- Oct 24, 2000
- 29,767
- 33
- 81
Crew confusion found in Athens plane crash
By Don Phillips
International Herald Tribune
WEDNESDAY, SEPTEMBER 7, 2005
Paris
The crew members of a Cypriot airliner that crashed Aug. 14 near Athens
became confused by a series of alarms as the plane climbed, failing to
recognize that the cabin was not pressurizing until they grew mentally
disoriented because of lack of oxygen and passed out, according to several
people connected with the investigation.
Complicating the cockpit confusion, neither the German pilot nor the young,
inexperienced Cypriot co-pilot could speak the same language fluently, and
each had difficulty understanding how the other spoke English, the worldwide
language of air traffic control.
A total of 121 people were killed in the crash after the plane climbed and
flew on autopilot, circling near Athens as it was programmed to do until one
engine stopped running because of a lack of fuel. The sudden imbalance of
power, with only one engine operating, caused the autopilot to disengage and
the plane to begin its final descent.
The Greek authorities have made cryptic statements hinting at oxygen
problems but have so far not announced the full findings of investigators.
The people interviewed for this article agreed to do so on condition that
they not be identified because none are official spokesmen for the
investigation and because of political sensitivities arising from a Cypriot
plane crashing in Greece.
Investigators pieced together the story of the crash from numerous sources.
In the wreckage, they found the first solid clues - the pressurization valve
and an air outflow valve set incorrectly. Air traffic control tapes provided
information on the confusion in the cockpit.
The plane had a sophisticated new flight data recorder that provided a
wealth of information. There were maintenance records from the night before,
and investigators interviewed the mechanics who worked on the plane.
Among other things, the investigators determined that the pilot was not in
his seat because he was up trying to solve a problem that turned out to be
not the greatest threat facing him.
The plane that crashed, a Boeing 737, underwent maintenance the night
before. The maintenance crew apparently left a pressurization controller
rotary knob out of place, according to the officials connected to the
investigation, and the crew did not catch the mistake during preflight
checks the next day. This meant that the plane could not pressurize.
At 10,000 feet, or 3,000 meters, as designed, an alarm went off to warn the
crew that the plane would not pressurize. However, the crew members
mistakenly thought that the alarm horn was a warning to tell them that their
controls were not set properly for takeoff, the officials said.
The same horn is used for both conditions, although it will sound for
takeoff configuration only while the plane is still on the ground.
The crew continued the climb on autopilot. At 14,000 feet, oxygen masks
deployed as designed and a master caution light illuminated in the cockpit.
Another alarm sounded at about the same time on an unrelated matter, warning
that there was insufficient cooling air in the compartment housing avionics
equipment.
The radio tapes showed that this created tremendous confusion in the
cockpit. Normally an aircraft cabin is held at 8,000 feet pressure, so the
crew at over 14,000 feet would already be experiencing some disorientation
because of a lack of oxygen.
During this time, the German captain and the Cypriot co-pilot discovered
they had no common language and that their English, while good enough for
normal air traffic control purposes, was not good enough for complicated
technical conversation in fixing the problem.
The crew members called the maintenance base in Cyprus and were told that
the circuit breaker to turn off the loud new alarm was in a cabinet behind
the captain. The captain got up from his seat to look for the circuit
breaker, apparently ignoring the confused co-pilot.
As the plane continued to climb on autopilot, the air grew so thin that the
crew became seriously impaired. The captain passed out first on the floor of
the cockpit, followed by the co-pilot, who remained in his seat, according
to the officials.
The autopilot did as it was programmed to do, flying the plane at 34,000
feet to Athens and entering a holding pattern. It remained in a long
circling pattern, shadowed by Greek military jets, until fuel ran low and
one engine quit.
Boeing, the maker of the plane, is-sued a notice shortly after the crash to
airlines that it would revise flight crew training manuals to stress to
crews that they must understand how the various warning systems work and
what to do about them.
The notice stresses that the takeoff configuration warning horn will not
sound under any circumstances after the plane has left the ground.
The same horn will then be used only for a cabin altitude warning. The
company notice said there had been other instances of confusion over the
horn by pilots.
"Confusion between the cabin altitude warning horn and the takeoff
configuration warning horn can be re-solved if the crew remembers that the
takeoff configuration warning horn is only armed when the airplane is on the
ground," the notice said. "If this horn is activated in flight, it indicates
that the cabin altitude has reached 10,000 feet."
