Rescue crews are searching
Indonesian waters for AirAsia Indonesia Flight 8501, which disappeared Sunday
with 162 passengers and crew onboard. The plane was flying from Surabaya,
Indonesia's second-largest city, and was about halfway to its destination, Singapore,
when it vanished from radar.
It is way too early to know for
sure, but here are some options. The plane was in the safest part of flight:
Just 10% of fatal crashes from 2004 through 2013 occurred while a plane was at
cruise elevation, according to a safety study published by Boeing in August.
Passing through bad weather such as
severe thunderstorms could have been a factor. Airbus jets have sophisticated
computers that automatically adjust to wind shears or other weather
disruptions. But weather--combined with pilot errors--has played a role in past
air disasters that occurred at cruise elevation, including the 2009 Air France
Flight 447 crash over the Atlantic Ocean.
Another possibility is some type of
catastrophic metal fatigue caused by the cycle of pressurisation and
depressurisation associated with each takeoff and landing cycle. This A320 had
had 13,600 takeoffs and landings. Many occurred in humid climate, which speeds
corrosion. Still, metal fatigue is unlikely because this plane is only 6 years
old.
Finally, there's the possibility of
terrorism or a mass murder by the pilot. There's no evidence of either action,
but neither can yet be ruled out.
What did the pilots say to air
traffic controllers?
The last communication between the
pilot and air traffic control was at 6.13 am Sunday (6.13 pm EST Saturday,
around 5 pm IST) when the pilot "asked to avoid clouds by turning left and
going higher to 38,000 feet (11,582 meters)." The last radar contact
occurred three minutes later. There was no distress call. But pilots are
trained to focus first on the emergency at hand and then communicate only when
free.
Isn't this the third Malaysian jet
to crash this year?
Sort of. Malaysia Airlines Flight
370 disappeared with 239 people aboard soon after takeoff from Kuala Lumpur for
Beijing on March 8. Its whereabouts and what happened remain one of the biggest
mysteries in commercial aviation. Another Malaysia Airlines flight, also a
Boeing 777, was shot down over rebel-controlled eastern Ukraine while en route
from Amsterdam to Kuala Lumpur on July 17. All 298 people aboard were killed.
AirAsia is also based in Malaysia.
But Flight 8501 was operated by AirAsia Indonesia, a subsidiary that's 49
percent owned by the Malaysian parent company. So technically, it's an
Indonesian airline. But the AirAsia brand is closely tied to the people of
Malaysia.
Is there a connection among all
these crashes?
No. It's just a very unfortunate
year for Southeast Asia. But that doesn't stop conspiracy theories from
sprouting. Ideas about what happened to Flight 370--both logical and
bizarre--keep appearing. The unsolved nature of that disappearance could
generate more attention for Flight 8501 and create a new batch of hypotheses.
How far could the jet have flown?
Looking at the flight's paperwork,
the plane had more than 18,000 pounds of jet fuel at takeoff, enough to fly
about 3½ hours, according to Phil Derner Jr., the founder of aviation
enthusiast website NYCAviation.com and a flight dispatcher for a U.S. airline.
He notes that that's less fuel than most flights tend to carry from New York to
Florida.
What's next?
Indonesia, Singapore and Malaysia
are conducting a search-and-rescue operation near Belitung island in the Java
Sea, the plane's last known whereabouts. Assuming that the jet didn't veer far
off course, the searchers should find wreckage, which can provide clues about
what happened. Investigators will also try to recover the flight data and
cockpit voice recorders, which often have the most detailed information about
the plane's final moments. Those so-called black boxes have homing beacons that
help searchers find them.
Is the Airbus A320 a safe jet?
The plane is a workhorse of modern
aviation. Similar to the Boeing 737, the single-aisle, twin-engine jet is used
to connect cities that are between one and five hours apart. Worldwide, 3,606
A320s are in operation, according to Airbus, which also makes nearly identical
versions of the plane: The smaller A318 and A319 and the stretched A321. An
additional 2,486 of those jets are flying. The A320 family has a good safety
record, with just 0.14 fatal accidents per million takeoffs, according to the
Boeing safety study.
What about Airasia?
Low-cost AirAsia has a strong
presence in most of Southeast Asia, and it recently expanded into India. Though
most of its flights are just a few hours long, it has tried to expand into
long-distance flying through its sister airline AirAsia X. None of its
subsidiaries has lost a plane before, and it has a generally good safety
record. But it does fly in a part of the world where air travel has expanded
faster than the number of qualified pilots, mechanics and air traffic
controllers.
What about flying in Indonesia?
The country has had a bumpy safety
record. In 2007, the crash rate and safety standards were so bad that the
European Union barred all of Indonesia's airlines from flying into any of its
member countries. Than ban was lifted in 2009. But Indonesia's main airline -
fast-growing Lion Air - is still banned by the EU.
What's it like to fly through a
thunderstorm at 34,000 feet?
Planes flying through thunderstorms
experience severe turbulence, with the aircraft moving up, down, sideways and
rolling. Anything not secured can float around in the cabin, bouncing off
things and people. Overhead bins can open up, spilling contents. Airsickness is
common.
What do pilots do to avoid
thunderstorms?
If at all possible, airline pilots
fly around thunderstorms, even if it means going far out of their way.
Airliners like the A320 typically are equipped with radar that provides highly
accurate weather information. Pilots can see a thunderstorm forming from over
100 miles away, giving them time to plot a way around the storm cluster or to
look for gaps to fly through. It's usually not a problem for commercial planes
to go 100 or more miles out of the way.
How high can an A320 safely fly? and
what if it exceeds that limit?
The A320 is certified to fly up to
39,000 feet, its maximum altitude before its rate of climb begins to erode. The
plane has an absolute flight limit of 42,000 feet. But it can begin to
experience problems as low as 37,000 feet, depending on temperature and weight,
including fuel, cargo and passengers. The plane's computers should reveal the
maximum altitude at which the plane can fly at its current weight and
temperature. Planes that exceed their maximum altitude may lose lift, causing
an aerodynamic stall. Or they can experience a pressurization blowout, damaging
the plane.
How does a plane just fall off
radar?
It's still unclear what traffic
controllers saw on their screens when the plane disappeared from radar.
Authorities haven't said whether they lost only the secondary radar target,
which is created by the plane's transponder, or whether the primary radar
target, created by energy reflected from the plane, was lost as well. If a
plane came apart in the air or suffered a loss of electrical power, the
secondary target would be lost, but the primary target is often still visible
on radar. But if the plane were descending at rate of over 6,000 feet a minute
- typical of a plane about to crash - the primary target might be lost as well.
How vital is air travel to the
region?
For many people, it's the only
option. Indonesia is a sprawling archipelago of 250 million people. To get from
one island to another, the easiest way is to fly. As the region's economy has
grown, so have the number of people flying. The International Air Transport
Association recently named Indonesia as one of the world's five fastest-growing
air travel markets, predicting an additional 183 million passengers would take
to the sky within two decades.
Routes to, from and within the
Asia-Pacific region are predicted by the industry trade group to see an extra
1.8 billion annual passengers by 2034, for an overall market size of 2.9
billion. Within two decades, the region is expected to account for 42 percent
of global passenger traffic.
The increase in regional airline
traffic reflects rapid economic growth. The International Monetary Fund expects
the Southeast Asian economies of Indonesia, Malaysia, Philippines, Thailand and
Vietnam to grow faster this year and next than anywhere except China, India and
sub-Saharan Africa.
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