Arrival

NARRATOR: YOU'RE 30,000 FEET UP IN THE SKY.

MAYBE YOU'RE GOING TO GO SEE FAMILY OR HEADING OFF ON A BUSINESS TRIP, BUT WHAT GOES UP MUST COME DOWN, AND BEFORE YOU GET WHERE YOU'RE GOING, YOU'RE GOING TO HAVE TO DO ONE CRUCIAL THING-- LAND.

ABOUT TWO.

NARRATOR: TO MOST OF US, LANDING IS JUST PART OF THE ROUTINE OF FLYING, BUT, THOUGH YOU MIGHT TAKE IT FOR GRANTED, GETTING YOU SAFELY BACK ON THE GROUND IS A COMPLEX AND DANGEROUS BUSINESS.

IT TAKES PILOTS WHO ARE READY FOR ANYTHING... VOICE: TERRAIN AHEAD.

PULL UP.

AVOID TERRAIN.

NARRATOR: AN ARMY OF SPECIALISTS MAKING SURE YOUR ROUTE IS CLEAR AND SAFE...

HUNDREDS OF LIVES THAT ARE AT STAKE.

NARRATOR: ENGINEERS WATCHING OVER YOUR PLANE FROM THE OTHER SIDE OF THE GLOBE, AND FIREFIGHTERS TRAINED FOR THE WORST EMERGENCIES... MAN: OK, SO WE GOT ONE VICTIM ON THE GROUND.

NARRATOR: ALL OF THIS HAPPENING BEFORE YOUR PLANE'S WHEELS EVEN TOUCH THE RUNWAY.

THIS IS THE CITY IN THE SKY, A CITY WHOSE POPULATION CONSISTS OF THE ONE MILLION PEOPLE AIRBORNE AT ANY TIME AND WHO ARE UP THERE RIGHT NOW... A FLYING CITY THAT STRADDLES NOT JUST COUNTRIES, BUT CONTINENTS.

IT'S BUILT OUT OF THE 100,000 FLIGHTS THAT CRISSCROSS THE PLANET EVERY SINGLE DAY.

THIS CITY IS AN INCREDIBLE FEAT OF ENGINEERING, DEPENDENT UPON ADVANCE TECHNOLOGY IN GLOBAL NETWORKS, A HIDDEN WORLD RARELY GLIMPSED BY OUTSIDERS UNTIL NOW.

NARRATOR: WHAT GOES UP MUST COME DOWN.

THIS IS GEORGIA'S ATLANTA HARTSFIELD JACKSON INTERNATIONAL AIRPORT, THE BUSIEST AIRPORT IN NORTH AMERICA, BY MOST MEASURES, THE BUSIEST AIRPORT IN THE WORLD.

ANY REGULAR FLYER IN THE U.S. WILL PROBABLY CONNECT THROUGH THIS PLACE.

THIS AIRPORT CAN HANDLE 130 LANDINGS AN HOUR.

THAT'S, ON AVERAGE, MORE THAN TWO EVERY MINUTE.

EACH ONE LOOKS EFFORTLESS, BUT AS YOU BRING YOUR SEAT TO ITS UPRIGHT POSITION AND PREPARE FOR LANDING, THERE'S A HIDDEN SEQUENCE OF EVENTS THAT HAS TO GO EXACTLY TO PLAN.

FROM THE VAST EMPTINESS OF THE SKY, YOUR PLANE HAS TO LINE UP PERFECTLY WITH A STRIP OF RUNWAY JUST 150 FEET WIDE... AND YOUR PILOT MUST BRING 100 TONS OF AIRCRAFT MOVING AT 150 MILES AN HOUR DROPPING AT 10 FEET A SECOND GENTLY TO THE GROUND.

WHEN THE WHEELS HIT, THE BRAKING FORCE WILL CREATE TEMPERATURES OF 700 DEGREES, AND THE ENGINES WILL THROW A QUARTER OF THEIR THRUST IN REVERSE TO SLOW YOUR PLANE DOWN TO A SAFE SPEED.

THE ENORMOUS ENERGY OF A PLANE IN FLIGHT IS DISSIPATED WITH EXQUISITE PRECISION, AND IT'S ALL GOT TO HAPPEN IN A WINDOW OF JUST A FEW SECONDS BECAUSE IN AIRPORTS LIKE ATLANTA, THERE ARE LIKELY TO BE ANOTHER 10 PLANES STACKED UP READY TO COME IN RIGHT BEHIND YOU.

IMAGINE THAT HAPPENING 100,000 TIMES PER DAY AROUND THE GLOBE IN SUN, RAIN, SNOW, AND FOG.

THIS IS THE STORY OF HOW YOU AND YOUR PLANE GETS SAFELY FROM 30,000 FEET IN THE AIR BACK TO THE GROUND... AND IT BEGINS WELL BEFORE YOUR FINAL APPROACH WITH YOUR PILOT.

MAN: STANDARD SET.

PASSING FLIGHT LEVEL... NARRATOR: IT CAN TAKE UP TO 10 YEARS OF TRAINING TO BECOME QUALIFIED TO LAND THE LARGEST JETS.

MAN: STANDARD--5-2, FLIGHT LEVEL--NINER-ZERO.

NARRATOR: HERE AT THESE CONTROLS, THE NEXT GENERATION ARE EARNING THEIR STRIPES.

SPEED IS GOOD AT THE MOMENT, BUT IT'S GOING TO VARY A LITTLE BIT WITH THESE GUSTY WINDS.

CORRECTING NICELY.

KEEP THE AIRCRAFT COMING DOWN.

NARRATOR: TODAY IT'S JUST A FLIGHT SIMULATOR NEAR LONDON, ENGLAND, BUT TOMORROW THESE PILOTS WILL BE BACK IN A REAL PLANE, RESPONSIBLE FOR HUNDREDS OF PASSENGERS' LIVES.

NICK COATES IS AN INSTRUCTOR AND EXAMINER WHO'S TRAINED OVER 700 PILOTS.

COATES, VOICE-OVER: THIS COCKPIT IS, UM, ALMOST EXACTLY THE SAME AS AN AIRPLANE COCKPIT, SO WE CAN DO ALL KINDS OF THINGS WITH THIS SIMULATOR FROM BASIC, UH, FLIGHT TRAINING UP TO, UH, FULL EMERGENCIES OR SCENARIOS PICKED BY THE INSTRUCTOR.

SO YOU NEED TO EASE IT ACROSS TO THE LEFT, LEFT A BIT, LEFT A BIT.

JUST LOOK INSIDE OCCASIONALLY.

CHECK YOUR SPEED, WHICH IS NOT TOO BAD, AND YOUR RATE OF DESCENT, AS WELL.

WE'RE LOOKING FOR ABOUT 750 FEET A MINUTE ON FINAL, SO YOU JUST NEED TO EASE THAT NOSE DOWN A BIT MORE.

THIS IS WHERE IT'S POSSIBLE THAT YOU'LL START TO SHY AWAY FROM THE LANDING AND MAYBE YOU'LL REDUCE YOUR RATE OF DESCENT AND JUST, UH, PULL THE NOSE UP A BIT, SO TRY AND KEEP THE AIRCRAFT COMING DOWN.

THAT'S GOOD.

NARRATOR: LANDING'S ONE OF THE MOST CHALLENGING PHASES OF ANY FLIGHT.

NICK CAN MAKE IT EVEN TRICKIER BY CHANGING ANY ASPECT OF THE WEATHER.

FOR THE NEXT TOUCHDOWN ATTEMPT, HE'S THROWING IN SOME CROSSWINDS... COATES: THAT'S IT.

YOU'RE CORRECTING NICELY.

KEEP THE AIRCRAFT COMING DOWN, BIT HIGH NOW.

NARRATOR: BUT TO LAND SAFELY, EVEN THE BEST-TRAINED PILOTS NEED AN AIRCRAFT THAT IS TOTALLY RELIABLE.

