Automatic take-off and landing of a Boeing 737 and a Predator B

Automatic take-off and landing of a Boeing 737 and a Predator B

            The two aircraft chosen for review are the Boeing 737 (manned) and the Predator B (unmanned).  Automatic take-off and landing systems have come as an increasingly beneficial feature in many manned an unmanned aircraft.  These systems were essentially designed to allow for safe landing in areas or situations previously thought too difficult to land in; this include areas of poor visibility or in adverse weather conditions (Larson, 2012).  Therefore, although it may often be ideal to have manned take-off and landing, it sometimes may be impossible or unfavorable to do so.

            The Boeing 737 utilizes an automatic landing system termed “autoland”.  Autoland systems typically consist of several components including an instrument landing system (ILS) radio that is responsible for receiving localizer and glideslope signals to help interpret the direction from the ILS frequency transmitter on ground for the approaching aircraft (Craig, Houck, & Shomber, 2003).  The automatic landing system of a Boeing 737 involves approximately 6 major phases upon descent.  The first two consist of the automatic approach.  In this case, the ILS radio utilizes the localizer and compass to determine azimuth and measures barometric height to determine elevation (Craig et al., 2003).  The next four phases are the automatic land phases including leader cable, attitude, flare, and kicking off drift  (Craig et al., 2003). 

Briefly, the pilot will first establish an approach.  Once this is done, the pilot will follow the ILS approach path that is indicated to him/her by the localizer.  The pilot then descends down the glide path to the decision height where he/she must determine weather or not there is enough visual information for a safe landing.  Safety precautions have been made in the design so that once autoland is engaged and have received ILS signals it will automatically land without any further human intervention and can only be disengaged by disconnecting the autopilot completely (Craig et al., 2003).  There are also redundancies in the system (typically at least two or three independent autopilot systems working together) to protect against any system failures and improve safety (Craig et al., 2003).  The Predator B’s autolanding system functions differently.

The Predator B is an unmanned aircraft used for intelligence, surveillance, and reconnaissance (General Autonomics, 2013).  The Predator B can successfully complete automatic takeoff and landing capability (ATLC) landings through its use of autonomy.  This UAS can autonomously track the centerline, reduce speed as necessary and even initiate the brakes once it has reached its targeted ground speed (Kasitz, 2012).  Additionally, the Predator B unlike the Boeing 737 is also able to takeoff autonomously, utilizing similar procedures to the landing.  The Predator B’s automated takeoff and landing also have the option of being fully autonomous or assisted.  In the latter, the pilot may perform certain actions, essentially acting as a supporting pilot as the Predator’s system takes over the remaining tasks.  Conversely, a pilot may also regain full control of the UAS and completely control the take-off and landing of the Predator, which is often the case (Austin, 2010).  The availability of these various flight options of the Predator adds a layer of safety to the system.

Safety is always a primary concern in any flight operation, as such both the autoland of the Boeing 737 as well as the ATLC and controlled landing of the Predator B help improve safety.  In the case of the Boeing 737, as once the autoland is engaged it is essentially locked in place for landing in order to avoid potential accidents (i.e. accidentally changing landing details).  Redundancies are also in place to improve safety.  The Predator on the other hand has several control options from fully autonomous, to partially autonomous and even fully controlled to help improve safety. 

Although all these options have their benefits and drawbacks, this author recommends a partial automation level as the best system to install in future variants of the Boeing 737 and Predator B.  The Predator B already contains this level of automation, however having a shared level of autonomy and pilot control seems to be the safest option as it offers an additional layer of decision-making.  This serves as a kind of ‘safety net’ with the pilot and the automated system performing as a sort of ‘check and balance’ for the other.  Perhaps instead of having 3 redundant systems in the UAS as previously mentioned, the Predator could have 2 redundant systems and a third system replaced with human control as the ‘check’ on the system.  However, future research would need to be studied in order to determine the plausibility of this design.

References

Austin, R. (2010). Unmanned Aircraft Systems. West Sussex, United Kingdom: John Wiley &

Sons Ltd.

