The Pilot's Lounge #54:
Tailwheels, Part III — Full Stall or Wheel Landing?
Those of you following the series on tailwheel airplanes by AVweb's Rick's Durden have been waiting for it — at last, he's done it. Rick put on his crash helmet (not to fly but to protect himself from flying objects) and entered The Pilot's Lounge to get opinions about tailwheel landings.
According to Garrison Keillor, Lake Woebegone always has quiet weeks. That isn't the case here in the Pilot's Lounge at the virtual airport, and we wouldn't have it any other way. We have been known to have some pretty raucous moments; particularly if Old Hack and a couple of other folks show up at the same time and get to, ahem, discussing, certain subjects. There are just some topics that generate emotional reactions, although I'm not sure why. One continues to be the use of flaps on landing. Another hot button is the question of whether three-point or wheel landings are "better" or safer. If you want to stir things up some evening when a bunch of tailwheel pilots are at the bar, look innocent as you make that inquiry. Wander away for 10 minutes or so. When you return, be ready to duck, as the chairs may be flying.
What's So Tough About Determining the Better Type of Landing?
Part of the problem lies with a simple lack of data on the type of landing made when looking at accident reports. We can separate out tailwheel airplanes themselves in NTSB data and, wonder of wonders, discover that pilots are far more prone to landing accidents in them than in the nosewheel variety. Big deal, insurance underwriters have known that for years. We aren't breaking any new ground. Unfortunately, the accident reports do not shed a lot of light on the issue of whether a three-point landing is generally safer than a wheel landing or the converse.
Some Background For the Discussion
I've gotten a lot of very good feedback from readers on this subject. I've also spoken with and exchanged e-mails with several very experienced tailwheel pilots and instructors as well as done a fair amount of reading on the subject. I had one reader correct me on something very basic: I was erroneously equating three-point landings with full-stall landings in the two earlier tailwheel columns. They are not necessarily the same. Many tailwheel airplanes are not fully stalled in three-point attitude. Those airplanes can roll the tailwheel first, if desired, on landing. A full-stall landing in those airplanes means the tailwheel rolls and then the mains drop in from some, usually small, distance. For convenience, I'm going to refer to three-point landings as a catchall so as to include the tailwheel-first, full-stall landings.
Infinite Variety of Wheel Landings
There are also nearly an infinite number of versions of wheel landings, although they can be broken down to being considered tail-high, with the airplane more horizontal, and tail-low where the tailwheel is relatively near, but not touching, the runway on landing. No matter what, if the tailwheel does not touch the runway (as a result of the pilot's intentional act) until some very definite time after the mains, it's a wheel landing.
The No-Man's-Land In-Between
The landing in which the mains touch followed by the smacking sound of the tailwheel impacting terra firm doesn't have a name beyond either "Oops" or "Oh, #$%^". It is generated in a number of ways: an attempt at a wheel landing in which the pilot does not release the back pressure on the stick when the mains touch, a wheel landing with a descent rate that is not arrested and in which the pilot allows the tail to continue going down after the mains make contact, or by an incomplete flare when going for a three-point arrival. No matter what the cause, the effect can rapidly become a bounding, bouncing, scary gyration as the airplane hops from tailwheel to main gear. If the pilot attempts to arrest things by thrashing the stick back and forth in hopes of turning the exercise back into a wheel landing, the most common consequence is further unpleasantness, which can become most amazingly loud as components of the airplane other than the wheels make contact with the globe. There are two good cures to this "crow hopping": full aft stick to keep the tail down, or a go-around. Experience and judgment are the only answers to the question of "Which should I do in that situation?" It may be possible to smoothly pull the stick all the way aft and hold it in position (along with full aileron deflection into the wind); however, if you're eating up runway or if there is any directional uncertainty, a go-around is probably the better maneuver.
In This Corner, The Advantages of Three-Point Landings
A three-point landing has the aerodynamic benefit of lots of drag during the initial portion of the landing roll. The airplane is pitched up, with the wings and bottom of the fuselage helping slow you down nicely ... remember your drag curves and how sharply they go up as you approach the stall, well, they don't suddenly go to zero on touchdown. Full flaps add agreeably to that drag, helping you slow down quickly in three-point attitude.
