AIRCRAFT

CONTENTS
AIRCRAFT
OVERVIEW
A PEDIGREE WINNER
2
THE JETSTREAM 41 ADVAN'T'AGE
4
CABIN COMFORT
6
FLIGHT DECK AND AVIONICS
12
POWERPLANT
Io
COMPREHENSIVE SUPPORT
2L ,
STRUCTURE
22
FLYING CONTROLS
24
LANDING GEAR AND BRAKES
26
ENVIRONMENTAL CONTROL SYSTEMS 26
ELECTRICAL SYSTEM
FUEL SYSTEM
30
32
HYDRAULIC SYSTEM
34
I CE AND RAIN PROTECTION
36
SERVICING AND HANDLING 38
VENDORS AND SUP LIERS 40
PERFORMANCE
44
A Pedigree
Winner
• Specifically
designed for the
demanding needs of
today's regional
airlines
• Using the best cost-
effective technology
in structures
avionics and engines
• Backed by the
experience gained
from the market
leading Jetstream 31
• World-wide
customer support
suite and the revolutionary digital
audio Primus 11 radios. Allied Signal
TPE331-14 engines provide fuel
efficient power, building upon Allied
Signal's long experience of the needs
of demanding regional operations.
The Jetstream 41 brings a new
dimension to the regional airline
operator. A highly efficient 29 seat
airliner designed to give today's
regional operator the competitive edge.
Produced for today's tough regional
airline world, Jetstream 41 offers an
optimum solution to meet demanding
market requirements - a careful balance
of competitive performance, comfort
and reliability, at minimum cost.
The Jetstream 41 incorporates the
experience gained from the world wide
operation of over 380 Jetstream 31's,
with an accumulated time of well over
6 million flights. This has been blended
with the results of extensive
consultations with leading regional
airlines worldwide throughout its
development.
Jetstream 41 is designed to the latest
FAR/JAR 25 standards. Technology
advances have been introduced into the
avionics and systems where reduced
costs could be demonstrated as well as
increased reliability and reduced pilot
work load. The changes include fitting
Honeywell's proven SPZ4500 avionics
system, which uses a developed EFIS
The four aircraft, 1500 hour, flight test
and certification programme was
completed on target in a record fourteen
months, culminating in JAA
certification on 23rd November 1992
followed by FAA certification on 9th
April 1993. J41 demonstrated all
performance and weight predictions
during the programme and aircraft are
now in service with operators around
the world. The process of product
development continues, with the design
weight and flat-rated power increases
announced in April 1993 - changes
aimed to cover tighter certification
requirements and passenger weight
i ncreases being introduced in several
parts of the world.
BAE SYSTEMS Regional Aircraft is proud of
their record on customer support and
product development and will ensure
these are major elements of the ongoing
Jetstream 41 program.
7
The Jetstream 41
Advantage
• Offering a careful
balance of
competitive
performance,
comfort and
reliability at
minimum cost
• Aircraft-mile costs
12% lower than the
nearest competitor,
together with lower
seat-mile costs
• The lowest increase
in break-even
passenger load over
a 19 seat operation
Following go-ahead for the Jetstream 41 in
The result is a 29/30 seater with the lowest
cost of ownership and the lowest break-even
l oad in its class. The 295 knot TAS cruise
speed gives competitive block times, and
field length requirements match the majority
of regional airports world-wide. The cabin
has been carefully styled by experienced
designers and stylists to delight both
passengers and operators alike.
May 1989, extensive dialogue with
numerous airlines culminated in the
formation of an Airline Advisory Committee
which brought together airline specialists
from three continents and Jetstream
Aircraft's engineers, pilots, designers and
marketeers.
The message received from potential
operators of 30-seat aircraft was clear:
•
Jetstream 41 must be tailored with the
right mix of features to please both the
airlines' passengers and the airlines'
investors.
•
Break even economics must not be
sacrificed for excesses in other areas
such as speed, field performance or
cabin volume.
• Use
proven, reliable technology to
match the capabilities of regional airline
flight crews and the needs of their
maintenance organisations.
Careful control of all design parameters has
produced low design weights and an
efficient engine size. Fuel-burns compare
very favourably with those of competitors,
and airport and navigation charges are
reduced to a minimum.
Jetstream 41 has been designed to both JAR
and FAR part 25 requirements with
emphasis on easy access for maintenance
and inspection, following the guidelines of
the latest MSG-3 maintenance system. Full
use has been made of the experience gained
from over 6 million flights of regional
airline operation with Jetstream 31 and
Super 31.