Craig, R., Houck, D., & Shomber, R. (2003, April 1). Approach navigation options.

Aeromagazine, 12-21.

General Autonomics. (2013). Predator B UAS. Retrieved from http://www.ga-

asi.com/products/aircraft/predator_b.php

Kasitz, K. (2012, September 17). Predator B Demonstrates Automatic Takeoff and Landing

Capability. Retrieved from General Autonomics: http://www.ga-asi.com/news_events/index.php?read=1&id=400

Larson, G. (2012, August 1). The first autolanding. Air & Space Magazine.

Does Shift Work Matter? A look into UAS Shift work schedules

UAS Shift Work Schedule

            Shift work is commonly used among UAS operators and other pilots in the United States Air Force (USAF).  For this particular review, the author will analyze a current hypothetical shift work schedule and make recommendations to improve pilot conditions.  For the purposes of this analysis the original schedule for an MQ-1B Medium Altitude, Long Endurance (MALE) UAS squadron will be comprised of active missions that take place 24/7, 365 days a year.  The current shift rotation follows a continuous shift work schedule of 6 days on, 2 days off for 4 teams as indicated by Figure 1. However, there are several issues with this schedule.

 According to the report, the current schedule resulted in many pilot complaints.  The primary complaint is that the UAS crews have been reporting many instances of extreme fatigue while on the job.  Further, there have been several complaints of inadequate sleep directly as a result from the current shift schedule.  For this reason, an alternative schedule has been mapped out in order to alleviate some of these stressors resulting in fatigue.

Figure 1. Original schedule.  This image depicts the original schedule of 6 days on 2 days off ratio.  Team 1 follows 6 day, 2 off, 6 Swing, 2 off, 6 night, 2 off pattern.  Team 2 follows 2 off, 6 swing, 2 off, 6 night, 2 off, and 6 days pattern.  Team 3 follows 4 night, 2 off, 6 day, 2 off, 6 swing, 2 off, 2 night pattern.  Team 4 follows 2 swing, 2 off, 6 night, 2 off, 6 day, 2 off, and 4 swing. 

            A common issue with the current schedule is the rotation from different shifts.  Moving from a day shift, to a swing shift, then a night shift disrupts an individual’s natural biological rhythm or circadian rhythm.   Studies indicate that the circadian rhythm regulates many body functions such as body temperature, blood pressure and certain hormone excretions; as such, circadian rhythms often directly influence whether or not an individual, such as a pilot, is sleepy or alert (Costa, 1996).  Additional studies found that weekly rotation schedules tend to perpetuate disturbed circadian rhythms; therefore it is better to incorporate monthly rotation schedules (Tvaryanas, Platte, Swigart, Colebank & Miller, 2008).  In Figure 2, a new schedule is proposed in order to help alleviate the circadian rhythm disruptions the UAV pilots are currently suffering.  This new schedule takes into consideration the negative impact of weekly rotations and eliminates it for the most part.

Figure 2.  Proposed schedule.  This image depicts the proposed schedule that aims to eliminate most of the weekly shift rotation.  Team 1 follows all day shifts with 6 days, 1 off, 6 days, 2 off, 5 days, 2 off, and 2 days.  Team 2 follows 1 night shift and the rest swing shifts with 1 night, 3 off, 6 swing, 1 off, 6 swing, 1 off, 5 swing, and 1 off.  Team 3 follows all night shift with 1 off, 6 night, 2 off, 6 night, 1 off, 6 night, 1 off and 1 night.  Lastly Team 4 serves as the ‘floater’ and fills in the gaps of the schedule with 4 swing, 2 off, 1 day, 2 night, 1 off, 1 swing, 2 off, 2 day, 1 night, 1 off, 1 swing, 2 off, 2 day, 1 night and 1 swing.  Team 4 is given extra off days to help offset the changes in shifts.

