Resilience Engineering #3: Miracle on The Hudson

by Gary Monti on June 21, 2011

Capt. “Sully” Sullenberger behaved memorably January 15, 2009 commanding US Airways flight 1549. Most of us know it as “The Miracle on the Hudson” where an Airbus A320 with 170 passengers was safely crash-landed on the Hudson. A six-minute flight encapsulated many of the traits associated with behavior driven by a resilient engineering frame of mind.

The Incident

At 3:27 PM, two minutes after take-off, the plane flew into a flock of geese at 3200 feet. Birds were ingested and both engines were immediately lost. Capt. Sullenberger took the controls while first officer Skiles began going through the three-page emergency procedures to restart the engines.

The Assessment

Passengers and the cabin crew reported hearing a very loud bang from both engines followed by flaming exhausts, then silence with the smell of unburned fuel filling the cabin. Radioing back to LaGuardia air traffic control Sullenberger was told that runway 13 was available for an emergency landing.

The Decision

Sullenberger made a quick assessment of the energy the airplane had at that time and felt that he would be unable to make it. (Later extensive analysis showed that the airplane probably did have sufficient energy to make it back to LaGuardia.) Similarly, an emergency landing at New Jersey’s Teterboro airport was considered but, again, Sullenberger felt the airplane lacked sufficient energy to make it that far. He decided to ditch in the Hudson.

The Consequences

The plane ended its 6 min. flight at 3:31 PM with unpowered ditching in the Hudson heading south at 130 kn. Fortunately throughout the flight auxiliary power was available to maintain control of the aircraft’s flight surfaces. Performing such a feat requires a good amount of luck as well as tremendous skill. An unpowered water landing can be extremely dangerous since any deviation from being perfectly level can lead to an asymmetrical landing, tearing the plane apart. Then there were the difficulties associated with gliding an airliner 2 knots above stall speed (stall speed is when the plane would just drop like a rock.)

The Emotions

When interviewed by CBS News Sullenberger said, “It was the most sickening feeling in the pit of my stomach, like falling through the floor. I knew immediately it was very bad. My initial reaction was one of disbelief, ‘I can’t believe this is happening. This doesn’t happen to me!’ ”

Patrick Hartson, LaGuardia air traffic controller stated, “I asked him to repeat himself even though I heard him just fine. I simply could not wrap my mind around those words. And when the plane disappeared from my radar screen it was the lowest low I had ever felt; truth was, I felt like I’d been hit by a bus.”

When interviewed by Larry King, Capt. Sullenberger stated, “I expect that this was not going to be like any other flight I’d flown in my entire career. And it probably would not end on a runway with the airplane undamaged.”

Trade Offs: Thinking Outside the Box…What Box!?

For Sullenberger and his copilot all they had trained for and anticipated lost any value. This was a unique situation where everything was initially a blur. Pilots are trained on how to deal with the loss of a single engine as well as how to make controlled landings from altitude. This, however, was not in the simulations.

In such crisis situations the ability to make a completely “right” decision disappears. The situation is highly constrained due to a lack of time, information, and resources. So, instead of making a “satisficing” decision, i.e., the “right” decision, one must make a sacrificing decision trading off threats against opportunities in an attempt to achieve the optimal results under the circumstances.

In line with this Sullenberger went on to say, “I quickly determined that we were at too low an altitude, at too low air speed, and therefore we didn’t have enough energy to return to LaGuardia. After briefly considering the only other nearby airport which was Teterboro in New Jersey, I realized it also was too far away. And the penalty for choosing wrongly, in attempting to make the runway, I could make a mighty catastrophe for all of us on the airplane plus people on the ground.”

So, the trade-off Sullenberger was faced with was either land in the Hudson and have a potentially damaging but non-catastrophic landing or try for the happy ending at LaGuardia with the downside being a totally catastrophic crash.

Another trade-off that needed to be considered was the fact that in attempting to relight the engines there was failure with engine #2 while engine #1 had a partial relight providing sufficient thrust to maintain hydraulics and electrical supply. So, the decision had to be made whether or not to continue limping along with some power which was useful for a controlled crash landing or risk attempting shutting off engine 1 and attempting to relight to get full thrust but risking loss of all thrust.

Again, all of this occurred during the last 4 minutes of a 6 min. flight.

In addition to being an experienced pilot with over 30 years experience between the Air Force and commercial aviation,

Sullenberger was also an experienced glider pilot, a skill that proved immeasurably valuable in saving the situation. He treated the airliner as if it was the world’s heaviest glider.

There is more to this story. While the pilot and copilot were working in the cockpit the cabin crew did their job maintaining composure among the passengers and conducting an orderly exit of the plane. This included evacuating one wheelchair-bound person and having passengers climb over the tops of the seats to reach the exit while water was rising in the cabin. Another issue was stopping a panicked passenger from opening a door that was partially underwater. Surprisingly, all were saved.

These actions set the stage for looking at resilience in depth as well as determining character traits possessed by resilient people working individually and as a team.

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