Automatic Takeoff and Landing

                                                   Automatic Takeoff and Landing

Automation of aircraft and associated systems is advancing at a very fast rate. Technological advancements have made it possible to incorporate significant upgrades to aerospace systems, with new changes occurring frequently. One of these fascinating new capabilities that have recently been utilized in both the commercial and military aviation sectors is auto-land.

The Northrop Grumman Fire Scout is one such military aircraft that has incorporated automation capability into its landing phase on board U.S. Naval ships. The MQ-8C Fire Scout model is the newest rendition of its Vertical Take-off and Landing (VTOL) Unmanned Aerial Vehicle (UAV) line. The MQ-8C is based off of the Bell 407 helicopter, which is bigger than its predecessor models which were based on the Schweitzer 333 (Naval-technology.com, n.d.).  With the increase in size, the MQ-8C brings an increase in systems capability as well as increased payload. The data link, system control station, associated hardware and software have had significant upgrades which will allow this UAV to effectively carry out a wide range of operation missions while supporting a wide array of capabilities for its Navy customer.

The Fire Scout utilizes a UCARS system that provides positioning information for use in the automated take-off and landing portions of flight. UCARS is composed of three major subsystems:

·       The Airborne Subsystem (AS) providing a UAV point source for precise position data

·       The Track Subsystem (TS), locating and tracking the UAV relative to the chosen landing point. A motion sensing system is also employed.

·       The Recovery System (RS) provides guidance and control functions utilizing the data link and provides for the human integration and control interfaces within the system. Several launch, control and monitoring functions are also completed by the recovery system (Ferrier, Sehgal, & Ernst, 2014).

The UCARS system operates as a “transponder based millimeter wave radar tracking system”, to track and provide location and position inputs (Ferrier, Sehgal, & Ernst, 2014). The Fire Scout does have safeguards in place allowing for manual landings and override when needed, controlled via the data link in the ground control station.

 A manned commercial aircraft that also has the capability to autonomously land is the Boeing MD-11. The MD-11 incorporates auto throttle control concurrently when its autopilot functions are enabled.  These systems “are completely unified and essentially operate as a combined system until disengagement at landing” (PMDG, 2010).

Auto land in initiated by pushing the APPR/LAND button, and provided an ILS frequency is being utilized that uses both a localizer and glide scope (automatically done by the Flight Management System (FMS), the aircraft will auto land unless manually overridden. Autopilot remains engaged after landing to ensure the aircraft remains aligned with the runway, requiring disconnection following the end of the landing rollout  (PMDG, 2010)

Three types of MD-11 auto land are identified below-

•           “If all your systems are operating normally you will see a green DUAL LAND annunciation on the PFD FMA indicating a full CAT III auto land” (PMDG, 2010).

•           “If you have failures that are not critical for the auto land (for example, one of the two autopilots inoperative or one HYD system failed) a white SINGLE LAND will be annunciated and a CAT II auto land will apply” (PMDG, 2010).

•           “If you have critical system failures, or excessive deviation from LOC or GS a white APPR ONLY will be annunciated and the auto land function will not be available. The aircraft will continue to track LOC and GS, but autopilot will disconnect at 100 ft AGL” (PMDG, 2010).

Crews of both aircraft have to receive initial qualification training, as well as subsequent periodic scheduled currency requirements.

                                                                References

Ferrier, B., Sehgal, A., & Ernst, R. (2014). Retrieved from http://www.auvsishow.org/auvsi2014/Custom/Handout/Speaker1851_Session767_1.pdf

Naval-technology.com. (n.d.). Fire Scout VTUAV - Naval Technology. Retrieved from http://www.naval-technology.com/projects/fire-scout-vtuav/

PMDG. (2010, February 19). Tips for Boeing pilots learning the MD-11 - PMDG Simulations. Retrieved from http://support.precisionmanuals.com/kb/a18/tips-for-boeing-pilots-learning-the-md-11.aspx

Shift Work Schedule

                                                          Shift Work Schedule

Regarding the previously used rotating shift schedule, there are many issues that arise as a result of the structure. This original schedule utilizes four teams rotating three eight hour shifts with a half hour turnover, working six days on and three days off. This pattern may lead to excessive fatigue, as crew members are required to work several continuous days and change shifts every week.  This leaves little time to spend with families, gives very little chance of having a weekend off, and cuts into training. On the pro side, this schedule does allow each team member to rotate shifts more frequently, allowing for less time on the less desirable shifts.

Using a re-designed shift schedule, the aim of reducing sleep issues and fatigue may be realized. The changes to the shift schedules include the elimination of the third shift, reductions of days worked in a month, reduction of continuous days worked, and an increase in the number of days off each month. Additionally, the changes allow for some added stability as the crew members have the opportunity to stay on a single shift for the entire month, hopefully allowing them to become more accustomed to the shift. Rotating shifts disrupts the crew member’s circadian rhythms and can increase fatigue effects.