There are both benefits and drawbacks to the new proposed schedule.  For the most part, it addresses the primary issue of rotating shifts.  Originally, the main UAS pilot complaint was fatigue due to the schedule rotation.  However, with the new schedule, teams 1, 2 and 3 all have a relatively set schedule.  Team 1 always works days, team 2 works 1 night and the rest swings, and team 3 works all night shifts.  The drawback comes with team 4, which is the ‘floater’ team.  This team serves to ‘plug the holes’ in the schedule, filling in wherever there is a schedule gap.  Although this means that team 4 will have a more irregular schedule, the team is compensated with the additional days off to help recoup sleep and help readjust their circadian rhythms.  

Further, with the proposed new schedule, each team would be assigned to their shift for a month, at which point they would then rotate to the next shift.  For example, team 1 would now become team 2, team 2 would become team 3, team 3 would become team 4 and team 4 would become team 1.  This allows for a more gradual shift change (over a period of a month rather than a week) and makes it easier to reduce fatigue due to circadian rhythm disruptions.  Additionally, this also makes it so that each team is assigned to the more difficult ‘floater’ shift only once per month with plenty of recoup time in the following regular shifts.

Conclusively, the move from the original schedule to the proposed schedule is one that would very likely allow the squadron to optimize operations while simultaneously improving the fatigue issues suffered by the crewmembers.  Although the original schedule allows for more regular shifts for team 4, having the ‘floater’ team 4 in the proposed schedule helps alleviate fatigue for teams 1-3.  Further, as this is a monthly schedule, the team assigned to the ‘floater’ position would only need to do so once every four months due to the nature of the monthly rotation.  Therefore, it is a practical solution that would ultimately yield positive results.

References

Costa, G. (1996). The impact of shift and night work on health. Applied Ergonomics 27(1):9-16.

Tyvaryanas, A., Platte, W., Swigart, C., Colebank, J. and Miller N. (March 2008).  A resurvey of

shift work-related fatigue in MQ-1 predator unmanned aircraft system crewmembers.  Naval Postgraduate School. 1-37.

Unmanned Aircraft System Beyond Line of Sight

 Unmanned Aircraft System Beyond Line of Sight

A Review of the MQ-1B Predator

            Many unmanned aircraft systems (UASs) can be operated through use of Line of Sight (LOS) operations; however, there are several UASs that also operate Beyond the Line of Sight (BLOS) missions.  Oftentimes, operators utilize a combination of both LOS and BLOS operations in order to successfully complete their mission.  As such, it is of interest to discuss both the advantages and disadvantages of LOS versus BLOS as well as how they are operated.

For the purposes of this review, the LOS and BLOS operations of the MQ-1B Predator will be discussed.

            The MQ-1B Predator is a remotely piloted aircraft with the primary goal of intelligence collection and the secondary goal of dynamic execution targets.  As such, the MQ-1B Predator is armed, multi-mission, medium-altitude, long-endurance and remotely piloted (US Air Force, 2010).  Due to the nature of its mission, the MQ-1B Predator is equipped with task-necessary infrastructure to support operations that includes the following: four sensor/weapon equipped aircraft, ground control station, and Predator Primary Satellite Link (US Air Force, 2010).  Additionally, the system requires maintenance and operations crews in the case of missions that require 24-hour operations.

 These crews are comprised of a pilot (tasked with mission command and aircraft control) and an enlisted aircrew member (tasked with sensor/weapon operations and mission coordination as necessary).  Dependent upon the stage of the mission, the crews will either remotely control the aircraft from the ground control station (GCS) through use of line-of-sight data link or satellite data link for beyond line-of-sight if the aircraft is too far out (US Air Force, 2010).  In the case of BLOS missions, the MQ-1B Predator is equipped with an infrared sensor, color daylight TV camera, laser designator/illuminator, and an image-intensified TV camera as well (UAS Air Force, 2010).  The cameras allow for viewing of full-motion video from the each imaging sensor, which can then be streamed independently or combined together into one video stream.  Moreover, the Predator can also utilize laser-guided missiles (it is equipped with two Hellfire missiles) for target execution.  These are operated somewhat differently when the aircraft is in the LOS versus BLOS.