By Don Phillips
International Herald Tribune
WEDNESDAY, SEPTEMBER 7, 2005
Paris
The crew members of a Cypriot airliner that crashed Aug. 14 near Athens
became confused by a series of alarms as the plane climbed, failing to
recognize that the cabin was not pressurizing until they grew mentally
disoriented because of lack of oxygen and passed out, according to several
people connected with the investigation.
Complicating the cockpit confusion, neither the German pilot nor the young,
inexperienced Cypriot co-pilot could speak the same language fluently, and
each had difficulty understanding how the other spoke English, the worldwide
language of air traffic control.
A total of 121 people were killed in the crash after the plane climbed and
flew on autopilot, circling near Athens as it was programmed to do until one
engine stopped running because of a lack of fuel. The sudden imbalance of
power, with only one engine operating, caused the autopilot to disengage and
the plane to begin its final descent.
The Greek authorities have made cryptic statements hinting at oxygen
problems but have so far not announced the full findings of investigators.
The people interviewed for this article agreed to do so on condition that
they not be identified because none are official spokesmen for the
investigation and because of political sensitivities arising from a Cypriot
plane crashing in Greece.
Investigators pieced together the story of the crash from numerous sources.
In the wreckage, they found the first solid clues - the pressurization valve
and an air outflow valve set incorrectly. Air traffic control tapes provided
information on the confusion in the cockpit.
The plane had a sophisticated new flight data recorder that provided a
wealth of information. There were maintenance records from the night before,
and investigators interviewed the mechanics who worked on the plane.
Among other things, the investigators determined that the pilot was not in
his seat because he was up trying to solve a problem that turned out to be
not the greatest threat facing him.
The plane that crashed, a Boeing 737, underwent maintenance the night
before. The maintenance crew apparently left a pressurization controller
rotary knob out of place, according to the officials connected to the
investigation, and the crew did not catch the mistake during preflight
checks the next day. This meant that the plane could not pressurize.
At 10,000 feet, or 3,000 meters, as designed, an alarm went off to warn the
crew that the plane would not pressurize. However, the crew members
mistakenly thought that the alarm horn was a warning to tell them that their
controls were not set properly for takeoff, the officials said.
The same horn is used for both conditions, although it will sound for
takeoff configuration only while the plane is still on the ground.
The crew continued the climb on autopilot. At 14,000 feet, oxygen masks
deployed as designed and a master caution light illuminated in the cockpit.
Another alarm sounded at about the same time on an unrelated matter, warning
that there was insufficient cooling air in the compartment housing avionics
equipment.
The radio tapes showed that this created tremendous confusion in the
cockpit. Normally an aircraft cabin is held at 8,000 feet pressure, so the
crew at over 14,000 feet would already be experiencing some disorientation
because of a lack of oxygen.
During this time, the German captain and the Cypriot co-pilot discovered
they had no common language and that their English, while good enough for
normal air traffic control purposes, was not good enough for complicated
technical conversation in fixing the problem.
The crew members called the maintenance base in Cyprus and were told that
the circuit breaker to turn off the loud new alarm was in a cabinet behind
the captain. The captain got up from his seat to look for the circuit
breaker, apparently ignoring the confused co-pilot.
As the plane continued to climb on autopilot, the air grew so thin that the
crew became seriously impaired. The captain passed out first on the floor of
the cockpit, followed by the co-pilot, who remained in his seat, according
to the officials.
The autopilot did as it was programmed to do, flying the plane at 34,000
feet to Athens and entering a holding pattern. It remained in a long
circling pattern, shadowed by Greek military jets, until fuel ran low and
one engine quit.
Boeing, the maker of the plane, is-sued a notice shortly after the crash to
airlines that it would revise flight crew training manuals to stress to
crews that they must understand how the various warning systems work and
what to do about them.
The notice stresses that the takeoff configuration warning horn will not
sound under any circumstances after the plane has left the ground.
The same horn will then be used only for a cabin altitude warning. The
company notice said there had been other instances of confusion over the
horn by pilots.
"Confusion between the cabin altitude warning horn and the takeoff
configuration warning horn can be re-solved if the crew remembers that the
takeoff configuration warning horn is only armed when the airplane is on the
ground," the notice said. "If this horn is activated in flight, it indicates
that the cabin altitude has reached 10,000 feet."
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