Why are Routine Flight Operations Killing Pilots and their Passengers?
Robert Baron
Presented at the Human
Performance, Situation Awareness and Automation Technology Conference (HPSAA),
March 24, 2004, Daytona Beach, FL.
ABSTRACT
Routine flight
operations present pilots with a myriad of latent threats. Three accident
scenarios are presented that exemplify how a routine flight operation can end in
disaster. The pilot's complex and dynamic psycho-cognitive behaviors are
analyzed and show that satisfactory technical training alone does not make a
safe pilot.
More emphasis needs to
be put on the "human system," the most likely system to fail in flight.
Recommendations address
the areas where intervention and education may mitigate some of these issues.
SCENARIO ONE
The crew had just
finished recurrent training. The instructor praised both pilots for exemplary
performance in the simulator, and attested to that fact with positive comments
on both pilot's grade sheets. Both pilots had thousands of hours of flight
experience and thousands of hours of combined time in the particular make and
model they were flying. They were back on the line the following day.
Their
first leg back on the line proved tragic, as both pilots, and 27 passengers were
killed when the aircraft descended prematurely on a non-precision approach at
night. As usual, the first question asked was "what happened?" How could such an
experienced and well-trained crew commit this type of error, especially the day
after they received recurrent training and were commended on their skills?
This
is but one example of a routine flight operation gone terribly wrong. The pilots
had flown into this airport on numerous occasions, albeit during daylight hours.
The weather was reported to be good Visual Flight Rules (VFR), the wind was
calm, and the runway was 10,000 feet long. Visual Approach Slope Indicators
(VASI's) were available to establish a proper glide angle to the runway
threshold. But for some reason, the crew descended below the VASI's prematurely,
causing the aircraft to impact the ground a few miles from the end of the
runway. Another classic Controlled Flight Into Terrain (CFIT) accident has
occurred. A perfectly airworthy airplane, under complete control, was flown
unintentionally into the ground without any prior awareness by the flightcrew.
This
example shows us, in its purest form, where technical training ends and human
factors begin. This type of accident occurs more frequently than one would be
led to believe. The pilots assumed this was a routine flight. After all,
the weather was good and there was nothing wrong with their aircraft just
minutes before landing.
As it
turns out, the captain, who was the pilot flying, was compelled to attempt a
night visual approach to the runway, even though the VOR Runway 17
instrument approach was briefed and set up earlier. When the first officer
queried the captain on this discrepancy, the captain replied that he "wanted to
shoot the visual approach since the weather was good and it would save some
time." That was the last discussion recorded on the Cockpit Voice Recorder (CVR)
before the sound of impact, approximately two minutes later.
In a
macro-analysis of this accident, it was concluded that the aircraft impacted
rising terrain approximately 2.3 miles from the runway threshold. Additionally,
the aircraft was 800 feet lower than it should have been at that point if the
pilots had executed the VOR Runway 17 instrument approach. For a technically
proficient crew, which this crew was, the instrument approach alternative would
have been routine, and the outcome would likely have had a more successful
result.
WHY?
This scenario might be considered a quintessential
example of failure in human performance. A fully trained, experienced, and
competent flight crew committed a series of errors that lead to a Controlled
Flight Into Terrain accident. Why?
"Why," as it relates to
aviation accidents, is a very complex and challenging question. The attempt to
analyze a pilot's cognitive thought processes extends far beyond the scope of
this paper. After all, only the pilot can really answer the question, "what were
you thinking?" We can however, use deductive reasoning to look at where some of
the problems manifest themselves.
For the sake of simplification,
we will look at only two distinct areas, (1) Training facility weaknesses, and
(2) Psycho-cognitive threats during routine flight. A breakdown in these areas
can pave the way for the highest and most undesirable event; an accident.
TRAINING FACILITY WEAKNESSES
Not enough emphasis put on the most unreliable
system in the aircraft, (the pilot):
Pilot training on a specific aircraft can last
anywhere from a few days, up to a few months, depending on the type of aircraft.