As previously mentioned, one Predator is operated by a crew that consists of a pilot and two sensor operators.  The pilot maneuvers the aircraft using controls that transmit their commands by way of a C-Band-Line-of-sight data link (US Air Force, 2010).  This differs from how the Predator is operated when the aircraft is beyond the ling of sight (see Figure 1).  In the case of BLOS missions, a Ku-Band satellite link is used instead in order to communicate commands and responses to and from the satellite and the UAV (US Air Force, 2010).  Particularly, orders in the form of data are transferred from an L-3 Com satellite data link system to the UAV; further, the information received from the UAV, such as video or images, are used by the pilot and crew to make decisions regarding how to maneuver the UAV (US Air Force, 2010).  This alters from line of sight operations in that it adds a few more steps.

With the line of sight operations, there is less room for signal disruption since there is a direct link from the Ground Control Station to the Predator.  However, when piloting in beyond line of sight operations, one disadvantage is that there is the additional step of the satellite relay.  In this case, the data is picked up by the Predator, sent to the Satellite, and transferred back to the Satellite Uplink Vehicle; a benefit to this method is that this data signal can also be sent to other military facilities (Valdes, 2004).  As one can guess, the switch from LOS to BLOS could consequently result in human factors issues particularly in regards to conduct operations.

Figure 1. Predator UAV Communication System.   This figure illustrates the design of the Predator UAV Communication System. It is composed for three main parts: 1) Ground Control Station 2) Predator Drone and 3) Satellite Relay.  The satellite relay serves as communication between the UAV and the GCS particularly in beyond line of sight missions. Figure was borrowed from Valdes (2004).

            One common human factors issue that occurs when a manned aircraft pilot makes the switch to a UAS is that pilots must now rely heavily on cameras to gain situational awareness.  Oftentimes, this may feel as though the pilot has to look through a narrow tunnel when accessing the video stream.  This significantly limits their ability to gain situational awareness.  Additionally, fatigue is a common human factors issue associated with piloting UASs.  Although this is seen with manned aircraft as well, it seems to be found in a different form.  UAS pilots must essentially stare at a monitor for long hours, which can result in boredom and fatigue.  Manned pilots do not have to do this, although they do suffer from other triggers of fatigue such as jet lag.  There are also human factors issues when switching from LOS to BLOS operations of UASs.

            LOS operations are a little more closely associated with manned aircraft human factors in that the pilot has a more physical notion of situational awareness.  Since they can visually have eyes on their aircraft it is easier to detect a nearby threat or obstacle and take decisive action.  However, this is more difficult to do when piloting BLOS.  In BLOS operations, the pilot and crew rely significantly on the data transmissions they receive from the satellite.  This means that any delay or error in the transmission may not be detected until it is too late, which could result in a mishap.  This also limits the crew’s situational awareness and makes them very dependent upon the satellite data stream.  The advantages of UAS BLOS however can serve as great potential for commercial industries.

            Some commercial applications for UAS BLOS can involve filming movies.  This is something that is becoming more common now as films are more and more often taking place in remote locations.  Additionally, shipping industries and retail industries can also take advantage of UAS BLOS for shipment of goods and products to users (this is currently being explored by Amazon).  Conclusively, UAS BLOS has its advantages and disadvantages; although it is subject to some unique human factors issues, the benefits of UAS BLOS seem to outweigh any negatives.

References

U.S Air Force. (2010, July 10). MQ-1B Predator. Retrieved November 14, 2014, from  

http://www.af.mil/AboutUs/FactSheets/Display/tabid/224/Article/104469/mq-1b-predator.aspx

Valdes, Robert. (2004, April 1). How the Predator UAV Works. Retrieved November 14, 2014,

from http://science.howstuffworks.com/predator.htm

Next Generation Air Transportation System: A Review of NextGen

Next Generation Air Transportation System, henceforth referred to as NextGen, is the future evolution of the current air transportation system.  Its aim is primarily to alleviate gridlock in the sky, thereby increasing safety, efficiency, and passenger comfort due to decreased flight and wait times.  It is projected that there will be additional increases in air travel over the next several decades; these increases to an already congested airspace would likely result in various negative outcomes such as longer wait times, increased use of fuel, decreased efficiency etc. if nothing were to be done (Vu, Kiken, Chiappe, Strybel, & Battiste, 2013). Fortunately, NextGen seems to be the answer.

