Hydraulics and Landing Gear
Systems
Dean Hefflinger
Boeing Commercial
Aviation Services
May-June 2005
Presented to:
787 Engineering &
Maintenance
Conference
Boeing Proprietary
Agenda
5000 psi Hydraulics System Configuration Update
Hydraulic Architecture
System Interfaces
Component Installations
Landing Gear Actuation System Overview
Landing Gear Actuation System
Steering System
Boeing Proprietary
5,000 psi Hydraulic System
Reduced weight
Proven Left,Center and Right
independent system architecture
Hydraulic Power Generation
Four 27 gpm Electric Induction Motor
Pumps
Two 25 gpm Engine Driven Pumps
One 19 gpm Ram Air Turbine
Hydraulic System
Architecture Overview
Control and Indication
Integrated into Common Core System (CCS)
Flight crew interfaces similar to 777
Common motor controllers for Electric
Motor Pumps
Hydraulic System Distribution
Volume integration by Partners
Boeing Proprietary
Hydraulic System
Architecture
A i l e r o n s
F l a p e r o n s
I n b o a r d
S p o i l e r s
O u t b o a r d
S p o i l e r s
E l e v a t o r
R u d d e r
T h r u s t
R e v e r s e r s
T r a i l i n g
E d g e F l a p s
L e a d i n g
E d g e F l a p s
N o s e L a n d i n g
G e a r & S t e e r i n g
M a i n L a n d i n g
G e a r
L e f t
E n g i n e
E n g i n e
D r i v e n
P u m p
( E D P )
E l e c t r i c
M o t o r
P u m p
( E M P )
L e f t W i n g
R i g h t W i n g
L e f t W i n g,# 3
R i g h t W i n g,# 1 2
L e f t W i n g
L e f t E l e v a t o r
E l e c t r i c
M o t o r
P u m p
( E M P )
E l e c t r i c
M o t o r
P u m p
( E M P )
R a m A i r
T u r b i n e
( R A T )
R i g h t W i n g
L e f t W i n g
R i g h t W i n g
L e f t W i n g,# 7
R i g h t W i n g,# 8
L e f t W i n g,# 1
R i g h t W i n g,# 1 4
L e f t E l e v a t o r
R i g h t E l e v a t o r
P C U
H y d r a u l i c M o t o r
H y d r a u l i c M o t o r
N o r m a l
R e s e r v e
L e f t & R i g h t
P C U
C e n t e r S y s t e mL e f t S y s t e m R i g h t S y s t e m
2 5 gp m
2 7 / 3 7 gp m 2 7 / 3 7 gp m 2 7 / 3 7 gp m 1 0 - 1 9 gp m
R i g h t
E n g i n e
E n g i n e
D r i v e n
P u m p
( E D P )
E l e c t r i c
M o t o r
P u m p
( E M P )
R i g h t W i n g
L e f t W i n g
L e f t W i n g,# 6
R i g h t W i n g,# 9
L e f t W i n g,# 2
R i g h t W i n g,# 1 3
R i g h t E l e v a t o r
P C U
2 5 gp m 2 7 / 3 7 gp m
L e f t E n g i n e R i g h t E n g i n e
Boeing Proprietary
Hydraulic System
Architecture (cont.)
5000 psi operating pressure
Saves weight on fluid,tubing,reservoirs
Utilize low density BMS 3-11 fluid,currently classified as Type IV Class 1,& Type V Grade A or B
Hydraulic Interface Function (HYDIF) software,Part of Common Core System (CCS)
Common hydraulic pumps on EDPs and EMPs
Electric Motor Pumps (EMPs)
Flooded Induction Motor – cooled by hyd fluid from pump case drain (change from DC motors)
~27/37 GPM @ 5000 psi
Motor controller for starting,controlling motor speed
Brake System is not hydraulic
Boeing Proprietary
Hydraulic System
Architecture (cont.)
New controlled system operating temperature to
approximately,100? – 160?F
Temperature control maintained by a bypass valve and fuel
tank heat exchanger in each system
Bypass valve is a mechanical thermostat type device
located on the case drain filter module
Bypass valve is designed for two positions:
Closed,flow through the heat exchanger (only)
Open,a percentage of flow bypassing the heat
exchanger
Boeing Proprietary
Hydraulic System
Architecture (cont.)
No bleed air used for hydraulic power
Bootstrap Reservoir
Chosen because bleed air not available for reservoir pressurization
Change from traditional air-over-oil configuration
Bootstrap system utilizes hydraulic system pressure to pressurize reservoir
Proven design on Douglas model airplanes
DC-10,MD-11
717,DC-8,DC-9,MD-80,MD-90
Boeing Proprietary
Hydraulic Systems
Bootstrap Reservoir Schematic
High pressure (Red)
5000psi
Low pressure
(Blue)
Boeing Proprietary
Hydraulic System
Architecture (cont.)
Ground test that require 5000 psi pressure:
Landing gear retraction
RAT functional tests (GSE)
High pressure hydraulic leakage checks
Flaps/slats operation (hydraulic mode – priority valve)
Primary flight controls actuation confidence test
Hydraulic Power Options for Ground Tests:
APU generator
Three or Four external ground power sources
Two external ground power sources can provide limited hydraulic power in maintenance mode
5000 psi ground cart
Boeing Proprietary
Hydraulic System
Transport Elements
System Pressure Tubing
Titanium,Ti-3-2.5
Requires thicker wall tubing
Qualification to 5080 psi for industry commonality
Threat zones will use 21-6-9 CRES tubing
(thrown tread area,pressure dome,etc.)
Return Pressure Tubing
Thin wall titanium,Ti-3-2.5
Aluminum inside the fuel tanks
Boeing Proprietary
Hydraulic System
Transport Elements (cont.)
Repair processes and techniques for 5,000 psi tubing are
anticipated to be nearly identical to current airplanes
Processes and techniques used on current airplanes will
be used with different parts
Example repair methods being developed include,
Cut-out and drop-in replacement tubing sections using
existing swaging techniques
5,000 psi flex hoses permitted for repair in lieu of hard
tubing runs
5000 psi Ti tubing replacement with 5000 psi CRES
tubing using 21-6-9 is planned (similar to 3000 psi
systems )
Replacement with OEM-built tube assemblies
Similar to 3000 psi airplanes,Boeing will offer to
cooperate with Airbus to harmonize repair methods and
repair tools
Boeing Proprietary
Hydraulic System
Transport Elements (cont.)
Hoses
CRES & Kevlar – new specification (SAE standard) for
5000 psi
Fittings
Permanent
5000 psi Ti tubing,Axially swaged fittings
Return tubing,Investigating the use of axial swaged
fittings
Re-connectable
5000 psi re-connectable fittings will use very fine
threads (compatible with Airbus)
New re-connectable tube end fitting
Boeing Proprietary
Hydraulic System
Transport Elements (cont.)
