When a single-engine pilot must fly over water, he (or she) knows to plan a route that keeps the airplane within gliding distance of shore, but sometimes that isn?t possible.
The Bahamas are a popular vacation destination, but terra firma is separated by miles of water, and most airplanes can?t fly high enough to glide to shore. The same is true for pilots who decide to take a direct route over most of the Great Lakes. Then there?s the possibility that a body of water, surrounded by inhospitable terrain, might be the best place to make a forced landing. Regardless what the possibilities are, knowing the proper ditching procedures, as published in the Aeronautical Information Manual, could be life-saving knowledge.
Understanding the terms identified with ditching and basic knowledge of sea evaluation are necessary because the ditching procedure you select may make the difference between "survival and sinking." Bodies of water have waves and swells. Wind creates the former and a distant disturbance creates the latter.
During an emergency descent over land, you need to fly your final approach into the wind. But when you ditch an airplane, it can be dangerous to land into the wind without taking into account the direction the swells are running. Always avoid landing on the face of a swell.
Ocean swells usually rise no higher than 15 to 25 feet between crest and trough, and they move primarily in a vertical motion. The swell may move into or across the local wind, and it will maintain its height once in motion.
When you ditch parallel to the swell, you can choose to touch down on top of the crest or in the trough. Certain wind conditions may justify a landing on the backside of a swell, but remember, you only have one chance to get it right. Landing on the face of the swell would be akin to landing uphill ? with the hill moving toward you, which makes it tough to judge your touchdown point.
To make your landing decision more challenging, you?ll usually have more than one variable to think about. A system of secondary swells often moves in the same direction as the wind, i.e. a different direction compared to the primary swells.
Because you?d like to land parallel to the primary swell, the wind and secondary swells would most likely be flowing at an angle to the primary. If the two swell systems are at a right angle, land parallel to the primary and down-swell to the secondary. If both systems are the same height, compromise and land on a heading 45 degrees down swell to both systems. In any case, landing in a greater crosswind is better than landing into the face of a swell.
If you land parallel to a single swell system, the touchdown will be similar to a smooth-sea landing. Landing into a heavy swell or turbulent water may break up the aircraft on impact, so evaluating the surface of the water is just as important as evaluating the surface of your forced landing area on land. The same is true about the wind direction in a water ditching and it?s often easier to figure out over water. Just look for the long streaks in the water, which will appear parallel to the wind direction. High winds usually produce whitecaps and foam, and this will give you a clue to the velocity.
Engine power is critical to a safe ditching. If you have power, fly a full-flap approach at 1.3 VSO and make a soft-field landing. You want to touch down with the slowest possible ground (water) speed. If your airplane has retractable landing gear, leave it up. Otherwise, it will probably catch in the water?s "soft surface" and flip the aircraft. When you flare to land, simultaneously raise the nose and increase the power a bit to avoid an early stall and "dropping it in." Don?t close the throttle until you?re only a few feet above the water.
If you have no power, do not allow your airspeed to fall below the airplane?s normal glide speed until you flare for landing. If your airplane is a low-wing design and you ditched because of fuel starvation, the empty tanks will keep it afloat a little longer than if it were a high wing airplane.
Naturally, you use the same emergency procedures you?d use over land, such as attempt a restart, radio a mayday call that gives your position, and set your transponder to the emergency code of 7700. Add to that some water-specific procedures, such as gliding toward any ship or boat you see.
Make sure you and your passengers have donned your life jackets during the descent. (Before takeoff, you should have briefed your passengers about how to use them.) Do not inflate your life vest until you and all of your passengers are out of the aircraft. Make sure you place the life raft so it won?t cause an impact injury when you land, but will be easy to get out of the airplane. Finally, before touchdown, open the doors and stick a shoe or some other item in the opening so the impact won?t jam them shut.
Once you?re out of the aircraft, stay with it as long as possible. The airplane is easier to see than you are. Naturally, you should have adequate survival equipment, e.g. drinking water and day and night signaling devices such as a mirror and flares.
Airplanes are meant to fly, so they are less than able swimmers (unless you?re flying a seaplane). But with a little additional knowledge, you should take some comfort in your ability to find an adequate emergency "landing strip" on the high seas.