NextGen utilizes active networking technology via use of airborne digital data and satellite.  Satellite data will be utilized to help map out shorter flight routes, which will alleviate present concerns with traffic congestion delays.  Additionally, the shorter routes will have the positive outcome of more efficient use of fuel, thereby saving on fuel costs (Federal Aviation Administration, 2008).  According to the Federal Aviation Administration (FAA), these new technologies will allow for changes in system operations that would ultimately result in a reduction of congestion in the National Air Space (NAS), thereby increasing passenger satisfaction and safety as it will also allow air traffic controllers to be able to safely monitor airspace traffic (Federal Aviation Administration, 2008). One of such technologies is the implementation of unmanned aviation systems (UASs) into the NAS in cooperation with manned aircraft and air traffic control towers (ATCTs).

A crucial component for the success of NextGen is the safe use of UASs to provide informational feedback to ATCTs.  In order for UASs to be helpful in NextGen, however, they must be successful at sense and avoid.  Sense and avoid, briefly put, is the capability a UAS has to be able to differentiate and evade a possible intruding aircraft (Kenny, 2013).  This is a crucial component to NextGen as the sense and avoid systems would be essential to aid in the avoidance of collisions by use of sensors, threat detection, and trackers (Kenny, 2013).  All of the information gathered by the UAS could then be relayed back to the air traffic control tower via satellite and would create a larger sense of situational awareness.   Additionally, the UASs’ ability to self separate and avoid collision are perhaps the key technological advancements necessary for successful UAS implementation into NextGen as these are crucial components to the sense and avoid system (Kenny, 2013).

There are several human factors that must be considered in order to integrate UASs into the NAS for use in NextGen.  One of these factors is that NAS has primarily been designed for manned aircraft operations.  Therefore, it is not currently optimized for UAS integration.  Consequently, this could result in various problems with communications, airspace operations, and human systems integration (Kenny, 2013).  Additionally, the visible or known use of UASs in the NAS may pose an issue in regards to public perception.  Although the involvement of UASs in NextGen would likely significantly improve passenger satisfaction, it may also result in unforeseen passenger complaints as well since the public tends to have a negative perception of ‘drones’.  Lastly, another concern to consider is the possibility of a lost link or faulty UAS and the effects it could have.  It may result in longer wait times rather than faster ones if technical issues ever arise.

Overall, however, I believe NextGen is a good step forward in technological advancements and will likely result in greater customer satisfaction.

References

Federal Aviation Administration (2008). FAA Surveillance and Broadcast Services
Retrieved November 7, 2014 from http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/enrou
te/surveillance_broadcast/

Kenny, C. (2013). Unmanned aircraft system (UAS) delegation of separation in NextGen
airspace.  SJSU ScholarWorks, 1-117.

Vu, K. L., Kiken, A., Chiappe, D., Strybel, T. Z., & Battiste, V. (2013). Application of part-
whole training methods to evaluate when to introduce NextGen air traffic management tools to students. The American Journal of Psychology, 126(4), 433-447. doi:http://dx.doi.org/10.5406/amerjpsyc.126.4.0433

The Hummingbird - A nano UAS

The hummingbird is a nano unmanned aircraft system that is cleverly disguised as a hummingbird.This design allows the UAS to fly following a similar flight motion as a hummingbird, through the use of wing strokes.  It is extremely light weight and adapts to wind just as a bird would.

The Ground Control System is a remote control for the Hummingbird which has built in navigation
buttons and knobs as well as a low-resolution monitor which utilizes radio transmission to receive images from the Hummingbird.

This is a really interesting idea to camouflage UASs. I have also attached a link to the video which shows how the GCS works and the Hummingbird in action.