Training facilities put a large amount of effort into teaching systems in the
shortest amount of time possible. And while the importance of good systems
knowledge is undeniably important, the most failure-prone system, the pilot, is
often overlooked or disregarded.
Crew Resource Management training is weak or
non-existent at many facilities:
Although many training facilities have begun to
incorporate a fair amount of CRM training into their programs, some facilities
do not have the time or properly trained facilitators to make a significant
impact during a normal training period. After a 2 hr training period, a single
CRM debriefing comment by the simulator instructor to the affect of "you should
speak up more next time," does not adequately address the problem.
Simulator training time is too compressed. Many
emergency/abnormal scenarios that are combined to save time are unfounded and
are extremely unlikely to occur in real life:
Some facilities, in the interest of time, will
combine multiple emergency/abnormal scenarios. It is extremely improbable that a
modern airliner or business jet will experience an engine failure and a total
hydraulic failure at the same exact time, and that the pilots will have to
execute a circle-to-land approach with the weather right at landing minimums.
Yet, these are the types of scenarios that some facilities are training and
testing pilots on.
"Routine" flight operations are under-emphasized.
Yet, routine flight operations claim many more lives than non-routine
operations:
Inasmuch as the previous topic depicted an overdose
of non-realistic scenarios, this topic highlights a relatively untouched realm
of training: Routine flight operations. Realistically, engine failures,
hydraulic failures, and popped circuit breakers are not killing pilots and their
passengers. The largest number of crashes and fatalities occur when nothing is
mechanically wrong with the aircraft.
PSYCHO-COGNITIVE THREATS DURING ROUTINE FLIGHT
The next level picks up where the training ends. At
this point, the crew has satisfactorily completed recurrent training and is back
on the flight line. All incidences referenced from this point forward are
considered "in-flight."
Keep in mind that all three
accident scenarios in this report were due to a failure in human performance,
and not a mechanical malfunction. In other words, the problems were not easily
identifiable in training, but they became blatantly clear later on.
During flight, the pilot's
psycho-cognitive system performs like a computer, inputting thousands of bits of
information, with the associated action commands performed as an output.
Occasionally, there is a "short circuit" in these processes and the stage is set
for problems.
The following list breaks down
the events for Scenario One into CRM marker clusters, as defined in FAA Advisory
Circular 120-51D. The author has incorporated additional clusters for clarity.
Refer to the figure below for a graphical flow of the Captain's behavioral
patterns.
Proficiency Training- The crew was
proficient with no training weaknesses noted.
Illness/Medication- Neither pilot tested
positive for alcohol or drugs, including over-the-counter medication.
Fatigue- The crew was well rested
Distractions- Distractions were not
considered a significant factor in the accident.
Stress- Stress was low. During the approach
phase of flight, stress levels will normally be somewhat elevated.
Workload- Workload was considered routine.
During the approach phase of flight, workload will normally be highest.
Task Management- Management of tasks became
somewhat ambiguous. A last minute change of the approach procedure by the
Captain was a factor.
Communicative Ability- The Captain's
decision to change the approach procedure and not re-brief was the beginning of
the "red zone."
Complacency- The Captain displayed signs of
complacency. He considered this a routine approach and the weather was good. He
had also been into that airport many times before.
Decision Making- Complacency likely
influenced the decision making misjudgment.
Personality Traits- Ingrained and hard to
change. The Captain's personality included a large amount of machismo, according
to pilots who had flown with him in the past.
Risk Taking- This is the area where decision
making and machismo converge. The Captain had decided to "take the risk."
Assertiveness- The First Officer may have
had the last chance to trap the Captain's bad judgment. However, the F/O did not
speak up and challenge the Captain.
Situation Awareness- Due to all the previous
unmitigated behavior problems, the crew experienced a loss of situation
awareness. A perfectly airworthy aircraft was flown into the ground without any
prior awareness by the flightcrew.
SCENARIO TWO
The crew successfully completed all of the training
requirements required for an annual pilot proficiency exam. As in the first
scenario, the crew, as a whole, was highly experienced both in total flight
hours and in the specific aircraft type.
