Page 32 - Volume 16 Number 10

By Thomas P. TurnerRunway overruns are among the most common scenarios for accidents in twin and turbine- powered airplanes. Although sometimes there are other variables—a runway too short for the airplane’s calculated performance under conditions of weight and/ or density altitude, or more commonly, attempting toTwin Proficiency:BWReFrom the NTSB: The pilot (of the pressurized piston twin) noted that the wind was calm as he made his traffic-pattern approach to the runway. He turned onto base leg early, which resulted in the airplane being higher than normal on the final approach. He reduced the engine power and lowered the nose in an attempt to land with enough runway surface remaining. The pilot reported that although the airplane floated much farther than he expected during landing, he believed that he could still brake to a stop safely. The airplane subsequently overran the runway’s end and came to rest on an embankment with collapsed landing gear and a bent wing. The pilot reported that he experienced no mechanical malfunctions with his airplane.The National Transportation Safety Board determined the probable cause(s) of this accident to be: the pilot’s misjudged approach and failure to attain the correct touchdown point, which resulted in a runway overrun.save time by landing straight in from the direction of arrival but with a tailwind component—usually the overruns occur on runways more than adequate for the airplane in its operating environment at the time.As a multiengine instructor, I find there is sometimes a great misunderstanding of the correct speed to use for an approach in a light twin. It’s not always a question of picking the proper speed—as we’ll see, that sometimes enters into it, but more often than not it’s a lack of having, and maintaining, a target airspeed on approach at all. It takes precision to arrive on speed in the landing zone every time. So, how do you know what speed to fly?Blue LineMultiengine pilots spend a great deal of time thinking about “blue line” airspeed. More correctly labeled VYSE, blue line speed is the indicated airspeed that results30 • TWIN & TURBINEOCTOBER 2012l