During the cold war era, reconnaissance missions were
left to the U-2, and SR-71 amongst others.
These missions required endurance stretching the human pilot to their
limits. Unmanned aircraft development
increased. The technology at the time to
remotely fly and gather the information was problematic with communication
systems and sensors that were inadequate and often failed.
UAV accidents can be classified to the categories of
human factors, maintenance, aircraft, and unknown. Human factors can be classified to more
specific factors such as issue with alerts/alarms, display design, procedural
error, skill based error, or other (Williams, 2004). In the accident report data collected in 2004, the percentage of human factors
varies across different aircraft from 21% - 68%.
For most unmanned aircraft, electromechanical failure was a greater
causal factor than human error.
The Navy’s RQ-2 Pioneer requires an external pilot for
takeoff and landing before operating autonomously, unlike a more sophisticated
UAV such as the Global Hawk. Human factors
accounted for 28% of accident causal
factors. Of the RQ-2’s 239
accidents, 156 are aircraft related.
There was 68 human factors related accidents; 13% of were due to aircrew
coordination, 68% from landing error,
10% from take-off error, and 9%
for weather. This data suggests there is much room for
improvement for this UAV’s landing procedures whether related to the landing
design, or lack of pilot training.
The Predator has different accident causal factors
than the older Pioneer. Also flown by a
ground control station (GCS) by joystick and rudder pedals, human factors
accounted for 67% of Predator accidents (up to 2004), with procedural error making up 75%.
An example of a procedural error involved and “handoff” of the aircraft
from one crew to the next. During the
handoff, the crew did not comply with checklist steps in the proper order which
resulted in the shutdown of the engines and stability augmentation system. The aircraft entered an un-commanded dive and
crashed. I will take a wild guess and assume
shortly after this incident, the combination of steps the pilots took should
cause alarm to suggest that procedure should not happen. Pressing UAV flight to
mandate certification of pilots through training and standardization of Human
Machine Interface shall lower the human related factors for UAV incidents.
Concluded from the breakdown of UAV accidents of some
the major UAV platforms in this discussion, human factors and aircraft factors
such as electromechanical reliability have in the past been principle causal
factors. Design of some user interfaces
in the past were not based on aviation display concepts, mainly because the
developers of those interfaces are not aircraft manufacturers (Williams,
2004). In the traditional sense of the
word, unmanned aircraft are not “flown,” they are “commanded.” This highlights the criticality of human
factors regarding pilot qualification and GCS interfaces.
References
Williams, K. W., & FEDERAL AVIATION ADMINISTRATION
OKLAHOMA CITY OK CIVIL AEROMEDICAL INST. (2004). A summary of unmanned aircraft
Accident/Incident data: Human factors implications
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