This particular leg was a
repositioning flight. Only the pilots were onboard, who were flying the aircraft
to another airport to pick up their passengers and fly them to their
destination. The repositioning flight was very short in duration, approximately
15 min. There were no known aircraft anomalies and the weather was considered
good for the short flight. The airport facilities were well suited for the type
of operation being conducted by this flight crew.
For some reason, the crew
decided to perform a circle-to-land maneuver (which requires excess maneuvering
to line up with the landing runway, as opposed to straight-in). During the
circle-to-land, something had gone terribly wrong. A post crash investigation
revealed that the aircraft experienced a loss of control at a low altitude and
airspeed, indicative of an accelerated stall. Both pilots were killed. The
investigation also verified no defects to the aircraft that may have contributed
to the loss of control.
The following list breaks down
the events for Scenario Two. Refer to the figure below for a graphical flow of
the Captain's behavioral patterns.
Proficiency Training- The crew was
proficient with no training weaknesses noted.
Illness/Medication- Neither pilot tested
positive for alcohol or drugs, including over-the-counter medication.
Fatigue- The crew was well rested
Communicative Ability- The crew had very
good communicative ability. Checklists were called for and accomplished at the
right time, briefings were thorough, and there was no ambiguity as to what
actions were going to be taken next.
Risk Taking- The Captain was not a known
risk taker. In fact, interviews with other pilots had indicated that he was
rather "passive" and "conservative" in his flying skills.
Complacency- It did not appear that
complacency played an active role in this accident. The fact that a
circle-to-land maneuver is not executed that often would likely have raised the
pilots awareness of the extra vigilance required for that particular maneuver.
Stress- Stress levels were in a high caution
area for two reasons: 1) Pressure for a timely arrival to pick up paying
passengers, and 2) An approach that requires a higher amount of monitoring due
excessive maneuvering at low altitudes.
Workload- The combination of maneuvering the
airplane, scanning for other traffic, and properly aligning the airplane with
the landing runway significantly increased the workload. This was the beginning
of the "red zone."
Task Management- Task management became an
extremely high threat as the Captain, who was the non-flying pilot, became
task-saturated in both monitoring the F/O's performance, scanning for other
traffic, and ensuring proper alignment with the landing runway.
Distractions- Pervasive distractions during
the most critical phase of the approach drew the Captain's attention away from
the F/O's dangerously slow airspeed and steep bank angle.
Personality Traits- The Captain had a Type-B
Personality. Immediate and corrective actions, such as taking the controls of
the airplane, may have been hampered by this personality trait.
Decision Making- This is the area where
distractions and Type-B Personality converge. The Captain decided to let the F/O
continue the approach with no apparent intervention.
Assertiveness- Assertion on the part of the
captain in the form of "callouts" or other verbal warnings were lacking.
Additionally, the Captain never made an attempt to take over the controls.
Situation Awareness- Due to all the previous
unmitigated behavior problems, the crew experienced a loss of situation
awareness. A perfectly airworthy aircraft was flown into a dangerous flight
regimeÉan accelerated stallÉclose to the groundÉfrom which recovery was not
possible.
SCENARIO THREE
The third and final scenario once again involved a
highly experienced crew. In this case a commuter operation. Their last
proficiency check included positive remarks on the captain's training record
reflecting "good use of CRM," and "excellent Situational Awareness." The first
officer's training record had included a notation "excellent flying skills,
should be considered for upgrade shortly."
Both pilots were well rested
after having the previous four days off. This was their first flight of the day.
A routine flight was forecast for the short leg with a passenger manifest of 16
and one flight attendant. The weather would not be a factor. As a matter of
fact, it was a remarkably clear spring day. Mechanically, there were no open
airworthiness items that could affect the safety of flight.
Approximately one and a half
minutes after takeoff, the commuter plane collided with a small general aviation
aircraft. Both pilots, all 16 passengers, and the flight attendant were killed
on the commuter. Additionally, the pilot and two passengers perished in the
Piper Cherokee single-engine general aviation aircraft.
The following list breaks down
the events for Scenario Three. Refer to the figure below for a graphical flow of
the Captain's behavioral patterns.
