Sunday, December 27, 2009

Keep it on the runway

The recent AA faux pas in Jamaica, almost going for a bath rather than a simple landing, reminded me of an early flight of mine that ended in a bad way. I was trying to land a Cessna 172 at NY38, Nedrow Air Park, a 2100 ft. paved runway with 50 ft trees at the north end. The field is no longer there ( I wish it hadn't been there then). Anyway I came in too high and fast and couldn't stop on the runway even by standing on the brakes. Unfortunately no reverse thrust available on the 172. However forward momentum was arrested by a well placed tree at the south end of the runway. I was lucky then to learn several lessons about landing. Lessons that stayed with me for the rest of my flying career.

So what were those pilots thinking as they tried to land a 737-800 with a questionable strong tailwind and a wet runway? Both of these factors: tailwind and water on the runway can significantly increase stopping distance of a landing airplane. These factors become much more critical if you are too high and too fast. In fact every 2 knots of tailwind will increase the landing distance (over no wind) by 10%. Standing water on the runway can increase the stoppping distance required by as much as 15%. So adding these things together makes for a challenging landing requiring speeds to be precise and touchdown as close to the threshold numbers as possible (not halfway down the runway).

According to Blake & Elliot in commercial aviation there is only one overrun per 3.6 million flights. They also state that 42% of commercial aviation accidents occur during final approach and landing.

So to avoid being a statistic when landing a pilot must plan his/her approach carefully keeping the following in mind. Fly the proper approach speed for plane configuration( no flaps to full flaps), wind conditions on the runway (allowing for gusts, head or tailwind etc), runway condition( dry,wet or icy). And of course length of runway including obstructions.

May your next landing be smooth and uneventful.

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