THROUGHOUT YOUR FLIGHT, THERE'S ONE PART OF YOUR PLANE THAT'S BEEN WORKING CONSTANTLY, AND MUST KEEP WORKING AND WORKING PERFECTLY UNTIL YOUR WHEELS ARE SAFELY ON THE GROUND-- THE ENGINE.

IT'S ONE PART OF THE PLANE WE HOPE WILL NEVER FAIL.

PILOTS KNOW THEY CAN RELY ON THEIR ENGINES BECAUSE THERE'S SOMEONE WATCHING OVER THEM.

NEW NETWORKS ARE NOW REACHING OUT ACROSS THE CITY IN THE SKY, TRACKING AND MONITORING THE HEALTH OF YOUR ENGINE.

HERE ON THE EDGE OF THE ENGLISH COUNTRYSIDE IS ONE OF SEVERAL GLOBAL CENTERS THAT KEEP A WATCHFUL EYE OVER AIRCRAFT ENGINES IN FLIGHT.

IT'S THE JOB OF THE PEOPLE IN THIS ROOM TO MAKE SURE THEY FUNCTION PERFECTLY UNTIL YOU'RE SAFELY ON THE GROUND WHEREVER YOU ARE IN THE WORLD.

SO WE'RE HERE IN THE OPERATIONAL SERVICE DESK.

THIS IS WHERE WE PROVIDE 24/7 SUPPORT TO OUR CIVIL LARGE-ENGINE FLEET.

THAT FLEET, AS IT'S FLYING RIGHT NOW, YOU CAN SEE IN FRONT OF YOU HERE, SO LITERALLY HUNDREDS AND HUNDREDS OF AIRCRAFT QUIETLY MAKING THEIR WAY TO THEIR DESTINATION UM, ARE REPRESENTED IN FRONT OF THIS MAP, AND THIS IS REALLY ACTUALLY PHYSICALLY WHERE THEY ARE RIGHT NOW AT THIS MOMENT.

NARRATOR: MODERN AIRCRAFT ENGINES ARE NOT ONLY A MARVEL OF ENGINEERING.

THEY'RE A MARVEL OF COMMUNICATION.

OF THE TENS OF THOUSANDS OF ENGINES CARRYING US TO OUR DESTINATIONS EVERY DAY, MANY SEND DATA VIA WIRELESS LINK TO FACILITIES ON THE GROUND THAT KEEP TRACK OF THEIR EVERY FUNCTION.

TINY SENSORS INSIDE EACH ONE MONITOR ITS VITAL SIGNS, FROM OPERATING TEMPERATURES TO FUEL PRESSURE, FLUID LEVELS, AND SPEED FLUCTUATIONS.

THE SMALLEST TREMOR, ANYTHING OUT OF THE ORDINARY, GETS QUICKLY FLAGGED.

IT'S LIKE A HEART MONITOR FOR THE GLOBAL ENGINE FLEET.

HERE IN DERBY, NICK WARD INTERPRETS THE DATA ROLLS-ROYCE ENGINES SEND FROM 30,000 FEET UP.

WARD: THIS ENGINE FLIES SOMETHING LIKE 10 MILLION MILES BETWEEN SERVICES.

CAN YOU IMAGINE THAT WITH YOUR FAMILY CAR?

ANY DUST OR SAND OR ICE PARTICLES, ANYTHING LIKE THAT THAT GETS INGESTED THROUGH THE ENGINE CAN START, OVER TIME, TO EFFECT PERFORMANCE OF THE ENGINE.

IT MIGHT START BURNING A LITTLE BIT MORE FUEL, SO THE DATA IS BEING RECORDED ON THE ENGINE ALL THE TIME ALL THE WAY THROUGH THE FLIGHT, AND WE CAN GET THAT DATA DOWNLOADED OFF THE AIRCRAFT.

IT GOES INTO OUR DATA CENTER.

WE'RE COLLECTING TERABYTES OF DATA EVERY YEAR TO THEN FIND THAT ONE LITTLE DATA POINT, THAT ONE ENGINE THAT MAYBE IS JUST STARTING TO CATCH A COLD.

IF WE SEE THAT, WE CAN GET ON TOP OF IT VERY, VERY QUICKLY.

WE CAN START TO REACT AND POSITION PEOPLE, PARTS, WHATEVER IT IS THAT NEEDS TO HAPPEN.

AS A TRAVELING MEMBER OF THE PUBLIC, YOU WOULDN'T EVEN BE AWARE ANY OF THIS IS HAPPENING.

IT'S ALL BEHIND THE SCENES.

NARRATOR: WITH A LARGE PASSENGER JET POWERED BY ROLLS-ROYCE ENGINES TAKING OFF OR LANDING EVERY 16 SECONDS, THE TEAM HAS TO BE READY FOR AN ALERT AT ANY TIME, AND, DESPITE ALL THE HIGH-TECH MONITORING, THIS TIME, THE CAUSE IS SOMETHING RATHER LOW-TECH.

BURNS: THIS AIRCRAFT'S BEEN, UM, ON THE GROUND.

UH, AIRPORTS ARE BUSY PLACES WHEN AIRCRAFT ARE ON THE GROUND, UH, UNFORTUNATELY GOT HIT BY A BAGGAGE CART, AND THE BAGGAGE CART'S HIT THE SIDE OF ONE OF OUR ENGINES, UM, AND CAUSED QUITE A BIT OF DAMAGE, SO WE'RE GOING TO HAVE TO CHANGE SOME OF THE COMPONENTS.

NARRATOR: THEY CAN DETECT POTENTIAL PROBLEMS IN FLIGHT, BUT THE ENGINEERS STILL NEED TO GET THEIR HANDS ON THE ENGINE IF ANYTHING NEEDS TO BE FIXED, AND ENGINES LANDING IN DIFFERENT PARTS OF THE WORLD TEND TO DEVELOP THEIR OWN CHARACTERISTIC PROBLEMS.

MAN: ENGINES THAT DO SHORT HOPPING BETWEEN ISLANDS, PLACE LIKE NEW ZEALAND OR JAPAN, WE EXPECT TO SEE THOSE ENGINES MORE OFTEN BECAUSE THEY'VE BEEN THROUGH MORE CYCLES, BUT, OF COURSE, IF THEY'RE AROUND SEAS, THEN THAT-- THEN THE CORROSION THAT YOU GET OFF THOSE SEAS ALSO AFFECTS IT.

ENGINES THAT ARE FLYING OUT OF DESERT ENVIRONMENTS, WE ALSO GET A--A LOT OF-- A LOT OF INFLUENCE BECAUSE OF THE DESERT ENVIRONMENTS BECAUSE OF THE TEMPERATURES.

A LOT OF THIS IS COVERED BY THE ENGINE HEALTH MONITORING SYSTEM, WHICH REALIZES WHAT KIND OF AN ENVIRONMENT IT'S IN IN TERMS OF HUMIDITY AND TEMPERATURE.

NARRATOR: WITH OVER 35,000 PARTS TO AN ENGINE OF THIS COMPLEXITY, TAKING IT APART TO FIX EVERY TINY PROBLEM WOULD KEEP THE ENGINE OUT OF ACTION FOR TOO LONG, ESPECIALLY WHEN THE PROBLEM LIES IN THE CORE, THE VERY DEEPEST AND MOST INACCESSIBLE PART OF THE ENGINE'S HEART, SO THE ENGINEERS HAVE A SOLUTION-- KEYHOLE SURGERY.

AJ SINGH IS A SPECIALIST AT REPAIRING TINY DEFECTS ON THE COMPRESSOR BLADES.

SO WE'RE LOOKING AT THE DAMAGE THAT'S BEEN REPORTED BY THE AIRLINE CUSTOMER.

WE'LL GO IN.

WE'LL DELICATELY REMOVE THE DEFECT.

NARRATOR: USING A MINUTE PRECISION METAL GRINDER, HE SMOOTHES OUT EACH DEFECT.

