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15 July 2013

Questions about the crash of Asiana flight 214

Over the past week, numerous questions and comments about the Asiana plane crash have been sent to Dr. Todd Curtis at Below are answers to some of the more popular questions posed by the public and the news media.

According to international protocol, who will be in charge of the investigation?

According to section five of Annex 13 to the Convention on International Civil Aviation, the state of occurrence of the accident (in this case, the United States) is required to begin an investigation, and has the option of delegating the investigation to another state or to a regional organization. Typically in the US, the NTSB leads airline accident investigations, unless it is determined to be caused by a criminal act. If that is the case, the FBI takes the lead in the investigation. So far, there is no indication that there was a criminal act, so the NTSB will likely lead and complete the investigation.

How long until this investigation is completed?

Typically, an NTSB investigation takes over a year to complete. The NTSB has published 13 reports on aircraft accidents that have occurred since the beginning of 2009. The shortest time until completion was just over nine months, and the longest was just under 27 months.

The information presented so far by the NTSB seems to point to either a case of pilot error or mechanical failure. From what you have seen, is there any way that you can say which one is more probable?

It is too early to focus on any one possible cause since the NTSB is still in the early part of the investigation, and has only processed and released some of the factual data from the investigation. It is also possible that the probable cause (or probable causes) may include something besides pilot error or mechanical failure. As the investigation continues, the NTSB will know more about the causes of the accident.

While Asiana Airlines stated that the pilot who was in control during the landing was an experienced airline pilot, his limited experience with the 777 seems to lend weight to the pilot error argument. What is the appropriate length of time for a pilot to be trained?

That question is beyond my expertise, but I will say that standards for airline pilots are extremely high around the world, and part of that high standard includes extensive training when airline pilots transition to new aircraft. That training includes ground school to familiarize pilots with systems and procedures, as well as training in high-fidelity aircraft simulators, including full motion simulators, that simulate the sights, sounds, and sensations pilots would experience in an actual aircraft. These training programs have often been developed in concert with the manufacturer to ensure that the training reflects the behavior of the aircraft.

The South Korean government as well as the world's largest organization of airline pilots, the nternational Federation of Air Line Pilot's Association, criticized the NTSB for revealing too much from the Asiana flight 214 investigation. What do you think about the press conferences held by the NTSB since the accident?

The press conferences have been an excellent source of information about the investigation. In my opinion, the kind of information the NTSB has provided is similar to what has been provided from past accidents. The biggest differences between this investigation and prior major investigations have been the access provided to the public and the NTSB's use of social media to inform the public of the availability of recorded press conferences, photographs, and other information from the investigation. In short, the NTSB is providing information much more quickly, and in a more accessible manner than before, but the kind of information being released is consistent with what has been released in the past.

The 777 is reportedly one of Boeing's flagship products and has a strong safety record. Why do you think this is the case?

There are many reasons for this record, and one of them are the high certification requirements of the FAA. At the time of its development, the 777 incorporated regulatory requirements of the FAA, and of the equivalent organizations in Europe and elsewhere. One of those requirements was the inclusion of 16G passenger seats.

A 16G seat is one that is tested in ways that simulate the loads that could be expected in a survivable accident. These seats must withstand two different accident scenarios, one in which the forces are mostly in the vertical or downward direction, and one in which the forces are predominantly in the forward or longitudinal direction. The highest load factor these seats must withstand is in the forward direction at 16Gs (16 times the force of gravity). It is unclear what kinds of forces were experienced by the seats on flight 214, but the NTSB will determine that as part of the investigation.

All aircraft certified by the FAA after 1988 had to have these seats, and since the 777 was certified after 1988, every 777 was delivered with these kinds of seats. The previous FAA standard for commercial airliners was 9G seats.

There are several other regulatory requirements and industry innovations that were incorporated into the 777, and I will mention just a few:

  • Cabin materials that are more fire resistant and less likely to produce dangerous fumes when burned,
  • Evacuation requirements that include emergency lighting on or near the cabin floor so that they can be more easily seen in a smoke-filled cabin.
  • Ground proximity warning systems to help warn pilots when they are flying too low or flying in an area of rising terrain,
  • Collision avoidance systems that warn pilots when other airliners are on a collision course or about to pass at an unsafe distance,
  • Emergency exit systems that allow a 777 with a full load of passengers to evacuate all passengers in 90 seconds or less while using only half of the eight available exits,
  • Multiply redundant aircraft systems, including a flight control system that will allow differential engine thrust to be used if flight control surfaces are not working,
  • Main landing gear that are designed to break off in a hard or crash landing in such a way that the wing fuel tanks are not punctured, and
  • Communications systems, including radios to communicate with airport personnel and cabin public address systems, that will continue to operate after a crash even if electrical power is no longer available from the engines or auxiliary power unit.

As an aviation safety expert, what do you think made this crash so survivable?

