The Magical 10,000 Foot Chime

After you have stowed your suitcase in the overhead bin and put your backpack under the seat in front of you, there isn’t much else to do until the door closes and you are told to turn off and stow your personal electronic devices (PED) for takeoff. Mid-flight, you get your laptop, tablet, and/or mp3 player out and do a bit of work until you are told again that all PEDs need to be powered down and stowed.

If you are a frequent flyer, you will note that there is a single chime before the purser (the lead flight attendant) announces that it is okay to power up your devices. That chime signifies that your aircraft has passed above (or below) 10,000 feet. What is magical about 10,000 feet? Because this is the loudest part of the flight, with the engines throttled up, flaps and gear hanging in the breeze and scared kids trying to drown out the noise with their screams and shouts, this is the time that you most want Metallica slamming into your eardrums but you’re not allowed to use your electronics.

Wash Hands Before Entering Cockpit

In 1981, after reviewing a series of accidents, the FAA determined that an aircraft below 10,000 feet is in a critical phase of flight and imposed the sterile cockpit rule. When the cockpit is sterile, no member of the aircrew, including flight attendants, are allowed to engage in any activity that could, “distract any flight crewmember from the performance of his or her duties or which could interfere in any way with the proper conduct of those duties.” Statistically speaking, an aircraft tends to be safest when it is cruising at altitude. Takeoffs and landings are very risky because of the number of variables involved and decisions to be made.

You may have noticed that when you are taking off and landing, there are many more aircraft in a smaller area than when you are cruising. In fact, there is a complicated set of handoffs between multiple ground and air controllers from the time that an aircraft leaves the gate until it reaches cruising altitude. Pilots need to change radio frequencies and direction in a rapid and accurate manner in a short period of time. One mistake and you could have a ground or mid-air collision.

So that explains why the crew has to have eyes forward and ears engaged, but what about us passengers? We aren’t doing anything that could impact the safety of the aircraft… are we? In fact, we could be, but not for the reasons that you might suspect. While the FCC banned the inflight use of 800 MHz cell phones because of potential interference with ground networks in 1991, there are more important reasons for not using PEDs during takeoff an landing.

Newton Was Right

The takeoff speed of the latest 747 is 160-180 miles per hour ( 257-290 km/h). What do you suppose would happen if the plane suddenly came to a halt, or twisted off of the runway? Just like the groceries in the back seat of your car come crashing into the back of the front seats, everything is thrown forward.

If the tray table in front of you was open, you would smash into it, posssibly bisecting your chest. That laptop or tablet you are holding would go flying forward, or if it was in the seat pocket in front of you, your knees might go into it, shattering the glass screen and embedding it into your flesh. And if you do need to quickly evacuate, it’s much easier if you don’t need to worry about where you’re going to stow your gear before you can get your butt out of the exit to safety.

Now Hear This!

What about wearing noise-cancelling headphones? In a sudden deceleration they also could become a projectile, hurling over the seat in front of you. Not to mention that if you have them on you wouldn’t be able to hear the brace or evacuation instructions endangering you and your fellow passengers. If your seat was reclined, it could some slamming forward, ejecting you or it could block the person behind you from getting out of their seat. And while were on the subject of flight safety, what’s with the instruction to keep our seatbelts buckled whenever we’re sitting down even if the seatbelt light isn’t illuminated?

In October 2008, Qantas flight 72 suffered an autopilot error causing the plane to drop for two seconds. In that very short period of time, almost all of the unrestrained occupants were thrown to the aircraft’s ceiling. At least 110 of the 303 passengers and nine of the 12 crew members were injured; 12 of the occupants were seriously injured and another 39 received hospital medical treatment. Even if I’m wearing my seatbelt, another passenger not wearing their seatbelt could be a threat to my personal safety if they go flying across the cabin.

So there you have it, written for adults. It’s not all about your personal electronic devices interfering with  the airplane’s electronics, rather it is all about trying to guarantee your safety by limiting loose projectiles and ensuring that the flight crew has your full attention in case something goes wrong.

Comments are always more than welcome and I hope that you’ll join the conversation.

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