SINGH: THIS PROCESS CAN TAKE ANYTHING UP TO 3 OR 4 HOURS PER BLADE DEPENDING ON HOW-- HOW DEEP THE DEFECT IS IN THE LEADING EDGE OF THE BLADE OR THE TRAILING EDGE OF THE BLADE.

IT'S VERY IMPORTANT THAT WE GET THE RIGHT PROFILE TO ENSURE THE SAFETY OF THE BLADE.

NARRATOR: CATCHING TINY IMPERFECTIONS EARLY IS CRUCIAL.

ON AN ENGINE TURNING AT 10,000 REVOLUTIONS A MINUTE, EVEN A SMALL BLEMISH COULD EVENTUALLY DEVELOP INTO A CRACK, AND WITH PASSENGERS' LIVES AT STAKE, NOTHING CAN BE LEFT TO CHANCE.

THE ENGINES FIXED HERE ARE METICULOUSLY TESTED AFTER EVERY REPAIR, AND ONLY IF THEY PASS WILL THEY RETURN TO THE SKIES.

THANKS TO EXTRAORDINARY TECHNOLOGY AND ATTENTION TO DETAIL, MODERN ENGINES SHUT DOWN, ON AVERAGE, JUST ONCE EVERY 500,000 FLIGHT HOURS.

BACK IN THE SKIES ABOVE ATLANTA AIRPORT, THE BUSIEST AIRPORT IN THE WORLD, YOUR FLIGHT IS NOW 20 MILES OUT, AND THERE'S ONLY A FEW MINUTES UNTIL TOUCHDOWN, BUT THE 100 MILLION PASSENGERS THAT LAND HERE EVERY YEAR CAN ONLY DO SO SAFELY THANKS TO THE GROUND OPERATIONS TEAM.

TWICE A DAY, NO MATTER WHAT THE CONDITIONS, THEY TAKE ON AN ABSOLUTELY VITAL TASK.

OP 6 WOULD LIKE TO INSPECT THE FULL LENGTH OF RUNWAY ONE-ZERO, UH, AND I'LL REMAIN OFF ALL RUNWAYS, GIVE WAY TO ALL AIRCRAFT AND ALL CRITICAL AREAS.

[RADIO CHATTER] MAN: SO RIGHT NOW, WE'RE DOING THE RUNWAY INSPECTION.

WE'RE LOOKING AT ANY TYPE OF DEBRIS, UH, METAL, ANY TYPES OF BOLTS, SCREWS, EVEN PLASTIC.

NARRATOR: JOHN RYAN IS RESPONSIBLE FOR FOREIGN OBJECT DEBRIS COLLECTION.

HE HAS TO SCOUR EVERY INCH OF ATLANTA'S RUNWAYS.

THE RUNWAY SAFETY INSPECTION INVOLVES LOOKING FOR ANY FRAGMENTS THAT MIGHT HAVE FALLEN FROM AN AIRCRAFT OR AIRPORT VEHICLE.

RYAN: WE'RE GOING DOWN THE RUNWAY AT 30 MILES AN HOUR LOOKING DOWN, LOOKING FOR ANY TYPE OF DEBRIS OUT THERE.

YOU'VE GOT TO HAVE REALLY GREAT VISION.

YOU GOT TO BE ABLE TO ENSURE THAT YOU'RE ABLE TO PICK UP ANY SMALL PARTS OR PIECES THAT COULD BE AS SMALL AS A BOLT OR BIG AS A FLASHLIGHT.

THIS IS JUST A SIMPLE BOLT THAT MAY HAVE COME OFF OF A BAGGAGE TUG, AND THEN WE HAVE FOUND UH, MECHANIC'S TOOLS, WHETHER IT BE A WRENCH LIKE THIS THAT HAD BEEN LEFT ON THE AIRPLANE, UM, AND ON TAKEOFF ROLL, IT MAY FALL OFF.

NARRATOR: PICKING UP JUNK MIGHT SOUND LIKE A DULL JOB UNTIL YOU REALIZE JOHN'S UNDER HOT PURSUIT FROM A 72-TON PASSENGER PLANE.

HE'S GOT JUST A 45-SECOND WINDOW BETWEEN LANDINGS TO CHECK AN ENTIRE RUNWAY.

RYAN: WE COME OUT AT LEAST ONCE A DAY, UH, FOR THE DAILY AIRFIELD INSPECTION, WHICH IS DAYTIME, AND WE ALSO DO A NIGHT INSPECTION, ALSO, UH, BUT WE DO SPECIAL INSPECTIONS DEPENDING ON IF WE DID CONSTRUCTION THAT DAY OR IF WE HAD A TAXIWAY CLOSURE OR EVEN SIGNIFICANT WEATHER.

WE GOT A LITTLE BIT OF DEBRIS RIGHT HERE.

WE GOT A ROCK OR A PEBBLE THAT WE'LL BE--WE'LL BE PICKING UP.

IT'S JUST A LITTLE PIECE OF RUBBER FROM A TIRE.

NARRATOR: THERE'S A CRUCIAL REASON FOR THIS HIGH-SPEED RUSH DOWN THE RUNWAY.

EVEN THE SMALLEST PIECE OF DEBRIS LEFT ON THE GROUND HAS THE POTENTIAL TO WREAK HAVOC.

IT COULD PUNCTURE A TIRE OR BE THROWN UP LIKE A PROJECTILE, DAMAGING AN AIRCRAFT OR PUNCTURING ITS FUEL TANKS.

SUCKED INTO AN ENGINE, A FRAGMENT COULD HIT BLADES SPINNING AT 150 REVOLUTIONS A SECOND, CAUSING SERIOUS DAMAGE.

RYAN: IT COULD HAVE A CATASTROPHIC EFFECT.

IT'S NOT JUST THAT AIRPLANE OR PIECE OF METAL.

IT'S HUNDREDS OF LIVES THAT ARE AT STAKE, SO WE--YOU KNOW, WE ARE AT, YOU KNOW THE HIGHEST LEVEL OF PERCEPTION, UH, FOR ANY TYPE OF DEBRIS OUT THERE.

NARRATOR: IT'S AN IMMENSE RESPONSIBILITY FOR JOHN AND HIS TEAM, KNOWING THAT IF THEY MISS ONE TINY BOLT, A PLANE AND ALL ITS PASSENGERS COULD BE IN MORTAL DANGER.

ALL OF THIS GOES UNNOTICED BY THE VAST MAJORITY OF TRAVELERS, BUT IT'S CRUCIAL TO THE ROUTINE OF LANDING OVER 1,000 PLANES EVERY DAY, BUT DESPITE EVERY PRECAUTION, NOT ALL FLIGHTS GO EXACTLY TO PLAN.

SOMETIMES EVEN THE BEST PILOTS AND PLANES RUN INTO A PROBLEM, AND WHEN THERE'S A SERIOUS EMERGENCY IN THE AIR, YOUR PILOT MAY NEED TO FIND SOMEWHERE TO PUT DOWN IN A HURRY... AND IF THAT HAPPENS, THIS IS ONE OF THE PLACES YOU MIGHT END UP-- BANGOR, MAINE, ON THE NORTHEASTERN SEABOARD.

ITS POPULATION IS JUST 33,000, YET THIS CITY HAS AN UNUSUAL CLAIM TO FAME-- A SPRAWLING, FULL-SIZE, INTERNATIONAL AIRPORT WITH A TWO-MILE-LONG RUNWAY THAT CAN ACCOMMODATE THE BIGGEST INTERCONTINENTAL JETLINERS.

IT'S CAPABLE OF PROCESSING THOUSANDS OF PASSENGERS, BUT FOR MOST OF THE TIME, THIS HUGE AIRPORT HANDLES JUST 20 DOMESTIC FLIGHTS A DAY.

IT MIGHT LOOK LIKE A GHOST AIRPORT, BUT THAT'S NO BAD THING.

BANGOR SPECIALIZES IN DEALING WITH EMERGENCY LANDINGS.

INTERNATIONAL FLIGHTS ONLY TOUCH DOWN HERE WHEN THEY NEED TO GET OUT OF THE SKY FAST.

