Short-Field and Soft/Rough-Field Takeoff And Landing, Turbulent Air Landing

Some time in training is to be dedicated to takeoff and landing procedures specific to certain conditions related to the terrain, and also the air status. That tutorial thus is about short or soft/rough-field takeoffs and landings, with some details too about turbulent air landing. The exercises should consist into taking off and landing like described as, in most of flying club vicinity, your instructor likely will know some short, or soft/rough surface fields where he will take you for practice, as turbulences may be the occasion of demonstrating the turbulent air landing

Short-Field Takeoff and Landing

A 'short field' points to a terrain at which the available distance to takeoff or land is short, or a terrain where obstructions exist for both takeoff or landing. You will note that the Pilot's Operating Handbook (POH) for your airplane may have to be followed in terms of what it prescribes about the power setting, flap setting, airspeed, and procedures concerned with our subject

• Short-Field Takeoff. The short-field takeoff technique mostly allows to clear obstacles which lie ahead of the runway's end. Two concepts are of use to takeoff from a short field, the one of 'best angle-of-climb speed' or Vx and the 'best rate-of-climb speed' or Vy. At Vx, the plane will acquire the greatest gain in altitude for a given distance (for, say, a quarter of a nautical miles, the craft will gain the most altitude possible). That involves both a pitch greater than usual and a airspeed barely above the stalling speed. At Vy, she will acquire the greatest gain in altitude for a given time (for, say, one minute of flight, the craft will acquire the greatest gain of altitude possible). That involves a appropriate combination of pitch and speed. For such maneuvers, the pilot must learn to perform a accurate control of the plane's attitude and airspeed. Let's describe how a short field takoff unfolds as we suppose the plane at the runup will have been set into the appropriate configuration for such a takeoff -or mostly with more flaps. The takeoff roll should start at the very beginning of the takeoff area with the appropriate flaps settings. Some source counsel to hold the brakes when applying power until the maximum obtainable engine r.p.m. is achieved before releasing the airplane to begin its takeoff run. That however, has not been established like resulting in a shorter takeoff run. Then you will begin the takeoff roll and checking that the plane’s pitch attitude and angle of attack provide for the minimum amount of drag and the quickest acceleration, which usually involves a neutral, or few elevator as most GA planes already have that low drag. As Vx is approaching (for a Cessna 172SP of the order of 62 kts at mean sea level), the plane is rotated through back-elevator action to a pitch which will result in takeoff at the best angle-of-climb airspeed. Once airborne more action on the elevator is required to keep speed at that Vx value. The Vx airpseed thus allows to a takeoff which clears any obstacles ahead. Once the obstacles cleared, the pitch may be now lowered slightly and the Vy airspeed applied. You will note that some planes have a natural tendency to lift off well before reaching Vx. The pilot in that case should allow the plane to liftoff accordingly and then level few above the ground until the plane accelerates to Vx (do that instead of forcing the airplane keep on ground through the elevator). Flaps should stay like they are until the obstacles cleared and Vy established (which provides the attention of the pilot to focus on piloting instead of flaps controls). You usually will raise the flaps by increments to avoid any sudden loss of lift. At last, the pilot should reduce power to normal climb setting
• Short-Field Landing. That technique is used when approaching and landing at a terrain with a short landing distance available, or with a approach made over obstacles. Both requires the same technique, or a low-speed approach and a accurate control of airspeed, rate of descent, and flare to stop his plane in the shortest possible distance. You will have mostly to fly the plane at the minimum controllable airspeed. You generally will set full flaps and use a wider than normal pattern to give time to properly configure your plane. The airspeed should be 1.3 the stalling speed at full flaps, or Vso which for the Cessna 172P should translate at 52 kts and established in the pattern's with the appropriate pitch and throttle settings. The final should be performed like too with a frequent check of the airspeed indicator to avoid any reaching of the stall speed. After flare, the plane upon touchdown should be held in a positive pitch as long as the elevators remain effective providing further aerodynamic braking to assist in deceleration. Appropriate braking is applied then to minimize after-landing roll. Should gusty air be extant on the approach, no more than one-half the gust factor should be added in terms of airspeed

a GA plane performing a short-field landing (non-clickable illustration)