4
Cabin
Comfort
• Light, spacious and
airy design with
strong passenger
appeal
• 29 seat layout as
standard - 30 seat
option available
• Flexibility to offer
all levels of cabin
service
• Total baggage
capacity of over
9.0 cu ft per
passenger
The design of Jetstream 41's i nterior has
benefited from the input of many
experienced regional airline operators and
expert stylists in its development from the
cabin of the highly successful Jetstream
Super 31.
The clear aisle and stand-up headroom of
over 5ft 10in (1.784 i n) gives the interior the
feel of a much larger aircraft, leading to the
i nstant passenger acceptability required for
today's regional services connecting with
wide-body jets. Carefully designed wash
lighting, deep sculpting and large windows
further enhance the soft wide-bodied feel of
t he cabin.
The comfortable pressurisation and air
conditioning of the cabin are designed to
provide a high level of passenger comfort.
I ndividual reading lights and air outlets are
available for heating and conditioning the
cabin on the ground.
Configuration flexibility
Cabin layout and features have been chosen
t o give maximum operational flexibility. The
layout illustration shows the standard FAA
29-seat layout which features 30 inches (76
cm) seat pitch throughout, except for a single
row at 31 inches (79 cm ) at the over wing
(type III) emergency exits. A large carry-on
stowage is available at the front of the cabin
opposite the passenger entry door and an
additional stowage is available forward of
t he door. An optional 31 inches (79 cm)
pitch overall is possible (except for a single
29 inch (74 cm) at the front LH single seat)
by reducing the width of the galley slightly
and making adjustments to two other
bulkheads.
The standard layout to UK CAA requirements
uses the narrower galley and has a 30 inch
(76 cm) seat pitch overall except for a row at
37 i nches (94 cm) at the overwing
exits.
A folding seat for the cabin attendant
i s installed in the rear vestibule
providing a clear view of the
passengers. The attendant's PA and
flight deck intercom handset is
conveniently mounted on the outside
of the toilet door, accessible at all
ti mes to the flight attendant. A briefing
headset or optional PA facility are also
available at the front of the cabin.
A supernumerary crew position is
formed by the flight deck door and a
fold-down seat hinged from the left
carry-on stowage. The toilet door latches
onto the aft bulkhead behind the RH seats so
t hat the rear vestibule forms a generouslysized toilet compartment, isolated from the
passenger cabin. The toilet is externally
serviced.
h
Loading of outsize items is aided by a door
to the passenger cabin in the RH side of the
forward bulkhead. This door can also be
used to provide the cabin attendant with
i n-flight emergency access to the baggage
compartment or to give routine access to
additional catering supplies, if held in the
baggage compartment.
Several interior options are available. These
i nclude a revised aft galley, taking a trolley
capable of holding up to 32 light meal
trays or bar refreshments, and a complete
galley service at the front of the cabin. A
l ayout in which a 30th seat replaces the aft
galley is also available for high-density
business markets with reduced in-flight
service requirements.
A further 47.5 cu ft (1.35m 3) of baggage
space is available in the unpressurised
ventral pod aft of the wing. This stowage,
with convenient 17 x 40 inches (0.43 x
1.02 m) doors at waist level on both sides,
adds extra loading flexibility and is ideal
for both checked or tagged carry-on
baggage.
Baggage stowage
The pressurised 170 cu ft (4.81m3 ) class D
checked baggage compartment aft of the
passenger cabin is designed to the latest
heat release and toxicity fire requirements.
The large 48 x 52 inch wide (1.22 x 1.32 in)
plug door is mounted on roller guides
t racking across the top of the compartment.
The two stowages provide a checked baggage
volume of 7.5 cu ft (0.21 m3) per passenger,
and both can be loaded to capacity without
requiring a tail stand and before passengers
are boarded.
Ample carry-on stowage
Carry-on stowage is provided by the
21.5 c:u ft (0.61 m 3 ) and 7.9 cu ft (0.22 m 3 )
compartments, at the front of the cabin and
t he enhanced underseat stowage; this allows
two large briefcases and additional carry-on
items to he stowed under the double seats
and a single slimline briefcase under the
single seats.