OVER THE LAST DECADE, AROUND 2,000 PLANES HAVE MADE UNSCHEDULED STOPS HERE, AND THERE'S A SIMPLE REASON WHY.

BANGOR IS THE FIRST PIECE OF AMERICAN SOIL MANY TRANSATLANTIC FLIGHTS REACH AFTER CROSSING 2,500 MILES OF OPEN OCEAN.

IF ANYTHING GOES WRONG WITH YOUR FLIGHT DURING THAT TIME, BANGOR'S YOUR BEST BET, SO THE TEAM HERE NEED TO BE ON STANDBY 24/7... READY FOR ANY KIND OF EMERGENCY.

NARRATOR: THIS IS THE REGULAR TRAINING DRILL OF THE EMERGENCY FIRE CREW.

PLANES MAKING EMERGENCY LANDINGS AT BANGOR CAN BE LADEN WITH UP TO 26,000 GALLONS OF JET FUEL, HIGHLY FLAMMABLE JET FUEL.

TODAY THE EMERGENCY TEAM ARE SIMULATING A FUEL FIRE WITH CASUALTIES ONBOARD.

IT'S AN EXERCISE DESIGNED TO TEST THEIR RESPONSE TIMES.

MAN: THE BIGGEST DIFFERENCE BETWEEN AIRCRAFT FIRES AND HOME FIRES IS PRIMARILY THE FUEL LOAD.

UH, AIRCRAFT FUEL USUALLY BURNS HOTTER THAN HOUSES DO, UH, UPWARDS OF 2,000 DEGREES, AND THEY'VE GOT 3 MINUTES TO GET FROM OUR FIREHOUSE TO ANYWHERE ON THE AIRFIELD.

THE FIRST TRUCK HAS TO BE THERE IN 3 MINUTES, AND THE LAST ONE HAS TO BE THERE IN 5.

ONCE ON SCENE, UH, WE KNOCK DOWN THE FIRE ENOUGH TO BE ABLE TO EITHER MAKE ENTRY INTO THE AIRCRAFT OR WE DEPLOY HAND LINES TO-- TO GO INTO THE AIRCRAFT TO, UH, SECURE THE AIRPLANE SO THAT FOLKS CAN GET OFF BOARD, GET OFF THE AIRCRAFT.

WE TRY AND MAKE IT AS REALISTIC AS POSSIBLE SO THAT IF SOMETHING HAPPENS REAL WORLD, THEN OUR FOLKS ARE PREPARED TO MAKE ENTRY.

THEY KNOW HOW THE AIRPLANE WORKS.

THEY KNOW HOW FIRE ACTS, UH, WHEN WE PUSH WATER THROUGH IT, SO TRY AND MAKE IT AS REALISTIC AS POSSIBLE.

NARRATOR: THERE ARE MANY REASONS FOR EMERGENCY LANDINGS, BUT THERE'S ONE WEATHER CONDITION THAT TENDS TO TRIGGER A HIGH PROPORTION OF THEM-- STRONG HEADWINDS ACROSS THE ATLANTIC.

THESE CAN CAUSE U.S.-BOUND PLANES TO RUN DANGEROUSLY SHORT OF FUEL AS THEY APPROACH THE EAST COAST.

MAN: IF THEY'RE FACING HEADWINDS, UM, COULD BE AN ISSUE WHERE THEY--THEY BURN MORE FUEL THAN THEY--THEY THOUGHT, THOUGH FOR SAFETY REASONS, THEY MAY NOT BE ABLE TO GET INTO ANOTHER AIRPORT RIGHT AWAY.

NARRATOR: FOR A PILOT RUNNING OUT OF FUEL OVER THE ATLANTIC, THIS AIRPORT'S A MOST WELCOME SIGHT.

BANGOR MAY BE THE GO-TO AIRPORT FOR AN EMERGENCY, BUT SOMETIMES MAKING IT TO ANY AIRPORT ISN'T AN OPTION, AND THE BEST PILOTS NEED TO BE PREPARED TO GET THE PLANE DOWN SAFELY, NO MATTER WHERE THEY ARE.

IN ONE OF THE MOST INFAMOUS INCIDENTS OF RECENT YEARS, AN ORDINARY, EVERYDAY FLIGHT SUDDENLY WENT DRAMATICALLY WRONG.

IT SERVED AS A STARK REMINDER OF THE IMPORTANCE OF THE PROFESSIONALS IN THE COCKPIT.

ON JANUARY 15, 2009, 3 MINUTES AFTER U.S. AIRWAYS FLIGHT 1549 TOOK OFF FROM NEW YORK CITY, MULTIPLE BIRD STRIKES CAUSED BOTH OF THE PLANE'S ENGINES TO FAIL.

THERE WAS NO TIME TO MAKE IT BACK TO THE AIRPORT, SO THE PILOT HAD TO LAND WHEREVER HE COULD.

HIS ONLY OPTION TURNED OUT TO BE THE HUDSON RIVER.

THANKS TO THE SKILL AND EXPERIENCE OF CAPTAIN CHESLEY SULLENBERGER AND CREW, EVERY PASSENGER GOT OUT ALIVE.

IT WAS A GRAPHIC ILLUSTRATION OF HOW AN EVERYDAY FLIGHT CAN STILL ENCOUNTER THE UNEXPECTED AT A SECOND'S NOTICE, AND IN THE YEARS SINCE, THE HUDSON RIVER INCIDENT'S HAD A HUGE IMPACT ON PILOT TRAINING.

TODAY BACK AT THE FLIGHT SIMULATOR FACILITY NEAR LONDON, TWO PILOTS ARE PRACTICING FOR A SIMILAR SCENARIO.

WELL, THE TAKEOFF CHECK'S COMPLETE.

RELEASE CABIN CREW.

NARRATOR: CAPTAIN OLIVER WALKER AND SENIOR FIRST OFFICER COLM PURCELL HAVE BOTH BEEN FLYING FOR 8 YEARS... WALKER: SO CABIN CREW AWARE, AIR TRAFFIC CONTROL AWARE... NARRATOR: BUT THEY'RE STILL REQUIRED TO SPEND TIME IN THE SIMULATOR.

IN THIS EMERGENCY EXERCISE, THE PLANE'S ENGINES ARE ABOUT TO FAIL DUE TO A BIRD STRIKE.

STANDARD SET, PASSING FLIGHT LEVEL 4-5.

NARRATOR: NO MATTER HOW EXPERIENCED THE PILOT, THIS IS A TOUGH TEST.

ALL RIGHT.

IT'S ON THE LEFT-HAND SIDE.

[ALARM] STRIKE HERE ON ENGINE NUMBER TWO.

MEMORY ITEMS FOR LOSS OF THRUST ON BOTH ENGINES, AND I'M HEADING BACK TOWARDS DUBLIN.

MAYDAY, MAYDAY, MAYDAY.

RYANAIR TWO-ZERO-TWO, DUAL ENGINE FAILURE.

ATTEMPTING TO RETURN TO RUNWAY 2-8 IN DUBLIN.

NARRATOR: FOR THE EXERCISE, THE PILOTS ARE TASKED WITH BRINGING THEIR PLANE BACK TO LAND SAFELY AT IRELAND'S DUBLIN AIRPORT.

IT'S A BIT TIGHT, 4,000 FEET IN 10 MILES, BUT I THINK WE CAN JUST ABOUT MAKE IT.

NARRATOR: NICK COATES IS ONCE AGAIN OVERSEEING THE TRAINING EXERCISE.

COATES: THIS IS ABSOLUTELY THE WORST-CASE SCENARIO.

THAT IS A 737 GLIDER, AND THEY'VE GOT ONE SHOT TO GET THAT ON THE GROUND.

GOT TO GET THE-- [ALARM] GEAR DOWN?

GEAR DOWN.

I'LL MAKE THE BRACE CALL.

MAKE THE BRACE CALL.

THANK YOU.

BRACE, BRACE.

VOICE: PULL UP.

PULL UP.

PULL UP.