The new shift schedule structure will be comprised of four teams, each of which is tasked to work a twelve hour shift. Teams one and three will work night shift from 7:30 PM to 8:00 AM (30 minutes turnover at the beginning of the shift), alternating on when the other team is off. Team two and four will work day shift from 7:30 AM to 8:00 PM (30 minutes turnover at the beginning of the shift), also alternating on when the other team is off. Each team will stay on their assigned shift for one month, and will then switch to the other shift at the beginning of the next month. The new shift works 2 on, 2 off, 3 on, 2 off, 2 on, three off. In any given month, this will allow each team to work approximately 14-16 days.

While this new schedule will most definitely improve the quality of life for the crew members and their work life balance, it may also significantly reduce some of the safety issues that are experienced during turnovers. As one of the shifts is removed from this new schedule, there are fewer turnovers that need to happen each day, and less information that has the possibility to get lost in a turnover.

Unfortunately, as fatigue is linked with shift work, the nightshift will experience issues with fatigue, and will require adjustment to maintain awareness. Circadian rhythms are aligned with a natural night sleep schedule, so disturbing this will negatively affect fatigue (Price, 2011). Allowing for fewer consecutive shifts should allow for a reduction of this fatigue and allow crew members the ability to adapt accordingly.

One potential issue with both of these schedules is with how to insert ancillary and proficiency training into the work schedules. One option with the refined schedule is to take the third day off at the end of the 2-2-3-2-2-3 schedule and use that as a training day.

                                                                 References

Price, M. (2011). The risks of night work. American Psychological Association, 42(1). Retrieved from http://www.apa.org/monitor/2011/01/night-work.aspx

Beyond Line of Sight

                                                       Beyond line of sight (BLOS)

The Fury 1500 was originally designed and built by AeroMech Engineering in San Luis Obispo CA, but the company was subsequently bought out by Chandler in 2009, and again by Lockheed Martin in 2012. The Fury is a small tactical Unmanned Aerial System (UAS) designed for intelligence, surveillance, and reconnaissance. The Fury boast a maximum altitude of 18,000 feet, while providing real time intelligence data for a maximum flight/loiter time of 16 hours (Kable Intelligence Limited, n.d.). Fury 1500 can be launched on land or shipboard, using a pneumatic launcher, and is recovered either with the use of a net recovery system or water connectors for water recovery  (Tarantola, 2014).

With the capability of both Line of Sight (LOS) and Beyond Line of Sight) BLOS) operations, the Fury 1500 is capable of expeditionary operations utilizing an Expeditionary Ground Control Station (xGCS) built form commercial off the shelf components (Hemmerdinger, 2014). With BLOS capability, the Fury 1500 is able to be forward deployed with minimal crews, putting ““puts Fury alone in the low-altitude, long-endurance, large payload, tactical UAS market” blurring “the line between tactical and strategic unmanned ISR without the need for a fixed runway” (UAS Vision, 2012).

LOS operation is enabled via a data link, while BLOS operation utilizes a high-bandwidth commercial off-the-shelf (COTS) SATCOM data link (UAS Vision, 2012). Autonomous operation is also enabled “using mission management software known as STANAG 4586 SharkFin, which carries out navigation control, video display and payload control missions” (Kable Intelligence Limited, n.d.).  Fury is equipped with both electric-optic and infrared sensors, and utilizes synthetic aperture radar.

BLOS operations have the distinct advantage of increasing the range and operational capability of UAS’s, enabling a more agile response with minimal personnel deployment. In the case of Fury 1500, utilization of a portable ground control station also offers an extension of the operational ability of the aircraft by allowing remote location access. A disadvantage of BLOS use is that operational and maintenance support is not always available at forward locations, and the potential for a lost signal resulting in loss of the aircraft.

LOS operations have the advantage of maintaining a direct link with the ground control station, reducing the likelihood of a disruption of signal. A disadvantage is that the aircraft is restricted to an operational range that maintains the LOS.  Additionally, LOS operation in a forward deployed environment means a larger logistics footprint for operations and support.

A human factors consideration in the switching between LOS and BLOS operations could be in the need for clear communication and strict adherence to transfer guidelines. Loss of signals during transfer, or incorrect information passed on to the receiving control station can create issues.

A potential benefit of BLOS in a commercial application would be in the area of civilian search and rescue operations. Allowing rescue crews to cover and investigate a larger ground area more efficiently could potentially save numerous lives.  Another potential use would be the transport of organ donations without the need to generate larger aircraft. This could save time and money and reduce the reliance on manned craft.

