Here’s a picture of the airliner that ditched into the Hudson.
https://en.wikipedia.org/wiki/US_Airways_Flight_1549#/media/File:N106US_aviation_museum.jpg
I imagine the bits that ripped off would have mostly sunk, and probably been nondescript junk anyway. It’s intact enough. I can’t find any mention of large oil slicks in connection to the incident.
Concerning MH370, it is hard to believe that not one shred of the airplane has been found …
There have been aircraft crashing on land that have not been found for years. I remember a while back a bizjet crashed in the United States, and it wasn’t found for a couple of years.
The 6g deceleration makes little sense, the actual deceleration will be MUCH higher
The nose impacts the water, and is stopped instantly. The remainder of the aircaft does not really go much slower, most of the energy goes into smashing the nose cone to bits. The force required to smash the nose cone to bits is insignificant compared to the force reqired to slow down the aircraft that follows, and so it continues with the entire airframe shreded to small pieces, barely decelerating at all. Only as the mass of the aircraft above the impact point gets lighter and lighter, deceleration will increase, with parts of the tail structure mos likely to survive in larger bits.
Just look at the debris field of the Germanwings murder…
The nose impacts the water, and is stopped instantly.
It certainly isn’t!
Just look at the debris field of the Germanwings murder…
That was a mountain, not a water surface!
There have been aircraft crashing on land that have not been found for years.
In the jungle you could walk right by an aircraft crash without seeing it, and there are still large swathes of rainforest in the Pacific where nobody ever sets foot. But in the sea, anything that floats will be spread around, and very probably some debris will be washed up on a beach somewhere eventually where it will be reasonably visible. It could take a long while though, and may not give any indication as to where the aircraft actually crashed.
Instantl = colloquial instantly. Think egg crashing on tile floor. The dent made by the eggshell into the floor is negligible.
Mountain or water matters very little at these speeds.
The simulation referred to earlier appears to make allowance for that. I think their general drift is that while the front is likely to get smashed (at say 150kt), the stress on the rest of the hull will be directed along the axis of the “tube” and that is where a tube is strongest.
Cobalt wrote:
Mountain or water matters very little at these speeds.
Of course it does! There are reports of people diving from a height of 50+ metres and surviving. That would correspond to an impact speed of about 60 knots. Clearly they don’t “stop instantly” There is even competitive diving from 27 m where divers would enter the water at about 45 kt.
Certainly 60 kt is lower than than what researchers assumed for an aircraft but also aircraft are sturdier than people and nothing magical happens when the speed goes up.
I trust proper computations taking into account actual physical properties of water far more than any gut feeling.
How about 500kt? The thread title was about a vertical impact at/above cruise speed. Nothing magical happens, but the energy is about 70x the energy to dissipate at 60kt.
For comparison: Space Shuttle Challenger’s remains hit the water at around 180kt. Estimated deceleration 200G.
Not exactly a nose-on vertical impact, but tumbling crew compartment wreckage impacting at terminal velocity.
NASA report here":http://history.nasa.gov/kerwin.html
AF447 impacted the ocean with a vertical speed of around 108kt. While not smashed to little bits, it definitely broke up quite badly. Again not a clean entry, but energy-wise 20-25x less than a 500kt impact.
Sure, overall destruction levels would not be the same as hitting solid ground, but there will still be loads of bits, luggage, etc.
The entire idea of an aircraft entering water when out of control and remaining in only few pieces is a bit implausible.
