Crew Actions And Safety Equipment Credited With Saving Passengers' Lives

The  NTSB has issued its probable cause report for US Airways flight 1549, in which a US Airways A320 jetliner bound for Charlotte was ditched into the Hudson River after striking a flock of Canada geese shortly after departing New York’s LaGuardia Airport. All of the 150 passengers and five crewmembers survived.

The NTSB determined that "the probable cause of this accident was the ingestion of large birds into each engine, which resulted in an almost total loss of thrust in both engines and the subsequent ditching on the Hudson River. Contributing to the fuselage damage and resulting unavailability of the aft slide/rafts were (1) the Federal Aviation Administration’s approval of ditching certification without determining whether pilots could attain the ditching parameters without engine thrust, (2) the lack of industry flight crew training and guidance on ditching techniques, and (3) the captain’s resulting difficulty maintaining his intended airspeed on final approach due to the task saturation resulting from the emergency situation."

In addition to the decisions and actions of the flight crewmembers, overwater safety equipment likely saved lives that might have otherwise been lost to drowning, the NTSB said.

The board met Tuesday to conclude its 15-month investigation into the January 15, 2009, accident.

Photo Credit Gregory Lam

Though it wasn't required on the New York to Charlotte flight, the A320 was certified for Extended Over Water (EOW) operations, meaning it carried forward slide/rafts and other specialized safety gear. Investigators said that, had the airplane not been so equipped, many of the 64 occupants of those rafts would likely have been submerged in the 41-degree Hudson River, potentially causing a phenomenon called “cold shock,” which can lead to drowning in as little as five minutes.

Good visibility, calm waters, and proximity of passenger ferries, which rescued everyone on flight 1549 within 20 minutes, were other post-accident factors the Safety Board credited with the survival of all aboard the aircraft.

“Once the birds and the airplane collided and the accident became inevitable, so many things went right,” said NTSB Chairman Deborah A.P. Hersman. “This is a great example of the professionalism of the crewmembers, air traffic controllers and emergency responders who all played a role in preserving the safety of everyone aboard.”

Photo Credit Gregory Lam

The report adopted by the Safety Board Tuesday validated the Captain’s decision to ditch into the Hudson River saying that it “provided the highest probability that the accident would be survivable.” Contributing to the survivability of the accident was the crew resource management between the captain and first officer, which allowed them to maintain control of the airplane, increasing the survivability of the impact with the water.

In addressing the hazards that birds pose to aircraft of all sizes, the report noted that most bird strike events occur within 500 feet of the ground while flight 1549 struck geese at 2700 feet. Investigators said that this difference demonstrates that “bird strike hazards to commercial aircraft are not limited to any predictable scenario.”

Concluding that engine screens or changes to design would not be a viable solution to protect against bird ingestion events on commercial jetliners, the Board made it clear that the potential for significant damage from encounters with birds remains a challenge to the aviation community. 

Photo Credit Gregory Lam

As part of its extensive examination into the behavior of the passengers and crewmembers from the time the plane left the gate at LaGuardia to the moment the last person was rescued in the river, the Board noted that since most of the passengers indicated that they had not paid attention to the preflight oral safety briefing, “more creative and effective methods of conveying safety information to passengers” was needed. Survival factors investigators also found that passengers had significant problems in donning the life vests that were stowed under each seat.

The Board made 35 safety recommendations on engine and aircraft certification standards, checklist design, flight crew training, airport wildlife mitigation, cabin safety equipment, and preflight passenger briefings.

“I believe the safety recommendations that have come out of this investigation have an extraordinary origin -- a very serious accident in which everyone survived,” said Chairman Hersman (pictured). “Even in an accident where everyone survives, there are lessons learned and areas that could use improvement.  Our report today takes these lessons learned so that, if our recommendations are implemented, every passenger and crewmember may have the opportunity to benefit from the advances in safety.”

Among the other recommendations from the NTSB:

• Require manufacturers of 14 Code of Federal Regulations Part 25-certificated aircraft to develop a checklist and procedure for a dual-engine failure occurring at a low altitude.
• Require 14 Code of Federal Regulations Part 121, Part 135, and Part 91 Subpart K operators to include a dual-engine failure scenario occurring at a low altitude in initial and recurrent ground and simulator training designed to improve pilots’ critical-thinking, task-shedding, decision-making, and workload-management skills.
• Require Airbus operators to amend the ditching portion of the Engine Dual Failure checklist and any other applicable checklists to include a step to select the ground proximity warning system and terrain alerts to OFF during the final descent.
• Require Airbus operators to expand the angle-of-attack-protection envelope limitations ground school training to inform pilots about alpha-protection mode features while in normal law that can affect the pitch response of the airplane. Require applicants for aircraft certification to demonstrate that their ditching parameters can be attained without engine power by pilots without the use of exceptional skill or strength.
• Require, on all new and in-service transport-category airplanes, that cabin safety equipment be stowed in locations that ensure that life rafts and/or slide/rafts remain accessible and that sufficient capacity is available for all occupants after a ditching.
• Require Airbus to redesign the frame 65 vertical beam on A318, A319, A320, and A321 series airplanes to lessen the likelihood that it will intrude into the cabin during a ditching or gear-up landing and Airbus operators to incorporate these changes on their airplanes.

The NTSB also recommends that the U.S. Department of Agriculture "(d)evelop and implement, in conjunction with the Federal Aviation Administration, innovative technologies that can be installed on aircraft that would reduce the likelihood of a bird strike."

FMI: www.ntsb.gov/Publictn/2010/AAR1003.htm