“Wired” nut:
1,Allows sleeve to
assemble off axis
2,Eliminates tube
twist
3,Reduces friction
and increases
sealing force
Spherical acorn sealing surface:
1,Allows sealing with off-axis assembly
2,Lack of pilot prevents jamming,reduces cost
3,Grit blasting not allowed on sealing surfaces
4,Eliminate chatter marks and out-of-round
sealing surfaces
union
sleeve
B-nut
Solid film lubricated B-nut
New Re-connectable
Tube End Fitting
Boeing Proprietary
Hydraulic System Architecture
7 E 7
H Y D R A U L I C
R O U T I N G
L EF T SY ST EM
C EN T ER SY ST EM
R I G H T SY ST EM
L
C
L
E
E
R
C
E
R
E
L
C
R
R
R
L
L
R A T
RAT
RAT
C
L
C
R A T
R
C R A T
L
C R A T
R
C
R
R A T
E D P
E D P
E M P
E M P
R E S V
R E S V
R E S V
TR
TR
E X T E N D
S T E E R
A L T
E X T E N D
LE
F L A P S
TE
F L A P S
R A T
E M P
E M P
HE
HE
HE
C R A T
MC
MC MC
MC
EL EC T R O -M EC H AN I C AL AC T U AT O R S
R AT PO W ER
C
Boeing Proprietary
Hydraulic Systems
Flight Deck Interface
HYDRAULIC
RPM
OIL PRE SS
APU
OIL T EMP
EGT
OIL Q TY
1160c
7.9125 c30 PSI
100.1
OXYGEN
CREW PRESS 1950
GEAR INDICA TION SYS
GEAR CO NTROL
ALTN GEAR EXTEND
NOSE GEAR UP SENSOR
L GEAR UP LOCK S ENSOR
R GEAR UP LOCK S ENSOR
NOSE GEAR DO OR SENSOR
L GEAR DO OR SENSOR
R GEAR DO OR SENSOR
PG 1
0.91
3100
0.90
3050
0.72
3110
QTY
PRESS
RF
L C R
NOS E GEAR
&
STEE RING
FLAPS
L REV R REV
NORM BRK S
ALTN/RSV
BRAKES
MAIN
GEAR &
STEE RINGFLT CTR L FLT CTR LFLT CTR L
CCS
HYDIF
Display
Function
Sensor
Inputs CCS
FLT CTRL
NOSE GEAR
& STEERING
L REV
FLAPS
PRESS PRESS3010 4990
ALTN/RSV
BRAKES
MAIN GEAR
& STEERINGFLT CTRLFLT CTRL
R REV
NORM BRKS
0.90
2990
L
ENG
SOV
LELEC
P
R
I
M
A
R
Y
D
E
M
A
N
D
0.90
3000
R
ENG
SOV
RELEC
P
R
I
M
A
R
Y
D
E
M
A
N
D
1.00
ELEC
C1
ELEC
C2
AIR
C1
AIR
C2
ISLN ISLN
Issues Commands to
Hydraulic System
Components
E N G B T L
1 D IS C H
D IS C H
L
D IS C H
E N G B T L
2 D IS C H
1 2
E
F
T
I
G
H
T
R
1 2
R i gh t
E ng i ne
E l e c tr i c
M oto r
P u m p
(E M P )
E ng i ne
D r i v e n
P um p
(E D P )
E l e c t r i c
M o tor
P um p
(E M P )
R a m A i r
T ur bi ne
(R A T )
O B A i l e r o n -
I B F l a p e r o n
S p o i l e r s -
I B & O B
E l e v a to r
R u d d e r
T h r u s t
R e v e r s e r
L e a d i n g E d g e
F l a p s
N o s e L a n d i n g
G e a r & S te e r i n g
M a i n L a n d i n g
G e a r
L W i n g,O B & I B
R W i n g,I B
L W i n g,3
R W i n g,1 2
L e f t
P C U
L e f t
N o rm al,
,R e se r ve
L e f t & R i g h t
L W i n g,I B
R Wi n g,OB
L W i n g,2,6
R W i n g,9,1 3
R i g h t
P C U
R i g h t
M o t o r
Le f t
E ng i ne
L e f t S y s t e m R ig h t S y s t e m
E ng i ne
D r i v e n
P um p
(E D P )
2 7 / 3 7 g p m
1 0 / 1 9 g p m
2 5 g p m
2 7 g p m
E l e c tr i c
M oto r
P u m p
( E M P )
E l e c tr i c
M oto r
P u m p
(E M P )
C e n t e r S y s t e m
L W i n g,O B
R W i n g,O B & I B
L W i n g,1,7
R W i n g,8,1 4
L e f t & R i g h t
P C U
+/ - 2 7 0 V D C
M o t o rT r a i l i n g E d g e
F l a p s
+/ - 2 7 0 V D C +/ - 2 7 0 V D C
2 7 / 3 7 g p m x 2
2 5 g p m
E L E C
H Y D R A U L I C
O N
F A U L T
L E N G
O N
F A U L T
O N
R E N G
C 1
A U T O
O NO F F
F A U L T
C 2
A U T O
O NO F F
F A U L T
P
R
I
M
A
R
Y
D
E
M
A
N
D
P
R
I
M
A
R
Y
D
E
M
A
N
D
A U T O
O NO F F
F A U L T
L E L E C
A U T O
O F F
R E L E C
F A U L T
P R E S S
U N L K D
R A M A I R
T U R B I N E
C Hyd System
Components
L Hyd System
Components
R Hyd System
Components
2122
2324
30
29
2929
29
30
INTERNAL LEAKAGE:
RAT PUM:
DEMAND PUMP:
PRIMARY PUMP:
SYSTEM PRESS:
UTC XX,XX,XXDATE,XX XXX XXHYD SYS PRESS L
HYDRAULIC INDICATION
NOSE GEAR &
STEERING
FLAPS
L REV R REV
NORM BRKS
ALTN/RSV
BRAKES
MAIN GEAR &
STEERING
FLT CTRL FLT CTRLFLT CTRL
L C L
3000
- -
2950
- -
2970
- -
RESERVOIR:
F/C S/O VLV:
PRES 3050 2980 2980 3000
TEM 103 75 75 -10
SEL ON ON ON ON
RUN - - YES YES
S /O VLV OPEN - - - - CLOSED
BRKS / STRG ISO:
BRKS / STRG ISO:
PRES 3050 2980 2980 3000
TEM 103 75 75 -10
SEL ON ON ON OFF
RUN YES YES YES NO
PRES - - 2950 - -
RPM - - 4550 - -
POS - - NOT ALLOWED - -
QTY 1.00 0.34 lo 0.95
PRESS NORM NORM LOW
TEMP 100 55 -25
TAIL NORM NORM CLOSED
WING NORM NORM NORM
VALVE POS - - NORM - -
VALVE POS - - NORM - -
Boeing Proprietary
Hydraulic Systems
Component Locations
Engine Driven Pump Integration – Rolls Royce
Pump
Disconnect
Panel/Firewall
Pump
Inlet & Self
Sealing Disconnect
Pressure &
Check Valve
Case Drain &
Check Valve
Disconnect Panel
& Firewall
(Pictorially Missing)
Inlet & Self
Sealing Disconnect
Pressure &
Check Valve
Case Drain &
Check Valve
Gearbox
Boeing Proprietary
Hydraulic Systems
Component Locations
Engine Driven Pump Integration – General Electric
Inlet & Self
Sealing Disconnect
Pressure Check
Valve
TBD Swivel Elbow
Seal Drain
Case Drain
Gearbox Right
Angle DriveGearbox
Boeing Proprietary
Electric Motor Pump
3 Phase Electrical
Terminal Block
Isolation Mounts For Wing
Body Fairing Installation
Grounding lugs
Motor Shaft Seal Drain
Pump Inlet
Pump
Discharge
Pump
(Parker)
V-Band
Alternate Pump
Seal Drain
Motor Cooling
Outlet
(Case Drain)
Motor
Cooling Inlet
Pump Case
Drain
Boeing Proprietary
EMP Installation in Aft Engine Strut
Fairing
EMP Motor
ReservoirReturn Filter
Case Drain
Filter
Pressure FilterGSE Connections
EMP Pump
Boeing Proprietary
EMP and Reservoir Installation
Wing to Body Fairing
EMP
Reservoir
Filters
View Looking Outboard & Forward
UP
FWD
Boeing Proprietary
