Transcript Presentation
Vera Martinovich 787 Stability & Control - Handling Qualities Boeing Commercial Airplanes SAE Aerospace Control and Guidance Systems Committee Meeting October 11-13, 2006 Williamsburg, VA
787 Flight Controls – The Journey So Far
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
787-8 210-250 passengers (three-class) 8,000 – 8,500 nmi | 14,800 – 15,700 km 787-3 290-330 passengers (two-class) 3,000 – 3,500 nmi | 5,500 – 6,500 km 787-9 250-290 passengers (three-class) 8,600 – 8,800 nmi | 15,700 - 16,300 km
32 Customers, 420 Orders
* * * * Leasing
Schedule
Airplane Announcement Authority to Offer Program Launch Firm Configuration Start of Major Assembly 787-8 First Flight 2002 2003 2004 2005 2006 2007 787-8 Enters Service 2008 2009 787-3 Enters Service 787-9 Enters Service 2010
Agenda
787 description
Control law philosophy
Control law overview
Concept Validation & Risk Reduction flight test
Looking ahead
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.
Agenda
787 description
Control law philosophy
Control law overview
Concept Validation & Risk Reduction flight test
Looking ahead
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.
Agenda
787 description Control law philosophy Control law overview Concept Validation & Risk Reduction flight test Looking ahead
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”