Because you had to position the ailerons and rudder to avoid drift prior to touchdown, they are probably going to be deflected in the correct directions when you do touch, so all that is needed is to smoothly move the ailerons to the stop and to be alive with the rudder to continue proceeding in the desired direction. As J.B. Stokley put it, "If your feet ain't movin', you're most likely about to screw up." The rudder may rapidly lose effectiveness due to deceleration and being blanked by the fuselage; however, a firmly pinned tailwheel should do a great deal to compensate for the loss of that aerodynamic control, especially if the landing is made on an unpaved surface where the drag of the tailwheel is a major benefit. An added benefit is that by the time the airplane has decelerated to the point where the aerodynamic effectiveness of the rudder is iffy, the brakes (assuming the airplane has them) have become quite effective, and their use will assist in control of the rollout.
A three-point landing is pretty forgiving of mistakes during the flare, making it especially useful for pilots with less tailwheel experience or for high-time pilots just getting used to a new type or who haven't flown a great deal recently. (We pilots have a tendency to not recognize just how amazingly fast our skills atrophy.) It's pretty much OK to drop the airplane in from several inches or a few feet when doing a three-point landing. So long as the stick is kept all the way aft, the airplane may or may not bounce, and, even if it does, a little power will suffice to let it down more gently the second time. The airplane is not likely to get into any kind of oscillation in such circumstances and the pilot is free to concentrate on the more important landing variable: directional control. OK, OK, with creative misuse of the throttle and full aft stick, a pilot can get into a pretty spectacular jam with the nose high and very little speed; however, I'll assume some degree of competence when talking about recovery from a bounced landing.
Even though the brakes are not terribly effective during the first few seconds of the landing roll, impressively short landings can be made because they start out with touchdown at minimal speed.
Three-Point Landings Aren't Perfect
The time involved in flaring to land in three-point attitude can lead to directional control problems in a strong crosswind. In some airplanes, particularly if the pilot is not willing to put the ailerons to the stop or has tacked on some extra speed on final, directional control can be challenging during the flare. Done correctly, a three-point touchdown in a crosswind means that the airplane is going to initially alight tailwheel first or at the same time as the upwind main gear, and it's going to roll along in that attitude for a few moments. It's perfectly controllable, but it may feel a bit odd.
If the airplane is stalled at touchdown, or nearly so, transfer of a significant portion of the weight of the airplane from the wings to the main gear takes a little while to occur. Consequently, the wheel brakes do not have a great deal of effectiveness in the early portion of the landing roll. The effect of the wing deflecting air downward causes some residual lift upward. When that is combined with the high aerodynamic drag, acting aft, the resultant load vector on the airplane is up and aft, away from the main gear. So, the first portion of the rollout during a three-point landing is best controlled with the flight controls and by nailing the tailwheel to the ground via full aft stick. The magnitude of the up and aft vector diminishes fairly quickly, losing the majority of its effect by the time you have completed about the first third of the landing roll (according to the folks who have measured that sort of thing, aerodynamic braking is more effective during the first third of the landing roll, wheel braking during the last two-thirds). You can help things along by retracting the flaps at about the one-third point in the rollout. Yes, I know, the FAA frowns on flap retraction during rollout and, yes, there is a risk of raising the landing gear if you grab the wrong switch or lever, so don't blame me if you do it, I warned you. Raising the flaps puts increased weight on the mains right away. Once the brakes are applied the resultant decelerative force on the airplane has the positive effect of increasing the weight on the mains, so the more you brake, the more effective the brakes become so the more you can brake. It also means you need to be somewhat judicious as the brakes on most tailwheel airplanes are fully capable of flipping the airplane over onto its back.
While the three-point landing is probably better for most airplanes and pilots who haven't been flying a great deal recently, there are some airplane specific exceptions to the general rule. There are airplanes that are far easier to wheel land than to three-point, such as the Globe/Temco Swift, the Beech 18 and DC-3. Pilots who want to do three-point landings in those had better be very current and quite good. It's also wise to be lucky that day.
Many airplanes manufactured in the 19-teens, '20s and early '30s were built for open-field airports where all takeoffs and landings were into the wind. These true "taildraggers" (they had skids rather than tailwheels) can be a distinct handful, or even uncontrollable, in a crosswind if a three-point landing is attempted. In fact, for many, a wheel landing may not help much; the pilot finds he or she just rolls a little further before discovering that the controls are not adequate for the task assigned.
