Ten Plane Crashes That Changed Aviation
Popular Mechanics | By David Noland | October 13, 2007

Flying in a jetliner is extraordinarily safe: There has been
only one fatal crash in the United States in the past five
years, an astounding record considering that more than
30,000 flights take off every day. How did flying get so
reliable? In part, because of accidents that triggered
crucial safety improvements. Here are eight crashes and two
emergency landings whose influence is felt -- for the good
-- each time you step on a plane.

1956 | GRAND CANYON | TWA FLIGHT 2 & UNITED FLIGHT 718
Upgrade: Improvements of air traffic control system;
creation of FAA
The TWA Super Constellation and the United DC-7 had taken
off from Los Angeles only 3 minutes apart, both headed east.
Ninety minutes later, out of contact with ground controllers
and flying under see-and-avoid visual flight rules, the two
aircraft were apparently maneuvering separately to give
their passengers views of the Grand Canyon when the DC-7's
left wing and propellers ripped into the Connie's tail. Both
aircraft crashed into the canyon, killing all 128 people
aboard both planes. The accident spurred a $250 million
upgrade of the air traffic control (ATC) system -- serious
money in those days. (It worked: There hasn't been a
collision between two airliners in the United States in 47
years.) The crash also triggered the creation in 1958 of the
Federal Aviation Agency (now Administration) to oversee air
safety.

1978 | PORTLAND | UNITED FLIGHT 173
Upgrade: Cockpit teamwork
United Flight 173, a DC-8 approaching Portland, Ore., with
181 passengers, circled near the airport for an hour as the
crew tried in vain to sort out a landing gear problem.
Although gently warned of the rapidly diminishing fuel
supply by the flight engineer on board, the captain -- later
described by one investigator as "an arrogant S.O.B." --
waited too long to begin his final approach. The DC-8 ran
out of fuel and crashed in a suburb, killing 10. In
response, United revamped its cockpit training procedures
around the then-new concept of Cockpit Resource Management
(CRM). Abandoning the traditional "the captain is god"
airline hierarchy, CRM emphasized teamwork and communication
among the crew, and has since become the industry standard.
"It's really paid off," says United captain Al Haynes, who
in 1989 remarkably managed to crash-land a crippled DC-10 at
Sioux City, Iowa, by varying engine thrust. "Without [CRM
training], it's a cinch we wouldn't have made it."

1983 | CINCINNATTI | AIR CANADA FLIGHT 797
Upgrade: Lav smoke sensors
The first signs of trouble on Air Canada 797, a DC-9 flying
at 33,000 ft. en route from Dallas to Toronto, were the
wisps of smoke wafting out of the rear lavatory. Soon, thick
black smoke started to fill the cabin, and the plane began
an emergency descent. Barely able to see the instrument
panel because of the smoke, the pilot landed the plane at
Cincinnati. But shortly after the doors and emergency exits
were opened, the cabin erupted in a flash fire before
everyone could get out. Of the 46 people aboard, 23 died.
The FAA subsequently mandated that aircraft lavatories be
equipped with smoke detectors and automatic fire
extinguishers. Within five years, all jetliners were
retrofitted with fire-blocking layers on seat cushions and
floor lighting to lead passengers to exits in dense smoke.
Planes built after 1988 have more flame-resistant interior
materials.

1985 | DALLAS/FORT WORTH | DELTA FLIGHT 191
Upgrade: Downdraft detection
As Delta Flight 191, a Lockheed L-1011, approached for
landing at Dallas/Fort Worth airport, a thunderstorm lurked
near the runway. Lightning flashed around the plane at 800
ft., and the jetliner encountered a microburst wind shear --
a strong downdraft and abrupt shift in the wind that caused
the plane to lose 54 knots of airspeed in a few seconds.
Sinking rapidly, the L-1011 hit the ground about a mile
short of the runway and bounced across a highway, crushing a
vehicle and killing the driver. The plane then veered left
and crashed into two huge airport water tanks. On board, 134
of 163 people were killed. The crash triggered a seven-year
NASA/FAA research effort, which led directly to the on-board
forward-looking radar wind-shear detectors that became
standard equipment on airliners in the mid-1990s. Only one
wind-shear-related accident has occurred since.

1986 | LOS ANGELES | AEROMEXICO FLIGHT 498
Upgrade: Collision avoidance
Although the post-Grand Canyon ATC system did a good job of
separating airliners, it failed to account for small private
planes like the four-seat Piper Archer that wandered into
the Los Angeles terminal control area on Aug. 31, 1986.
Undetected by ground controllers, the Piper blundered into
the path of an Aeromexico DC-9 approaching to land at LAX,
knocking off the DC-9's left horizontal stabilizer. Both
planes plummeted into a residential neighborhood 20 miles
east of the airport, killing 82 people, including 15 on the
ground.