EMP and Reservoir Installation
Wing to Body Fairing
View Looking Forward
UP
FWD
Boeing Proprietary
Hydraulic Systems
Ram Air Turbine
Deployed,looking
inboard
Deployed,looking
outboard
Turbine
Lower
Gearbox
Pump/
Control
Module
(LRU)
Strut
Frame
Actuator
(hidden by
frame)
Generator
A/C brackets
(shown for
reference)
Pressure
Filter
(LRU)
Pressure
Transducer
(LRU)
Door Link
(LRU,not
shown)
Boeing Proprietary
RAT Installation
Wing to Body Fairing
UP
FWD
View Looking Down and Aft
Boeing Proprietary
Landing Gear Systems
Boeing Proprietary
Landing Gear Actuation & Steering
Architecture/Overview
Nose Wheel Steering
System
Steer-By-Wire
Integrated with Flight
Controls
Dual tillers are baseline
5000 psi actuation
Landing Gear Actuation System
Actuation & Sequencing By-Wire
Lower part count and weight
Advanced health monitoring
5000 psi actuation
Boeing Proprietary
Landing Gear Systems
New Control-by-Wire
Landing Gear Actuation
Electronic control and sequencing
Proximity sensors to monitor Landing Gear and Door
position & control sequencing
Steering Control
Control-by-wire rudder pedals and dual tillers
Boeing Proprietary
Landing Gear Control
Highlights
LG Control System:
Does not use any indication system inputs to apply valve
commands
Two redundant ‘Control’ prox sensors are installed at
each location
LG Position Indication:
Provides position icons and alert messages for landing
gear and gear doors
Status messages and maintenance page information
provided by either LG Indication or LG Control software
as appropriate
Depends on proximity sensor data
LG software in CCS provides information to Alerting &
Displays software
Boeing Proprietary
Normal Landing Gear Actuation and
Indication Systems Overview
A l t e r n a t e
G e a r & D o o r
R e l e a s e A c t u a t o r s
R e t r a c t,D o o r
& L o c k A c t u a t o r s
R e t r a c t,D o o r,L o c k
& T r u c k T i l t A c t u a t o r s
G e a r,D o o r
& T r u c k T i l t
P o s i t i o n
I n d i c a t i o n
G e a r,D o o r &
T r u c k S e q u e n c i n g
C o n t r o l
G r o u n d D o o r
R e l e a s e S y s t e m
F w d
R D C s
A f t
R D C s
L e f t ( R i g h t )
M a i n G e a r & D o o r
E l e c t r o - H y d r a u l i c
S e q u e n c i n g
C o n t r o l V a l v e s &
M i s c E l e c t r o n i c s
N o s e G e a r & D o o r
E l e c t r o - H y d r a u l i c
S e q u e n c i n g
C o n t r o l V a l v e s &
M i s c E l e c t r o n i c s
G e a r & D o o r
P o s i t i o n
I n d i c a t i o n
G e a r & D o o r
S e q u e n c i n g
C o n t r o l
A l t e r n a t e
G e a r & D o o r
R e l e a s e
A c t u a t o r s
N L G
C o m m o n D a t a N e t w o r k ( C D N )
A l t e r n a t e E x t e n s i o n
S y s t e m
C e n t e r
H y d r a u l i c
S y s t e m
C e n t e r
H y d r a u l i c
S y s t e m
L ( R )
M L G
D I S P L A Y S
F L I G H T D E C K
C o n t r o l s a n d I n d i c a t i o n
F l i g h t D e c k
R D C s
A L T N
E X T
U P
D O W N
C C R s
( L a n d i n g G e a r
C o n t r o l,
I n d i c a t i o n &
H e a l t h M g m t )
F w d
R P D U s
A f t
R P D U s
E L E C T R I C A L
D A T A B U S E S
H Y D R A U L I C S N O R M A L
H Y D R A U L I C S A L T E R N A T E
P O S I T I O N T R A N S D U C E R
P S D C s
P S D C s
N o t e,P S D C = P r o x i m i t y S e n s o r D a t a C o n c e n t r a t o r
C
A
N
B
u
s
C
A
N
B
u
s
P o w e r
P a n e l s
Boeing Proprietary
LGA Control Overview
P r o x i m i t y
S e n s o r s
P S D C
RDCs
A FD X
S w i t c h e s
R e m o t e P o w e r
D r i v e U n i t s
( R P D U s )
G e n e r a l
P r o c e s s i n g
M o d u l e s
( G P M s )
A FD X
S w i t c h e s
L A N D I N G
G E A R
L E V E R
RDCs
C A N
b u s
R e d u n d a n t
Lane
R P D U s
V A L V E S
N O R M A L
G E A R / D O O R
A C T U A T O R S
A L T E R N A T E
E X T E N D
S W I T C H
A l t E x t e n d
P o w e r
R e l a y s
A l t E x t e n d
M o t o r
I n t e r l o c k
R e l a y s
RDCs
G r o u n d D o o r
R e l e a s e
S w i t c h
H y d r a u l i c
S t a n d p i p e
H y d r a u l i c
P u m p
A L T E R N A T E
G E A R / D O O R
A C T U A T O R S
C e n t e r
H y d r a u l i c
S y s t e m
N O R M A L C O N T R O L F U N C T I O N S
A L T E R N A T E
E X T E N D
F U N C T I O N S
C C S a n d C D N
Boeing Proprietary
Alternate Extension & Ground Door
Release Systems Overview
N L G
H o t
B a t t e r y
B u s
A l t n E x t
P o w e r P a c k
C e n t e r H y d r a u l i c
S y s t e m R e s e r v o i r
R e s e t C o m m a n d
S i g n a l M o n i t o r
L e f t M L G D o o r
S a f e t y V a l v e
P r e s s u r e
S w i t c h
P o w e r
R e l a y s
D o o r U n s a f e
L i g h t
D o o r U n s a f e
L i g h t
A l t n E x t
H y d r a u l i c
S t a n d p i p e
L M L G
A r m D o o r s
S w i t c h e s
O p e n
A l l D o o r s O p e n &
M L G D o o r s C l o s e
S w i t c h e s
A r m
R i g h t M L G D o o r
S a f e t y V a l v e
N o s e & M a i n
G e a r & D o o r
N o r m a l H y d
S y s t e m
N o s e G e a r A l t n
R e l e a s e A c t u a t o r s
M a i n G e a r A l t n
R e l e a s e A c t u a t o r s
D o o r
G e a r
M a i n G e a r A l t n
R e l e a s e A c t u a t o r s
G e a r
D o o r
N o s e G e a r D o o r
S a f e t y V a l v e
D o o r U n s a f e
L i g h t
G e a r
D o o r
R M L G
A r m D o o r s
S w i t c h
N o s e D o o r s
C l o s e S w i t c h
A r m
S l o w D o o r s
C l o s e
C o m m a n d