10
Overall baggage capability on Jetstream 41 is
over 9.0 cu ft (0.25 m 3 ) per passenger, with
wide C.G. flexibility and weight capability,
allowing, in typical configurations, two
checked bags per passenger.
Maintainability
In order to reduce maintenance and spares
costs, design emphasis has been placed on the
modular concept and interchangeability of
panels and units. Furnishing mounting isolators
are jigged, and panels and units can be replaced
without fitting or trimming of edges, as can all
the carpets.
The forward passenger door and large rear
baggage door make Jetstream 41 ideal for
cargo operations. Configurations being
evaluated include a QC freight system,
which could allow passenger operations
during the (lay and freight operations at
night, and a dedicated all-cargo
configuration with loading accomplished
t hrough both the forward entrance door and
the baggage hay door. Alternatively, for night
operation of a passenger configuration, seat
converters could be utilised to convert seats
i nto containers for small packages.
,Routine
maintenance is minimal with all parts
on condition'. The PSU coves can be hinged
down for maintenance access to lights and
ducting and to all wiring looms which run
along the cabin. Wash lighting can he changed
without removing the coves.
Acoustics
Many years' experience has been applied to
the noise reduction capability of the cabin
i nterior. The furnishing panels form an inner
shell acoustically isolated from the fuselage
structure. Careful attention has been paid to
acoustic gap sealing, the fitting of insulation
bags and to the selection of noise attenuating
materials. Overall attenuation of the
furnished cabin is 17 dBA relative to the bare
structural shell. Acoustic development is
continuing in line with advancing
technology. Acoustic dampers are fitted to
t he fuselage frames in the vicinity of the
propeller plane, and active noise control is
available as an option. The average cabin
noise level with dampers fitted is in the
region of 80 dB(A).
11
Flight Deck
and Avionics
• Designed for
maximum crew
comfort and
minimum crew
fatigue
• Proven Honeywell
EFIS and avionics
suite
• Extensive use of
built-in test
equipment
• Easy access to
avionics
components
• Category II landing
option
Flight Deck And Avionics
The flight deck is designed for maximum
comfort and minimum crew fatigue over
demanding regional mufti-sector routes and
meets JAR/FAR 25 requirements. The
uncluttered instrument panels are designed
around an established Honeywell four-tube
EFIS system and the easy-to-use multi-colour
electronic Primus 11 radio management
system. Engine instrumentation is an
LED-based unit showing both analogue and
digital readouts. Weather radar information
is shown on the EHSI display or on the
dedicated weather radar display. The new
V-shaped windshield meets Part 25
requirements for both greater vision and split
heater elements; the rear panels open for
direct ground communication and crew
emergency exit. Ample stowage space is
provided for crew convenience, and
(e quipment accessibility is designed for quick
maintenance .
Crew comfort is enhanced by individual
temperature and air flow controls, while
wide crew seats are fully adjustable. The
rudder pedals also adjust fore and aft.
Avionics - A proven digital package
Jetstream 41 has a Honeywell SPZ-4500
digital avionics package specifically selected
for today's regional airlines, focused on
bottom line economics. This proven system
gives operators high despatch reliability,
reduced pilot work load, and reduced cost of
ownership.
The SPZ-4511(1 is a completely integrated flight
director/air data system which has a full
complement of horizontal and vertical flight
guidance modes. A three axis autopilot is
standard. Pilots and engineers will like the
user-friendly hill colour flight instruments.
clear digital radios, high performance weather
radar and comprehensive self-diagnostic
features.
• DFZ-450
• EDZ-805
•
600 ( Dual)
•
800 ( Dual)
• Primus 650
• 300
• Primus II
• CAI' I Autopilot
Digital Flight
Director/Control
System.
Four-tube Electronic
Flight Instrument
System
( EFIS).
Altitude and heading
reference systems
( AHRS).
Digital air data
computers.
Colour weather radar.
Radio altimeter
system.
Digital audio,
i ntegrated radio
system.
The systems are based on proven
technology which has been carefully
tailored to meet the needs of Jetstream
41 operators and to give growth
potential. Particular attention has been
paid to development of the EFIS display
symbology to ensure clear and precise
display formats.
14
EFIS Reliability
The large 5x6 inch four-tube EDZ-805 EFIS
and conventional servoed electric altimeter
provide all flight information in a concise
visual scan area and in an easy-to-read
format. Display formats vary with flight
conditions, reducing clutter and providing
effective, simplified presentations. For
example, the EFIS can overlay both weather
returns and navigation map on the compass
presentation for easy interpretation of the
current situation.