Benefits of Wheel Landings
There is a shorter period of time during which the airplane is decelerating in the flare than in a three-point landing, so it is easier to avoid drift prior to touchdown.
In a strong, gusty crosswind a more advanced pilot can land the airplane (depending on the type) in nearly level flight attitude and may be able to go to a negative angle of attack, or one so low that virtually all of the airplane's weight is on the main landing gear, allowing for heavy braking immediately. It has to be kept in mind that braking with the tail up is a very advanced procedure and, done wrong, will result in serious damage to the airplane and injury or death to the occupants. The bush pilots who fly the Cessna 185 have developed a very impressive short-field technique using an almost constant pitch attitude on short final, with descent controlled with power and the landing taking place simultaneously with application of brakes to keep the airplane firmly on the ground. Again, it is a very advanced technique to be learned from one schooled in the procedure.
An experienced pilot who is very current in the particular airplane can land the airplane shorter with a wheel landing than a three-point landing because of the ability to use the brakes right after touchdown. However, it takes immediate, heavy braking to do so, and a mistake can be extremely expensive and painful.
Because it is not unusual to have to make a go-around at some point during the rollout in a tailwheel airplane, it is generally easier to do so while the airplane is still rolling on its main gear, rather than from three-point attitude. This can be airplane-specific, as some higher-powered airplanes will go around very quickly from three-point attitude.
In most tailwheel airplanes, the pilot has much better visibility of the world ahead during a wheel landing. This may be particularly important at night or in a strong crosswind.
Because the pilot makes the decision when to lower the tail (and should never just let the tail descend on its own) one can take maximum advantage of the relative effectiveness of flight versus rolling controls during rollout. A pilot who knows the airplane can keep the tail in the air, making maximum use of the airflow over the rudder for directional control, until such time as the airplane has slowed to the point where better directional control is available via the tailwheel, and lower the tail at that moment. As was said to me repeatedly, determining the proper moment is a matter of knowing the airplane.
On older airplanes or ones with more "fragile" tailwheels, the wheel landing prolongs the life of the component. I discovered that one day when making a three-point landing in a ski-equipped Luscombe on packed, rutted snow. The tailwheel broke off and I didn't realize it (I'd made a touch and go) until I was back in the air and got a call on Unicom. Following the next landing I discovered it was possible to taxi a ski-equipped Luscombe with the tail in the air almost all the way to the tiedown.
Wheel Landings Have Shortcomings?
Although approach speed for a wheel landing is exactly the same as for a three-point landing, the touchdown itself is at a higher speed. Extra speed can be a big negative once on the ground. It requires that the pilot have the skill and that the aircraft have effective enough controls to manage the energy of the airplane while slowing to a stop.
Pilot after pilot related to me that one of the greatest misconceptions involved with wheel landings is that one comes down final fast. It just absolutely, positively isn't so. Final approach to a wheel landing should never, ever, ever be flown faster than final approach for a three-point landing. 1.3 Vso plus half the gust factor is the fastest the airplane should ever be flown on final. Excess speed on final has been proven time and time and time again to get pilots into serious trouble. There is a temptation to come in too fast on wheel landings, leading to loss of control on rollout or, even more embarrassing, going off the far end of the runway. Way too many pilots, who should know better, like the way the airplane feels when coming in fast. I think it's going to take some Stooge-slaps to get those folks to catch on and understand that extra speed on final is not their friend. They are at far less risk of loss of control on final than they are once on the runway. Wheel landings have an ugly tendency to cause pilots to fly final too fast and then come to grief during rollout. In an e-mail to me on the subject, Chris Basham, a Canadian pilot, mentioned that tight control of altitude and speed leading to touchdown on a wheel landing is essential. I've got tremendous respect for Canadian pilots — they do more tailwheel flying than we here in the U.S., and they operate off of generally more difficult airports — so when they talk, I pay attention. Lou Day, who has flown most everything with a tailwheel on it and has a soft spot for the Curtiss C-46 Commando, told me that he prefers wheel landings because he feels that he can fly out of one that is going bad more easily than out of a three-point landing gone south; however, he said that he thought that the wheel landing has more potential for disaster when done inappropriately or badly. I have to second that opinion.