S l o w D o o r s
C l o s e
C o m m a n d
S l o w D o o r s
C l o s e
C o m m a n d
C l o s e
H o t B a t t e r y B u s
L D C
B u s
E L E C T R I C A L
D A T A B U S
H Y D R A U L I C A L T E R N A T E
A l t n
B y p a s s
C o m m a n d
F w d E E - B a y
R D C s
F L I G H T D E C K
C o n t r o l s a n d I n d i c a t i o n
F l i g h t D e c k
R D C s
C C R s
( L a n d i n g G e a r
C o n t r o l,
I n d i c a t i o n &
B I T E )
U P
D O W N
D I S P L A Y S
A L T N
E X T
L D C B u s
M o n i t o r
M o n i t o r
C o m m o n D a t a N e t w o r k ( C D N )
Boeing Proprietary
Nose Wheel Well – Component
Locations
Door Control Valve
NLG Auto-off/
Bypass Valve
NLG Door Safety ValveNG Lock Actuator
NLG Control Valve
Door Actuator
Alt Ext
Door
Release
Actuator
NLG Alt Ext Release
Actuator
Retract Actuator
Boeing Proprietary
Left MLG Wheel Well – Component
Locations
MLG Door Actuator
MLG Door Control
Valve
MLG Control Valve
MLG Auto-off
Bypass Valve
MLG Door Lock
Actuator
Boeing Proprietary
Right MLG Wheel Well – Component
Locations
MLG Door Actuator
MLG Alt Ext
Release Actuator
MLG Door
Lock Actuator
MLG Uplock
Actuator
MLG Door Alt Ext
Release Actuator
(hidden)
Boeing Proprietary
Mechanical Systems
NLG - Component Locations
STEERING VALVE,
RVDTs,ACTRS
NOSE WHEELS,
TIRES
(LOCK SENSORS)
IN-AXLE RDC
-TPIS
STEERING REU
(P-40 PANEL)
FWD
Boeing Proprietary
Mechanical Systems
MLG – Component Locations
FWD
IN-AXLE RDC
WHEEL SPEED-
BTMS-TPIS
MLG RETRACT
ACTUATOR
DOWNLOCK
ACTUATORS
(& SENSORS)
TRUCK TILT
ACTUATOR
TIRES,WHEELS &,
BRAKES
(TRUCK STOW
SENSORS)
Boeing Proprietary
Mechanical Systems
Steering System
Steer by Wire
Electronically controlled
Fault detection and isolation
Incorporates advanced control laws
Flight Deck
Tillers
Handle motion range,+/- 80 deg (777 is +/- 350 deg)
No interconnect between pilots tillers
Passive feel forces (No position feedback from nose wheels to tiller)
Rudder pedal disconnect switch
Rudder pedal and tiller command path gains - Reduced at high speed
Displays - EICAS information available
Maintenance data available
Boeing Proprietary
R P D S
F L I G H T C O N T R O L
E L E C T R O N I C S
F L I G H T D E C K C O N T R O L S A N D I N D I C A T I O N
R P D U
C A P T T I L L E R
E L E C T R I C A L
D A T A B U S E S
H Y D R A U L I C S
P O S I T I O N T R A N S D U C E R
M E C H A N I C A L
R P D S R U D D E R P E D A L
D I S C S W I T C H
R D C
R D C
( F L I G H T D E C K )
( F O R W A R D E E B A Y )
R U D D E R P E D A L S
S E R V O C O N T R O L
A N D M O N I T O R I N G
S I G N A L S
N O S E W H E E L
A N G L E
S T E E R I N G
C O L L A R
C E N T E R
H Y D R A U L I C
S Y S T E M
T O W I N G
D I S C O N N E C T
L E V E R
N G S T E E R I N G
V A L V E
M O D U L E
N G S T E E R I N G
R E U
( S E R V O C O N T R O L,
B I T E )
R U D D E R
P E D A L
P O S I T I O N
C O M M O N D A T A N E T W O R K ( C D N )
R P D S
F O T I L L E R
( N O S E G E A R )
C C R
C O N T R O L L A W S
F A U L T M O N I T O R
E I C A S
O N - B O A R D M A I N T
O P E R I N I T T E S T
D I S P L A Y S
( F O R W A R D E E B A Y )
S W I V E L
V A L V E
F B T R A N S D U C E R
M O D U L E
N W S
A C T U A T O R
Mechanical Systems
Steering System Architecture
Boeing Proprietary
Mechanical Systems
NWS System Command PathR U D D E R P E D A L S
C A P T A I N
T I L L E R
R P D S
R P D S
F O
T I L L E R
O R
7 0
0
V
R P T R I M
0
V
N O S E W H E E L
P O S I T I O N C O M
T I L L E R C O M
Y A W R A T E
S T E E R I N G
A C T U A T I O N
S Y S T E M
A U T O -
P I L O T
R U D D E R
A C T U A T I O N
S Y S T E M
0
T I L L E R C O M
R U D D E R
P O S I T I O N C O M
H I G H S P E E D
L O C K O U T
N o s e W h e e l S t e e r i n g S y s t e m
F l i g h t C o n t r o l S y s t e m
+ 8
- 8
I T A C
D I S A B L E D
B E L O W 4 0 k n
I T A C - I n e r t i a l T h r u s t A s y m m e t r y C o m p e n s a t i o n
L I M I T E R
Boeing Proprietary
Mechanical Systems
NWS System Control Gain & Authority
Rudder pedal gain schedules is preliminary
(To be optimized in simulator tests for all normal and airplane
failure conditions)
N W S C o m m a n d
to F u l l T i l l e r D i s p l a c e m e n t
0
10
20
30
40
50
60
70
80
0 20 40 60 80 100 120 140 160
G r o u n d S p e e d ( K n o t s )
N
o
s
e
W
h
e
e
l
A
n
g
l
e
(
d
e
g
)
N W S C o m m a n d
to F u l l R u d d e r Pe d a l D i s p l a c e m e n t
0
1
2
3
4
5
6
7
8
9
10
0 20 40 60 80 100 120 140 160
G r o u n d S p e e d ( K n o t s )
N
o
s
e
W
h
e
e
l
A
n
g
l
e
(
d
e
g
)
Boeing Proprietary
Mechanical Systems
Flight Deck Integration
BRAKE + STEERING (RUDDER)
PEDAL SENSORS
LG CONTROL
LEVER + ALT
EXTENSION
(THRUST
LEVERS)
(SPEEDBRAKE)
PARK
BRAKE
AUTOBRAKE
SELECT
DUAL
STEERING
TILLERS
Boeing Proprietary
Systems
Dean Hefflinger
Boeing Commercial
Aviation Services
May-June 2005
Presented to:
787 Engineering &
Maintenance
Conference
Boeing Proprietary
Agenda
5000 psi Hydraulics System Configuration Update
Hydraulic Architecture
System Interfaces
Component Installations
Landing Gear Actuation System Overview
Landing Gear Actuation System
Steering System
Boeing Proprietary
5,000 psi Hydraulic System
Reduced weight
Proven Left,Center and Right
independent system architecture
Hydraulic Power Generation
Four 27 gpm Electric Induction Motor
Pumps
Two 25 gpm Engine Driven Pumps
One 19 gpm Ram Air Turbine
