NTSB Aircraft Accident Report
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be needed.”
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Further, the report stated that emergency and abnormal checklists and procedures
must include the necessary information and steps to respond appropriately and that, when
designing checklists and procedures for emergency and abnormal situations, attention should be
paid to the wording, organization, and structure of the checklists and procedures to ensure that
they are easy to use, clear, and complete. The report also indicated that, because attention
narrows during emergency and abnormal situations due to increased workload and stress,
checklists and procedures should minimize the memory load on flight crews and that some
airlines and manufacturers have reduced the number of memory items.
Accidents and incidents have shown that pilots can become so fixated on an emergency
or abnormal situation that routine items (for example, configuring for landing) are overlooked.
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For this reason, emergency and abnormal checklists often include reminders to pilots of items
that may be forgotten. Additionally, pilots can lose their place in a checklist if they are required
to alternate between various checklists or are distracted by other cockpit duties; however, as
shown with the Engine Dual Failure checklist, combining checklists can result in lengthy
procedures. Therefore, checklists should not be overly cumbersome but should still contain all of
the critical items that must be accomplished and should not require pilots to rely heavily on
memory items. Shorter checklists increase the likelihood that pilots can complete all pertinent
items related to the emergency or abnormal situation without distracting them from other cockpit
duties. Unfortunately, many checklists are designed such that pilots become “stuck” in the
checklist and, therefore, complete procedures that may not be appropriate or practical for a given
emergency (such as trying to restart engines). According to a NASA representative’s public
hearing testimony, to minimize the risk of becoming stuck in an inapplicable portion of a
checklist, checklists can be designed to give pilots “opt out” points or “gates,” which are
conditional if-then statements. (For example, “if the aircraft is below 3,000 feet, then go to step
27.”) Incorporating such points into checklists will encourage pilots to reevaluate the situation
and determine whether they are using the appropriate checklist or portion of a checklist and
whether the task focus should be shifted.
The NTSB notes that this is not the first accident in which checklist design was
recognized as a safety issue. For example, after the September 2, 1998, Swissair flight 111
accident in which a seemingly innocuous smoke event evolved, after several minutes, into a
sudden and severe in-flight fire, the Transportation Safety Board of Canada determined that the
checklist that the flight crew attempted to use would have taken about 20 to 30 minutes to
complete.
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However, only 20 minutes elapsed from the time that the on-board fire was detected
until the crash occurred. In late 2004, the Flight Safety Foundation began an international
initiative, which included the participation of manufacturers, airlines, pilots, and government
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B.K. Burian, I. Barshi, and K. Dismukes.
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For examples of such accidents and incidents, see (a) Wheels-Up Landing, Continental Flight 1943,
Douglas DC-9-32, N10556, Houston, Texas, February 19, 1996, Aircraft Accident Report NTSB/AAR-97/01
(Washington, DC: National Transportation Safety Board, 1997). (b) The reports for NTSB case numbers
CHI94FA039 and DCA06MA009 are available online at <http://www.ntsb.gov/ntsb/query.asp>.
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See In-Flight Fire Leading to Collision with Water, SwissAir Transport Limited, McDonnell Douglas MD-
11, HB-IWF, Peggy’s Cove, Nova Scotia, 5 nm SW, 2 September 1998, Aviation Investigation Report A98H0003
(Quebec, Canada: Transportation Safety Board of Canada, 2003).