PULL UP.

STAY BRAKE IS UP.

STAY BRAKE IS UP.

MAXIMUM MANUAL BRAKING.

THRUST REVERSERS GONE.

AUTO BRAKE DISARM.

100 KNOTS.

COATES: THEY'VE DONE WELL.

THEY'VE GOT IT DOWN, UH, ON THE GROUND.

60 KNOTS.

COATES: THIS TYPE OF TRAINING IS--IS REALLY IMPORTANT FOR PILOTS BECAUSE YOU NEVER KNOW WHEN YOU'RE GONNA EXPERIENCE SOMETHING LIKE THIS, AND WE'VE SEEN EXAMPLES OF THESE SORTS OF INCIDENTS HAPPENING OVER THE LAST FEW YEARS, JUST CROPPING UP EVERY NOW AND AGAIN, VERY RARE, BUT THEY DO HAPPEN, SO THE TRAINING FOR THIS GIVES OUR PILOTS A BIT OF PRACTICE BEFORE IT HAPPENS.

PURCELL: I SUPPOSE THE REALISM STARTS WITH THE VISUALS.

IT'S LIKE IF YOU'RE FLYING INTO THE ACTUAL AIRPORT.

INSIDE, IT'S BASED ON THE EXACT AIRCRAFT.

THE SYSTEMS WORK IN A VERY REALISTIC WAY, SO IF WE WERE HOPEFULLY APPLYING THOSE TECHNIQUES TO A REAL WORLD EVENT, THEREFORE ENSURING A SAFE OUTCOME.

GIVES OUR PILOTS REALLY GOOD CONFIDENCE.

FINGERS CROSSED, WE'LL GET IT RIGHT WHEN IT HAPPENS.

NARRATOR: THANKS PARTLY TO TRAINING LIKE THIS, YOUR CHANCES OF BEING IN AN AIRPLANE ACCIDENT ARE TODAY AT AN ALL-TIME LOW.

EVEN AS THE NUMBER OF FLIGHTS WE TAKE HAS SOARED.

BY SOME MEASURES, AVIATION IS NOW UP TO 50 TIMES SAFER THAN DRIVING, BUT ACHIEVING THIS HAS TAKEN MORE THAN PILOT TRAINING ALONE.

YOU'RE NOW 5 MILES OUT FROM ATLANTA AIRPORT ON FINAL APPROACH.

GUIDING YOUR PLANE DOWN NOW BECOMES THE TASK OF AIR TRAFFIC CONTROLLERS IN THE TOWER... AND TODAY THEY'VE GOT THEIR WORK CUT OUT.

IT'S THE WEEK OF THANKSGIVING, WITH OVER 1,000 AIRCRAFT A DAY LANDING AT ATLANTA.

THAT'S, ON AVERAGE, MORE THAN ONE PLANE EVERY MINUTE.

BRIAN KELLMAN'S ONE OF THE CONTROLLERS RESPONSIBLE FOR GUIDING THEM IN.

KELLMAN: WE HAVE TO KEEP THIS VERY EFFICIENT BECAUSE SOON AS WE SLOW DOWN, IT COULD, UM, SLOW UP THE WHOLE, UH, NATIONAL AIRSPACE SYSTEM.

WE TRY OUR BEST TO JUST KEEP IT ROLLING.

NARRATOR: ATLANTA'S EFFICIENCY AT LANDING PLANES IS DUE TO A NUMBER OF FEATURES THAT MANY PASSENGER MIGHT NOT EVEN NOTICE.

THE FIRST OF THESE IS THE LAYOUT OF THE RUNWAYS.

THE AIRPORT HAS 5 RUNWAYS, ALL RUNNING PARALLEL, ALLOWING 3 PLANES TO LAND AT THE SAME TIME.

KELLMAN: I CONSIDER THIS AIRPORT TO BE A RACETRACK OF--OF AIRCRAFT.

UH, WE MOVE PLANES IN AND OUT VERY EFFICIENTLY, AND, UH, I--I CALL IT THE SPEEDWAY OF, UH, AIR TRAFFIC RIGHT HERE.

NARRATOR: BUT THAT RACETRACK COULD NOT OPERATE SAFELY WITHOUT RADAR AND TRANSMITTER TECHNOLOGY THAT GUIDES PILOTS IN FOR A SMOOTH TOUCHDOWN.

CHUCK MURPHY IS RESPONSIBLE FOR KEEPING THESE CRUCIAL SYSTEMS WORKING WITHOUT FAIL.

MURPHY: WHEN THE PLANES ARE ON FINAL APPROACH AT ABOUT 18 MILES OUT, THEY LOCK INTO THE INSTRUMENT LANDING SYSTEM.

PART OF THAT INSTRUMENT LANDING SYSTEM IS THE LOCALIZER.

THIS LOCALIZER ARRAY RIGHT HERE KEEPS THE PILOT IN THE CENTER OF THE RUNWAY, AND WHEN THEY'RE IN THE CENTER, THEY KNOW WHEN THEY LAND, THEY'RE GONNA HIT PRECISELY WHERE THEY NEED TO TO SAFELY LAND ON THE RUNWAY.

NARRATOR: THE LOCALIZER GIVES PLANES A PATH TO FOLLOW TO THE CENTER OF THE RUNWAY.

IT EMITS TWO CONES OF DIFFERENT RADIO FREQUENCY AT PRECISE ANGLES TO THE RUNWAY'S CENTER LINE.

THE INSTRUMENTS ON AN APPROACHING PLANE DETECT WHERE THESE FREQUENCIES OVERLAP, GIVING THEM THE EXACT LINE THEY MUST FOLLOW TO MAKE THE PERFECT APPROACH.

THE CONTROLLERS ALSO NEED TO BE ABSOLUTELY CERTAIN THE PLANES AREN'T FLYING IN TOO CLOSELY TO EACH OTHER, AND THAT'S POSSIBLE THANKS TO A SYSTEM THAT PINPOINTS THE PLANE'S POSITIONS TO WITHIN HALF AN INCH.

MURPHY: WE ALSO HAVE A RADAR SYSTEM CALLED A PRECISION RUNWAY MONITOR THAT PICKS UP THE PLANES, AND WE SOMETIMES LAND 3 PLANES AT EXACTLY THE SAME TIME ON THOSE RUNWAYS.

IT'S CALLED TRIPLE APPROACHES.

YOU CANNOT DO THAT WITHOUT THE PRECISION RUNWAY MONITOR.

RADAR IS THE KEY AND THE ADVANCE RADARS THAT WE HAVE MEANS WE CAN LAND MORE PLANES AT ONCE VERY SAFELY.

YOU CAN TELL EXACTLY WHERE THOSE PLANES ARE, AND YOU CAN REDUCE THE AMOUNT OF DISTANCE BETWEEN THOSE PLANES.

WE CAN BRING THEM MUCH CLOSER TOGETHER WITH THESE PRECISE RADARS THAN WITHOUT THEM.

NARRATOR: THANKS TO THESE GUIDANCE SYSTEMS, ATLANTA IS ABLE TO HANDLE THE ENORMOUS NUMBER OF AIRCRAFT WANTING TO LAND HERE NOT JUST SAFELY, BUT, CHANCES ARE, ON TIME.

MURPHY: WITHOUT THE RADAR SYSTEMS, WE HAVE THE CONTROLLERS BASICALLY WORKING BLIND.

NARRATOR: ALL THESE SYSTEMS ARE FOCUSED ON THE VERY FINAL CRUCIAL PHASE OF YOUR FLIGHT-- THE MOMENT OF LANDING ITSELF.

AT AN AIRPORT LIKE ATLANTA, THE GUIDANCE SYSTEMS MAKE IT SIGNIFICANTLY EASIER FOR PILOTS TO LAND WITHOUT INCIDENT, BUT THERE ARE SOME AIRPORTS IN THE WORLD THAT DON'T HAVE THE LUXURY OF SUCH HIGH-END TECHNOLOGY.

PARO BHUTAN DEEP IN THE HIMALAYAS.

