Flight Testing Advanced Unmanned Aircraft Michael McDaniel - AIR 5.1.6.3 Naval Air Systems Command NAS Patuxent River, MD, USA DISTRIBUTION STATEMENT A:

Flight Testing Advanced Unmanned Aircraft

Michael McDaniel - AIR 5.1.6.3 Naval Air Systems CommandNAS 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


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 simulatedDISTRIBUTION 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


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


Loss of Control - Challenge

• Software failure• Airplane loses navigation

solution– Leaves test range

• Can be serious risk


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


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


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



GHMD Mission Plan segment for NAS Patuxent River

Winds aloft limits for FL500



• 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


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


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


Risk Management for Early Flights - Challenge

• Risk management– Technical– Programmatic

• Exploration of control envelope

• Chase aircraft


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


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)


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


Questions?


Flight Testing Advanced Unmanned Aircraft Michael McDaniel - AIR 5.1.6.3 Naval Air Systems Command NAS Patuxent River, MD, USA DISTRIBUTION STATEMENT A:

Documents

public release distribution

usa distribution statement

range safety challenge

range personnel

flight hours

sil test

range safety destruct

global hawk program