Not having FDR data, I can't say for certain precisely why the landing went wrong. Speculation is often perilous. But I have an idea about how to replicate such a scenario.fortis risk wrote:Could an experienced float pilot please explain any and all mistakes made in this landing. I would appreciate it. Thank you.
If a floatplane touches down in a slightly nose-low attitude, the floats will tend to "dig". "Digging" happens when the floats aren't at the optimum angle. The angle that yields the lowest water drag is found in a very narrow band when on the "step", with only the very bottom centre of the keel (the step) in the water. During take-off, incorrect angle--either too nose-high or too nose-low--will lead to a much longer take-off run and often prevent the aircraft from lifting off at all, due to higher than optimum drag. Slight changes in fore- or aft-pressure on the stick or yoke will yield instant and very perceptible changes in drag.
During landing, training and repetition will help a pilot develop a sight picture that closely replicates the attitude the aircraft (and floats) had on take-off, for a perfect, low-drag touchdown. Unless of course he is attempting a short-lake landing, in which case the attitude can be deliberately adjusted either at or slightly after touchdown to a very slight nose-low attitude, thus producing an immediate large increase in drag and shortening the landing "roll" considerably. The aircraft is not very likely to flip over as a result, but it is a disconcerting feeling.
Where the problem arises is if this nose-low manoeuvre is combined with a cross-wind landing, or, in the case of glassy water, a normal landing is attempted and the combination of incorrect too-low pitch attitude exists and insufficient care has been exercised in making sure the aircraft isn't in a state of yaw at the moment of touchdown. The first float to touch will decelerate instantly, causing instantaneous yaw around that float. Momentum and centripetal force will result in shift in weight to the other float (and also wingtip) somewhere around the 90 degree point of the yaw, which now results in even faster yaw in the opposite direction. Eventually the aircraft may end up on its nose.
In this particular situation, the water appears to be glassy. Glassy water landing are tricky because it is completely impossible to tell how high you are above the water. Where normally the correct moment to round out into the flare is easy to judge, in glassy water conditions this is not possible. So other techniques must be employed. If it is a narrow river, or there is a straight nearby shoreline, or there are islands, landing very close to these physical features will keep them peripheral vision and the proper time to flare can still be judged. Any ripple or boat-wake can help. Reed beds are also useful. If you can do the approach over land to a very low height, for example flying over a beach with no obstacles on it, down to say two or three feet, then setting it down as soon as you are over water also works well.
If physical features can't be used, then the only option is to descend to as low as you dare, but high enough that you are absolutely certain you are not overly close to the water. Then you round out into the flare, adopting the optimum touchdown attitude, while simultaneously adding power so as to not lose speed and energy, with only a very slight rate of descent. This attitude is then maintained to touchdown, with power being tweaked as needed. The point and time of touchdown is often unexpected, sometimes in that it happens sooner than you though it would, sometimes it takes far longer (and far more lake) than you thought would be required until you actual touch. I can usually feel an almost imperceptible increase in speed as I transition into ground effect, cuing a very slight reduction in power. On a perfect day, the touchdown is not felt; you only know you are on the water when you see water spray in your peripheral vision. This method can require a lot of lake to safely accomplish.
Judging by this video, none of these options were employed. Obviously with the mountain in the background, a straight-in over-land approach to low altitude wasn't possible--or more correctly, wasn't safe. No other physical features were available for an aid to judge the flare height. And the aircraft appeared to maintain a normal--that is, non-glassy landing--rate of descent into the flare. The roundout into the flare appeared to be abrupt and late, and it did not appear that the nose was raised high enough to achieve the optimum angle for touchdown. One float touched down first, "dug", and an immediate yaw occurred, with the sequence then progressing as you see in the video.
What mistakes were made? Can't say for certain. As stated earlier, it appears that for this particular approach, no physical features were available to help the pilot judge his height above water, so the open-water glassy water technique may have been the prudent technique to be employed, which as mentioned earlier, can require a long straight stretch of water. It is not apparent from the video is how much lake he had available to execute this landing. If he had lots of lake available, it would appear that he didn't use it wisely. If he didn't have lots of lake available for this direction of landing, he should have chosen to land in a direction where he had a longer run available. Or, he could have flown close and parallel to the mountain you see in the background of the video, while descending to low altitude using his peripheral vision. Once really low, he could have turned in the desired direction perpendicular to the mountain, and adopted the landing attitude while using engine power to reduce the rate of descent. This more prudent approach would not have been as dramatic as the one appearing in video, but then the landing would also have been much less dramatic.
Stories sometimes float around that local pilots, when asked by the film crew to attempt the approach and landing as seen in the video, flatly refused. Other stories tell of the aircraft in the video being quite willingly made available to the non-local pilot for the right price after being insured to the hilt. Obviously these legends have evolved over time into quite tall versions of the truth.