IT'S ONE OF THE HIGHEST AIRPORTS ON THE PLANET.

MAN: THAT'S THE HIGHEST POINT ON EARTH--MOUNT EVEREST, MEASURING AT 29,035 FEET, OR 8,850 METERS.

BEAUTIFUL VIEW OF MOUNT EVEREST.

THANK YOU.

NARRATOR: MOUNT EVEREST IS ONE OF THE GREATEST VIEWS YOU CAN HAVE FROM AN AIRPLANE WINDOW, BUT THIS ENTIRE HIMALAYAN REGION CONSISTS OF JAGGED MOUNTAINS AND DEEP VALLEYS, NOT THE EASIEST PLACE TO LAND A JET PLANE.

IN FACT, BHUTAN'S PARO AIRPORT IS ONE OF THE VERY FEW PLACES IN THE HIGH HIMALAYAS A MID-SIZE AIRCRAFT CAN PUT DOWN, BUT THE AIRPORT'S NESTLED IN A NARROW VALLEY SURROUNDED BY TOWERING, 18,000-FOOT PEAKS.

CAPTAIN KINGA TSHERING IS ONE OF ONLY 26 PILOTS IN THE WORLD QUALIFIED TO LAND AT PARO.

NARRATOR: 20 MILES OUT AT 15,000 FEET, CAPTAIN TSHERING PREPARES FOR HIS APPROACH.

TIME TO SWITCH OFF THE AUTO PILOT.

[BEEP BEEP BEEP] NARRATOR: THERE'S NO OPTION OTHER THAN TO LAND MANUALLY AT PARO.

THIS AIRPORT HAS NO RADAR TO GUIDE PLANES IN.

CAPTAIN TSHERING MUST MAKE HIS FINAL APPROACH THROUGH A LONG NARROW VALLEY, AND JUST 1,600 FEET BEFORE THE AIRPORT, THERE'S A HIGH RIDGE.

UNTIL THE PLANE PASSES IT, THE RUNWAY'S HIDDEN FROM VIEW.

IT'S THE TRICKIEST PART.

ONCE THE PLANE MAKES ITS TURN AROUND THE RIDGE, IT MUST BE PERFECTLY LINED UP WITH THE RUNWAY AT JUST THE RIGHT HEIGHT.

IT SHOULD THEN BE 100 FEET OFF THE GROUND AND SECONDS AWAY FROM TOUCHDOWN.

THAT'S THE THEORY.

NOW FOR THE REAL THING.

CAPTAIN TSHERING IS NOW ENTERING THE VALLEY, AND HE'S FLYING JUST A FEW HUNDRED FEET FROM THE MOUNTAINSIDE.

VOICE: TERRAIN AHEAD.

TERRAIN AHEAD.

PULL UP.

AVOID TERRAIN.

VOICE: 500.

NARRATOR: HE'S DESCENDING FAST, AND THE RUNWAY IS STILL OUT OF VISUAL RANGE.

AT LAST THE RIDGE COMES INTO VIEW, AND CAPTAIN TSHERING MAKES HIS CRUCIAL TURN.

IT'S LOOKING PROMISING, BUT THE CAPTAIN'S STILL GOT TO GET US SAFELY ONTO THE RUNWAY.

AT LITTLE OVER A MILE LONG AND 98 FEET WIDE, PARO'S RUNWAY IS MUCH SHORTER AND NARROWER THAN MOST.

VOICE: 50, 40, 30, 20...

RETARD.

RETARD.

NARRATOR: TOUCHDOWN, BUT THERE'S NOT AN INCH TO SPARE.

CAPTAIN TSHERING'S TIMING MUST BE PERFECT.

NARRATOR: FLIGHT KB205 HAS ARRIVED IN BHUTAN.

THIS IS ONE OF THE MOST SPECTACULAR AND HAIR-RAISING LANDINGS IN THE WORLD.

FOR INTREPID VISITORS, IT'S WELL WORTH THE ROLLER COASTER RIDE IN, BUT WITHOUT THE PILOTS SPECIALLY TRAINED TO LAND HERE, VERY FEW OUTSIDERS WOULD EVER GET TO SEE THIS HIMALAYAN LOST WORLD.

BACK AT ATLANTA, YOUR FLIGHT IS NOW SECONDS AWAY FROM LANDING.

IT'S THE MOST CRITICAL MOMENT OF YOUR FLIGHT SINCE THE WHEELS LEFT THE GROUND.

FOR A GENTLE TOUCHDOWN, THE ANGLE OF THE WINGS MUST BE PERFECT.

THE WHEELS HAVE TO WITHSTAND AN ACCELERATION OF ZERO TO 150 MILES PER HOUR IN JUST A SPLIT-SECOND.

THE BRAKES HEAT UP TO 700 DEGREES, AND REVERSE THRUST HELPS SLOW YOUR 100-TON PLANE... TO A SEDATE 20 MILES AN HOUR.

YOU'RE DOWN, BUT THERE'S A DIFFERENT KIND OF PROBLEM HERE, ONE YOU DEFINITELY WON'T ENCOUNTER AT A QUIET AIRPORT IN THE HIMALAYAS.

IN ATLANTA, THERE MIGHT BE AS MANY AS 10 PLANES LINED UP BEHIND YOU, ALL WAITING TO LAND, SO YOUR PLANE NEEDS TO GET OFF THE RUNWAY AND REACH THE GATE FAST... AND AT MANY AIRPORTS, SERIOUS HOLDUPS OCCUR WHEN PLANES WAIT TO CROSS AN ACTIVE RUNWAY ON THEIR WAY TO THE TERMINAL.

FORTUNATELY, THE BUSIEST AIRPORT IN THE WORLD HAS AN ACE UP ITS SLEEVE.

AN UNREMARKABLE-LOOKING STRETCH OF PAVEMENT NAMED TAXIWAY VICTOR.

WOMAN: WE HAVE AN END-AROUND TAXIWAY WHICH WE CALL OUR TAXIWAY VICTOR WHICH ALLOWS THE AIRCRAFT TO GO ALL THE WAY FROM THE RUNWAY, TAXI TO THEIR GATE WITHOUT STOPPING.

NARRATOR: AN END AROUND TAXIWAY LIKE VICTOR MEANS THAT AIRCRAFT THAT HAVE LANDED DON'T HAVE TO CROSS ACTIVE RUNWAYS TO REACH THEIR GATE, A SIMPLE IDEA WITH A MASSIVE IMPACT.

WADE: MOST OF THE TIME, AIRPLANES HAVE TO STOP TO GET PERMISSION TO CROSS THE DEPARTURE RUNWAY, BUT BY GOING AROUND THE END OF THE DEPARTURE RUNWAY, THEY SAVE A LOT OF TIME, AND WE'RE A LOT MORE EFFICIENT.

NARRATOR: ONLY A HANDFUL OF AIRPORTS IN THE WORLD HAVE THE SPACE FOR THIS INGENIOUS LAYOUT.

WADE: SOME PEOPLE MIGHT THINK IT'S JUST ANOTHER TAXIWAY, ANOTHER PIECE OF PAVEMENT THAT WE HAVE OUT HERE, BUT IT'S REALLY LIKE A SECRET WEAPON.

HAVING THAT ABILITY TO CONTINUOUSLY TAXI WITHOUT HAVING TO STOP IS INCREDIBLY, UH, HELPFUL TO OUR OPERATION.

FOR OTHER AIRPORTS THAT HAVE TO STOP THEIR TRAFFIC TO CROSS THEIR DEPARTURE RUNWAY, IT'S A VERY LIMITING FACTOR FOR THEM.

IT HAS A-A HUGE IMPACT ON THE NUMBER OF AIRCRAFT THAT THEY CAN BRING IN OR HAVE SCHEDULED FOR DEPARTURE.

IT LIMITS THEIR OPERATION.

