Last night I watched a show on National Geographic that showed the crash landing of United Flight 232 on July 19th, 1989. This is an amazing story that I would like to share.
At 3:16PM on that fateful day, a loud bang could be heard on United Flight 232 and the crew determined that the number two engine on the DC-10 had blown. Normally that wouldn’t be a big deal because the DC-10 has two other engines; one on each wing (The number two engine is on the tail of the plane).
The pilots went through the normal procedure to completely shut down the number two engine, but after doing so they noticed that they were losing hydraulics in all 3 hydraulic systems. These systems are completely separate and have built-in redundancy, so the chances of losing all 3 systems at the same time are almost impossible.
To give you an idea of the grave situation these pilots were dealing with, as a result of losing the 3 hydraulic systems, the pilots could not control the ailerons (to bank the airplane), the rudder (to turn the airplane), the elevators (To pitch the airplane up or down) and the flaps (to slow the plane down when landing).
This situation is every pilots worst nightmare and at the time it was inconceivable that it could even happen. Since this situation had never happened before, there was no training that the pilots had received in order to deal with this situation. The Captain of the flight, Al Haynes was an experienced pilot with 30,000 hours of flight time. He determined that the only chance they had to survive would be to perform an emergency landing by guiding the plane solely by adjusting the engine throttles for the two remaining engines. To turn left, they increased power in the right engine and vice versa.
Fortunately an experienced DC-10 training pilot with over 3,000 hours on the DC-10 was a passenger on the plane, so he helped the crew by controlling the throttles while the Captain prepared for the emergency landing.
With impossible odds, the crew was able to line the plane up to a runway at Sioux City airport for the emergency landing. Since it was extremely difficult to descend smoothly, they were descending at over 1,600 feet per minute and when the plane landed on the runway the right wing tipped down and the plane broke apart into 3 main pieces and erupted into a ball of fire.
Unfortunately 112 people died in the crash landing, but miraculously, 184 people survived the crash including the 4 pilots in the cockpit. In a NASA interview 2 years after the crash, Captain Al Haynes explains the first factor in the fact that people were able to survive the crash as luck. Subsequent simulator tests showed that other DC-10 pilots were unable to land the aircraft in the condition 232 was in, so it could be considered a miracle that they were able to survive. In the interview, Captain Haines said he and the other pilots didn’t think they would make the airport, so they were surveying for flat fields nearby that they would aim for if they weren’t able to make it to the airport.
After investigating the incident they determined that the engine blew because of a small cavity in the fan disk in the engine as a result of a manufacturers defect. They also concluded there was human error in the inspection since the cavity should have been visible when the fan was inspected. Fragments from the fan and the engine casings blew through all 3 hydraulic systems causing the fluid to run out in all 3 systems. The results of the investigation drastically changed the inspection and training procedures in the airline industry to ensure this would never happen again.
If you’ve ever landed a jet in a flight simulator with working controls, you can probably appreciate how difficult it would be to land a plane with no controls. These pilots did an amazing job under the circumstances and everyone who survived owes their lives to these 4 men.