                                                                       References

Hemmerdinger, J. (2014, May 13). AUVSI: Lockheed integrates xGCS with Fury UAV - 5/13/2014 - Flight Global. Retrieved from http://www.flightglobal.com/news/articles/auvsi-lockheed-integrates-xgcs-with-fury-uav-399069/

Kable Intelligence Limited. (n.d.). Fury 1500 Unmanned Aerial Vehicle - Airforce Technology. Retrieved from http://www.airforce-technology.com/projects/fury-1500-uav/

Tarantola, A. (2014, May 16). This Furious High-Flying Drone Can Spy Overhead For 15 Hours. Retrieved from http://gizmodo.com/this-furious-high-flying-drone-can-spy-overhead-for-15-1573344431

UAS Vision. (2012, September 11). Fury 1500 Tactical UAS Achieves SATCOM Video Downlink, Delivers Beyond Line of Sight Capability. Retrieved from http://www.uasvision.com/2012/09/11/fury-1500-tactical-uas-achieves-satcom-video-downlink-delivers-beyond-line-of-sight-capability/

UAS Integration in the NAS

Activity 3.5

            Much like our nation’s roads has experienced with cars, our National Airspace (NAS) has become increasingly congested as more and more aircraft are crowding our skies. To combat this issue, the Federal Aviation Administration (FAA) has developed a plan of action to increase efficiency and safety within our NAS. This plan of action is known as NextGen. NextGen encompasses a shift from the traditional ground based navigation system currently employed within the NAS to a satellite based navigational system. Currently, the aircraft in our skies fly inefficient indirect routes that waste fuel and time and congest our nation’s airports. The implementation of NextGen between 2012 and 2015 is expected to save billions of dollars in the long run, while increasing efficient use of airport capacity and ground movement, enabling more efficient direct flights and approaches/departures that are safer, reducing delays and costs associated with traffic and maneuvering and reduce stacking at airports. Ultimately, reducing gridlock and increasing the efficient utilization of our NAS will enhance safety and provide additional needed airspace capacity (Federal Aviation Administration, 2013).

Specifically, the goals of NextGen include increased efficiency and advancement of:   “Trajectory-based operations, arrivals/departures at high-density airports, flexible terminals and airports as well as optimized profile descent” (Federal Aviation Administration, 2009). These evolutions will be dependent on Performance-Based Navigation (PBN), which is a framework of performance requirements and are comprised of two main components- Area Navigation (RNAV) and Required Navigation Performance (RNP). “RNAV enables aircraft to fly on any desired flight path within the coverage of ground- or spaced-based navigation aids, within the limits of the capability of the self-contained systems, or a combination of both capabilities” (Federal Aviation Administration, 2009). RNP is essentially RNAV with additional on-board performance monitoring and alert capability (Federal Aviation Administration, 2009).

Unmanned Aircraft have proven to be a challenge for integration into the future NAS, as proven and realistic sense, detect and avoid technologies can sometimes be inhibitive or cost preventative to low weight performance UAS. The added weight of proven cooperative systems such as Traffic Collision Avoidance Systems (TCAS) can restrict the capability of the system, and may not be able to adequately relay required communication. These systems also typically require other aircraft to be equipped with the technology for it to be effective. Non-cooperative active technology such as radar and lasers, or passive technology, such as motion sensing and infrared are increasingly being utilized or incorporated into UAS (Barnhart, Shappee & Marshall, 2011). Lost link conditions are another area of concern, as failure for the UAS to adequately follow flight rules in the case of a lost link has the potential to create a dangerous situation (Mullins, 2012).

Besides the Sense Detect and Avoid issues that can present dangerous situations, one major area of concern for the NextGen system and integration of UAS into the NAS is the difficulty of monitoring and tracking of the aircraft and their associated flight plans. Traditional manned aircraft flight plans are tracked from point to point, which is what the computers are designed to monitor. UAS have the unique ability to remain aloft for days, weeks or potentially years. Additionally, these aircraft also typically fly at a slower pace that other commercial aircraft which may cause additional congestion and avoidance routing (Robertson, 2014).

References

Barnhart, R. K., Shappee, E., & Marshall, D. M. (2011). Introduction to Unmanned Aircraft Systems. London, GBR: CRC Press. Retrieved from http://www.ebrary.com

Federal Aviation Administration. (2009, April 24). Fact Sheet – NextGen Goal: Performance-Based Navigation. Retrieved from http://www.faa.gov/news/fact_sheets/news_story.cfm?newsId=8768

Federal Aviation Administration. (2013, January 14). NextGen – What is NextGen? Retrieved from https://www.faa.gov/nextgen/slides/?slide=1

Mullins, R. (2012, April 25). UAV Sense-And-Avoid Called Biggest Challenge To Integration | AWIN content from Aviation Week. Retrieved from http://aviationweek.com/awin/uav-sense-and-avoid-called-biggest-challenge-integration

Robertson, A. (2014, September 25). FAA says air traffic control isn't ready for drones | The Verge. Retrieved from http://www.theverge.com/2014/9/25/6843303/faa-says-air-traffic-control-isnt-ready-for-drones