![]() We operate a Pilatus PC-12 out of and find it necessary to aim for 300' down the runway to make the 4,000 foot landing distance more comfortable. I enjoyed your Business & Commercial Aviation magazine article Staying on Glidepath but it brought to light something we in our flight department have been doing. The distance covered in 3.43 seconds at 125 KCAS: Distance covered in the flare = 3.43 seconds ( 125 nm 1 hr ) ( 6076 feet 1 nm ) ( 1 hr 3600 sec ) = 723 feet If we want to start a flare at 20', which is appropriate in this airplane, we will arrive at that 20' point 572' from the threshold: Distance from 50' to the 20' point = 50 - 20 feet tan ( 3 ) = 572 feetįor the sake of the math, let's say we smoothly cut our descent from 600 fpm to my technique target rate of 100 fpm in a linear fashion, so that the average descent rate for the entire 20 feet comes to the average of (600 + 100) / 2 = 350 fpm: Time to descend 20' at average sink rate = 20 feet ( 60 sec 350 feet ) = 3.43 seconds Without a flare, the distance to touchdown from the 50 foot point can be found easily found with a little trigonometry: Distance from 50' without a flare = 50 feet tan ( 3 ) = 954 feet If you consciously try to avoid flaring to level flight, instead aim for that 100 feet per minute sink rate, you will be able to get close to those AFM numbers and forever avoid a floating down the runway landing.įor example, a G450 flying a 3° approach at 125 KCAS will typically be sinking 600 fpm prior to initiating the flare, which should begin around 20 feet. I've found that cutting the descent rate to 100 feet per minute gives you a soft touchdown while consuming less than an additional 400 feet. That equates to cutting your approach sink rate by less than half it is a noticeable arrival. Source: G450 Aircraft Operating Manual, §13-03-20Ī 6 FPS sink rate at touchdown equates to 360 feet per minute. Landing distances based on 3.0° glide path at 50 feet and 6 FPS sink rate at touchdown. Assuming the pilot's eyes are at the point used for the center of the pilot's mass, we can deduce: Distance between pilot's eyes and main gear = 39.1 + ( 7.1 / 12 ) = 39.7 feetįurther research leads us to a Gulfstream Eye Wheel Height Paper which tells us the pilot's eyes will be between 10.4 and 10.8 feet off the ground, depending on weight and center of gravity. The G450 Weight and Balance Manual tells us the nose wheel has a horizontal arm of 48.1" while the pilot is at 41.0", 7.1" forward of the nose gear. In the case of the G450, the operating manual gives us the distance between wheels: 39' 1-1/4". ![]() ![]() That may take some detective work or perhaps just a good tape measure. Specifically, you need the distance between the aft-most landing gear and the pilot's eyes. If you want to find the distance between where your eyes are pointed on approach and landing versus where your wheels are, you will need some dimensions. This kind of thing bends metal all the time. (And if was, KAUS is only 13 nm away and has a 12,250' runway.) Either way, this "brick one" approach was unnecessary. Now let's say they were at a normal landing weight. Even if you add the standard 15 percent landing distance assessment, they only needed 4,025'. The charts say they had a landing distance of 3,500'. We know they had a headwind so let's say no wind. Let's suppose the airplane was landing at its maximum weight (42,000 lbs), let's say it was a very hot day (100F) and that drove the pressure altitude above the field elevation (620') to a PA of 1,000'. The runway is 6,025' long and has 5,425' of pavement available after the threshold - so there is no shortage of runway.There is a perfectly good RNAV(GPS) with LPV and LNAV/VNAV minimums as well as PAPI - so there is no shortage of glide path information.This Falcon 900 was obviously aiming for the start of the runway and managed to touch down in the displaced threshold. I am continually amazed when I see or hear about someone aiming for the first inch of a runway.
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