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Ditching is a precautionary or forced landing of a landplane in water. The mere mention of this sort of an emergency procedure usually triggers thoughts of small airplanes crossing large oceans or of pilots who intentionally fly beyond gliding distance of land while crossing channels, lakes, or bays.
Certainly these pilots need to be familiar with ditching procedures, but they are not the only ones. Thirty to 40 general aviation ditchings occur in U.S. coastal or inland waters each year. Many of these are performed by pilots who usually do not venture over water. Sometimes it is unavoidable, such as when operating IFR between coastal airports. Arrival and departure routes for these areas frequently require pilots to fly beyond gliding distance of land for uncomfortably long periods of time.
There also are occasions when pilots opt to land in the water because this appears safer than landing on a crowded or rocky beach. Consider, for example, the dilemma faced by Takis Hinofotis, a flight instructor based in Santa Monica, California. While flying along the coast of Malibu one September, the engine of his Piper Turbo Arrow IV failed catastrophically because of a shattered connecting rod. The beach was crowded with sun worshipers, Highway 101 was choked with traffic, and the rugged, coastal palisades were even less inviting. With time and altitude in short supply, Hinofotis opted to ditch in the Pacific.
The procedure was performed well enough, for both the instructor and his student survived without a scratch. After they swam to shore, the aircraft drifted toward the beach and was tugged onto the sand by helpful onlookers, including actor Larry Hagman.
Consider also the pilot of a Cessna Skylane who was crossing the Rocky Mountains on a VFR flight between Spokane, Washington, and Cut Bank, Montana. Certainly, he had no reason to be concerned with ditching. Yet that is exactly what he did shortly after his engine failed. Instead of trying to find a soft spot in the granite, he landed in a mountain lake and survived unscathed. (Since he had broadcast his predicament and location prior to losing much altitude, the pilot and his family ultimately were rescued by helicopter.)
Although total power failure (usually caused by fuel exhaustion) is the most common reason for pilots having to ditch, there are a host of other reasons why a water landing may be necessary. Oddly, the need to ditch often is not recognized or accepted soon enough, and this can be the most hazardous factor in the overall operation. Assuming a splashdown is unavoidable, take advantage of all available time and altitude to prepare for what could be the most dangerous landing you ever will make.
As in any emergency, the pilot first must control the airplane. If the need to ditch is caused by an engine failure, pilots tend to establish a normal glide. But unless attempting to reach land, there usually is no reason to maximize glide range. After all, the water ahead usually is no different than the water below. Instead, fly the aircraft at the minimum-sink speed (about halfway between stall and normal glide speed). Although this reduces glide range, it also reduces sink rate and increases substantially the time required to lose altitude and the time available to prepare for the landing itself. When 1,000 feet above the water, normal glide speed should be resumed because maneuvering may be required.
One exception to this is when a maximum-range glide is needed to reach a distant surface vessel, which is the best assurance of assistance if a landing cannot be made close to shore. An attempt should be made to ditch ahead of the ship to increase the probability that someone on board will see you. Also, land to one side of the vessel, not directly in front of it�a large ship may not be sufficiently maneuverable to avoid collision.
While still at altitude, attempt communicating with any ground facility or even another aircraft. It is imperative to alert someone who can initiate an immediate rescue operation. Additionally, activate the emergency locator transmitter (ELT), if possible, and transmit the emergency code (7700) on the transponder, even if you believe the aircraft is too far from land to be detected. In certain areas, long-range radar extends 1,000 miles seaward.
During extended overwater operations, a pilot may recognize the eventual need to ditch even though he still can remain airborne for some lengthy period of time (such as when he knows insufficient fuel is available to make landfall). At such a time he might be able to communicate (via relay) with a Coast Guard or Air Force Rescue Coordination Center. A rescue center usually can provide nearby ship positions and recommend ditch headings based on forecast wind and sea conditions. With enough warning, a rescue center even can launch an escort aircraft to provide navigational assistance (if a pilot is lost), illuminate a ditch area at night, drop survival equipment, and provide a plethora of advice and moral support.
While time still is available (during a glide, for example), be certain to review with passengers the use of emergency exits and insist that evacuation not begin until the aircraft comes to rest. Although life jackets should be put on as soon as possible, they should not be inflated until outside the aircraft. This is because an inflated life jacket hampers an escape from tight quarters and is prone to puncture by a sharp piece or corner of the aircraft structure. In reality, your best bet is to wear a life jacket at all times when flying over water because it can be difficult to don when inside the cabin (especially for the pilot). Life jackets are not normally designed to be worn regularly, but special ones designed for this purpose are available.
