The Aircraft: Interior and Safety: Airplane and Airline FAQ

Anyone who’s ever boarded an airplane knows well that these aircraft are so vast it’s nearly impossible to see from front to rear. When it comes right down to it, the dimensions are imposing. The interior of a 767 is 133 feet long, the ceiling is 9 feet, 5 inches, and there’s a total of 1981 square feet—better than an average-sized house. The in side of a 747 is even larger—3529 square feet. But to fully appreciate how enormous these widebody planes are, consider: The Wright brother’s entire first flight, from takeoff through cruise and then landing, could have been completed inside one of these giant airplanes.

THE DOORS

You board a plane usually through one of two doors, the forward or the mid-cabin entry door.

All the doors on an aircraft—the entry and galley doors, emergency exits, over-wing exits—are plug-type doors.

What this means is that the door itself is larger than the fuselage opening. These doors are primarily secured with metal bolts and latches, but what makes them impossible to open in flight is the internal cabin pressure that firmly plugs the doors in place.

On widebody aircraft, the plug doors open inward and upward into the ceiling. They have primary electric systems and a spring-loaded backup. On narrow-body aircraft, where the curve of the airplane doesn’t leave enough space for the door to be stowed in the overhead area, the doors open inward—remember, they are larger than the opening—then slightly fold and rotate outward through the opening.

THE NUMBER OF DOORS

The number of doors and emergency exits on an airplane are specifically dictated by FAA regulations. Doors, including emergency and over-wing exits, can’t be more than 60 feet apart. From any seat in the plane you would have to move no more than 30 feet to reach an exit. This calculation is based on a worst-case scenario. In the event of an emergency evacuation, for whatever reason, if half the doors were unusable or blocked, the entire load of passengers could still be evacuated within 90 seconds.

ARMED AND CROSS-CHECKED DOORS

All doors have a two-position lever, which, when turned one way or another, makes them either armed or unarmed. Often on pushback, passengers hear the flight attendants say, “Armed and cross-checked.” What they’re doing is arming the automatic escape or evacuation slides. These slides are located within the doors themselves. If a door slide is armed and the emergency handle is pulled, the door will move out of the closed position and the escape slides will deploy. This can’t happen in the air because once the plane is pressurized, moving the handle and opening the door is impossible.

SEATS

Each seat is flash and fire resistant. So are the carpets, ceilings, and any other upholstered surface on board the plane. Every seat is required to have a seat belt. If it doesn’t, or if it doesn’t work, that seat can’t be occupied. The tray tables must fully retract and lock for the seat to be usable. The seat back doesn’t necessarily have to recline, but must stay locked upright to be used.

Additionally, these seats all have what is mislabeled a breakaway feature. Not that they come off the floor or break apart. What this means is that if the plane were making an emergency landing and the passengers were in emergency landing position—head between knees and braced with arms—the seat in front of you will, on impact, give about six to eight inches. In other words, the seat back will move forward from the upright position and absorb some of the force.

It has never been proven that seats in one section of an airplane are safer than another. But there are little things to note. The plane is most stable near its center of gravity, the midsection. Aircraft are quieter if you can sit in front of the engines. Most have engines on the wings, so it’s going to be somewhat quieter in front. Aircraft could be built to be almost completely soundproof—however, acoustic studies have proven that the background noise from the engines helps dampen the sound of conversations, making multiple conversations possible without generating the noise level of an auditorium.

The first row of any section—the first row behind what’s called the bulkhead—has slightly more leg room. The same with emergency-exit rows. Window seats are good for viewing, aisle seats for getting up and walking around. For those who want to sleep on a long flight, it’s important to know that seats in the first row behind any bulkhead have tray tables in the armrests, which prevents them from being raised.

The window seat immediately in front of an over-wing exit—the row directly in front of the emergency exits— doesn’t recline. If it did, it would block the exit. No more than one infant is allowed in a single row. This is because there’s only one extra oxygen mask per row.

If you don’t select a seat for yourself, the computer will automatically do so. The computers are programmed to randomly seat passengers throughout the airplane in a way that provides maximum comfort and the most even distribution of weight.

OVERHEAD BINS

According to FAA regulations, passengers may not take on board more than two pieces of carry-on baggage, excluding purses, diaper bags, camera cases, and umbrellas. There are two reasons for this:

1. Central load control, which calculates the exact weight and balance of the plane before each flight, must make weight assumptions regarding carry-on luggage. To make these estimates as accurate as possible, the FAA imposes a two-piece limit.

2. Since all carry-on luggage must fit underneath a seat or in an overhead bin, so as not to restrict your ability to quickly evacuate in an emergency, the two-piece limit is proportional to how much cabin storage is available. Since many passengers prefer to carry on their luggage rather than check it, the new aircraft are being built with more than 2 1/2 cubic feet of overhead storage area per passenger.