NARRATOR: IT'S A CLEVER DESIGN TRICK THAT HELPS YOUR PLANE REACH ITS GATE WITHOUT DELAY AND HELPS ATLANTA RETAIN ITS CROWN OF BUSIEST AIRPORT IN THE WORLD.

YOU'VE MADE IT.

YOUR JOURNEY THROUGH THE CITY IN THE SKY IS ALMOST OVER, BUT BEFORE YOU LEAVE THE AIRPORT, MAKE SURE YOU DON'T FORGET...

YOUR LUGGAGE.

AROUND 3.5 BILLION SUITCASES FLY AROUND THE WORLD ALONGSIDE US EVERY YEAR.

THE TECHNOLOGY IN PLACE TO GET THEM TO THE RIGHT DESTINATION GETS EVER MORE SOPHISTICATED, YET DESPITE MULTIMILLION-DOLLAR, HIGH-TECH SYSTEMS, AROUND 7 BAGS PER 1,000 PASSENGERS STILL GO ASTRAY.

MOST LOST BAGS CATCH UP WITH THEIR OWNERS WITHIN A DAY OR TWO, BUT NOT ALL OF THEM.

AN ESTIMATED 1.4 MILLION BAGS PER YEAR ARE NEVER REUNITED WITH THEIR OWNERS.

SOME LOSE THEIR TAGS.

OTHERS ARE SIMPLY ABANDONED.

IF YOU NEVER PICK UP YOUR LUGGAGE, IT COULD END UP IN A PLACE LIKE THIS-- A LOST LUGGAGE AUCTION IN GERMANY.

CRUCIALLY, THIS IS A BLIND AUCTION.

YOU'RE NOT ALLOWED TO SEE INSIDE THE BAG BEFORE BIDDING.

YOU'RE NOT EVEN ALLOWED TO TOUCH IT.

ANY ONE OF THE BAGS ON SALE TODAY COULD POTENTIALLY CONTAIN RICH PICKINGS OR NOTHING.

NARRATOR: IT'S A GAMBLE, BUT SOME REGULARS HAVE LEARNED THE TRICK OF SNIFFING OUT THE RIGHT BAG AND MAKE A PROFIT BY RESELLING THEIR CONTENTS.

MARCO HAMLER HAS TAKEN YEARS TO MASTER THIS ART.

HAMLER: IT'S LIKE A DRUG BECAUSE YOU NEVER KNOW WHAT YOU--WHAT YOU HAVE INSIDE THIS CASE, AND THEN YOU COME HOME AND OPEN THIS CASE.

IT'S VERY EXCITING.

NARRATOR: AT 12 NOON, THE AUCTION KICKS OFF.

[SPEAKING GERMAN] NARRATOR: THEY'VE GOT 400 BAGS TO SELL BY THE END OF THE DAY, SO THEY DON'T WASTE TIME... NARRATOR: BUT SOME BAGS ATTRACT MORE ATTENTION THAN OTHERS.

[SPEAKS GERMAN] [CHEERING AND APPLAUSE] NARRATOR: THE AUCTION'S DOWN TO THE LAST 100 BAGS, AND FINALLY, MARCO BIDS SUCCESSFULLY FOR THE ONE HE HAD HIS EYE ON.

CASH HANDED OVER, IT'S THE MOMENT OF TRUTH.

AND WE WILL SEE WHAT'S INSIDE.

OH, SO EVERYTHING IS FOR KIDS.

LOVELY, NICE T-SHIRT.

NARRATOR: THIS TIME, MARCO'S BEEN UNLUCKY, BUT THE BLIND LUGGAGE AUCTION CAN REWARD PATIENCE WITH UNEXPECTED TREASURES.

HAMLER: IN ONE CASE, I FOUND A CABLE, A VERY, VERY, UH, EXPENSIVE CABLE FOR A HI-FI, UM, UM, RECEIVER.

UM, IT WAS LIKE, SO, 1,400 EUROS, SO IT WAS VERY, VERY GREAT.

NARRATOR: SINCE 2011, THEY'VE AUCTIONED OFF OVER 20,000 BAGS HERE.

IF THESE HADN'T BEEN SOLD, THEY MIGHT HAVE ENDED UP AS LANDFILL.

GLOBALLY, THAT COULD MEAN 1,000 TONS OF GARBAGE A YEAR...

BUT WHILE EVEN LOST BAGS WILL EVENTUALLY FIND A HOME, YOUR PLANE MIGHT NOT BE SO LUCKY.

AT THE END OF THEIR JOURNEY THROUGH THE CITY IN THE SKY, SOMETIMES AIRCRAFT FIND THEMSELVES NO LONGER NEEDED.

AFTER 9/11, THE DOWNTURN IN AIR PASSENGERS LED TO HUNDREDS OF PLANES BEING LEFT UNUSED BY AIRLINES, BUT WHERE DO YOU PARK A FEW DOZEN SPARE JETS WHEN THE COST OF STORING THEM IN AN AIRPORT HANGAR IS SKY HIGH?

THAT'S WHERE ARIZONA COMES IN.

THE STATE'S AVERAGE RAINFALL IS JUST 7 INCHES A YEAR, SO METAL BARELY RUSTS, MAKING IT THE IDEAL PLACE TO STORE PLANES, A PLACE WHERE UNWANTED AIRCRAFT GO INTO SUSPENDED ANIMATION.

THIS SPRAWLING, 400-ACRE SITE'S CURRENTLY HOME TO SOME 150 AIRLINERS.

FOR NOW, THESE PLANES MAY BE QUIETLY HIBERNATING, BUT AT ANY MOMENT, AN AIRLINE MIGHT CALL UP AND ORDER ONE OF THEIR SLEEPING GIANTS BACK INTO THE SKY.

ED MEYER AND HIS TEAM OF AIRCRAFT MAINTENANCE TECHNICIANS KEEP THEM PRIMED TO GO STRAIGHT BACK INTO OPERATION AFTER MONTHS, OR EVEN YEARS, ON THE GROUND.

MEYER: THE AIRPLANE CAN SIT, BASICALLY, INDEFINITELY AS LONG AS YOU'RE KEEPING ALL THE DIFFERENT SYSTEMS ACTIVATED, AS LONG AS YOU'RE KEEPING EVERYTHING SERVICED.

ESSENTIALLY, AS LONG AS YOU KEEP ALL THOSE ACTIVITIES GOING, THE AIRPLANE CAN SIT LIKE THIS FOR YEARS.

NARRATOR: BUT THIS ISN'T JUST A PLACE WHERE PLANES COME FOR A VACATION IN THE SUN.

THE TIME COMES FOR EVERY WORKHORSE OF THE SKY TO BE PUT OUT TO PASTURE.

SADLY, THERE'S NO LONG AND LEISURELY RETIREMENT IN STORE.

THIS IS WHERE SOME PLANES COME TO DIE.

THIS IS A McDONNELL DOUGLAS DC-9.

IT'S 36 YEARS OLD.

IT'S COMPLETED 77,854 FLIGHT HOURS, AND THIS IS ITS VERY LAST DAY ON EARTH.

EVEN AT THE END OF A PLANE'S WORKING LIFE, MANY OF ITS COMPONENTS STILL HAVE A RESALE VALUE.

ITS DISMEMBERED GUTS ARE PACKED WITH VALUABLE MATERIALS, SO IT MIGHT LOOK LIKE THE END, BUT, IN ACTUAL FACT, THIS PLANE WILL SOON BE BORN AGAIN.

NARRATOR: FINALLY, THEY'RE LEFT WITH JUST AN EMPTY CARCASS, THE HOLLOWED-OUT FUSELAGE.

GLOBALLY, PLANES ARE BEING SCRAPPED ON A VAST SCALE.

SINCE THE DAWN OF THE JET AGE BACK IN THE 1950s, OVER 8,500 PASSENGER PLANES HAVE WINGED THEIR WAY TO THE JUNK YARD.

STACKED 4 DEEP, THEY'D FILL A SCRAP YARD THE SIZE OF CENTRAL PARK.

