Planes are unable to float on water for more than a few minutes, except for seaplanes that are specifically designed to land and float on water.

Virtually all planes would suffer damage from landing on water, as landing on water at high speed isn’t very different from landing on concrete, with the added problem that the plane would sink in the water.

Water crash landings have been proven to be only slightly safer than crash landings on the ground, though crash landings on the water are usually preferable if the water is calm and not too deep.

How Planes Are Able to Float on Water

Planes are able to float on water (though not for long) because of the pockets of air trapped in the plane’s body, in places like the cargo bay or fuel tanks, during a water landing.

The popular aircraft manufacturer Airbus that design planes that you have likely flown on before, equip some of their planes with a ditch switch to make their planes as watertight as possible, so they can stay afloat for longer.

How Long a Plane Can Float on Water

Planes usually float on water for no more than a few minutes, which may or may not be enough time for an emergency evacuation to be completed, depending on the type of emergency.

How long a plane floats on the water depends on how well-sealed it is once it crash lands in the water. 

Plane Can’t Land on Water

Planes cannot technically land on water, as airplanes require a flat, hard surface to land on.

At best, a plane may achieve a successful emergency landing on water if it descends at low speeds and the water is smooth with long swells. 

An example of this is the Miracle of Hudson.

In 2009 US Airways flight 1594 suffered a bird strike, forcing the plane to land in the Hudson River.

This event is deemed the most successful attempt at landing a plane on water. 

What Happens if an Airplane Lands on Water

An airplane will likely suffer damage from landing on water. Since water isn’t an incompressible fluid, hitting water at high speed is like hitting concrete. 

Additionally, if a plane landed in water at high speed, it could cartwheel if the plane’s wings weren’t level. The plane’s propellers are likely to break, and the tail may also break off. If landing on water breaches its fuselage, the plane will likely sink rapidly.

In short, landing on water will almost definitely damage the plane. 

The Chance of Survival is Higher for Water Crash Landings

Crash water landings are more survivable than crash landings on land. As long as the water is calm, most passengers will probably survive a crash water landing.

When crash landing into water, the biggest concern is being rescued before passengers succumb to hypothermia. 

During a land-based crash landing, the people onboard the plane are much more likely to be physically injured.

That being said, multiple variables, like the aircraft’s size and external conditions, dictate which landing would be safer in a particular scenario. 

For example, crash landing into a rough sea may be more dangerous than crash landing on a smooth nearby beach. Conversely, crash landing in a calm and shallow river is likely to be less dangerous than crash landing on a concrete road. 

Seaplanes Are Able to Float on Water

Seaplanes are unable to land on land, but can float and land on water.

There are two types of seaplanes, both of which are designed to land on water: float planes and flying boats.

Float planes have two pontoons under each wing, whereas a flying boat lands on its fuselage and has floats only designed to be used as aids.

Both type of planes also usually have retractable landing gears. 

In conclusion:

  • Most planes are unable to float on water for longer than a few minutes, which is usually only long enough to complete an emergency evacuation.
  • Planes are able to float on water for a short time because of pockets of air stored in the plane’s body, like in its cargo bay or wing, that prevent water from getting in. 
  • Most planes cannot land on water and would suffer damage from doing so.
  • Landing on water at high speed is like landing on concrete.
  • Yet, crash landings on water are mostly safer for passengers than ones on the ground, although this can vary depending on the situation.
  • Crashing landings on the water are preferable if the water is calm and not too deep.

Helen Krasner holds a PPL(A), with 15 years experience flying fixed-wing aircraft; a PPL(H), with 13 years experience flying helicopters; and a CPL(H), Helicopter Instructor Rating, with 12 years working as a helicopter instructor.

Helen is an accomplished aviation writer with 12 years of experience, having authored several books and published numerous articles while also serving as the Editor of the BWPA (British Women Pilots Association) newsletter, with her excellent work having been recognized with her nomination of the “Aviation Journalist of the Year” award.

Helen has won the “Dawn to Dusk” International Flying Competition, along with the best all-female competitors, three times with her copilot.