From a paper:
LINE PILOT PERFORMANCE OF MEMORY ITEMS
Howard Au
Boeing Commercial Airplane Group*
P.O. Box 3707 MC 67-TC
Seattle, WA 98124, USA
* This research was paid for through out-of-pocket expenses by the author. It was conducted while the author was a
student at Embry-Riddle Aeronautical University in partial fulfillment for the degree of M.S. Aeronautics.
Even though the method used in this study did not
induce stress, it allowed for an evaluation of the pilots’
knowledge of the memory items without prior
preparation. Pilots generally perform well during their
PCs, and possibly better than inflight, because they
expect an evaluation and can prepare for it. Pilot
performance observed in this study may be closer to
that in an inflight emergency, in which the pilots are
unprepared to perform their memory items.
Clearly, an inflight emergency places a pilot under a
great deal of stress. Based on the literature review, it
can be inferred that errors similar to those observed
here may occur inflight during an actual emergency,
and may even occur more frequently due to increased
stress. Conducting a similar study in a full-flight
simulator may provide a level of stress similar to what
is experienced in a real emergency. The results
obtained from a simulator could be a more realistic
representation of the results obtained inflight.
The results demonstrate that pilots have difficulty
identifying the cause of the failure and selecting the
correct procedure. After identifying the situation,
knowledge of the appropriate memory items is such
that pilots commit errors in recall even during
unstressed conditions with a poster of the flight deck
for context.
None of the five failure scenarios in this study had a
distinct indicator light that would annunciate the
condition. Pilots were forced to analyze the cues and
determine the appropriate procedure. This is an
uncommon and involved task, and not performing it
may force pilots to complete only those tasks they are
familiar with, such as following an illuminated LOW
OIL PRESSURE light to the Low Oil Pressure
checklist during an aborted engine start, or fixating on
abnormal engine noises and performing the Engine
Fire/Severe Damage/Separation checklist, instead of
the more appropriate Engine Limit/Surge/Stall
checklist.
The observed checklist step errors showed that pilots
commit a number of errors. The majority of the
commission errors were steps performed by pilots to
resolve a failure based on their knowledge of the
airplane systems. Some of these commission errors
The results demonstrate that pilots have difficulty
identifying the cause of the failure and selecting the
correct procedure. After identifying the situation,
knowledge of the appropriate memory items is such
that pilots commit errors in recall even during
unstressed conditions with a poster of the flight deck
for context.
None of the five failure scenarios in this study had a
distinct indicator light that would annunciate the
condition. Pilots were forced to analyze the cues and
determine the appropriate procedure. This is an
uncommon and involved task, and not performing it
may force pilots to complete only those tasks they are
familiar with, such as following an illuminated LOW
OIL PRESSURE light to the Low Oil Pressure
checklist during an aborted engine start, or fixating on
abnormal engine noises and performing the Engine
Fire/Severe Damage/Separation checklist, instead of
the more appropriate Engine Limit/Surge/Stall
checklist.
The observed checklist step errors showed that pilots
commit a number of errors. The majority of the
commission errors were steps performed by pilots to
resolve a failure based on their knowledge of the
airplane systems. Some of these commission errors
demonstrated a misunderstanding of how the systems
in the 737 functioned. Other errors were a result of
either knowledge gained during a real experience in
the past, or a belief carried over from previous
organizations and airplanes, which may no longer be
applicable.
Implications
Even though the method used in this study did not
induce stress, it allowed for an evaluation of the pilots’
knowledge of the memory items without prior
preparation. Pilots generally perform well during their
PCs, and possibly better than inflight, because they
expect an evaluation and can prepare for it. Pilot
performance observed in this study may be closer to
that in an inflight emergency, in which the pilots are
unprepared to perform their memory items.
Clearly, an inflight emergency places a pilot under a
great deal of stress. Based on the literature review, it
can be inferred that errors similar to those observed
here may occur inflight during an actual emergency,
and may even occur more frequently due to increased
stress. Conducting a similar study in a full-flight
simulator may provide a level of stress similar to what
is experienced in a real emergency. The results
obtained from a simulator could be a more realistic
representation of the results obtained inflight.