Hydraulic System
Architecture Overview
Control and Indication
Integrated into Common Core System (CCS)
Flight crew interfaces similar to 777
Common motor controllers for Electric
Motor Pumps
Hydraulic System Distribution
Volume integration by Partners
Boeing Proprietary
Hydraulic System
Architecture
A i l e r o n s
F l a p e r o n s
I n b o a r d
S p o i l e r s
O u t b o a r d
S p o i l e r s
E l e v a t o r
R u d d e r
T h r u s t
R e v e r s e r s
T r a i l i n g
E d g e F l a p s
L e a d i n g
E d g e F l a p s
N o s e L a n d i n g
G e a r & S t e e r i n g
M a i n L a n d i n g
G e a r
L e f t
E n g i n e
E n g i n e
D r i v e n
P u m p
( E D P )
E l e c t r i c
M o t o r
P u m p
( E M P )
L e f t W i n g
R i g h t W i n g
L e f t W i n g,# 3
R i g h t W i n g,# 1 2
L e f t W i n g
L e f t E l e v a t o r
E l e c t r i c
M o t o r
P u m p
( E M P )
E l e c t r i c
M o t o r
P u m p
( E M P )
R a m A i r
T u r b i n e
( R A T )
R i g h t W i n g
L e f t W i n g
R i g h t W i n g
L e f t W i n g,# 7
R i g h t W i n g,# 8
L e f t W i n g,# 1
R i g h t W i n g,# 1 4
L e f t E l e v a t o r
R i g h t E l e v a t o r
P C U
H y d r a u l i c M o t o r
H y d r a u l i c M o t o r
N o r m a l
R e s e r v e
L e f t & R i g h t
P C U
C e n t e r S y s t e mL e f t S y s t e m R i g h t S y s t e m
2 5 gp m
2 7 / 3 7 gp m 2 7 / 3 7 gp m 2 7 / 3 7 gp m 1 0 - 1 9 gp m
R i g h t
E n g i n e
E n g i n e
D r i v e n
P u m p
( E D P )
E l e c t r i c
M o t o r
P u m p
( E M P )
R i g h t W i n g
L e f t W i n g
L e f t W i n g,# 6
R i g h t W i n g,# 9
L e f t W i n g,# 2
R i g h t W i n g,# 1 3
R i g h t E l e v a t o r
P C U
2 5 gp m 2 7 / 3 7 gp m
L e f t E n g i n e R i g h t E n g i n e
Boeing Proprietary
Hydraulic System
Architecture (cont.)
5000 psi operating pressure
Saves weight on fluid,tubing,reservoirs
Utilize low density BMS 3-11 fluid,currently classified as Type IV Class 1,& Type V Grade A or B
Hydraulic Interface Function (HYDIF) software,Part of Common Core System (CCS)
Common hydraulic pumps on EDPs and EMPs
Electric Motor Pumps (EMPs)
Flooded Induction Motor – cooled by hyd fluid from pump case drain (change from DC motors)
~27/37 GPM @ 5000 psi
Motor controller for starting,controlling motor speed
Brake System is not hydraulic
Boeing Proprietary
Hydraulic System
Architecture (cont.)
New controlled system operating temperature to
approximately,100? – 160?F
Temperature control maintained by a bypass valve and fuel
tank heat exchanger in each system
Bypass valve is a mechanical thermostat type device
located on the case drain filter module
Bypass valve is designed for two positions:
Closed,flow through the heat exchanger (only)
Open,a percentage of flow bypassing the heat
exchanger
Boeing Proprietary
Hydraulic System
Architecture (cont.)
No bleed air used for hydraulic power
Bootstrap Reservoir
Chosen because bleed air not available for reservoir pressurization
Change from traditional air-over-oil configuration
Bootstrap system utilizes hydraulic system pressure to pressurize reservoir
Proven design on Douglas model airplanes
DC-10,MD-11
717,DC-8,DC-9,MD-80,MD-90
Boeing Proprietary
Hydraulic Systems
Bootstrap Reservoir Schematic
High pressure (Red)
5000psi
Low pressure
(Blue)
Boeing Proprietary
Hydraulic System
Architecture (cont.)
Ground test that require 5000 psi pressure:
Landing gear retraction
RAT functional tests (GSE)
High pressure hydraulic leakage checks
Flaps/slats operation (hydraulic mode – priority valve)
Primary flight controls actuation confidence test
Hydraulic Power Options for Ground Tests:
APU generator
Three or Four external ground power sources
Two external ground power sources can provide limited hydraulic power in maintenance mode
5000 psi ground cart
Boeing Proprietary
Hydraulic System
Transport Elements
System Pressure Tubing
Titanium,Ti-3-2.5
Requires thicker wall tubing
Qualification to 5080 psi for industry commonality
Threat zones will use 21-6-9 CRES tubing
(thrown tread area,pressure dome,etc.)
Return Pressure Tubing
Thin wall titanium,Ti-3-2.5
Aluminum inside the fuel tanks
Boeing Proprietary
Hydraulic System
Transport Elements (cont.)
Repair processes and techniques for 5,000 psi tubing are
anticipated to be nearly identical to current airplanes
Processes and techniques used on current airplanes will
be used with different parts
Example repair methods being developed include,
Cut-out and drop-in replacement tubing sections using
existing swaging techniques
5,000 psi flex hoses permitted for repair in lieu of hard
tubing runs
5000 psi Ti tubing replacement with 5000 psi CRES
tubing using 21-6-9 is planned (similar to 3000 psi
systems )
Replacement with OEM-built tube assemblies
Similar to 3000 psi airplanes,Boeing will offer to
cooperate with Airbus to harmonize repair methods and
repair tools
Boeing Proprietary
Hydraulic System
Transport Elements (cont.)
Hoses
CRES & Kevlar – new specification (SAE standard) for
5000 psi
Fittings
Permanent
5000 psi Ti tubing,Axially swaged fittings
Return tubing,Investigating the use of axial swaged
fittings
Re-connectable
5000 psi re-connectable fittings will use very fine
threads (compatible with Airbus)
New re-connectable tube end fitting
Boeing Proprietary
Hydraulic System
Transport Elements (cont.)
