Statistically, it is a challenge to prove that landing on water is less safe than landing on ground, simply because more forced landings have occurred on ground rather than water. However, common sense will tell you, that unless you are flying a seaplane, the design of your aircraft could significantly affect the success rate, and survival rate of your landing. A land plane is in essence designed to land more successfully on land, so in the interests of safety, always choose this as your primary option. In the case that you have no other option, then here are some considerations:
Location – If you know the area well, and a shallow pan is an option, then this would be a better option than a large lake or dam. Rivers can be more of a challenge especially if they have twists and turns, there is other water-born traffic, or the depth is unknown. The problem with deeper water is that there can be swells and waves which can cause a loss of control, and should your aircraft break apart, it could sink very quickly. As we are not trained to land terrestrial aircraft on water, it is a good idea to try and choose the calmest spot available to you, and one where you are more likely to get help quickly. Also take into account the survival factors if you do manage to land safely – if it is Winter, and the water is freezing then you will probably succumb to hyperthermia before being rescued. Most general aviation aircraft over land do not carry life vests, another consideration especially if you land some distance from terra firma and you, or your passengers swim like bricks or have injuries.
Aircraft design and configuration – Land aircraft are not tested with water landings, and so their performance will for the most part will be unpredictable, however, the more ‘boat-like’ or hull-shaped the fuselage, the better it might perform on water. That is, provided you are able to ensure it is water tight, by closing off all vents. Undercarriage is another important consideration, if you have retractable, then this is far more favourable for water landings. Tricycle gear would be far more tricky, as directional control will be difficult – one wheel caught at the wrong angle on the water, could have you spinning or flipping right over. When it comes to wings, one would think that a low wing would probably float better, but the likelihood of a single wing slapping a wave is pretty high, which means that you could flip over before getting to the floating stage. The key here, in maintaining control is to keep your wings as level as possible. High wings do offer better clearance over water and other nearby obstacles, and have a higher level of stability by straightening themselves out after a disruption. Which is better when it comes to floating? The difference between a high wing and low wing is probably marginal due water gaining access through vents, panels etc.
Pressurisation – If you are flying a pressurised aircraft then this will provide a slight advantage when it comes to floatation, provided that all vents can be sealed off. This is the case with Airbus which has a ‘ditching’ switch which will close off all vents in the case of a water landing. How long an aircraft will float is subject to a few variables, including how controlled the landing was, how bad the impact was and related damage to the fuselage was, and how bad the weather and water conditions (wave size and direction) are.
As you can see, landing on water with a land plane is really not recommended, and should be avoided at all costs, but if there is really no other option, then here are some tips:
- Fly as high as possible over water, so if you should need to glide, you might have enough height to reach the shore.
- Maintain control as long as possible by flying the plane, keep the wings level, and land with the nose high.
- Close off all vents if you have this option.
- Before touch down plan an escape route – open the canopy or doors slightly and wedge a shoe or other object in there, as water pressure could make these impossible to open. Make sure everyone on board knows which door is open, for example left door, left leg, so that even if you are inverted, you will know where your left leg is.
- Undercarriage up if you have retractable.
- Seatbelts – Make sure that you and your passengers know where the buckle is, so that these can be undone quickly even if you are in an unusual position.
- Life vests – If you have these on board make sure they are on-hand but NOT inflated. Empty, sealed containers (eg: cold drink bottles) with air inside, can also be useful flotation devices.
- Land into wind if possible – As is the case with land, this will result in a slower impact speed and less damage.
- Swells or Waves – You don’t want to come down in the face of a wave or large swell, so in this case go along the swell or parallel to the wave. The top or back side of a swell is also a better option than facing the rising swell.
- Control your rate of descent and airspeed – Avoid the stall, especially while flying low and slow. If you cannot judge your height above the water (where the water is smooth), then try for a low rate of descent.
The concept of a water landing is one of a no option emergency in a land plane. The idea of tempting to practice this, or any form of ‘water-skiing’ should not be tempted, even if you think you are a great pilot! Rather go and fly some seaplanes for some water fun…