Air'crafts'

Must you raise your window shades during take-off and landing?

Yes, the seatbelt is essential and so is straightening your seat and folding back your tray table. But do you really have to raise your window shades?

Here’s what you need to know:

Take-off and landing are the trickiest stages of the flight. This is when things are most likely to go wrong, if at all. Cabin crew are required to prepare the aircraft for any contingencies. Apart from ensuring that able-bodied persons man emergency exit doors, they also ensure that passengers are buckled up, electronic devices switched off and bags safely stowed in overhead bins. And then there are those window shades.

In case of an emergency, protocol requires cabin crew to get everyone out of the aircraft in just 90 seconds. Raising the window shades and adjusting cabin lights ensures that your eyes are well-adjusted to the light outside. In an emergency, you will be able to assess the situation outside without wasting crucial seconds. Raising window shades also gives rescue personnel better visibility inside the craft. In short, this could be the difference between life and death.

Plus, it always helps to have an extra pair of eyes. During take-off and landing, passengers have better visibility of the wings and other parts of the aircraft. In case of trouble, they can spot it early and raise a flag.

So try not to be grumpy the next time you’re woken up just to raise your window shades. Someone’s probably saving your life.

On the topic of aircraft windows, do you know "Why do aircraft windows have rounded edges?"

Short answer: to keep you alive

It may not seem so, but the rounded window design is one of the crucial safety features of an aircraft, perhaps more important than your seat-belt and that life-jacket that you hope never to reach for.

Commercial passenger aircraft usually fly at altitudes over 30,000 feet, where air pressure is very low. This can cause severe health complications. To prevent this, pilots turn a knob to maintain a steady air pressure inside the cabin. However, as the aircraft climbs, the pressure inside the cabin becomes much higher than what it is outside.

While the metal fuselage can easily endure this stress, it is the windows that pose a bit of a problem. Stress tends to concentrate towards the edges, which is why surfaces with sharp corners crack easily. With rounded corners, the force is evenly distributed across the pane, making your window virtually shatter-proof.

It is a physics lesson the aviation industry learned the hard way at the start of the jet-age. The first commercial jet-liner, the de Havilland Comet, was built with square windows. In 1954, two years into service, a flight carrying 26 passengers and nine crew members crashed shortly after taking off from Rome. Two years later, another aircraft of the same make met the same fate. In both cases, it was metal fatigue around the windows that ripped the fuselage mid-air.

That was then. Today, aircraft windows are designed to handle loads way beyond what they experience. They also come in a three-layer structure: a convex external window pane shielded by a middle layer buffered by an acrylic screen, which is what you smudge your nose against. There’s also a tiny pinhole in the middle layer, which releases some of the cabin pressure on to the outermost pane. This ensures that if the pressure gets too much to handle, it is the outermost window that will crack, and the middle layer will act as a buffer, ensuring you return to ground as planned.

Courtesy: cntraveller.in