Comments

Ouch! I'm going to have to side with my fellow professional pilots who reacted less than favorably to the somewhat 'incendiary' paragraph of your otherwise benign treatise on the challenges of tail wheel landings. Though I'm sure your intent was not to raise the ire of readers who pilot transport category aircraft, their reaction, like my own, was understandably defensive. In truth, landing larger, heavier airplanes presents unique challenges just as taildraggers do, so we as pilots can benefit from understanding the dynamics and pilot techniques employed in both worlds. Judging by the number and scope of the comments, the subject of your blog is one that clearly interested pilots from both worlds, so I think this would be a good opportunity to add a few more comments related to the transport category world. For generalization purposes, my comments will primarily address multi-engine, swept-wing, transport category jet airplanes of 30,000 pounds MTOW or more, for which the term 'larger airplane' will apply. Likewise, the term 'smaller airplane' will apply to light, piston-single GA airplanes. No offense intended to any aircraft or pilot left out of this generalization! : ) For starters, I'm glad you mentioned the stabilized approach and smooth touchdown you experienced. Achieving both of those objectives actually requires a set of highly-developed flying skills in larger airplanes due to their larger mass and less than immediate response to pilot commands than we enjoy in smaller airplanes. As such, every change in configuration, control input, or power made during approach by the pilot of a larger airplane must accurately anticipate the effect of that change so as to avoid the need for any more than minimal correction. Like smaller airplanes, precise airspeed control is the key to a stabilized approach and a 'safe' landing in larger airplanes. Depending on the situation, 'smoothness' is not always possible or even desirable. When airplane and pilot are functioning normally and weather is cooperating, even the largest airplane can be landed with extreme precision - touchdown occurring precisely on target, on speed, and on the centerline, but not necessarily aligned with it! You may be surprised to learn that many larger airplanes have 'geometry' limitations which govern the maximum combination of pitch and roll that can be employed during landing in order to prevent a wingtip, engine nacelle, or the tail from striking the runway. So, in strong crosswind conditions, these limitations may require the pilot to touchdown deliberately out of alignment with the centerline, which can create quite a challenge on a narrow runway - especially when it's slippery! In extreme cases, the pilot must be able to accurately position the front of the airplane somewhere over the upwind side of the runway so that touchdown occurs with the main gear (in some airplanes 50 to 100 feet behind the pilot's seat) straddling the centerline. We all earned our wings learning the crab to sideslip crosswind landing technique which once mastered becomes second nature, so I'm certain any pilot will appreciate how difficult it would be to 'unlearn' what becomes so ingrained after thousands of hours of flying. Such was the case for me when I began flying the Citation X and learned that touching down in a crab would be necessary to prevent the delicate tips of its radically swept wings from striking the runway during crosswind landings. The first time I tried it the crosswind component was just 18 knots, but even so touching down with the airplane pointing away from the centerline seemed in violation of a sacred aviation commandment. I could expand on the low speed characteristics of swept wings and how this adds to the challenges of landing larger airplanes, but lets talk about the 'tricky' stuff that happens after touchdown. You mentioned the airplane moving left and right after touchdown and imagined it was the work of the pilot, but in many cases it is simply the result of physical properties over which the pilot has no immediate control. I talked about mass earlier and when a larger airplane touches down even slightly crabbed on a dry runway, it will align itself with the direction the mass is traveling, presumably down the centerline. Depending on the winds, the effects of this self-alignment process may be imperceptible to the passengers or may induce a noticeable 'swaying' sensation, which will be more noticeable to passengers seated further away from the main gear. When touching down in a crab on a slippery runway, self-alignment will not occur if the force of the moving mass exceeds the cornering force of the tires and good old-fashioned footwork must used to align the airplane with the centerline. It's a busy time during the transition from touchdown to rollout because you still have to get this large moving mass stopped, which means employing aerodynamic braking devices, thrust reversers, and wheel brakes all in a prescribed sequence - and all of which introduce more physical effects that further challenge aircraft handling. Another commenter also observed, thrust reversers don't always deploy at exactly the same time and reverse thrust isn't always equal between engines. When this occurs, the pilot must dutifully work the rudder pedals to regain and/or maintain the airplane's track down the centerline. To complicate matters, reverse thrust can disrupt airflow to the rudder, thereby reducing its effectiveness - especially on airplanes with aft mounted engines. Further, the effects of a crosswind even during symmetrical reverse thrust deployment can introduce a side force that can cause the airplane to 'skid' sideways toward the downwind side of the runway, which will have the pilot working the rudder pedals even more up front and the passengers swaying even more in back. This is especially true on slippery runways, which is why landing procedures for some airplanes may require stowing the thrust reversers sooner (at a higher speed) on wet or contaminated runways than dry. As if that's not enough, when crosswinds necessitate 'cross-control' aileron input to prevent the upwind wing from rising, this increases the load on the upwind landing gear as well as the braking force of the upwind wheels and tires,which can cause an into-the-wind turning force even during symmetrical wheel brake application. A few comments also mentioned the 'tiller', so lets talk about that. Yes the tiller is used for ground steering on larger airplanes, but primarily for taxiing and only below prescribed speeds during the takeoff roll and landing rollout. While the rudder pedals do steer the nosewheel, the small degree of steering angle available using rudder pedals alone is usually insufficient for taxiing expect in a straight line. Conversely, the tiller provides a large degree of steering angle that can get you around the tightest corners, but becomes too sensitive to pilot input at higher speeds. So, during the takeoff roll, as speed increases and the rudder becomes increasingly more effective, the pilot must transition from the tiller to rudder pedal steering. During the landing rollout, the rudder pedals are initially used for steering while the rudder is effective; however, as speed decreases and rudder pedal steering becomes increasingly less effective, the pilot must eventually transition to the tiller. The exact speed at which these transition occurs is stated in procedures and varies among airplanes, but all share one commonality - transitioning to the tiller too soon during the landing rollout will produce a 'squirrely' steering experience for the pilots an the passengers! Hopefully my comments have provided you and other fellow pilots a better understanding and appreciation of the challenges of landing larger airplanes. So, next time you're sitting in back of an airliner and experience a firm touchdown or swaying sensation during the rollout you'll be less inclined to criticize the pilots or judge a 'safe' landing as 'botched' because it didn't meet a subjective criteria for 'smoothness'. While smoothness is always a goal of professional pilots, safety is always the number one priority. That's something I think all pilots can agree on!