Anyone who has seen a late-night rerun of The High and the Mighty probably knows the rest of the drill. Loose objects that could become missiles during a crash landing should be stowed or thrown overboard. Collars, neckties, dentures, and eyeglasses should be removed, lap belts and shoulder harnesses should be cinched tightly, and cushioning (such as jackets or pillows) should be placed so as to provide maximum protection during the landing. With respect to shoes, these should be removed if it is necessary to swim without benefit of a life jacket. However, when wearing a life jacket, they probably should be worn to provide some degree of insulation and protection (from small sea creatures with big mouths and sharp teeth).
When approximately one minute from touchdown, each rear-seat passenger should be instructed to assume the crash position: cross forearms, grab and hold onto the top of the seat immediately in front, and rest forehead on arms. (A front-seat passenger can do the same using the top of the glare shield.) Finally, the pilot should remove his headset to prevent becoming entangled in wire during evacuation.
One final preparatory item is the subject of some controversy. Many argue that the cabin door should be kept closed during ditching to keep the cabin as watertight as possible. The Coast Guard points out, however, that structural distortion of the fuselage and doorframe might occur during a water landing and jam the door permanently. Unless other exits are available, the occupants could become entombed.
Others argue, therefore, that the door should be opened when on final approach and kept ajar by jamming a shoe or other article between the door and its frame. This, of course, will sacrifice some buoyancy.
Another subject of controversy is the relative seaworthiness of high-wing versus low-wing airplanes and fixed gear versus retractable gear. Most pilots contend that the ideal airplane for ditching is a low-wing aircraft with landing gear retracted. Statistics, however, do not substantiate this. Aircraft geometry and landing gear configuration do not appear to affect survivability appreciably.
Although low-wing aircraft do offer superior planing and buoyancy (especially with empty fuel tanks), they should not be landed in water with flaps fully extended because this can cause pronounced nose-down pitching and make the aircraft behave like a submarine. Also, flaps hanging from a tow wing may be torn away during touchdown, which might create gaping holes in the wings and have a disastrous effect on buoyancy. Consequently, low-wing airplanes typically land faster, increasing the probability of damage and injury.
Since the flaps of high-wing aircraft are less susceptible to water damage, they should be used to the maximum extent possible to reduce impact speed.
Another significant disadvantage of a low-wing configuration is that it is easier to dig a wingtip into a rolling sea during initial touchdown. This can result in a lethal cartwheel. Also, the ailerons on high-wing airplanes are most effective in maintaining lateral control because they are kept "high and dry" throughout most of the landing rollout.
The Coast Guard does recommend that a ditching be made with the landing gear retracted, but this should not be construed to mean that retractable-gear aircraft are more suitable for ditching than fixed-gear aircraft. Just the opposite may be true. Of the 104 ditchings made in U.S. waters during a recent three-year period, half were made in retractable-gear aircraft, yet these accounted for two-thirds of the fatalities that occurred during splashdown. This apparent paradox, however, does not suggest extending the gear for a ditching. What the statistics probably indicate is that, since retractables generally have higher stall speeds than fixed-gear aircraft, they usually are landed somewhat faster and subjected to greater deceleration forces.
Landing with the gear down can result in violent, destructive impact forces. The wheels should be kept in their wells, particularly when ditching high-performance aircraft. When touching down with a smooth belly, however, the aircraft tends to skip just the way a flat, spinning rock can when tossed toward a deep puddle at an acute angle. This initial touchdown generally is quite mild. But hang on; the second impact is likely to be much more severe, especially as the elevator loses effectiveness (because of airspeed decay) and the nose begins to dig in. Depending on many factors, this may even cause the aircraft to submerge. But, do not fret; it should bob to the surface quickly and provide sufficient time for evacuation before sinking.
Those who have ditched slow, fixed-gear aircraft, however, report that the main gear digging in during initial impact prevents the aircraft from skipping and subsequently striking the water in a stalled, nose-low attitude. The aircraft simply decelerates rapidly with the nose burrowing only slightly. Fixed-gear proponents claim this is safer than risking the secondary, nose-low impact frequently associated with retractables.
Considering all of the arguments, experts have yet to decide the optimum aircraft for ditching except perhaps that it should have STOL characteristics, be built of wood, and be stuffed with Ping-Pong balls.
When ditching in a lake, a pilot obviously should plan to land into the wind. Should a river be his goal, the landing should be made downstream (to reduce impact speed) unless a strong wind dictates otherwise. But when landing in the ocean, much more thought must be given to the safest landing direction.
The surface of an ocean almost always is characterized by long, parallel swells. These large undulations are caused by distant storms and are not wave irregularities caused by local winds. It is important that a landing be made parallel to these swells because landing into the face of one can be like flying into the side of a mountain. Although water often is regarded as a soft substance, it can be as hard as granite when struck head on at landing speeds (as anyone who has done a belly flop from a lofty diving board can attest).
