Tuesday, March 24, 2009
The Last 50 ft.
Making it all come together
|When you’re on short final and descending through 50 feet, it really doesn’t make much difference how good you are at centering airways, whether you can spout FARs or if you scored 100% on the written: The only thing that counts is how well you actually fly. Everything else is superfluous because every single thing you know about actually flying the airplane is compressed into a 10-second time span and an ever-decreasing sliver of altitude. This is literally where the rubber meets the road and where every one of your moves has measurable consequences. |
3) MAKE POWER REDUCTIONS AND CONFIGURATION CHANGES IN THE SAME PLACE AND THE SAME WAY EVERY TIME.
The interplay between lift and drag and power and altitude during the last 50 feet is best accomplished by understanding what’s happening and knowing how to correct for deviation.
Changing the power and setting flaps on downwind affects the airplane’s energy and glideslope, so start that change in the same place and with the same timing (power back at same rate, flaps down at same rate) to keep the energy change consistent. From that point on, whether power is increased or decreased depends on the traffic, wind, etc. If you’re doing a full power-off landing (power cut opposite the threshold on downwind), this consistency sets up a glideslope that will be essentially the same every time. 4) HOLDING AN EXACT AIRSPEED IS YOUR GOAL.
Any deviation, over or under, the POH
-recommended approach speed (usually best glide speed) results in unnecessary altitude losses. This is another way of saying, “Once the power is off, configuration is changed and attitude for the correct speed is established, note the nose’s relationship to the horizon and hold it there.” Speed changes will be seen first in the windshield (the nose goes up or down). At the same time, sharp ears will hear a change in the tenor of the wind noise. The airspeed indicator will eventually catch up, but it’s historical information. Speed changes happen in the windshield first. 5) VISUALLY LOCK ONTO THE MOVEMENT OF THE RUNWAY NUMBERS AS YOUR GLIDESLOPE.
If the numbers seem to be moving away (up the windshield), then you’ll be short. If they’re coming toward you (down the windshield), then you’ll go over them. The goal is to hold them stationary in your vision through power, configuration changes or slips. That will point your glideslope at the numbers, and when you break the glide and flair, you’ll land past them by a modest distance. Try to be at a reasonable height over the threshold, between 20 and 40 feet. That’ll put you on the runway 500 to 700 feet past the numbers, so no runway will be short, because you’ll be able to easily turn off at 1,500 to 1,800 feet.
Okay, so now you’re on short final and coming down to 50 feet (which is an arbitrary number for the sake of discussion; it’ll change with every airplane type). This is where the magic begins and the graceful reunion with the ground is initiated. And “graceful” is the right adjective: There’s nothing more graceful than a well-executed landing.
So now you’re on short final at, say 70 mph, with the nose down. You want to contact the runway as close to stall speed as practical on the main gear (for a tricycle-gear airplane), and the nosegear will be held off the runway for as long as practical. That’s a beautiful, graceful landing. Your position on short final is separated from your roll out on the runway by the process sometimes referred to as “the flair” or “round out.” This consists of slowing the airplane down while simultaneously changing the attitude at a rate that gives up just the right amount of altitude so you gradually close on the ground. The attitude change will be such that it will put the mains on the runway with the nosegear clear. That’s what you want to do. But there are some things you don’t want to do.
For one thing, you don’t want to come barreling down toward the runway and yank the airplane level at 10 feet while still showing approach speed on the clock (70 mph). This guarantees that the airplane is going to skate along in ground effect while you try hard to get rid of excess speed without ballooning, which can be a real chore.
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