“Wired” nut:
1,Allows sleeve to
assemble off axis
2,Eliminates tube
twist
3,Reduces friction
and increases
sealing force
Spherical acorn sealing surface:
1,Allows sealing with off-axis assembly
2,Lack of pilot prevents jamming,reduces cost
3,Grit blasting not allowed on sealing surfaces
4,Eliminate chatter marks and out-of-round
sealing surfaces
union
sleeve
B-nut
Solid film lubricated B-nut
New Re-connectable
Tube End Fitting
Boeing Proprietary
Hydraulic System Architecture
7 E 7
H Y D R A U L I C
R O U T I N G
L EF T SY ST EM
C EN T ER SY ST EM
R I G H T SY ST EM
L
C
L
E
E
R
C
E
R
E
L
C
R
R
R
L
L
R A T
RAT
RAT
C
L
C
R A T
R
C R A T
L
C R A T
R
C
R
R A T
E D P
E D P
E M P
E M P
R E S V
R E S V
R E S V
TR
TR
E X T E N D
S T E E R
A L T
E X T E N D
LE
F L A P S
TE
F L A P S
R A T
E M P
E M P
HE
HE
HE
C R A T
MC
MC MC
MC
EL EC T R O -M EC H AN I C AL AC T U AT O R S
R AT PO W ER
C
Boeing Proprietary
Hydraulic Systems
Flight Deck Interface
HYDRAULIC
RPM
OIL PRE SS
APU
OIL T EMP
EGT
OIL Q TY
1160c
7.9125 c30 PSI
100.1
OXYGEN
CREW PRESS 1950
GEAR INDICA TION SYS
GEAR CO NTROL
ALTN GEAR EXTEND
NOSE GEAR UP SENSOR
L GEAR UP LOCK S ENSOR
R GEAR UP LOCK S ENSOR
NOSE GEAR DO OR SENSOR
L GEAR DO OR SENSOR
R GEAR DO OR SENSOR
PG 1
0.91
3100
0.90
3050
0.72
3110
QTY
PRESS
RF
L C R
NOS E GEAR
&
STEE RING
FLAPS
L REV R REV
NORM BRK S
ALTN/RSV
BRAKES
MAIN
GEAR &
STEE RINGFLT CTR L FLT CTR LFLT CTR L
CCS
HYDIF
Display
Function
Sensor
Inputs CCS
FLT CTRL
NOSE GEAR
& STEERING
L REV
FLAPS
PRESS PRESS3010 4990
ALTN/RSV
BRAKES
MAIN GEAR
& STEERINGFLT CTRLFLT CTRL
R REV
NORM BRKS
0.90
2990
L
ENG
SOV
LELEC
P
R
I
M
A
R
Y
D
E
M
A
N
D
0.90
3000
R
ENG
SOV
RELEC
P
R
I
M
A
R
Y
D
E
M
A
N
D
1.00
ELEC
C1
ELEC
C2
AIR
C1
AIR
C2
ISLN ISLN
Issues Commands to
Hydraulic System
Components
E N G B T L
1 D IS C H
D IS C H
L
D IS C H
E N G B T L
2 D IS C H
1 2
E
F
T
I
G
H
T
R
1 2
R i gh t
E ng i ne
E l e c tr i c
M oto r
P u m p
(E M P )
E ng i ne
D r i v e n
P um p
(E D P )
E l e c t r i c
M o tor
P um p
(E M P )
R a m A i r
T ur bi ne
(R A T )
O B A i l e r o n -
I B F l a p e r o n
S p o i l e r s -
I B & O B
E l e v a to r
R u d d e r
T h r u s t
R e v e r s e r
L e a d i n g E d g e
F l a p s
N o s e L a n d i n g
G e a r & S te e r i n g
M a i n L a n d i n g
G e a r
L W i n g,O B & I B
R W i n g,I B
L W i n g,3
R W i n g,1 2
L e f t
P C U
L e f t
N o rm al,
,R e se r ve
L e f t & R i g h t
L W i n g,I B
R Wi n g,OB
L W i n g,2,6
R W i n g,9,1 3
R i g h t
P C U
R i g h t
M o t o r
Le f t
E ng i ne
L e f t S y s t e m R ig h t S y s t e m
E ng i ne
D r i v e n
P um p
(E D P )
2 7 / 3 7 g p m
1 0 / 1 9 g p m
2 5 g p m
2 7 g p m
E l e c tr i c
M oto r
P u m p
( E M P )
E l e c tr i c
M oto r
P u m p
(E M P )
C e n t e r S y s t e m
L W i n g,O B
R W i n g,O B & I B
L W i n g,1,7
R W i n g,8,1 4
L e f t & R i g h t
P C U
+/ - 2 7 0 V D C
M o t o rT r a i l i n g E d g e
F l a p s
+/ - 2 7 0 V D C +/ - 2 7 0 V D C
2 7 / 3 7 g p m x 2
2 5 g p m
E L E C
H Y D R A U L I C
O N
F A U L T
L E N G
O N
F A U L T
O N
R E N G
C 1
A U T O
O NO F F
F A U L T
C 2
A U T O
O NO F F
F A U L T
P
R
I
M
A
R
Y
D
E
M
A
N
D
P
R
I
M
A
R
Y
D
E
M
A
N
D
A U T O
O NO F F
F A U L T
L E L E C
A U T O
O F F
R E L E C
F A U L T
P R E S S
U N L K D
R A M A I R
T U R B I N E
C Hyd System
Components
L Hyd System
Components
R Hyd System
Components
2122
2324
30
29
2929
29
30
INTERNAL LEAKAGE:
RAT PUM:
DEMAND PUMP:
PRIMARY PUMP:
SYSTEM PRESS:
UTC XX,XX,XXDATE,XX XXX XXHYD SYS PRESS L
HYDRAULIC INDICATION
NOSE GEAR &
STEERING
FLAPS
L REV R REV
NORM BRKS
ALTN/RSV
BRAKES
MAIN GEAR &
STEERING
FLT CTRL FLT CTRLFLT CTRL
L C L
3000
- -
2950
- -
2970
- -
RESERVOIR:
F/C S/O VLV:
PRES 3050 2980 2980 3000
TEM 103 75 75 -10
SEL ON ON ON ON
RUN - - YES YES
S /O VLV OPEN - - - - CLOSED
BRKS / STRG ISO:
BRKS / STRG ISO:
PRES 3050 2980 2980 3000
TEM 103 75 75 -10
SEL ON ON ON OFF
RUN YES YES YES NO
PRES - - 2950 - -
RPM - - 4550 - -
POS - - NOT ALLOWED - -
QTY 1.00 0.34 lo 0.95
PRESS NORM NORM LOW
TEMP 100 55 -25
TAIL NORM NORM CLOSED
WING NORM NORM NORM
VALVE POS - - NORM - -
VALVE POS - - NORM - -
Boeing Proprietary
Hydraulic Systems
Component Locations
Engine Driven Pump Integration – Rolls Royce
Pump
Disconnect
Panel/Firewall
Pump
Inlet & Self
Sealing Disconnect
Pressure &
Check Valve
Case Drain &
Check Valve
Disconnect Panel
& Firewall
(Pictorially Missing)
Inlet & Self
Sealing Disconnect
Pressure &
Check Valve
Case Drain &
Check Valve
Gearbox
Boeing Proprietary
Hydraulic Systems
Component Locations
Engine Driven Pump Integration – General Electric
Inlet & Self
Sealing Disconnect
Pressure Check
Valve
TBD Swivel Elbow
Seal Drain
Case Drain
Gearbox Right
Angle DriveGearbox
Boeing Proprietary
Electric Motor Pump
3 Phase Electrical
Terminal Block
Isolation Mounts For Wing
Body Fairing Installation
Grounding lugs
Motor Shaft Seal Drain
Pump Inlet
Pump
Discharge
Pump
(Parker)
V-Band
Alternate Pump
Seal Drain
Motor Cooling
Outlet
(Case Drain)
Motor
Cooling Inlet
Pump Case
Drain
Boeing Proprietary
EMP Installation in Aft Engine Strut
Fairing
EMP Motor
ReservoirReturn Filter
Case Drain
Filter