EFIS reliability and redundancy are at a
high level, due to proven digital symbol
generation techniques, effective back up
display modes, and cross-side switching
capability that ensures no single failure will
cause loss of primary altitude or heading
data at either pilot's station. The navigation
displays can be switched to the EADI
displays and either of the two symbol
generators is capable of driving all four
displays.
The EADI display integrates airspeed,
vertical speed. and when appropriate, flight
director command cues, glide slope, radio
altimeter and flight control mode
annunciators. The EHSI offers pilotselection of a full compass rose, expandable
compass arc, map mode, and weather radar
display.
Optional Category II Capability
The DFZ-450 digital flight control system
i ntegrates the flight director, autopilot
(optional), yaw damper and trine functions.
The system provides smooth guidance
commands which are displayed on the EFIS
and can control a fail passive/fail soft 3-axis
autopilot. The autopilot can be cleared for
both Category 1 and Category II landing
minimum s.
Colour Weather Radar with
Unique Features
The Prirnus 650 colour weather radar
system has an integrated
receiver/transmitter/antenna with a single
control head. Weather is displayed with
four weather intensity levels, on either of
the EHSIs or on the dedicated display.
The Rain Echo Attenuation Compensation
(REACT) is a unique safety feature which
maintains target calibration by
compensating for attenuation caused by
intervening rainfall and alerts the crew to
areas where storms may be hidden behind
other storms.
Crystal Clear Radio
The Primus radio system combines VHF
communications and transponder functions
in a single comm unit, while the nay unit
combines VOR/ILS/MB receiver, dual ADF
and six channel scanning DME. The pilotfriendly, full colour radio management
units (RMU) combine pushbuttons and
traditional tuning knob to provide instant
access and display of up to 12 stored comm
frequencies and 12 nay frequencies. Either
RMU can provide complete control of
operating modes, frequencies and codes for
both on-side and cross-side radios. Another
pilot favourite is the digital audio system,
which gives crystal clear reception with
i mmunity to 400 Hz hum and the virtual
elimination of crosstalk between channels.
Overall System Integrity
In addition to the built-in redundancy of
the SPZ-4500 system, integrity of flight
i nformation is further enhanced by a suite
of standby instruments, comprising dual
RMls, artificial horizon with ILS pointers,
ASI, altimeter and compass. Power supply
i ntegrity is hacked by an emergency
independent battery system which powers
t he RMIs and artificial horizon in the event
of a total power failure. This system also
powers the AHRS during engine starts to
ensure that the required alignment process
is not interrupted so that AHRS are valid
and "on line" on completion of the engine
start cycle.
The majority of the avionics units are
mounted in the ventilated and insulated
nosebag which has large lockable doors for
good access. A maintenance panel is
located in the hay to reduce testing time to
a minimum.
LEI) Engine Instrumentation
Engine instrumentation is centrally located
on the flight deck in clear view of both
pilots. The primary system is a Smiths
integrated engine instrument system (EIS),
giving lower cost of ownership than
alternative instrumentation. This solid state
unit contains all signal conditioning and
monitoring functions. Dual secondary
triple-indicators are provided for fuel and
oil pressure and oil temperature.
CVR and FDR
A Universal Navigation Cockpit Voice
Recorder and a Fairchild Flight Data
Recorder with the latest channel
requirements are fitted as standard in the
rear equipment bay.
Options
Available options include CPS and TCAS.
Built in Test Equipment
Maintainability and availability is ensured
by providing a high level of built-in test
equipment (BITE) on all major systems,
Ii
i ncluding engine computers, engine
i ndicators annunciators, avionics and
pressurisation. Most systems
automatically self test at power on and
t herefore reduce flight crew workload
especially at busy departure times. All
i nstruments, controllers, indicators and
light filaments are front removable/
replaceable. Maintenance panels are
incorporated: one each, in the nose, flight
deck and electric's bay. These incorporate
resettable latching indicators to record
transient faults. The total effect is a flight
deck with reduced clutter for the crew
and improved maintenance for
technicians.
Central Annunicator Panel
Prominent in the centre of the panels is
the central annunicator panel (CAP).
This is specifically designed to reduce
crew workload and error by
incorporating a series of 'collector
captions' for major systems. These alert
the crew and direct their attention to the
fault 'area' where further information is
displayed. Take-off configuration
warning is also provided. All
annunciators on the panel and through
t he flight deck are tested from the CAP.