The FAA subsequently required small aircraft entering
control areas to use transponders --electronic devices that
broadcast position and altitude to controllers.
Additionally, airliners were required to have TCAS II
collision-avoidance systems, which detect potential
collisions with other transponder-equipped aircraft and
advise pilots to climb or dive in response. Since then, no
small plane has collided with an airliner in flight in the
United States.

1988 | MAUI | ALOHA FLIGHT 243
Upgrade: Retiring tin
As Aloha Flight 243, a weary, 19-year-old Boeing 737 on a
short hop from Hilo, Hawaii, to Honolulu, leveled off at
24,000 ft., a large section of its fuselage blew off,
leaving dozens of passengers riding in the open-air breeze.
Miraculously, the rest of the plane held together long
enough for the pilots to land safely. Only one person, a
flight attendant who was swept out of the plane, was killed.

The National Transportation Safety Board (NTSB) blamed a
combination of corrosion and widespread fatigue damage, the
result of repeated pressurization cycles during the plane's
89,000-plus flights. In response, the FAA began the National
Aging Aircraft Research Program in 1991, which tightened
inspection and maintenance requirements for high-use and
high-cycle aircraft. Post-Aloha, there has been only one
American fatigue-related jet accident -- the Sioux City DC-10.

1994 | PITTSBURGH | USAIR FLIGHT 427
Upgrade: Rudder Rx
When USAir Flight 427 began its approach to land at
Pittsburgh, the Boeing 737 suddenly rolled to the left and
plunged 5000 ft. to the ground, killing all 132 on board.
The plane’s black box revealed that the rudder had abruptly
moved to the full-left position, triggering the roll. But
why? USAir blamed the plane. Boeing blamed the crew. It took
nearly five years for the NTSB to conclude that a jammed
valve in the rudder-control system had caused the rudder to
reverse: As the pilots frantically pressed on the right
rudder pedal, the rudder went left. As a result, Boeing
spent $500 million to retrofit all 2800 of the world's most
popular jetliner. And, in response to conflicts between the
airline and the victims' families, Congress passed the
Aviation Disaster Family Assistance Act, which transferred
survivor services to the NTSB.

1996 | MIAMI | VALUJET FLIGHT 592
Upgrade: Fire prevention in the hold
Although the FAA took anti-cabin-fire measures after the
1983 Air Canada accident, it did nothing to protect
passenger jet cargo compartments -- despite NTSB warnings
after a 1988 cargo fire in which the plane managed to land
safely. It took the horrific crash of ValuJet 592 into the
Everglades near Miami to finally spur the agency to action.
The fire in the DC-9 was caused by chemical oxygen
generators that had been illegally packaged by SabreTech,
the airline's maintenance contractor. A bump apparently set
one off, and the resulting heat started a fire, which was
fed by the oxygen being given off. The pilots were unable to
land the burning plane in time, and 110 people died. The FAA
responded by mandating smoke detectors and automatic fire
extinguishers in the cargo holds of all commercial
airliners. It also bolstered rules against carrying
hazardous cargo on aircraft.

1996 | LONG ISLAND | TWA FLIGHT 800
Upgrade: electrical spark elimination
It was everybody's nightmare: a plane that blew up in midair
for no apparent reason. The explosion of TWA Flight 800, a
Boeing 747 that had just taken off from JFK bound for Paris,
killed all 230 people aboard and stirred great controversy.
After painstakingly reassembling the wreckage, the NTSB
dismissed the possibility of a terrorist bomb or missile
attack and concluded that fumes in the plane's nearly empty
center-wing fuel tank had ignited, most likely after a short
circuit in a wire bundle led to a spark in the fuel gauge
sensor. The FAA has since mandated changes to reduce sparks
from faulty wiring and other sources. Boeing, meanwhile, has
developed a fuel-inerting system that injects nitrogen gas
into fuel tanks to reduce the chance of explosions. It will
install the system in all its newly built planes, starting
in 2008. Retrofit kits for in-service Boeings will also be
available.

1998 | NOVA SCOTIA | SWISSAIR FLIGHT 111
Upgrade: Insulation swap-out
About an hour after takeoff, the pilots of Swissair's Flight
111 from New York to Geneva -- a McDonnell Douglas MD-11 --
smelled smoke in the cockpit. Four minutes later, they began
an immediate descent toward Halifax, Nova Scotia, about 65
miles away. But with the fire spreading and cockpit lights
and instruments failing, the plane crashed into the Atlantic
about 5 miles off the Nova Scotia coast. All 229 people
aboard were killed.

Investigators traced the fire to the plane's in-flight
entertainment network, whose installation led to arcing in
vulnerable Kapton wires above the cockpit. The resulting
fire spread rapidly along flammable Mylar fuselage
insulation. The FAA ordered the Mylar insulation replaced
with fire-resistant materials in about 700 McDonnell Douglas
jets.