Pressure FilterGSE Connections
EMP Pump
Boeing Proprietary
EMP and Reservoir Installation
Wing to Body Fairing
EMP
Reservoir
Filters
View Looking Outboard & Forward
UP
FWD
Boeing Proprietary
EMP and Reservoir Installation
Wing to Body Fairing
View Looking Forward
UP
FWD
Boeing Proprietary
Hydraulic Systems
Ram Air Turbine
Deployed,looking
inboard
Deployed,looking
outboard
Turbine
Lower
Gearbox
Pump/
Control
Module
(LRU)
Strut
Frame
Actuator
(hidden by
frame)
Generator
A/C brackets
(shown for
reference)
Pressure
Filter
(LRU)
Pressure
Transducer
(LRU)
Door Link
(LRU,not
shown)
Boeing Proprietary
RAT Installation
Wing to Body Fairing
UP
FWD
View Looking Down and Aft
Boeing Proprietary
Landing Gear Systems
Boeing Proprietary
Landing Gear Actuation & Steering
Architecture/Overview
Nose Wheel Steering
System
Steer-By-Wire
Integrated with Flight
Controls
Dual tillers are baseline
5000 psi actuation
Landing Gear Actuation System
Actuation & Sequencing By-Wire
Lower part count and weight
Advanced health monitoring
5000 psi actuation
Boeing Proprietary
Landing Gear Systems
New Control-by-Wire
Landing Gear Actuation
Electronic control and sequencing
Proximity sensors to monitor Landing Gear and Door
position & control sequencing
Steering Control
Control-by-wire rudder pedals and dual tillers
Boeing Proprietary
Landing Gear Control
Highlights
LG Control System:
Does not use any indication system inputs to apply valve
commands
Two redundant ‘Control’ prox sensors are installed at
each location
LG Position Indication:
Provides position icons and alert messages for landing
gear and gear doors
Status messages and maintenance page information
provided by either LG Indication or LG Control software
as appropriate
Depends on proximity sensor data
LG software in CCS provides information to Alerting &
Displays software
Boeing Proprietary
Normal Landing Gear Actuation and
Indication Systems Overview
A l t e r n a t e
G e a r & D o o r
R e l e a s e A c t u a t o r s
R e t r a c t,D o o r
& L o c k A c t u a t o r s
R e t r a c t,D o o r,L o c k
& T r u c k T i l t A c t u a t o r s
G e a r,D o o r
& T r u c k T i l t
P o s i t i o n
I n d i c a t i o n
G e a r,D o o r &
T r u c k S e q u e n c i n g
C o n t r o l
G r o u n d D o o r
R e l e a s e S y s t e m
F w d
R D C s
A f t
R D C s
L e f t ( R i g h t )
M a i n G e a r & D o o r
E l e c t r o - H y d r a u l i c
S e q u e n c i n g
C o n t r o l V a l v e s &
M i s c E l e c t r o n i c s
N o s e G e a r & D o o r
E l e c t r o - H y d r a u l i c
S e q u e n c i n g
C o n t r o l V a l v e s &
M i s c E l e c t r o n i c s
G e a r & D o o r
P o s i t i o n
I n d i c a t i o n
G e a r & D o o r
S e q u e n c i n g
C o n t r o l
A l t e r n a t e
G e a r & D o o r
R e l e a s e
A c t u a t o r s
N L G
C o m m o n D a t a N e t w o r k ( C D N )
A l t e r n a t e E x t e n s i o n
S y s t e m
C e n t e r
H y d r a u l i c
S y s t e m
C e n t e r
H y d r a u l i c
S y s t e m
L ( R )
M L G
D I S P L A Y S
F L I G H T D E C K
C o n t r o l s a n d I n d i c a t i o n
F l i g h t D e c k
R D C s
A L T N
E X T
U P
D O W N
C C R s
( L a n d i n g G e a r
C o n t r o l,
I n d i c a t i o n &
H e a l t h M g m t )
F w d
R P D U s
A f t
R P D U s
E L E C T R I C A L
D A T A B U S E S
H Y D R A U L I C S N O R M A L
H Y D R A U L I C S A L T E R N A T E
P O S I T I O N T R A N S D U C E R
P S D C s
P S D C s
N o t e,P S D C = P r o x i m i t y S e n s o r D a t a C o n c e n t r a t o r
C
A
N
B
u
s
C
A
N
B
u
s
P o w e r
P a n e l s
Boeing Proprietary
LGA Control Overview
P r o x i m i t y
S e n s o r s
P S D C
RDCs
A FD X
S w i t c h e s
R e m o t e P o w e r
D r i v e U n i t s
( R P D U s )
G e n e r a l
P r o c e s s i n g
M o d u l e s
( G P M s )
A FD X
S w i t c h e s
L A N D I N G
G E A R
L E V E R
RDCs
C A N
b u s
R e d u n d a n t
Lane
R P D U s
V A L V E S
N O R M A L
G E A R / D O O R
A C T U A T O R S
A L T E R N A T E
E X T E N D
S W I T C H
A l t E x t e n d
P o w e r
R e l a y s
A l t E x t e n d
M o t o r
I n t e r l o c k
R e l a y s
RDCs
G r o u n d D o o r
R e l e a s e
S w i t c h
H y d r a u l i c
S t a n d p i p e
H y d r a u l i c
P u m p
A L T E R N A T E
G E A R / D O O R
A C T U A T O R S
C e n t e r
H y d r a u l i c
S y s t e m
N O R M A L C O N T R O L F U N C T I O N S
A L T E R N A T E
E X T E N D
F U N C T I O N S
C C S a n d C D N
Boeing Proprietary
Alternate Extension & Ground Door
Release Systems Overview
N L G
H o t
B a t t e r y
B u s
A l t n E x t
P o w e r P a c k
C e n t e r H y d r a u l i c
S y s t e m R e s e r v o i r
R e s e t C o m m a n d
S i g n a l M o n i t o r
L e f t M L G D o o r
S a f e t y V a l v e
P r e s s u r e
S w i t c h
P o w e r
R e l a y s
D o o r U n s a f e
L i g h t
D o o r U n s a f e
L i g h t
A l t n E x t
H y d r a u l i c
S t a n d p i p e
L M L G
A r m D o o r s
S w i t c h e s
O p e n
A l l D o o r s O p e n &
M L G D o o r s C l o s e
S w i t c h e s
A r m
R i g h t M L G D o o r
S a f e t y V a l v e
N o s e & M a i n
G e a r & D o o r
N o r m a l H y d
S y s t e m
N o s e G e a r A l t n