All captions are monitored by attentiongetting captions on the coaming panel.
Connected to the CAP alert functions is
an audio tone generator which activates
for specific warnings and captions via
the audio intercom system.
Powerplant
• Fuel-efficient
Allied Signal TPE
331-14 engines
• Single Shaft
simplicity
• Modular engine
design for easy
maintenance and
low spares holding
• Low noise and
emissions
• Metal, five-bladed
McCauley propellers Jetstream 41 is powered by fuel efficient
Allied Signal TPE331-14 GR/HR
for cost-effective
t urboprop engines driving cost effective
operation
five-bladed McCauley metal propellers a perfect match to the airframe.
Fuel efficient power
The engine, which has a power reserve
thermodynamic rating of 1946 SHP, is
flat rated at a conservative 1650 SHP to
23°C at sea level. The Automatic Power
Reserve System (APR) extends the flat
rated power limit to 36°C at sea level by
automatically increasing the power of
t he live engine by up to 110% after an
engine failure on take-off. In addition,
continuous power
augumentation can be
selected following the
setting of maximum
16
continuous power. As a further
enhancement to scheduled performance,
when APR has been armed for a take-off,
the propeller of a failed engine is
feathered automatically. At other power
settings, a negative torque sensing
system moves the propeller of a failing
engine towards the feathered position
and the feathering action is completed
manually.
The power management and control
system provides two modes of operation
- the ground operation mode (theta) and
t he propeller-governing mode,
accomplished through four major
hydromechanical components - engine
fuel control. propeller pitch control,
propeller governor, and propeller oil
transfer tube - and the digital
Integrated Electronic Control.
Structure
• Rugged design for
demanding regional
operations
• Extensive use of
traditional materials
allows easy repair
and inspection
• Highly effective
corrosion
protection
Rugged structure
A conservative approach has been adopted
for the design of Jetstream 41; one which
builds on the experience of the extensively
tested and service proven Jetstream 31, but
with strict attention being paid to the latest
requirements for damage tolerance. The
design aims are to achieve at least 30,000
flights crack free and an economic repair life
of at least 60,000 flights.
These aims can be secured by designing
durability into the structure using a coherent
"damage tolerance" design philosophy. The
main elements of this philosophy comprise
low stress levels to give slow crack
propagation and long periods before
i nitiation, comprehensive corrosion
protection and easy inspection capability.
Inspection periods and thresholds are
derived using the MSG-3 maintenance
development system. Alternative load path
design is used where possible so that
structural inspections can be limited to
simple visuals. In other areas, particular
attention is paid in design and testing to
demonstrating slow crack propagation. A full
scale fuselage damage tolerance test has
proven the basic structure to be capable of
surviving the required two-frame hay crack
under full pressure differential.
Only materials which are backed by
comprehensive test data and have good
service histories are used. The primary
structure is predominantly made of
aluminium alloy and use of advanced
materials is limited to secondary structure,
or where fire-proofing requirements exist, as
follows:
Engine cowls - Titanium.
Floor panels/fairings - Glass fibre composite
with nomex honeycomb core.
Main landing gear doors - Kevlar composite.
Apart from more extensive use of machined
structural components, the only significant
structural design changes from Jetstream 31
are a continuous torsion box wing using new
engine nacelles with forward retracting main
landing gear, and plug type doors in the
extended fuselage. Construction methods
follow well tried Jetstream 31 and Super 31
experience and extensive use of automatic
riveting gives good consistency. The
chemical etching of skin panels, which
reduces skin thickness in lightly loaded
areas, is used extensively for high structural
efficiency and excellent surface finish. For
the wings the panels are bonded to the
stringers giving a very smooth finish.
Flying
Controls
• Manual primary
flying controls
meeting FAR/JAR
25 requirements
• Impressive
handling qualities
• Efficient flap
system for good
airfield
performance
• Automatic ground
spoilers for
improved braking
efficiency
Jetstream 41 primary flight controls,
consisting of ailerons, elevators and rudders.
are manually operated through a system of
chain/sprocket. cable/pulley and rod/lever
mechanisms. The control wheel columns are
floor mounted and rudder pedals are of the
i nverted pendulum type with fore and aft
adjustment. Secondary controls are the
manual aileron, elevator and rudder trim
systems, hydraulic wing flaps and spoiler
systems and the gust lock system. The
design. to JAR/FAR 25 requirements,
i ncludes protection against incorrect
assembly, bird strike damage and tab flutter.
