787 Flight Controls – The Journey So Far

787 Flight Controls –The Journey So Far Vera Martinovich 787 Stability & Control - Handling Qualities Boeing Commercial Airplanes SAE Aerospace Control and Guidance Systems Committee Meeting October 11-13, 2006 Williamsburg, VA

Agenda • 787 description • Control law requirements and philosophy • Control law overview • Concept Validation & Risk Reduction flight test • Looking ahead

Agenda • 787 description • Control law philosophy • Control law overview • Concept Validation & Risk Reduction flight test • Looking ahead

Driving Market Forces • Direct flights from many smaller airports vs. hub-and-spoke system • Rising fuel prices • Environmental concerns • Noise • Emissions →Efficient, “middle-of-the-market” airplane

787 Features • Middle-of-the-market size (210-330 passengers) • Opens 450 new city pairs • Composite fuselage and wings • Low noise and pollution emissions • 85 dBA noise footprint • 20% less fuel burn per pax than comparably-sized airplanes • Improved passenger comfort • Higher humidity and cabin pressure • Larger windows • Advanced flight deck • Dual Heads-Up Displays • Electronic Flight Bag • Longer maintenance intervals

787 description 787-3 290-330 passengers (two-class) 3,000 – 3,500 nmi | 5,500 – 6,500 km 787-8 210-250 passengers (three-class) 8,000 – 8,500 nmi | 14,800 – 15,700 km 787-9 250-290 passengers (three-class) 8,600 – 8,800 nmi | 15,700 - 16,300 km

* * * 32 Customers, 420 Orders * Leasing

Schedule Start of Major Assembly 787-8First Flight 787-8 Enters Service 787-9EntersService 787-3EntersService Program Launch Authority to Offer Airplane Announcement Firm Configuration 2002 2003 2004 2005 2006 2007 2008 2009 2010

Overall Design Requirements • Mixed-fleet flying with 777 • Good handling qualities & ride qualities • Reduced structural loads (and weight) • Enhanced safety • Low pilot workload

Mixed Fleet Flying • Goal is to fly like the 777 • 3-5 day differences training • No full flight simulator training for pilots transitioning to 787 • Training required for transitions to 777 • Common type rating?

Handling Qualities Criteria • Certification regulations • Lessons learned from wealth of Boeing experience • Industry-standard handling qualities criteria • CONDUIT software • Implements Lower-Order Equivalent Systems • Allows evaluation of multiple criteria simultaneously

Load Reduction • Reduce vertical tail size • Size for engine-out control • Maintain static and dynamic directional stability • Take advantage of active load alleviation • Composite structure allows a significant benefit of static load reduction without fatigue restrictions • Reduce peak maneuver loads in empennage and wing

Safety and Pilot Workload • Minimize stall susceptibility • Reduce roll upset effects • Large gusts • Wake vortex encounter • Engine failure • Full-time asymmetry compensation on ground and in air

Design Philosophy, Part 1 • The pilot shall have ultimate responsibility and authority over the use of the airplane’s control capability. • Pilot intuition, based on training and past experience, shall be preserved. • Pilot awareness of the flight control task performance shall be emphasized. • Control functions shall assist the pilot in avoidance of, or recovery from, inadvertent exceedance of the operational boundaries. • Protection functions shall not reduce useful performance.

Design Philosophy, Part 2 • Pilots use visual and tactile feedback from controllers to evaluate flight control inputs and anticipate airplane response. Controller design must provide these visual and tactile cues. • Both pilots share in the ultimate responsibility for safe conduct of flight. • The pilot and copilot are aware of each other’s input. • Control laws provide ideal conventional airplane response characteristics and minimize pilot training requirements. • Control laws reduce pilot workload and improve ride quality.

Development History • Started with 777 control laws as a baseline three years ago • Employed extensive engineering and piloted simulation of candidate control law architectures • Arrived at integrated full-axis augmentation as the best means of satisfying design requirements

Design Process • Integrated design • Aerodynamics, Primary Flight Controls, Autoflight & Structures • Simulation • Desktop, fixed-base, motion-base • Concept Validation and Risk Reduction (CVRR) flight test • 787 flight test

Agenda • 787 description • Control law philosophy • Control law overview • Concept Validation & Risk Reduction (CVRR) flight test • Looking ahead

CVRR Purpose • Validate 787 requirements before 787 flight test • Validate control law design and testing processes • Demonstrate new functions perform as intended and provide acceptable levels of stability and handling qualities • Focus on functions that cannot be adequately evaluated on ground-based simulators • Check control law function integration • Mitigate risk of late redesign/rework due to issues with new flight controls functions

CVRR Vehicle • Leased American Airlines 777-200ER with Rolls Royce Trent 892 engines

Program Details • 8-month flight test program • 787 control laws were added into a test-only 777 Primary Flight Computer software load • Gains tuned for 777 airframe • Planned software updates • Can switch back and forth between 777 and full or partial 787 functionality • Extensive safety checks before testing • Bench testing in lab • Piloted simulation with hardware in the loop • Ground testing for modal stability • Flight regression testing and modal stability testing with telemetry as needed

Longitudinal Maneuvers • Push-overs and pull-ups • Roller coaster maneuvers • Stall entries • Straight and turning flight • Idle and power-on • Accelerated • Wind-up turns • Windshear / Controlled Flight Into Terrain avoidance • Unusual attitude recoveries

Lateral-Directional Maneuvers • Ground handling • Simulated engine-out (one engine at idle) • Simulated Vmc with throttle chops (on-ground and in-air) • “Single-engine” ILS approaches • Crosswind operations, including engine-out • Air-ground transitions • Turn entries and turn coordination • Roll responses, roll checkbacks, and roll attitude tracking • Steady heading sideslips

Lessons Learned from 777 and CVRR, Part 1 • Define control philosophy early and design to it • Start with what works and build on that • Maintain close cooperation among Stability & Control, Flight Controls, Flight Deck, Loads, Flutter, and Flight Test • Use handling qualities criteria proven through long fleet history • Use a flying simulator to test new control law concepts • Model aeroservoelasticity effects early

Lessons Learned from 777 and CVRR, Part 2 • Design for PIO avoidance – use design criteria and test, test, test with many pilots • Pilot interfaces and response types should be as conventional as possible to take advantage of pilot training and experience • Be conservative when it comes to redundancy • Much time in flight test is spent tuning and integrating separate functions. Designing a single integrated control law simplifies this process.

Looking Ahead • 787 flight test starts in summer 2007! • Tasks for the coming year: • Switch design focus from 777 (CVRR) to 787 airframe characteristics • Incorporate CVRR lessons learned into processes and tools • Update control law gains as aero models improve • Conduct piloted handling qualities simulations (full-up and failure scenarios) • Test control system, including hardware, in “iron bird”

787 Flight Controls – The Journey So Far