Click here to view Hummingbird UAS video

The unmanned aviation system chosen for this review is DARPA’s nano UAS known simply as the Hummingbird. The Hummingbird gets its name from its distinct design that replicates both the appearance and wing motion of a hummingbird. This design is intended to mimic the flight of a hummingbird as accurately as possible while giving the control pilot the ability to quite literally get a birds eye view of its surroundings. The natural design also helps disguise the UAS to avoid detection from anyone who may pose a threat.

DARPA’s Hummingbird has a very unique design (see Figure 1). In fact, the design for the wings alone took over 300 tries before settling on the final product (Ward, 2011). This nano UAS is battery powered and remote controlled (see Figure 2). The Hummingbird is equipped with a low-resolution forward facing camera beneath the birds beak. This camera allows the individual using the Ground Control System (GCS) to have an aerial view of his/her surroundings in full color video. The video is transmitted to a handheld device (the GCS) that is equipped with a screen and control buttons to manipulate the Hummingbird.

Launch of the UAS is also rather simple. The pilot simply holds out their palm with the bottom of the Hummingbird resting on his hand. They can then use the control button on the GCS to trigger the Hummingbird’s wing-strokes. The transmission between the GCS and the UAS allows the pilot to regulate the wing-stroke velocity that can ultimately enable 11 mph flight rate (Ward, 2011). Once the wing-stroke velocity has been increased, the Hummingbird flies away from the control pilot’s palm. There are many benefits from this design from the stand-point of human factors.

The handheld GCS is similar to many other UAS designs or electronic flying toy designs so it complies with many individual’s mental models of remote controlled devices. Additionally, the launch requires very little effort or set up since the Hummingbird can launch straight from one’s palm. This also increases efficiency and reduces the amount of time needed to perform the surveillance task at hand since set up and launch is rather easy. Unfortunately, there are some negative human factors to consider as well.

The Hummingbird is still a new design in development and has not yet been widely implemented. As such, it is difficult to predict what negative outcomes may arise in the realm of human factors; however, there are some concerns that should be considered. One such factor is the limitation of situational awareness. Although the intention of the nano UAS Hummingbird is surveillance, this can be compromised by its very limited capacity to be aware of its surroundings. The Hummingbird has a very narrow scope of vision and it is also in low-resolution. Due to these limitations, the controller may misjudge a situation or make a poor decision based off of misleading information gathered from the low quality stream of information from the Hummingbird and the lack of situational awareness. Further, the use of this UAS would require sustained attention, which could ultimately lead in boredom and thereby result in decreased attention.

Studies indicate that operators currently controlling unmanned aerial vehicles report a high level of boredom (Cummings, Mastracchio, Thornburg, & Mkrtchyan, 2013). This significant boredom often results in distraction and general lack of attention to the task at hand (Cummings et al., 2013). This is particularly an issue among controllers who spend long duration of time in a vigilance task with the GCS. However, there are some simple changes that can be made to mitigate these problems.
One solution the issue of situational awareness would be to increase the monitor and camera from a low-resolution stream to a high-resolution stream. This would help increase visibility and make it easier to ascertain situational awareness. Further, adding an additional camera to the backside of the Hummingbird would also allow for a 360-degree view of ones surroundings during flight. The issue of boredom can also be alleviated with the implementation of efficient attention switching as indicated by Cummings et al. (2011). Occasional attention switching resulted in increased performance and decreased boredom, therefore by using this technique one could help improve the GCS. Interestingly, these human factors issues are also present in manned aircraft as pilots must also face situational awareness and boredom/attention issues.

References 

Cummings, M., Mastracchio, C., Thornburg, K., and Mkrtchyan, A. (2013). Boredome and distraction in multiple unmanned vehicle supervisory control. Interact. Comput. doi: 10.1093/iwc/iws011

Ward, Logan (2011). Flight reimagined: the first robotic hummingbird [Online image]. Retrieved October 29, 2014 from http://www.popularmechanics.com/technology/ military/planes-uavs/flight-reimagined-the-first-robotic-hummingbird