The RQ Raven Small
Unmanned Aerial Vehicle is one of the most frequently used UAS in the US
military. With the ability to be operated in a manual or autonomous mode, it
can be rapidly deployed and used in low-altitude surveillance and
reconnaissance missions. With a wing spanning about 4.5 feet and weighing 4.2
pounds, the Raven can fly and ay missions for up to 10 kilometers. (Aerovironment, 2019). In order to reduce
the chance of mishaps, it is important to manage the risks associated with the
operation of the UAS using the Operational risk Management assessment tool.
Preliminary Hazard List
The first task is to
identify the potential hazards that will likely be encountered during operation
of the UAS. This involves brainstorming with stakeholders and coming up with the potential list of hazards
and then assigning a probability and severity level to the identified
risks/hazards. In the list, hazards that have been identified are System
Malfunctions, Loss of Link/Communication, Wrong Maintenance, Remote Pilot
Error, Mid-air collision, Terrain collision, stall, flyaway, Aggressive
maneuvers, and failure to launch vehicles.
Preliminary Hazard List
|
Track#
|
Hazard
|
Probability
|
Severity
|
RL
|
Mitigating
Action
|
RRL
|
Notes
|
|
|
|
|
|
|
1
|
|
1.
|
System
Malfunction
|
occasional(C)
|
Critical
II
|
3
|
Preventive
maintenance
|
1
|
|
2
|
Loss
of Link/Communication
|
probable(B),
|
Marginal
|
3
|
Reposition
GCS
|
1
|
|
3
|
Wrong
Maintenance
|
remote
(D)
|
Critical
|
1
|
Proper
Maintenance, training
|
1
|
|
4
|
Remote
Pilot Error
|
Probable(D)
|
Critical
|
2
|
Proper
training, procedures
|
1
|
|
5
|
Mid-air
collision
|
Remote(D)
|
Catastrophic
|
3
|
Check
flight data, weather conditions before the flight
|
1
|
|
6
|
Terrain
collision
|
Probable(B)
|
Critical
|
1
|
Avoid
High obstacle areas
|
1
|
|
7
|
Stall
|
Remote(D)
|
Critical
|
1
|
Adjust altitude
|
1
|
|
8
|
Flyaway
|
Remote(D)
|
Critical
|
1
|
Verify routes before the flight
|
1
|
|
9
|
Aggressive maneuver
|
Occasional (C)
|
Marginal
|
1
|
Return UAS to Base
|
1
|
|
10
|
Failure to launch
|
Frequent(A)
|
Critical
|
2
|
Check procedures before launch, Use mounted launch
|
1
|
|
Preliminary Hazard Assessment (PHA)
The next
phase is to conduct a preliminary
hazard analysis (PHA) by finding the best possible ways to mitigate the listed
hazards or risks. Based on the listed hazards, the mitigation procedures are
listed in Table 1. After the mitigation procedures are applied to the risks,
another probability and severity level is conducted showing the residual risk.
The residual risk is usually equal or less than the risk/hazard initially.
Operational Hazard Review and
Analysis (OHR&A)
The Operational Hazard Review and
Analysis (OHR&A) tool is like a preliminary hazard list. The
difference is that the OHR&A is used to analyze whether the mitigation
procedures adequately addressed the risks listed in the PHL. If they were not
adequately addressed, they are listed again in the OHR&A.
RQ 11 Raven Risk Assessment
|
UAS flight training
|
|
|
|
|
|
Risk
|
|
Risk Level
|
|
|
1
|
2
|
3
|
4
|
Pilot Error
|
|
Automated Pilot
|
|
|
Manual control
|
Terrain collision
|
|
Large area free of obstacles
|
Large area with some obstacles
|
No obstacle
|
Obstacle present in area
|
Failure to launch
|
|
Mounted launch
|
|
|
Hand launch
|
Stall
|
|
100-300ft AGL
|
|
|
400ft AGL
|
Total Value
|
|
Low
|
0-20
|
|
Moderate
|
21-40
|
|
High
|
41-60
|
|
Finally, an ORM&A
table showing if it is safe to fly the UAS. Each line of risk is added to get
the total risk which determines the level of risk for the mission. for example,
the total of the risk assessment is 25, which places the mission at moderate
risk.
Reference
Aerovironment. (2019). Retrieved from
https://www.avinc.com/uas/view/raven