ENTERTAINMENT SYSTEMS

On aircraft designed for longer flights, each individual seat has its own entertainment system. On the latest generation of airplanes, these entertainment systems are wireless. Each seat has its own receiver to pick up the audio-visual signals for the music and movie. The weight savings of the equipment and associated wires justifies the added cost of the equipment.

LIGHTS AND FANS

The reading lights above the seats are individually con trolled. If a bulb is not working, they can be changed.

Above each seat is a fan outlet. Cold air from the aircraft gasper fan can be used to adjust the temperature around your seat. Some are manually opened and closed, others operate from a push button in your armrest.

FOOD AND BEVERAGES

A major airline has approximately 2500 flights serving 150,000 passengers a day. This translates into 130,000 meals and snacks, 375,000 beverages, of which 133,000 are coffee and tea, 40,000 cocktails, 186,000 soft drinks, and 16,000 glasses of wine and champagne each and every day.

To chill these beverages takes 105,000 pounds of ice daily. According to one carrier, a fully-provisioned 747 holds 491 cups, 972 plates, 847 glasses, 176 bottles of wine, and 25 gallons of liquor.

LAVATORIES

The number of toilets is dictated by the capacity of the airplane and the assumption that one-quarter of all passengers will use the bathroom every hour. Passengers new to flying are sometimes alarmed by the noise of the toilets. Since all waste is remotely stored in one or more holding tanks, which hold 120 gallons each, a rather substantial 4½ horsepower flushing motor is required for toilet operation. By comparison, a push-type home lawnmower is about two horsepower. Since these flush motors use electrical power and are subject to wear and tear, above 16,000 feet cabin pressure differential is used instead. Using just seven ounces of water, waste is literally sucked to the holding tanks. No waste is ever dumped overboard. The waste tanks are emptied between flights.

FIRE SAFETY EQUIPMENT

Each of the airplane’s galleys is equipped with a traditional fire extinguisher, a water and anti-freeze mix pressurized with carbon dioxide housed in a green bottle. These are for paper-type fires and their use is limited.

The most adaptable fire extinguishers, stored in red fire bottles, are Halon fire extinguishers. These are pressurized liquefied gas extinguishers. The Halon extinguishers are good on all types of fires, including electrical, fuel, grease, and paper.

To prevent smoke inhalation while fighting an on-board fire, all planes are equipped with protective breathing equipment. These hoodlike devices fit over the head, pro viding fifteen minutes of oxygen and thermal protection, enabling crew members to fight a fire from closer range.

FIRST-AID KITS

Airplanes are stocked with standard first-aid kits, which are checked and, if necessary, restocked before every departure. These kits include: antiseptic swabs, burn ointments, compress bandages, scissors, regular bandages, ammonia inhalants, splints, adhesive tape, CPR masks with one-way breathing valves, as well as other items normally found in such kits. They are located throughout the cabin.

MEDICAL KITS

This is relatively new. But the FAA now requires all airplanes to have emergency medical kits on board. The medical kit is stored in the cockpit and is only to be used by a fully licensed medical doctor. It is illegal for any of the flight crew, from pilot to flight attendants, to open this kit. Inside, there’s a blood pressure cuff, stethoscope, alcohol swabs, some prescription medication, syringes, needles, nitroglycerin tablets, tourniquets, and surgical gloves.

Any medical emergency that would require use of the medical kit would, with the consultation of a doctor on board, cause the pilot to declare the flight a medical emergency. In the event of an emergency, the captain could call the flight a lifeguard flight, to automatically receive priority handling. Additionally, in a life-threatening situation, the captain would alter the flight plan to land at the nearest suitable airport that could provide appropriate medical support.

DEPRESSURIZATION

All aircraft have multiple pressurization systems: one or two automatic systems, a standby system, and a manual backup. In the statistically improbable event they all failed at once, you would experience a slow depressurization because the airplane can be made airtight. In all likelihood, the flight crew would be able to descend even before any supplemental oxygen would be needed.

The rapid depressurization is what would catch our attention. Let’s take a worst-case scenario. Say a large hole was blown in the side of the fuselage. First, all aircraft are required to be built so that if the fuselage sustained a 20-square-foot hole, the plane would still be flyable. Manufacturers routinely double that figure to 40 square feet to provide extra protection.

Second, if there was an explosive depressurization, the cabin pressure inside would equalize the cabin pressure outside almost instantly. Passengers sitting immediately adjacent to a large explosive hole and not wearing their seat belts would be lost, but milliseconds later the risk to everyone else would diminish to zero.