Soft/Rough-Field Takeoff and Landing

'Soft,' or 'rough field' hints to a terrain the surface of which is uneven for cause of too much softness (like with mud, sand, snow and the like) or of too much roughness (mostly like with grass-eroded grass terrain). Both such qualities of surface lead either to produce drag at takeoff and braking at landing, or a danger to the landing gear, respectively

• Soft/Rough-Field Takeoff. The aim of the pilot in that case should be to have the plane airborne as soon as possible to alleviate the drag induced by the quality of the terrain or preserve landing gear. The technique mainly consists into to transfer support of the airplane’s weight from the wheels to the wings as the takeoff roll unfolds. Let's see how a soft/rough-field takeoff is to unfold! Flaps should be appropriately set before takeoff. A other concept of importance for such a takeoff is that the plane never should come to stop on such a surface lest it bogs down. The plane therefore should, first, proceed with the runup checklist on a hard surface and then be kept into a sufficient and continuous motion -through power- until lining up on the runway. Once there, just apply more throttle continuously and apply a back-elevator pressure enough to that the plane establishes a positive angle of attack and to reduce the weight unto nosewheel as soon as possible. Such a pitch maintained along the takeoff roll will have the wings relieve the landing gear more and more as speed and lift are building up. That will just cause the plane to minimize the drag induced by the runway's surface. At some point, the plane will just get airborne by itself (at a speed slower than the usual takeoff speed). After airborne, the pilot should lowered the pitch very gently to level, few above the ground, to allow the craft to accelerate to Vy (of Vx in case of obstacles further) as the safe usual climb speed may not be attained enough before overflying runway's end (should it be, you may let the plane reach that speed). Once Vy reached, you will retract flaps and the power may be set to normal climb setting. Such a takeoff may also take advantage of the ground effect (about the concept of ground effect, check our tutorial 'Taking Off and Landing in a GA Plane'). Once the plane's weigt passed unto the wings, the ground effect will allow the plane to takeoff before the published takeoff airspeed reached. The pilot will have then to decrease the plane's pitch so to reach the published airspeed and the plane will get out of the ground effect!
• Soft/Rough-Field Landing. The objective of the pilot should in that case to touch down as smoothly as possible and to have the wings support the plane's weight as long as possible. Let's describe such a landing, which is a kind of opposite to what we previously saw. Full flaps are recommended as the flaps however should endure damage from surface thrown by main landing gear. As it seems indavisable to retract flaps immediately after landing, that might be a good practice to avoid such damage at the condition the action upon the flaps command to be near automatic. The technique we described for a short-field landing is mostly the one to use now as the main difference lies with the flare and after-landing roll. Once flared, the plane should be held level at that little height of 1 to 2 feet above the ground the longest possible to reach the lowest speed possible and touchdown at that speed in a nose-high pitch attitude. Power may be used throughout level-off and touchdown to a appropriate speed at touchdown! At that moment most of the plane's weight is supported by wings. Then, just keep a back-elevator pressure to keep the nosewheel off the runway! That is to the effect of controlling the rate at which the weight is translated from wings to the landing gear. No full touchdown of the nosewheel and full transfer of weight unto all wheels should be performed until a hard surface or taxiway reached and the plane has to be kept about like at some point of a takeoff from a soft/rough-field (which requires applying some power or even applying more). When reaching to a hard surface, the nosewheel should be lowered (usually with some more power applied). Brakes on a soft field are of not use and should be avoided and bringing the nosewheel to dig in for example. The terrain's surface will provide enough braking by itself

The Case of Turbulent Air Approach and Landing

In case of turbulent air during a approach and landing, a speed slightly above the normal approach speed should be applied. That allows for a more controllable plane during wind gusts or up and down drafts. Also a minimum flare should be performed when the touchdown occurs to land the earlier possible, which can be controlled by setting less than full flaps (and thus having a higher pitch) and levelling the plane during flare and with the touchdown in the same attitude instead of pitching the plane. A counseled airspeed for a turbulent air landing may be the normal approach speed plus a half of the wind gusts factors. For a Cessna 172SP, for example, should wind gusts reach about 15 kts, the landing speed should be of 75 + 7, or 82 kts. There also the settings should be conform to the airplane's handbook. In such conditions retarding the throttle may occur only once the wheels touch down. Brakes should be applied smoothly as no forward pressure applied unto the nosewheel