AROUND 50% OF THE WEIGHT OF A DISMANTLED AIRCRAFT IS REUSABLE, AND MOST OF THE REST CAN BE RECYCLED.

WITH A NEW PLANE COSTING HUNDREDS OF MILLIONS OF DOLLARS, MACHINE PARTS ARE EXTREMELY VALUABLE, WITH ENGINES BEING, BY FAR, THE MOST SOUGHT-AFTER...

BUT THE DOLLAR VALUE OF THIS SCAVENGED FUSELAGE NOW LIES SOLELY IN THE SCRAP METAL IT WILL PROVIDE WHEN PULLED APART, AND IT'S NO GENTLE DEMISE.

MEET THE CRUSHER.

IN THE SPACE OF 45 MINUTES, A MACHINE THAT ONCE SOARED OVER OCEANS AND CONTINENTS... LIKE A FATALLY WOUNDED ANIMAL BEING TORN APART BITE BY BITE, IS REDUCED TO NOTHING MORE THAN A 10-FOOT-HIGH PILE OF SCRAP... A HEAP OF GARBAGE THAT SEEMS FAR TOO SMALL TO HAVE EVER BEEN A PASSENGER JET.

THIS PLANE'S LIFE IN THE CITY IN THE SKY HAS COME TO AN END, BUT THE RELENTLESS GROWTH OF AVIATION MEANS THAT NEW PLANES ARE BEING BUILT FAR FASTER THAN OLD ONES ARE BEING SCRAPPED... AND A FEW DECADES FROM NOW, YOUR JOURNEY INTO THE CITY IN THE SKY MIGHT NOT EVEN BE ON BOARD A PLANE.

IN FACT, YOU MAY NOT EVEN DEPART FROM AN AIRPORT.

MILLIONS OF DOLLARS ARE BEING PUMPED INTO RESEARCH TO FIND ALTERNATIVE TECHNOLOGIES TO KEEP THE CITY IN THE SKY FLYING.

IN A GIGANTIC HANGAR JUST OUTSIDE BEDFORD, ENGLAND, ONE RADICAL SOLUTION IS TAKING SHAPE.

THIS IS THE WORLD'S LARGEST AIRCRAFT.

IT'S NOT A PLANE, NOR IS IT A SIMPLE AIRSHIP.

IT'S A HYBRID, A CROSS BETWEEN THE TWO.

IT'S CALLED THE AIRLANDER 10.

ITS HOLLOW DOUBLE HULLS CONTAIN A MIXTURE OF AIR AND INERT HELIUM.

THIS MAKES IT LIGHTER THAN AIR AND SO ABLE TO TAKE OFF EFFORTLESSLY, AND, THOUGH NOT OBVIOUS AT FIRST GLANCE, THE AIRLANDER'S SHAPE IS A VAST, INFLATABLE WING, MAKING THIS A PHENOMENALLY EFFICIENT FLYING MACHINE.

IT'S A 21st-CENTURY REINVENTION OF A CONCEPT THAT'S BEEN AROUND SINCE THE DAWN OF AVIATION.

MAN: YOU KNOW, WE'RE--WE'RE BUILDING ON HUNDREDS OF YEARS OF AVIATION, UH, EXPERTISE, BRINGING THE-- THE OLD, UM, METHODS USED IN THE PAST, ADDING SOME NEW, AND ULTIMATELY JUST CREATING A--A BRAND-NEW VEHICLE, REALLY.

NARRATOR: THE AIRLANDER IS UNIQUE BECAUSE OF WHAT IT CAN DO.

MAN: THE AIRLANDER CAN DO TWO THINGS THAT OTHER AIRCRAFT CAN'T DO.

ONE IS, IT CAN STAY IN THE AIR FOR A LONG, LONG TIME, AND WE'RE TALKING 3 WEEKS RATHER THAN HOURS AND DAYS, AND THAT ALLOWS IT TO DO SOME AMAZING THINGS, LIKE SEARCH AND RESCUE, LIKE GOING IN WHEN TSUNAMIS HAVE HAPPENED OR WHERE THERE'S FLOODS, REALLY SEARCHING THE AREA FOR AS LONG AS IT TAKES TO FIND PEOPLE AND TO HELP OUT... AND THE SECOND THING IT CAN DO IS LAND AND TAKE OFF FROM ANY SURFACE, WHETHER IT'S WATER OR ICE OR DESERT OR MARSH, AND THAT ALLOWS IT TO CONNECT THE WORLD, DELIVER THINGS TO REMOTE AREAS, AND NO OTHER AIRCRAFT TYPE CAN DO THAT.

NARRATOR: THE FLEXIBILITY OF AIRCRAFT LIKE THIS COULD MEAN A FUTURE WITHOUT ANYTHING THAT WE'D RECOGNIZE AS AN AIRPORT, BUT OF ALL THE FEATURES MAKING THE AIRLANDER A VIABLE POSSIBILITY, THE MOST COMPELLING IS EFFICIENCY.

THE AIRLANDER'S DESIGNERS CLAIM IT COULD USE LESS THAN A THIRD OF THE FUEL A JET PLANE WOULD CONSUME ON A COMPARABLE JOURNEY.

DANIELS: NATURALLY, WE GO SLOWER THAN A JET AIRCRAFT, SO WE FLY AT ABOUT 90 MILES AN HOUR, MAYBE A LITTLE BIT QUICKER THAN THAT ON OCCASIONS, UM, BUT THAT SPEED IS QUICKER THAN LORRIES.

IT'S QUICKER THAN SHIPS, AND IT GIVES US ALL THE FLEXIBILITY TO TAKE THINGS WHEREVER WE WANT IN THE WORLD, AND ALSO, MOST CARGO AND MOST ENDURANCE TASKS DON'T NEED SPEED, SO IT'S A SUPER FLEXIBLE AIRCRAFT.

I WOULD LOVE THE TIME--AND IT WILL HAPPEN IN MY LIFETIME-- WHERE THERE'LL BE HUNDREDS OF THESE FLYING OVER BRITAIN AND OVER THE WORLD.

NARRATOR: OTHER DESIGNERS HAVE EVEN MORE RADICAL VISIONS OF THE SHAPE OF PLANES TO COME.

AIRBUS IS DEVELOPING ELECTRIC PASSENGER PLANES.

ALREADY THEIR PROTOTYPE, THE E-FAN, HAS BECOME THE FIRST ELECTRIC AIRCRAFT TO CROSS THE ENGLISH CHANNEL... AND TWO PIONEERING SWISS SCIENTISTS RECENTLY MADE A RECORD-BREAKING FLIGHT IN THEIR SOLAR-POWERED PLANE.

THE SOLAR IMPULSE FLEW 5,000 MILES NONSTOP FROM JAPAN TO HAWAII.

THESE AND OTHER NEWLY EVOLVING TECHNOLOGIES COULD TOTALLY RESHAPE AVIATION IN THE DECADES AHEAD AND MAKE YOUR FUTURE JOURNEYS INTO THE SKY UNRECOGNIZABLE.

100 YEARS AGO, NOBODY COULD HAVE PREDICTED THAT THE AIRBORNE METROPOLIS WOULD BECOME A GLOBE-SPANNING NETWORK REACHING THE MOST FAR-FLUNG PLACES OR THAT IT WOULD CARRY 9 MILLION PASSENGERS A DAY AND DEVELOP ITS OWN UNIVERSAL SYSTEMS AND LANGUAGE.

EVEN WITH CURRENT TRENDS, THE CITY IN THE SKY'S SET TO DOUBLE IN SIZE OVER THE NEXT 20 YEARS.

IF IT'S TO KEEP GROWING, WE WILL NEED TO FIND NEW WAYS TO BUILD AND POWER IT, BUT IF THE EXTRAORDINARY INNOVATIONS OF THE CITY CONTINUE, THE SKY IS QUITE LITERALLY THE LIMIT.

ANNOUNCER: "CITY IN THE SKY" IS AVAILABLE ON DVD.

TO ORDER, VISIT SHOPPBS.ORG OR CALL 1-800-PLAY-PBS.