What would happen in such a scenario? After hearing a fairly loud noise, there would be a very rapid cooling and fogging of the air caused by the very cold outside air mixing with the warm cabin air. Your ears might pop or feel blocked from the rapid pressure change. The flight crew would begin a rapid descent to 14,000 or below while you donned your emergency oxygen mask. Two to three minutes later you would be in warmer, breathable air, and the crew would proceed to the nearest suitable airport.

EMERGENCY OXYGEN

At cruising altitudes above 14,000 feet it is an FAA requirement to carry on-board supplemental oxygen. The reason: as the plane ascends, even though the percentage of oxygen in the air remains the same, the pressure of the air decreases. At 18,000 feet the pressure of the atmosphere is half that of sea level, and it decreases further with altitude. For this reason, aircraft are pressurized to maintain a normal breathing atmosphere. At normal cruising altitudes the air inside the cabin is pressurized to a comfortable 7000 feet. What this means is, with the airplane flying at 35,000 feet you will feel like you are at 7000 feet. For comparison, Denver, Colorado, is 5300 feet, and most mountain towns in the Sierra and Rocky Mountains are much higher.

In the unlikely event of a cabin depressurization, oxygen masks would drop from the ceiling or pop out of the seat back in front of you. Masks drop automatically any time the internal cabin altitude climbs above 14,000 feet. If the automatic function does not operate properly, there is a flight-deck-controlled manual backup release. There is al ways one extra mask per row. Three seats would equal four masks just in case someone is holding a child in their lap.

Older planes utilize a gaseous oxygen system, meaning oxygen is stored in a large compressed air-type tank in the forward belly area of the plane. When your mask is pulled toward you, the flow of oxygen begins immediately. On a fully-loaded plane, there is enough oxygen to last twelve minutes.

Newer airplanes, in an effort to save weight, now use chemically generated oxygen. Located above every seat is a small oxygen generator. As the mask is pulled, a chemical reaction whose by-product is oxygen begins the oxygen flow immediately, though it can take up to twenty seconds to increase to full pressure. Again, assuming all masks are in use, there is about twelve minutes of oxygen.

Although twelve minutes of oxygen may seem like a paltry amount, in reality, an emergency descent necessitated by a cabin depressurization would only take two to three minutes, leaving ample reserve.

PORTABLE OXYGEN

There are small tanks of portable oxygen on board, designated for use by flight attendants who, in the event of an emergency, would be required to move around the cabin. These walkaround oxygen bottles double as emergency medical oxygen.

EMERGENCY EXITS

All the exits on an airplane have bright red exit lights located above them. Recently, though, the airlines and the FAA have realized that if a fire were to fill the plane with smoke, these signs might be difficult if not impossible to see. Older airplanes have been retrofitted, and newer air planes are equipped with emergency path lighting, or track lighting, on the floor. These are a series of mostly white lights situated on the aisles of the floor, extending the length of the plane. The floor lights become red at or very near the exits. If the plane filled with smoke, passengers would be instructed to get as low as possible and crawl to the emergency exits. As a rule, heads should be kept no higher than the seat armrests. Passengers would then follow the white lights on the floor until they found the red lights. Then they’d make a ninety-degree turn and go out the door or emergency over-wing exits. Knowing the closest exit before an emergency is a safe habit to develop.

EMERGENCY ESCAPE SLIDES

On the narrow-body aircraft—including the MD-80, Boeing 737 and 727—the escape slides will open and fully inflate within three seconds. On the 757 it takes four seconds. Larger airplanes, like the 767 and 747, having larger slides because they are higher off the ground, require about five seconds.

If a slide fails to inflate automatically, there is a manual backup activated by pulling a well-labeled lanyard.

The slides on new airplanes also double as rafts for emergency ditchings. The older planes used to store their rafts in the ceiling, but as rafts became larger and heavier, carrying a raft to the emergency exit became more difficult. Within these rafts are survival kits, including such items as bailing buckets, an emergency inflation pump, a signal mirror, a canopy to protect from the sun, signaling flares, first-aid kits, flashlights, a sea anchor to slow the drift of the raft, a survival manual, seasickness pills, a whistle, drinking water, and even candy snacks.

LIFE PRESERVERS

For all extended flights over water, like the Gulf of Mexico, the Great Lakes, or the oceans, there must be flotation equipment on board. Besides the rafts that have already been mentioned, every seat has its own life preserver. They are located beneath the seat. You can double-check that it’s there by feeling underneath the seat. They are checked regularly. Passenger life preservers are yellow; crew members wear orange.

They are inflated by pulling a lanyard, which triggers a compressed air cylinder. If that failed to work, there are manual inflation tubes to blow into. A tiny water-activated light that illuminates automatically is attached to the life preserver’s shoulder. The light will work for eight to ten hours.

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