difficulty ratings. Hard sites tend to combine:

High altitude (>3000 m, thin air + hypoxia)
Narrow/technical launch slope
Shorter decision line
Obstacles close to launch
Strong thermal turbulence typical
Or wind acceleration through terrain features (Venturi)

Examples: Weissmies (3991 m) — altitude + terrain. Klein Matterhorn (3792 m) — altitude + often strong winds. Fronalpstock (1883 m) — technical launch. Uetliberg (740 m) — surprising for its altitude, but urban/obstacle complexity.

A flyability app should not gate by pilot skill (we don't know the user's rating). But in user-facing copy, Hard sites should carry a visible note that weather "green" doesn't overrule terrain difficulty.