Very likely several of the items mentioned in the previous answer helped to keep the number of fatalities low, particularly the use of fire resistant cabin materials, the design of the emergency evacuation systems, the design of the main landing gear, the availability of aircraft communications systems, and the presence of the emergency exit lighting on or near the floor. Another factor was the prompt response from emergency and medical personnel who were at and near the airport.

According to the NTSB, the pilots ordered the passengers to remain seated for 90 seconds after the plane came to a halt, until the cabin crew noticed a fire when the evacuation was initiated. Were 90 seconds too long?

The decision to evacuate an aircraft after a crash is made by the crew based on the conditions inside and outside the aircraft. According to the NTSB, the crew made the decision to evacuate when fire was seen outside the cabin. The NTSB will review the accident to determine if there were any problems or errors in the timing of the evacuation decision or the execution of the evacuation.

According to international protocol, how are accident victims usually compensated?

Compensation for events involving international flights is covered by the Montreal Convention, and damage sustained by a passenger or a passenger's baggage in the event of an accident is not subject to any financial limit. How the compensation happens can be complex, especially since the accident took place in the United States. Because of the location of the accident, there may be a variety of international, federal, and state of California laws that may be relevant. Typically, the parties involved agree to a settlement without having a trial, and the terms of the settlement are not shared with the public.

Who is responsible for paying for the claims of victims?

Usually, any private company, government organization, or private individual that has some or all of the legal responsibility for the accident may have to pay victim claims. While many different entities may be legally responsible, in the US, typically only private companies end up paying compensation to victims or their families.

Does the NTSB determine who is legally responsible for paying for the claims of victims?

The NTSB investigation is separate from the process for determining legal liability. While the NTSB investigation is typically completed in about a year, legal proceedings involving victim compensation may take much, much longer to complete.

There remains substantial data from Boeing and the airline that must be reviewed. What do you think is the focal point of this ongoing investigation?

I currently don't have an opinion about what the focus will be because the investigation is still in the early stages. The focus of the NTSB investigation is to determine the probable cause or probable causes that led directly to the accident, as well as to identify those contributing causes that indirectly led to the accident. As the NTSB stated in several of their briefings last week, there is still a substantial amount of information that has to be gathered and analyzed before they will be able narrow the focus of the investigation.

As far as safety is concerned, what long-lasting influence will this accident have in the aviation field?

The long term effects will largely be determined by the recommendations that come out of the NTSB investigation, and any additional insights that the industry may gain from this accident. Until the investigation is complete, it is very difficult to predict the long-term influences of this accident.

Additional information 13 July 2013 summarizing the two prior NTSB press conferences 10 July 2013 article on the role of the autothrottle 8 July 2013 article on early findings of the crash investigation
Other Asiana plane crashes
Other 777 plane crashes
Accident details from Aviation Safety Network
Wikipedia page on this accident

The day after the crash, Dr. Curtis of and Capt. Tom Bunn of the SOAR fear of flying program, who both spent several hours on the day of the crash on cable news programs providing expert commentary, discussed the media's response to the accident and shared their thoughts on the early reports of the crash.

1 comment:

  1. I have worked the flight line at JFK Airport in New York City for over 20 years in the field of Avionics.
    And I have seen many air tragedies and near tragedies.
    It is standard safety protocal that the this aircraft would have had Defueling Trucks at that the site to remove fuel from the aircraft.
    After two go-arounds 'as stated in the news',the remaing fuel within the tanks was usurped at full throttle.....leaving only fuel tank vapors as what happened in the air tragedy of USAIR Flight 427. Whereby the absence of fuel disabaled the the Hydraulic Fuel Exchangers which were located within the fuel tanks and cooled by fuel within the fuel tanks. This disabled the Flight Control System by causing a hydraulic seizure of the Wing Surfaces, Rudder and Horizontal Stabilizer thus...initiatibg a nose dive of this aircraft.
    Lastly, if there was fuel within the main tanks on the impact of this landing, the spillage would have initiated an inferno causing the loss of much more lives.
    The truth of this will surface in Court whereas all the Log Book records and data from from Flight Recorder and Voice Recorder will be released.
    In was the abense of fuel within the Center Fuel Tank of TWA Flight 800 that allowed the high torque D.C. motor of the Scavenger Pump th initiate the intense spark which ignited the explosion.
    As an Avionics Tecchician at TWA,it was instructed in training to enforce this FAA Airworthingness to all times keep all Scavenger Pumps submerged by the coolant of fuel.
    During the Arab Oil Embargo in the 1970's this A.W. was lifted thus, causing a tremendous financial gain by all Airlines (including Cargo Carriers) to substitute the take weight of fuel for cargo.
    This was never re-instated until the air tragedy of TWA Flight 800.
    It was Attorney Alan Wolk who representated the victims of USAIR Flight 427 in Pittsburgh PA
    said the that the FAA, Airliines and Aircraft Manufactuers are onon the same side when there is an air tragedy.
    The truth of the cause of this air tragedy will surface during legal recourse.