A wheel landing can lead to an upside-down airplane if the field is soft. If in doubt about runway conditions, three-point the airplane.
If there is any sort of descent rate at touchdown, there is a tendency for the tail to continue downward, increasing the angle of attack and bouncing the airplane back into the air. Most bounces on wheel landings are not due to the landing gear, they are due to an increase in angle of attack. A bounced wheel landing can be trouble as the natural tendency is to push the stick forward to try and catch the airplane and "pin" it on the runway. The pilot gets precisely 180 degrees out of phase with the airplane, leading to pilot-induced oscillation (pio), which can quickly generate a bent airplane and worse. This problem seems to be aggravated by one of the old wives tales still running around that says that a pilot must "pin" the airplane on the ground with forward stick on touchdown. That is repeated in the FAA's otherwise outstanding new Airplane Flying Handbook on page 15-6. I recommend that book for a lot of things except for teaching wheel landings.
Some airplanes cannot be wheel-landed because they do not have enough propeller clearance. Randy Sohn of the C.A.F. advises that the Grumman Bearcat is a good example of an airplane that is three-pointed for takeoff and landing.
OK, Which is Safer?
After a great deal of discussion, research and reflection, it appears that the entire issue boils down to three major variables that must be taken into consideration by the pilot before deciding on the type of landing to make in any given weather conditions: 1) The overall skill level of the pilot; 2) the type of airplane being flown; and probably the most important variable, 3) whether the pilot has had recent (within a few weeks) experience in the specific airplane being flown.
If a pilot is not current, or does not have a lot of tailwheel time, and if there is not a strong or gusty crosswind (each individual pilot has to define strong), a three-point landing is usually the better way to go. There is less kinetic energy to deal with during the rollout, and flaring at the wrong height or making a hard landing is no big deal, so the pilot can concentrate on just one variable, directional control. It is the more conservative landing in most airplanes, and when in doubt, the conservative approach to dealing with a moving object is often the better one.
If there is a strong or gusty crosswind, and the pilot is not experienced, current and in practice, the safer approach is to postpone the flight or find a runway into the wind.
If a strong or gusty crosswind has to be faced, a wheel landing is generally better for control of the airplane; however, the higher risk of extra speed at touchdown has to be recognized and accepted. It also means the pilot, no matter how experienced, should be ready to make a go-around any time things are not going as planned or if there is any question at all about directional control. As a further, general rule, if a wheel landing is bounced twice, it should be abandoned and a three-point landing or a go-around conducted.
If the pilot is experienced, current and knows the airplane, a wheel landing appears to be safer unless the runway is soft. A good pilot, flying a capable tailwheel airplane, in my opinion can handle a stronger crosswind than in a nosewheel airplane, usually because the tailwheel airplane has greater control authority (you bet there are exceptions, some early biplanes come to mind). Face it: A wheel landing requires expert manipulation and dissipation of the considerable force involved with that collection of metal hurtling along a runway while balanced on two wheels. Nevertheless, a good pilot can use the skills developed over time to handle that energy by using the aerodynamic and rolling controls to cause the airplane to go precisely where and decelerate when desired. While an airplane with very effective controls may be difficult to learn to operate (it's tougher to fly a Pitts than an Ercoupe), the effort of learning and keeping one's skills honed is amply rewarded by the ability to make that airplane do things that others cannot. One of those rewards is to be able to land safely in strong, adverse winds. That ability comes with a known risk: Improper handling of those controls will result in tearing up the airplane and the people inside.
Tailwheel airplanes require more skill and judgment to land than nosewheel airplanes. The accident reports reflect that fact rather boldly. It means that those who fly tailwheel airplanes need to be willing to self-asses their skill level constantly, be willing to examine the variables facing any landing, and use their educated judgment. Whether a three-point or wheel landing is safer in a particular airplane is not ever going to be a simple question. It is an issue that has to be resolved by each individual pilot for the conditions he or she faces at any given time. It looks to me as if the question of whether rolling it on the mains or three-pointing the airplane is going to lead to a safe landing is one that is only answered after a frank appraisal of one's skills while considering the type of airplane and the recency of one's experience.
See you next month.