Both JAA and FAA pilots were impressed
with the aircraft's handling and flight deck
ergonomics. Subsequently, pilots with
experience ranging from STOL 19 seaters to
medium sized jets have reaffirmed these
views, having little problem in converting to
t he aircraft.
Ailerons, elevators and rudder with
split control runs
The elevator and aileron control are split,
with manual disconnection to enable the two
control columns to be de-coupled in the
24
event of a circuit jam. Control runs are
separated vertically in the fuselage to
reduce vulnerability to a disc-burst. The
rudder control system forward of the wing
is duplicated with vertical separation for
added safety from a disc burst.
The three trim control hand wheels and
i ndicators are located on the central
console, electric elevator trim is fitted as
part of the autopilot system.
Stall protection
A stall warning system, using fuselage
mounted vanes provides an audible stick
shake when a stall is approached. If the
stall ident angle of attack is reached. a
visual warning is given on the flight deck
coaming panel in front of each pilot and a
hydraulically - powered stick push is
given. The push system deactivates
automatically when the angle of attack is
reduced. It can also be deactivated by
pressing either of the stall light/switches
when they are illuminated. The stall ident
angles vary with flap angle and are re-set
to l over angles when engine anti-ice is
selected on.
Landing Gear
and Brakes
shortening mechanism, a steering control
valve and rack and pinion steering
mechanism. The shock absorber is a single
stage oleo- puematic type with a stroke of 10
inches. The upper cylinder of the shock
absorber slides within the nose-leg casing
and is attached to a linkage which is straight
when the leg is locked down so that loads
are transferred to the leg pintles. As the leg is
retracted the linkage folds and draws the
shock absorber assembly through the casing,
so shortening the retracted leg length by 9
inches. The nose wheels are fitted with 17.5
x 6.25-68PR tyres inflated to 42 psi.
• Rugged, low drag
design
• Electronic anti-skid
system as standard
• Steel brakes for
cost effective
operation
Powered steering
The hydraulically powered rack and pinion
nose wheel steering is controlled by a steering
handle on the left side console and provides
powered steering up to + or - 42.5 deg.
The nose wheel can caster a further 57.5 deg
up to + or - 100 deg when manoeuvering
with asymmetric braking or power. Centring
is automatic during retraction.
Rugged, low drag landing gear
Jetstream 41 has a rugged tricycle landing
gear with two wheels on each leg. Each leg
retracts forward; the nose leg into the front
fuselage forward of the pressure bulkhead
and the main legs into the underside of the
engine nacelles. All the fairing doors are
mechanically operated by landing gear
movement with the forward doors returning
to the closed position after the gear has
l ocked down. Retraction, lowering and
l ocking are by hydro-mechanical means.
Main landing gear
Each main gear consists of a vee braced
casing, a shock absorber with integral axle
and folding drag stay. The shock absorber is
a single stage oleo-pneumatic type with a
t otal stroke of 15 inches. Standard tyres are
22 x 6.75-10 12PR inflated to 125 psi at
maximum take-off weight. Each wheel has
t hree fusible plugs to give controlled
deflation in the event of overheating.
Nose landing gear
The nose leg consists of a vee armed casing,
a shock absorber with separate axle, a
26
Electronic anti-skid braking
Each of the four mainwheels accommodates
an interchangeable Dunlop steel rotor brake
pack. The packs are designed to achieve in
excess of 2000 stops at a typical service
energy and are sized to avoid brake energy
li mitations for an emergency stop in the most
adverse combination of take-off weight,
airfield elevation and temperature.
The hydraulic brakes are operated through
t he pilot's or co-pilot's toe pedals and a
power brake relay valve. The dual I Hydro-aire
electronic anti-skid system, fitted as
standard, maximises braking performance on
both dry and contaminated runway surfaces.
For smooth operation and efficiency, one
system controls the inboard wheels and the
other controls the outhoard wheels.
Parking brake with take-off warning
Emergency braking is provided by an
emergency hydraulic accumulator and brake
valve, cable operated via a parking/
emergency brake handle.