Proficiency Training- The crew was
proficient with no training weaknesses noted.
Illness/Medication- Neither pilot tested
positive for alcohol or drugs, including over-the-counter medication.
Fatigue- The crew was well rested
Communicative Ability- The Captain's
communicative ability was cause for a moderate amount of caution. In general, he
tended to be very impulsive and act without regard to input from previous F/O's
that had flown with him.
Situation Awareness- Situation awareness was
also in a moderate caution area. Pushback and taxi to the active runway was
routine and the crew was cognizant of their taxi route, departure clearance, and
other potentially conflicting ground traffic.
Stress- Stress levels became elevated due to
the crew's acceptance of an immediate takeoff clearance before completion of the
Before Takeoff Checklist.
Complacency- The Captain's decision to be
rushed into a takeoff clearance may have been partially influenced by
complacency. This can be corroborated by the Captains comment of "I've done this
a thousand times before," captured on the Cockpit Voice Recorder. This was the
beginning of the "red zone."
Workload- During the rushed takeoff
procedure, workload increased to a point where there were so many tasks
(checklist procedures) that needed to be accomplished in such a short period of
time, that some tasks were omitted.
Task Management- Task management was
severely degraded due to the reasons stated in the previous cluster.
Personality Traits- The Captain's
personality traits included a Type-A Personality, which can be classified as a
very high caution area. Other pilots who had flown with the Captain described
him as a person "always in a rush to get things done."
Decision Making- This is the area where task
management and Type-A Personality converge. The combination of the Captain's
impulsive behavior, coupled with poor task management, led to a spontaneous and
risky decision (acceptance of a premature takeoff clearance).
Risk Taking- Both the Captain and F/O were
willing to assume the risk of an immediate departure based on a repetitive and
successful schema ("we've done this so many times before").
Assertiveness- The First Officer may have
had the last chance to trap the Captain's bad decision. However, the F/O did not
speak up and challenge the Captain.
Distractions- One of the items omitted on
the before takeoff checklist was turning on the Traffic Collision Avoidance
System (TCAS). Shortly after becoming airborne, the crew continued to try to
"catch up" on the checklist items that should have been completed prior to
takeoff. Both pilots were working inside the cockpit and neither was looking
outside for conflicting traffic. Due to all the previous unmitigated behavior
problems, a perfectly airworthy aircraft was involved in a mid-air collision.
RECOMMENDATIONS
These accident scenarios are a
classic representation of human error in its purest form. Human performance is a
complex and challenging science. More attention needs to be focused on "why
pilots do some of the things they do (or don't do)," and what the associated
consequences of those actions might be. Recommendations for improving the system
should address the following areas:
1.
Training facilities must put more emphasis on human performance. This might be
accomplished with a stand-alone training module that addresses
this area in more detail.
2. CRM
training needs to become mandated for all flight operations (currently,
the FAA does not require Part 135 on-demand charter pilots to have formal CRM
training).
3. CRM
Facilitators should have some formal training on proper training and
debriefing methods.
4.
Simulator training should concentrate on more realistic flight and
emergency/abnormal scenarios and avoid simultaneous unrelated systems failures,
compounded by the worst possible weather.
5.
During ground school and simulator training, an emphasis should be made that
"routine flight operations" can become a significant threat and complacency can
exacerbate the problem.
6. Pilot
selection, particularly below the airline level (i.e., Part 135 charter and
corporate aviation) should implement or expand on the use of psychological
testing.
7. All
pilots should be required to take a formal (credit or non-credit) course on
psychology.
CONCLUSION
In summary, routine flight operations, as benign as
it sounds, can and will continue to be a latent threat to flightcrews. Training
facilities and pilots need to increase their vigilance of this threat and expand
on safeguards and awareness training.
On a research level, both NASA
and FAA have stepped up investigation into this area. NASA's research on
Cognitive Performance in Aviation Training and Operations, and FAA's AAR-100
Human Factors Division, continue to provide valuable data for incorporation into
aviation training programs at all levels.
REFERENCES
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