R e l e a s e A c t u a t o r s
M a i n G e a r A l t n
R e l e a s e A c t u a t o r s
D o o r
G e a r
M a i n G e a r A l t n
R e l e a s e A c t u a t o r s
G e a r
D o o r
N o s e G e a r D o o r
S a f e t y V a l v e
D o o r U n s a f e
L i g h t
G e a r
D o o r
R M L G
A r m D o o r s
S w i t c h
N o s e D o o r s
C l o s e S w i t c h
A r m
S l o w D o o r s
C l o s e
C o m m a n d
S l o w D o o r s
C l o s e
C o m m a n d
S l o w D o o r s
C l o s e
C o m m a n d
C l o s e
H o t B a t t e r y B u s
L D C
B u s
E L E C T R I C A L
D A T A B U S
H Y D R A U L I C A L T E R N A T E
A l t n
B y p a s s
C o m m a n d
F w d E E - B a y
R D C s
F L I G H T D E C K
C o n t r o l s a n d I n d i c a t i o n
F l i g h t D e c k
R D C s
C C R s
( L a n d i n g G e a r
C o n t r o l,
I n d i c a t i o n &
B I T E )
U P
D O W N
D I S P L A Y S
A L T N
E X T
L D C B u s
M o n i t o r
M o n i t o r
C o m m o n D a t a N e t w o r k ( C D N )
Boeing Proprietary
Nose Wheel Well – Component
Locations
Door Control Valve
NLG Auto-off/
Bypass Valve
NLG Door Safety ValveNG Lock Actuator
NLG Control Valve
Door Actuator
Alt Ext
Door
Release
Actuator
NLG Alt Ext Release
Actuator
Retract Actuator
Boeing Proprietary
Left MLG Wheel Well – Component
Locations
MLG Door Actuator
MLG Door Control
Valve
MLG Control Valve
MLG Auto-off
Bypass Valve
MLG Door Lock
Actuator
Boeing Proprietary
Right MLG Wheel Well – Component
Locations
MLG Door Actuator
MLG Alt Ext
Release Actuator
MLG Door
Lock Actuator
MLG Uplock
Actuator
MLG Door Alt Ext
Release Actuator
(hidden)
Boeing Proprietary
Mechanical Systems
NLG - Component Locations
STEERING VALVE,
RVDTs,ACTRS
NOSE WHEELS,
TIRES
(LOCK SENSORS)
IN-AXLE RDC
-TPIS
STEERING REU
(P-40 PANEL)
FWD
Boeing Proprietary
Mechanical Systems
MLG – Component Locations
FWD
IN-AXLE RDC
WHEEL SPEED-
BTMS-TPIS
MLG RETRACT
ACTUATOR
DOWNLOCK
ACTUATORS
(& SENSORS)
TRUCK TILT
ACTUATOR
TIRES,WHEELS &,
BRAKES
(TRUCK STOW
SENSORS)
Boeing Proprietary
Mechanical Systems
Steering System
Steer by Wire
Electronically controlled
Fault detection and isolation
Incorporates advanced control laws
Flight Deck
Tillers
Handle motion range,+/- 80 deg (777 is +/- 350 deg)
No interconnect between pilots tillers
Passive feel forces (No position feedback from nose wheels to tiller)
Rudder pedal disconnect switch
Rudder pedal and tiller command path gains - Reduced at high speed
Displays - EICAS information available
Maintenance data available
Boeing Proprietary
R P D S
F L I G H T C O N T R O L
E L E C T R O N I C S
F L I G H T D E C K C O N T R O L S A N D I N D I C A T I O N
R P D U
C A P T T I L L E R
E L E C T R I C A L
D A T A B U S E S
H Y D R A U L I C S
P O S I T I O N T R A N S D U C E R
M E C H A N I C A L
R P D S R U D D E R P E D A L
D I S C S W I T C H
R D C
R D C
( F L I G H T D E C K )
( F O R W A R D E E B A Y )
R U D D E R P E D A L S
S E R V O C O N T R O L
A N D M O N I T O R I N G
S I G N A L S
N O S E W H E E L
A N G L E
S T E E R I N G
C O L L A R
C E N T E R
H Y D R A U L I C
S Y S T E M
T O W I N G
D I S C O N N E C T
L E V E R
N G S T E E R I N G
V A L V E
M O D U L E
N G S T E E R I N G
R E U
( S E R V O C O N T R O L,
B I T E )
R U D D E R
P E D A L
P O S I T I O N
C O M M O N D A T A N E T W O R K ( C D N )
R P D S
F O T I L L E R
( N O S E G E A R )
C C R
C O N T R O L L A W S
F A U L T M O N I T O R
E I C A S
O N - B O A R D M A I N T
O P E R I N I T T E S T
D I S P L A Y S
( F O R W A R D E E B A Y )
S W I V E L
V A L V E
F B T R A N S D U C E R
M O D U L E
N W S
A C T U A T O R
Mechanical Systems
Steering System Architecture
Boeing Proprietary
Mechanical Systems
NWS System Command PathR U D D E R P E D A L S
C A P T A I N
T I L L E R
R P D S
R P D S
F O
T I L L E R
O R
7 0
0
V
R P T R I M
0
V
N O S E W H E E L
P O S I T I O N C O M
T I L L E R C O M
Y A W R A T E
S T E E R I N G
A C T U A T I O N
S Y S T E M
A U T O -
P I L O T
R U D D E R
A C T U A T I O N
S Y S T E M
0
T I L L E R C O M
R U D D E R
P O S I T I O N C O M
H I G H S P E E D
L O C K O U T
N o s e W h e e l S t e e r i n g S y s t e m
F l i g h t C o n t r o l S y s t e m
+ 8
- 8
I T A C
D I S A B L E D
B E L O W 4 0 k n
I T A C - I n e r t i a l T h r u s t A s y m m e t r y C o m p e n s a t i o n
L I M I T E R
Boeing Proprietary
Mechanical Systems
NWS System Control Gain & Authority
Rudder pedal gain schedules is preliminary
(To be optimized in simulator tests for all normal and airplane
failure conditions)
N W S C o m m a n d
to F u l l T i l l e r D i s p l a c e m e n t
0
10
20
30
40
50
60
70
80
0 20 40 60 80 100 120 140 160
G r o u n d S p e e d ( K n o t s )
N
o
s
e
W
h
e
e
l
A
n
g
l
e
(
d
e
g
)
N W S C o m m a n d
to F u l l R u d d e r Pe d a l D i s p l a c e m e n t
0
1
2
3
4
5
6
7
8
9
10
0 20 40 60 80 100 120 140 160
G r o u n d S p e e d ( K n o t s )
N
o
s
e
W
h
e
e
l
A
n
g
l
e
(
d
e
g
)
Boeing Proprietary
Mechanical Systems
Flight Deck Integration
BRAKE + STEERING (RUDDER)
PEDAL SENSORS
LG CONTROL
LEVER + ALT
EXTENSION
(THRUST
LEVERS)
(SPEEDBRAKE)
PARK
BRAKE
AUTOBRAKE
SELECT
DUAL
STEERING
TILLERS
Boeing Proprietary
