The Demise of Flight 232

UA232-aircrafttype
My eyes moisten at the thought of what happened about 77 miles to the northeast of my home one Summer afternoon 25 years ago.  United Airlines Flight 232 was midway through an unremarkable trip from Denver, Colorado to Chicago, Illinois. The McDonnell Douglas DC-10’s captain Alfred Haynes, first officer William Records, and second officer Dudley Dvorak were in the cockpit overseeing the flight operations.  All three were veterans of several thousands of flight hours.  Seated in First Class was off-duty DC-10 flight instructor/pilot Denny Fitch. Fitch had hitched the ride home and chose Flight 232 at random in Denver.

UA232-IowaMap

Somewhere over the Alta, Iowa vicinity, Fitch and everyone else heard an explosion in the tail engine.  He noticed that the crew was having difficulty maintaining a steady path for the airliner.  Fitch stopped the passing head stewardess, identified himself as a certified DC-10 instructor, and offered to help the flight crew.

Upon entering the cockpit, he noticed that the three crewmen were struggling to maintain control of the aircraft. He glanced at the hydraulic guages then realized the situation was dire and beyond anything he had ever encountered.  The readings for all three systems were at zero.

The crewmembers were trying to fly the airplane with the normal controls but to no effect.  The only way to fly was to manipulate the throttle controls for the two remaining engines.  In order to avoid rolling the airplane upside down, which would be terminal, the engines needed to be variously brought to full thrust and then backed off.  Because there was no control by means of ailerons, elevators, nor rudder, the craft path began to alternate up and down in a manner called the Phugoid cycle.

Fitch was put to work on his knees at the throttle levers while Haynes and Records monitored the instruments and tried to use the steering controls. The aircraft kept aloft while Fitch guided the direction by varying the thrust of the port engine, then, in a similar fashion to the starboard engine.  The aircraft was taken through a series of 360-right turns over Northwest Iowa.UA232-path

Meantime, on the ground, Air traffic control officials determined that the best chance for the aircraft was in landing at Sioux Gateway Airport near Sioux City, Iowa.  Emergency crews were activated and rescue efforts began.  Coincidentally, the Iowa Air National Guard had been on duty at the airport for training maneuvers.  This meant that 285 trained personnel were already on hand for the emergency.

The cockpit crew began to prepare for a crash landing at Sioux City. The four men deliberated over what might happen if the landing gear was lowered. Even though the hydraulic system was completely lost, the landing gear has a fail-safe built in.  When the control lever is lowered, gravity will allow the wheels to fall and lock into place. On the other hand, if the landing gear was deployed, how would the change in aerodynamics affect the ability to maintain the slight amount of direction control they had?  In the end, they decided to lower the wheels to soften the impact of landing.

Ground controllers originally assigned for Flight 232 to land on the airport’s longest runway, however, the aircraft control difficulties made maneuvering to that course, impossible.  Meantime the aircraft continued to quickly descend and was found lined up with a runway that had been permanently closed the year before.  This is where the emergency vehicles and crew were waiting, too.  As soon as possible everyone and everything was moved out of the way for the airplane.

On final approach the plane was moving forward at 240-knots, 100-knots faster than normal landing speed. The craft was dropping at 1,850 feet per minute or 1550 feet per minute faster than a safe landing requires.  The flight crew and the ground crew otherwise noted that the airplane was perfectly in line for a successful landing.

UA232-airport

Just moments before touching down, the plane went into a final downward phugoid cycle.  There was no time to counter the effect.  The right wing hit the tarmac first. Fuel was spilled and ignited instantly. Seconds later, the tail section broke away.  The remainder of the aircraft rolled upside down while the cockpit portion broke free.  All of the main parts of the plane came to rest in a cornfield near the runway.

Out of 296 people aboard, 111 were killed in the crash. 35 of them died due to smoke ihalation, the rest died as a result of multiple impacts of the craft on the ground.  UA232-victimsMany of the survivors were able to walk out through gaps in the broken fuselage. It took more than half-an-hour for rescuers to discover the cockpit debris.  All four of the pilots had survived but were seriously injured.

After the lengthy investigation, when all was said and done, everyone agreed that having any survivors was a miracle. The four pilots went beyond the call of duty and gave the emergency everything they had under the dire circumstances.  They somehow managed to maintain composure for the sake of the safety of the passengers and everyone concerned.

The number of people aboard who survived was increased by some important factors. Instrumental was the lucky coincidence of having the Air National Guard on hand for their routine exercises. Crucially, the accident happened during daylight hours.  Just as crucial as the other factors, at the same time, there were two shift changes of employees at the regional trauma center and at the regional burn treatment center in Sioux City. The shift changes meant that there were more medics, on hand, to treat the victims.

Investigators gave high praise to the actions of the flight crew. The cause of the tragedy was due to the failure of United Airlines’ maintenance procedure and mechanics to detect the existing fatigue crack in the engine’s fan disk and blade assembly. The failure to detect the defect was blamed on human error.

UA232-tail

The disintegrating disc threw debris through the protective housing. The metal instantly sliced through all three of the hydraulic control lines in the tail of the airplane. The result was complete loss of hydraulic fluid.  Without hydraulics, it is next to impossible to control a large aircraft.

In the aftermath, the remaining DC-10s have been retrofitted with additional backup parts, failsafe devices and mechanisms.  New training and duties of air crew have been implemented.

Ciao
1984aThe Blue Jay of Happiness notes that the heroics of the crew were dramatized in the made for TV movie, “Crash Landing: The Rescue of Flight 232” which aired on ABC-TV. The film originally aired on February 24, 1992.

About swabby429

An eclectic guy who likes to observe the world around him and comment about those observations.
This entry was posted in History, Hometown, Transportation and tagged , , , , . Bookmark the permalink.

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