Unfortunately, it is very difficult to detect swell movement when below' 2,000 feet msl. The state of the sea must be assessed from a higher altitude and even this is not particularly easy unless the swells are pronounced. Learning to recognize swell direction, however, is one aspect of ditching that can be practiced during routine flights along a shoreline.
The Coast Guard often refers to secondary swells that also may influence the direction of landing; but since these usually are visible only to the trained eye, any further discussion of them is only of academic interest, except for one point. Occasionally, major and minor swell systems interact (even in rough seas) to form areas of relatively smooth water. This occurs where the peaks of one swell system fill the valleys of another. So, if time and altitude permit, execute a shallow', 360-degree turn to see if such an oceanic oasis can be found.
Although it is tempting to disregard swell movement and land directly into the wind, this must be avoided. Landing into the face of a well-developed swell can be catastrophic unless the wind component across the swells exceeds one-third of the touchdown speed. In this ease, the pilot probably should compromise between landing parallel to the swells and into the wind. If the crosswind component exceeds half the landing speed, it might be wiser to land into the wind as long as the touchdown can be made in a valley between swells or on the backside of a swell. To this must be added, "Good luck."
The Coast Guard recommends that high-wing aircraft be landed with full flaps and that low-wing aircraft be landed either with the flaps retracted or extended only slightly. Although the initial touchdown should be at as low an airspeed as possible, a full-stall landing is dangerous because of the possibility of striking the water nose-first. Instead, fixed-gear aircraft should touch down in a 10-to-12-degree, nose-high attitude; retractables should use a 5- to 8-degree attitude. These target attitudes are considered critical because if the aircraft lands with the nose too high, the tail may strike first and force the nose down too rapidly; if aircraft attitude is too flat, the nose may dig in prematurely.
After initial contact with the water, apply maximum up-elevator (assuming it is still attached) to keep the nose out of the water and work feverishly to keep the wings parallel to the surface; do not lower a wing to compensate for a crosswind. Otherwise a wingtip may dig in and cause total loss of control.
The aircraft most likely will come to rest in a nose-down attitude because an airplane's center of gravity usually is ahead of its center of buoyancy. Immediate evacuation is imperative even if the aircraft appears to be floating well. The typical general aviation aircraft will flood and submerge in about one minute, but don't let that worry you needlessly. Many aircraft float so long that they become a hazardous to surface vessels and have to be sunk. Also, whether an aircraft sinks or floats does not appear to effect the excellent survival rate.
If the door cannot be opened because of water pressure from outside the cabin, open a window and wait for water entering the cabin to equalize the pressure. The door should then open quite easily. If it still cannot be opened because of structural jamming, someone should crawl into the back of the cabin (where a pocket of air usually can be found). He should place his back against one side of the cabin, extend his legs and push out a window on the other side with his feet.
Although less than 15% of all ditchings involve fatalities, the U.S. Coast Guard points out that most of those who perish usually survive the procedure itself. Many of the fatalities occur after evacuation and are due to drowning because flotation equipment is unavailable. On occasion, life jackets are on board but out of reach, are damaged during evacuation, or fail to inflate.
Another major threat�especially in winter�is hypothermia, a disabling condition in which the temperature of the human body drops below normal (98.6 degrees F). Hypothermia occurs most rapidly when the body is immersed in cold water because water carries off body heat much more rapidly than does air.
When body temperature drops to 96 degrees F, shivering becomes uncontrollable; below 90 degrees F, shivering gives way to muscular rigidity and impaired mental acuity. With a body temperature of less than 80 degrees F, the average person loses consciousness and eventually experiences heart failure.
Although the ability to endure hypothermia varies among individuals and circumstances, the U.S. Navy claims that no one can survive in 32 degrees F water for more than one hour. As water temperature increases, however, the likelihood of survival increases dramatically. But hypothermia can occur eventually even when the water is relatively warm.
If possible, either swim to shore or have an inflatable raft readily available. In water temperatures of less than 35 degrees, pilots have reported such a rapid onset of hypothermia that they did not have the strength to swim to a nearby raft. Ditching is a complex subject that has had experts debating for years. A pilot, however, has only one shot at perfection, with lives hanging in the balance. Preparedness is the key to his survival.
For additional information related to this subject on Equipped To Survive™:
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Article authored by Barry Schiff
Email to: [email protected]
Published by Doug Ritter
Email: Doug Ritter
URL:
http://www.equipped.org/bschiff-ditching.htm
Revision: 02 September 3, 1999
Email to: [email protected]
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© 1983 Barry Schiff - All rights reserved. Photos © 1992 Aviation Media, Inc. - All Rights Reserved Check our Copyright Information page for additional information. |
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