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Flight Testing Advanced Unmanned Aircraft. Michael McDaniel - AIR 5.1.6.3 Naval Air Systems Command NAS Patuxent River, MD, USA. DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017. Advanced Unmanned Aircraft.
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Flight Testing Advanced Unmanned Aircraft Michael McDaniel - AIR 5.1.6.3 Naval Air Systems Command NAS Patuxent River, MD, USA DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Advanced Unmanned Aircraft • High level of automation • e.g. Global Hawk • These aircraft are not simply remotely operated manned aircraft • Unconventional controls • No direct control of flight control surfaces • Command output, not method • Many tasks automated • Takeoff, landing, emergency procedures • Testing carries significant challenges • Especially early flights DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Major Test Challenges • Loss of communications • Loss of control • Subsystem failures in flight • Range safety • Crew resource manangement • Risk management for early flights *All screens are simulated DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Loss of Communications – Challenge • Loss of command & control link between aircraft and ground station • Management of concerns • Program leadership • Range safety • Airspace controlling authority DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Loss of Communications – Response • Use redundant links • Example: Standard Global Hawk procedure is to use 2+ links • If lost-communications procedures are tested in flight, have a method to recover comms • May want special software to tell airplane to ignore a working link for test • Design to operate without link • Example: Global Hawk has lost-communication actions in mission plan • Understand response of system • Loss of communications does not mean out-of-control • Brief all participants beforehand • Including program managers, range personnel, airspace authorities • Prevent panic responses DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Loss of Control - Challenge • Software failure • Airplane loses navigation solution • Leaves test range • Can be serious risk DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Loss of Control - Response • Build a good Systems Integration Laboratory (SIL) • Must use flight hardware • Exercises all functions in simulated flight environment • High demand item • Need to have at least 1 year in advance • May want multiple SILs • Test all software functions and possible failures in SIL • Test on ground • Taxi tests • Do not fly until you are certain software is thoroughly tested • Example: Global Hawk program has 30,000+ flight hours, has never lost an aircraft due to flawed software • May need range safety destruct system for early flights DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Range Safety - Challenge • Reduce risk to acceptable level • Overflight of populated areas • Airspace • Flight termination systems • Minimize impact on other test activities • Many range safety personnel unfamiliar with unmanned aircraft DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Range Safety - Response • Early engagement • Identify no-fly areas • Explain system operation in detail • Practice ground handling • Tying up runways is a major issue • GHMD operations clear runway quickly • Smart planning • Avoid no-fly areas • Stay in test airspace • May need to limit winds aloft DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Range Safety - Response GHMD Mission Plan segment for NAS Patuxent River Winds aloft limits for FL500 DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Range Safety - Response • Flight termination system (destruct system) • Balance risks • FTS adds one risk to reduce risk from out-of-control flight • When guidance & control is proven, FTS is greater risk • Remove FTS at that point DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Crew Resource Management - Challenge • Manage flight crew and test team communications • Get critical information quickly • Test team has more information than pilot • Keep lines of communication clear • Inform pilot • Don’t overwhelm pilot DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Crew Resource Management - Response • Crew = Pilot + other flight crew + test team • If test team is > 5-7 people, have a hierarchy • Guidance & Control, Structures, ECS, etc. • Multiple engineers for each discipline • One engineer speaks for that discipline • One person talks to the pilot & chase aircraft • Anyone can break in if aircraft is threatened • Manage terminology • Have one term for aircraft destruction, use only for that purpose • Train before flight • Formal CRM training • Simulated flights if possible • Example: Prior to 1st flight, the ACTD Global Hawk test team did ~5 simulated flights with simulated emergencies DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Risk Management for Early Flights - Challenge • Risk management • Technical • Programmatic • Exploration of control envelope • Chase aircraft DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Risk Management for Early Flights - Response • Gradual test program • Manage risk • Risk tolerance in early tests < risk tolerance later in program • Expand command envelope in manner similar to flight envelope • Example: Early ACTD Global Hawk test program • 1st flight: Fully preprogrammed • 2nd flight: On-track override commands • 3rd flight: Off-track override commands • Test in the SIL, then test in taxi, then test in flight • Test team must control test program • Program pressure to fly before safe must be resisted DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Risk Management for Early Flights - Response • Define RTB criteria beforehand • Lay out abort criteria • Write them down • Use if needed • Know the limits of the aircraft • Can affect RTB • Example: ACTD Global Hawk first flight • Unable to get gear locked up • Test team knew gear speed limit >Vne for airframe • Pressed with mission successfully • Chase aircraft • Brief mission plan and contingencies • May need multiple chase aircraft for different portions of flight • Example: Early ACTD Global Hawk test program • F-16 for climb (ROC~5,000 ft/min) • T-39 for landing (approach speed ~120 KCAS) DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Conclusion • Unmanned aircraft will make up a large part of future flight testing • High levels of automatic operation pose special challenges • Challenges can be met with flexible planning and good test discipline DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.
Questions? DISTRIBUTION STATEMENT A: Approved for public release; Distribution is unlimited. 20 October 2009, 09-1017.