Written on 12 February 2020, 04:22pm
3 reasons to go vegetarian/vegan/flexitarian
- It’s better for your health: https://www.netflix.com/lu-en/title/81157840
- It’s better for the non-human animal welfare: https://www.lesswrong.com/posts/LbbyQhLkcwAwWmBoj/why-eat-less-meat
- It’s better for the environment: https://www.bbc.co.uk/food/articles/vegan_vs_flexitarian
Why do the helicopters crash more often?
- they are used in risky situations: search and rescue operations, military, medical evacuation, etc
- more vulnerable than planes to bad weather
- they fly at lower altitudes, so higher risk to hit obstacles and less time to recover in case things go wrong
- they take off and land more often than the planes (shorter routes)
- more moving parts, so more possibilities to fail
- can’t glide
- a bit more difficult to control than planes
Why the commercial aircraft do not have a parachute?
Well, some of the small planes do. But the commercial aircraft don’t and are unlikely to have in the future because of how physics works:
- if there would be a single parachute, the shock when it will be engaged will simply destroy the aircraft structure
- multiple parachutes make things impractical: they would have to be deployed in the same time, would increase the total weight and significantly decrease the payload
- a parachute system would require a very complex maintenance process (periodic tests, replacements, etc).
- it would also require a complex safety system to prevent accidental deployment
- a parachute system for a large airplane (like the Airbus A380 – 850 people or Boeing 747 – 500 people) will have to ditch everything except for the pressurized passenger cabin. Again, not practical, and how do you control where the rest of plane ends when the pilot engages this system?
OK, then why don’t the airlines give parachutes to the passengers?
Simply put, they are unlikely to save lives.
- first problem: at which stage of the flight do you tell the passengers to use the parachutes? Life vests are simple, everybody knows when to use them. But parachutes?
- the physics laws prevent the hatch to be opened at high altitudes. So an explosives system would be needed if you want to jump at 35000 feet (10700m)
- if you still want to jump at that altitude, you would likely enter a thermal shock (negative 60 degrees Celsius) and lose conscience in a few seconds due to the lack of oxygen. Unlikely to land alive.
- so you will have to blast the door and jump somewhere lower, maybe 15000 feet (4500m). Except – you’re not alone. A few hundreds passengers will try to do the same thing before the plane hits the ground.
- assuming that the passengers can jump in an orderly manner, and allocating 10 seconds per jump, you would still need around 40 minutes for a 250 passenger plane to be evacuated in mid-air. Only 20 minutes if you open 2 doors.
- if you manage to jump, you will hope to avoid being sucked into the engines (if you use the front doors) or sliced by the horizontal stabilizers (if you use the back doors). More importantly, you will pray to avoid fatal injuries when the parachute deploys: your plane will probably fly way past the safety jump speed limit
- BTW, did you ever strap your parachute and actually jump from a plane? And did you ever land by yourself?
- You see, the chances of coming down alive using a parachute are becoming increasingly small. Not to mention that you might land in the middle of a freezing ocean, with the parachute coming down on you.
- Also, most of the aircraft accidents happen during takeoff and landing, when the parachutes simply won’t work