8.soft-field-landing. Soft-Field Landing
A soft-field landing is a technique used to land on surfaces that are not firm—such as grass, sod, sand, mud, snow, or surfaces softened by recent rain. The objective is to transfer the airplane's weight from the wings to the landing gear as gently and as slowly as possible, minimizing the load on the nosewheel and preventing it from digging into the soft surface, which can damage the aircraft or cause a nose-over.
Approach
The approach for a soft-field landing is essentially the same as a normal approach. The recommended airspeed published in the Pilot's Operating Handbook (POH) should be used—typically 1.3 × V_S0 with appropriate gust factor added. Wing flaps should be extended to the manufacturer's recommended setting (usually full) to permit a slower touchdown speed and to soften the contact with the surface.
Key approach considerations:
- Survey the field before landing for obstructions, ruts, soft spots, standing water, or snow depth.
- Plan the touchdown into the wind and at the slowest controllable airspeed.
- Carry a small amount of power into the flare; this is a defining feature of the technique.
Roundout and Touchdown
The roundout is initiated at the normal height. As the airplane settles, the pilot holds the airplane just above the surface with increasing back pressure on the elevator while simultaneously using just enough power to slow the descent rate to a minimum. The airplane should be allowed to touch down at the slowest possible airspeed, with the airplane in a nose-high pitch attitude. The mains contact the surface so gently that the touchdown is barely perceptible.
After the main wheels touch:
- Maintain back-elevator pressure to keep the nosewheel off the surface as long as possible.
- Reduce power slowly; abruptly chopping power can cause the nose to drop quickly.
- As airspeed decays, gradually relax back pressure, allowing the nosewheel to settle gently to the surface—but not before elevator authority is nearly gone.
After Touchdown
Once all three wheels are on the ground, the pilot must keep the airplane moving at a speed sufficient to taxi off the soft surface without becoming bogged down. Avoid stopping on a soft surface unless absolutely necessary, because stopping may make it impossible to start moving again without considerable power application.
Braking on a soft field:
- Use brakes sparingly, or not at all. The soft surface itself provides considerable rolling resistance and slows the airplane quickly.
- Heavy braking can cause the nosewheel to dig in, the tires to skid, or the airplane to nose over.
- Keep elevator full aft during the rollout to keep weight off the nosewheel.
Crosswind Considerations
Crosswind technique during a soft-field landing follows the same principles as a normal crosswind landing. The wing-low (sideslip) method is used to maintain alignment with the intended track. However, on very soft surfaces a crab-to-wing-low transition just before touchdown may be preferred to avoid sideloading the gear. Aileron deflection into the wind is increased as the airplane slows during rollout.
Common Errors
The AFH identifies several common errors during soft-field landings:
- Excessive descent rate during the final approach.
- Excessive airspeed during the approach and roundout.
- Inadequate power management during the roundout, resulting in a hard touchdown.
- Failure to hold the airplane off the surface, allowing the nosewheel to contact first.
- Closing the throttle too rapidly after touchdown, allowing the nosewheel to drop.
- Allowing the airplane to stop on the soft surface.
- Improper use of brakes, causing the nosewheel to dig in.
- Failure to maintain back-elevator pressure throughout the rollout.
Example
Consider a Cessna 172 with V_S0 of 40 KIAS landing on a grass strip. A typical approach speed would be 1.3 × 40 = 52 KIAS, plus half the gust factor. Full flaps (30°) are used. The pilot crosses the threshold at approximately 55 KIAS, begins the roundout at the normal height, and as the airplane decelerates carries 200–300 RPM into the flare. The mains touch at near-stall speed in a nose-high attitude. The pilot holds full aft elevator, reduces throttle gradually, and allows the airplane to roll out without using brakes, taxiing clear of the soft area before stopping for the after-landing checklist.
A properly executed soft-field landing protects the airplane, prepares the pilot for operations at unimproved fields, and is a required task on the Private Pilot Airman Certification Standards (ACS).