Human Error in Air Travel - A Cold Reality

Human error is one of leading causes of airline accidents. Luckily it
wasn't the case with  "The Miracle On The Hudson", the landing of
a US Airways jet on the Hudson River in New York. By the grace of God
and the skill of an experienced pilot, all passengers and crew escaped
serious injury. When I first heard of the crash, I immediately thought
of another crash that landed in a river, but the results were not as
good. Many factors can cause an accident such as mechanical failure,
weather and human error or more commonly known as pilot error.
Let's go back 27 years to January 13, 1982. Washington D.C was
battling a snowstorm all day slowing operations at the National
Airport, now known as Reagan National Airport. The gates were clogged
with delayed aircraft, anxiously awaiting the weather to clear so they
could get in the air. One of the planes was a 737-200 belonging to Air
Florida. Flight 90, or Palm 90 which was its radio call sign, sat at
gate B-12 as the snow continued to fall and the visibility grew worse
with every passing moment. Finally at around 2:15, the flight was
given clearance to finally board.
Seventy-four passengers squeezed aboard the single aisle jet which was
on its way to sunny and warmer Tampa, Florida. None of the passengers
knew that in less than two hours, their lives would be changed
forever. Ironically it wouldn't be just because of the bad weather,
but because of human error.
This crash is a classic example of a chain of events that unfolded to
cause an accident. There was nothing mechanically wrong with the
airplane before it left the ground. A string of human errors however
culminated to bring this flight to an abrupt and tragic end. Let's
start with the crew or more specifically the Captain and the Co-pilot.
Up in the flight deck that day were Captain Larry Wheaton and First
Officer Roger Petit. Captain Wheaton ordered a de-icing of the
aircraft which is standard procedure when flying in winter weather. De-
icing is when the aircraft is sprayed with a special fluid of ethylene
glycol or propylene glycol used to remove snow and ice from the jet's
wings and fuselage. Any coating of ice or snow on the wings will
reduce the aircraft's ability to gain and sustain lift when it tries
to take off. The de-icing was a standard and practiced procedure. What
was not normal however was what happened when the aircraft was given
clearance to push back from the gate. A tow tractor is used because a
jet has no reverse gear so it needs help. Well there was so much snow
that the tug couldn't move the plane. So the captain, in what he
thought was a good idea, decided to apply reverse thrust to the
engines. This is usually only used on landing to slow down the plane.
When applied in this case, it caused more harm than good because it
ended up sucking up ice, snow and other debris into the engines. The
second mistake that was made was when neither pilot turned on the
engine anti-ice function. There are probes inside the engines that
measure how much thrust or power the engine is producing. If these
probes are frozen over, they will give an inaccurate reading, which is
what they eventually did.
Palm 90 finally left the gate and was roughly number eleven in line
for take off. The snow was still falling heavily when it was given its
take-off clearance. At 3:59pm, Captain Wheaton pushed the throttles
forward and the 737 sluggishly lumbered down the runway. The co-pilot
noticed the engine instruments didn't look right and said so to the
captain, but the captain failed to abort the take off. The EPR or
Engine Pressure Ratio readings which tell the flight crew how much
thrust the engine is producing were showing inconsistent readings. It
was later determined in the investigation that because the engine ant-
ice was not activated, the engine probes froze over.  They did
get off the ground, but failed to gain enough lift and air speed to
keep flying. With the snow on the wings and the fact that they took
off with about 80% power, they had no chance. It crashed into the
Potomac River after hitting a bridge and killing 74 people on board.
Five survivors ended up clinging to wreckage in the water while
waiting for rescue.
A rescue helicopter from the Parks Department showed up and plucked
three passengers and one crew member from the icy Potomac. Another
survivor kept passing the rescue rope to the other survivors. When
rescuers went back to get him, the wreckage had dragged him down to
the bottom of the river and he was not rescued. Unfortunately two more
winter related incidents occurred about seven years later before the
people in government started paying attention and passed some rules to
better regulate the industry. This is known by some in the industry as
Tombstone Technology where government agencies need a significant body
count before deciding a rule needs to be changed. Human error is going
to happen and so will accidents. However with new technology being
developed and airline participation in programs like CRM or Cockpit
Resource Management, the rate of accidents can be reduced.

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