ASCI 638 Assignment 2-5

The Predator Unmanned Aircraft System (UAS) in various series and configurations has been in operation since 1994, (General Atomics, n.d.a).  Depending upon configuration and series the Predator can be used in armed and unarmed roles for missions ranging from Intelligence Surveillance and Reconnaissance (ISR) to a variety of strike missions (General Atomics, n.d.b.).  Depending upon series and configuration the Predator has a maximum operating altitude of up to 50,000 feet, Predator B, or 25,000 feet, Predator (Airforce-technology.com, n.d.). 

The ground control station for the Predator is located in a 30 foot long commercial style trailer housing pilot and payload operator seating positions and relies on external power for electrical support,  each GCS controls 1 Predator aircraft (FAS, 1997).  The latest versions of the GCS are equipped with 3 Boeing data and mission consoles as well as various radar and sensor terminals (Airforce-technology.com, n.d.).  This configuration has led to one of the primary ergonomic/human factors complaints of the system and that is one of too many screens in what amounts to a frustratingly non-ergonomic collection of screens and controls which can potentially contribute to pilot error induced crashes (Freedburg, 2012). 

The U.S Air Force and the U.S. Army are testing a possible and potentially promising solution, the General Atomics Aeronautical Systems (GA-ASI) Advanced Cockpit Ground Control Station (GCS).  The open architecture design allows for possible use with other maker’s UAS as well a variety of models and series of its’ own manufacture (UAS Vision, 2013).  The GCS under testing serves to mitigate the screen dilemma through the use of wrap–around style display screens as well as various other ergonomic and functional improvements such as an integrated moving display map and integrated digital checklists (UAS Vision, 2013).  The wrap-around screens effectively give the impression of an actual cockpit view and combine displays from a multitude of sensors and control commands into a more efficient layout that provides a reduced pilot workload (UAS Vision, 2013). 

A second ergonomic flaw, and one which was a contributory factor in the Department of Homeland Security (DHS) 2006 crash of a Predator B in Nogales, Arizona, is the existing design of the Predator throttle quadrant as related to its’ configuration for use by a sensor operator and pilot (Carrigan, et al, 2008).  The dual consoles, one for the sensor operator (PPO-2) and one for the pilot (PPO-1) have identical throttle quadrants and layouts allowing for ease of convertibility of stations. 

When used by PPO-1 the throttle quadrant functions in a fairly traditional mannerwith the condition lever being a critical factor in this incident (Carrigan, et al, 2008).  In PPO-1 operation moving the condition lever forward allows fuel flow to the engine, the middle position cuts fuel and shuts the engine off and the rear position feathers the propeller.  In PPO-2 operation the condition lever controls camera iris opening positions.  As described by Carrigan (2008), switching PPO-1 and PPO-2 positions requires the use of a checklist and dictates the PPO-2 quadrant be configured to the same settings as the PPO-1 quadrant prior to changeover.  There is no lockout or warning to prevent changeover without completing the checklist or confirming quadrant settings.  In the 2006 Nogales accident the PPO-2 quadrant settings were not configured to the PPO-1 settings prior to changeover, this along with other contributing factors led to loss of control of the aircraft and the resulting crash (NTSB, 2014).  The NTSB ultimately determined the primary cause of the crash to be the pilot’s failure to use the required checklist when switching operational control from the PPO-1 position to the PPO-2 position (NTSB, 2014).  

Though the NTSB determined this to be pilot error, the human factor failure in the design of the system cannot be overlooked.  A simple electronic interlock that prevents switchover without the 2 quadrants being in the same position would have prevented this loss of aircraft.  Additionally, electronic checklists that populate on one of the multiple control screens can be implemented which will serve as a fail-safe reminder.  This change has in fact has been incorporated in the GA-ASI Advanced Cockpit GCS currently undergoing testing with the U.S Air Force and U.S Army (UAS Vision, 2013).

Information overload and multiple displays were and continue to be a factor in aircraft design.  The UAS industry’s current experience is similar to the transition the manned aircraft industry experienced with the introduction of “glass cockpits” and ever increasing automation.  Though initially met with mixed results the transition has been generally well accepted (Weiner, 1989) and has resulted significant improvements to aircraft safety and operability (Prinzel, 2004).

References

Airforce-technology.com.  (n.d.).  Predator RQ-1 / MQ-1 / MQ-9 Reaper UAV, United States of America.

http://www.airforce-technology.com/projects/predator-uav/

FAS.  (1997).  UAV Ground Control Station (GCS).  Retrieved from

http://fas.org/irp/program/collect/uav_gcs.htm

Carrigan, G., Long, D., Cummings, M., Duffner J.  (2008).  MIT Humans and Automation Lab.  Human Factors Analysis of Predator B Crash.  Retrieved from  http://web.mit.edu/aeroastro/labs/halab/papers/Carrigan_AUVSI.pdf

FAS.  (n.d.).  UAV Ground Control Station (GCS).  Retrieved from http://fas.org/irp/program/collect/uav_gcs.htm

Freedburg, S.  (2012).  Breaking Defense.  Too Many Screens: Why Drones Are So Hard To Fly, So Easy To Crash.  Retrieved from

http://breakingdefense.com/2012/08/too-many-screens-why-drones-are-so-hard-to-fly-and-so-easy/

General Atomics.  (n.d.a.).  Predator UAS.  Retrieved from

http://www.ga-asi.com/products/aircraft/predator.php

General Atomics.  (n.d.b.).  Predator B UAS.  Retrieved from http://www.ga-asi.com/products/aircraft/predator_b.php

NTSB.  (2007).  Aviation Accident Database and Synopses.  CHI06MA121.  Retrieved from http://www.ntsb.gov/_layouts/ntsb.aviation/index.aspx

Prinzel, L., Risser, M.  (2004).  NASA/TM-2004-213000 (corrected copy).   Head-Up Displays and Attention Capture.  Retrieved from  http://ntrs.nasa.gov/search.jsp?

UAS Vision.  (April 25, 2013).  General Atomics Next-Generation GCS Successfully Integrates Flagship and Advanced Predator Platforms.  Retrieved from  http://www.uasvision.com/2013/04/25/general-atomics-next-generation