The most common type of airplane accident involves departure from the runway on landing. Some pilots lose control and go off the side of the runway with plenty of pavement remaining, but many others simply run out of room and go off the end. The FAA and NTSB are so concerned about landing runway accidents that there is a proposal to add 15 percent to the required runway length for all airplanes that have a runway requirement. In general, small airplanes-those weighing less than 12,500 pounds maximum-do not have certified landing runway length requirements, but all large airplanes and all jets certified so far, no matter what the weight, do have requirements. The proposal is on hold, but I expect some new rule to require jet pilots to use longer runways will appear.
I believe one of the biggest issues in a landing runway accident is that many pilots of all types of airplanes simply don't understand what the information in their pilot operating handbook (POH) or airplane flight manual (AFM) means, and how it was collected.
Once again, airplanes of different weights are treated differently by the FAA. For large airplanes and jets, the landing distances in the manuals are approved by the FAA. And so is the data for most propeller airplanes that have maximum takeoff weights of more than 6,000 pounds. But performance information for piston-powered airplanes weighing less than 6,000 pounds maximum gross weight may or may not be FAA approved. The manual must clearly indicate if the landing runway length data, for example, is or isn't approved.
It probably doesn't matter all that much if your airplane has approved landing runway length information or not, because the manufacturers conduct the tests using the same procedures. Knowing and understanding the flight test procedure is the important thing.
For newer piston airplanes certified under FAR Part 23, and for jets and large airplanes, the landing runway length test is clear. The test pilot must maintain a steady three-degree approach path at Vref airspeed. The runway length required is measured from the point where the airplane is 50 feet above the runway until it stops.
Vref final approach airspeed is typically 1.3 times the stalling speed at the weight of the airplane as it approaches to land. However, some piston singles that trace their certification roots back to the old CAR 3 rules-which includes many airplanes in the fleet-use Vref speeds as low as 1.2 times stall to calculate landing distance. That's a little too slow for my taste. You can find out by comparing the recommended Vref on the landing distance chart to the stalling speed chart and doing the math. Many piston single manuals have a short field landing chart as well as a normal landing distance. Often the short field chart will require an approach speed of 1.2 times stall, and/or a steeper than three-degree approach. There is no such thing as a short field landing distance for larger airplanes, as all landings are treated the same.
The importance of maintaining Vref airspeed is obvious. Every knot above Vref on approach will cause the airplane to float more before touchdown, and will add more energy for the brakes to overcome in the stop. You can be sure that the test pilots who collected the data for landing runway length in your airplane manual were not a single knot over Vref because if they were, they went back and did the test again.
What you probably don't know is that the test pilot almost certainly yanked power back to idle at the 50-foot above the runway point. The rules require the approach to be completely stable at a three-degree approach angle, and that requires power. But at the 50-foot mark, all bets are off and the quickest way to get from 50 feet to the runway is to pull off all of the power.
Most of us, except in the lightest airplane, carry at least a little power into the landing flare because some thrust makes it easier to feel for that smooth touchdown. But that extra power and "feeling" for the runway is using up many, even hundreds, of feet that the test pilot didn't use. The rules don't require test pilots to make a "good" landing, only a safe landing that doesn't overstress the landing gear or airframe. Test pilots talk about "minimum flare" on their landings, and that means just enough to keep from hitting on the nose first. Depending on the airplane, it can be a challenge to land when you chop the power at 50 feet with no extra airspeed. Turboprops can be the most demanding because their propellers go immediately to flat pitch to maintain turbine speed, and that creates a lot of drag. You can make very short landings in turboprops just like the manual says, but you need to be very quick at getting the nose up as the power comes off. I bet you won't be happy with the results the first time you try it.