I
Environmental
Control Systems
• Automatic
pressurisation
control for low
crew workload
• Powerful air
conditioning
system for effective
cabin temperature
control
• Easy accessibility
for maintenance
Jetstream 41 has state-of-the-art ABC Semca
pressurisation and Normalair Garrett air
conditioning systems. Bleed air from each
engine is ducted to an independent air
conditioning pack (ACP) and is
independently regulated. Either system is
capable of meeting flow and cabin
pressurisation requirements. HP bleed air is
used when the engine's condition levers are
at TAXI, with an automatic change to LP
bleed air when the levers are advanced into
the flight range. The two
ACPs are located in the
forward ventral fairing
which has excellent
access for the minimal
scheduled maintenance
requirement.
Powerful air conditioning
The air bearing air conditioning packs are
capable of cooling the pressurisation flow to
a cabin inlet temperature of 3°C (37°F) with
the engines at ground idle and an outside
t emperature of ISA +25°C (104°F at sea
level) or heating the flow to 75°C (167°F) in
flight with an outside temperature of ISA 25°C (14°F at sea level). Cabin and cockpit
temperatures are independently selectable
Environmental control
options include a
supplemental cabin
cooling system and a
supplemental cabin
heater system.
Automatic
pressurisation
control
Pressurisation has
automatic electronic control with a manual
pneumatic back-up system; crew action
normally being limited to setting the landing
field altitude before take-off. Any
unscheduled maintenance is streamlined by
the automatic self-diagnostic testing which
will show failure codes on the digital cabin
altitude display on start-up or if a failure
occurs during flight.
The maximum cabin differential is 5.7 psi
which gives a cabin altitude of 8,000 ft at the
maximum operating altitude of 26,000 ft.
The maximum operating altitude may he
li mited to 25,000 ft for some national
operating regulations giving a maximum
cabin altitude of 7,400 fl for the same
differential.
28
in the range 18°C (64°F) to 27°C (81°F). For
normal operation the right hand pack
delivers air preferentially to the flight deck,
supplying footwarmers, windscreen demist
and individual adjustable vents.
Thermostatic valves direct conditioned air
below 15°C (59°F) to the high level cabin
PSU ducts and warm air above 28°C (82°F)
to the floor ducts. At temperatures between
these values, air is distributed to both ducts.
Oxygen systems
Optional portable and passenger emergency
oxygen systems are available to meet
national operational requirements. Space is
provided in the PSU covers for the drop out
face masks.
system
Electrical
• High integrity
design with low
pilot workload
• 28v DC system
with two
independent
channels
• AC power
provided by
inverters from
each DC channel
• Low maintenance
requirements and
easy accessibility
Two independent channels
The DC electrical system comprises two
i ndependent channels, each powered by an
engine driven 28 volt, 550/825 ampere
starter/generator. Under normal operation
t he two channels are both mechanically and
electrically isolated, thus ensuring that no
single active fault, combined with a dormant
fault, results in a failure of both generator
systems.
Two 24 volt. 28 ampere-hour nickel
cadmium batteries are installed as standard
for engine starting and emergency power
conditions. Larger nicad and sealed lead acid
batteries are available as options.
I n addition to the electrical system batteries.
power supply integrity is enhanced by an
emergency independent battery system. This
system powers the AHRS during engine
starts, ensuring that the references are valid
and 'on line' at the end of an optimised
departure procedure. The independent
battery system also powers the standby
i nstruments in the event of a total power
failure.
High integrity, low pilot workload
and low maintenance
The distribution system is designed for high
i ntegrity and low pilot workload. Each
channel bas a power distribution unit (PDU)
which contains all the contactors and remote
controlled circuit breakers (RCCB)
controlling the interconnection of the
channel's busbars. The PDU saves weight,
space and maintenance time.
All switches are logically and clearly
grouped on the overhead roof panel.
Automatic load shedding is provided for
' bands off control during failure conditions.
Two circuit breaker ( CB) panels are available
for manual load shedding to aid fault or
smoke isolation. Located just forward of the
flight deck door, a separate avionics CB
panel is located aft of the roof switch panel.
30
AC power
115 volt and 26 volt, 400 Hz, AC power is
provided by an inverter in each of the DC
power channels. Maximum continuous
power output available from each inverter
from a combination of 115 VAC and 26 VAC
is 85 VA; up to 60 VA of this is available on
t he 26 VAC output for instrument and
navigation system loads. The 115 VAC
supply powers the Flight Data Recorder
( FDR).
Good maintenance access
The main electrical system components are
grouped in the electrics bay situated forward
of the ventral baggage bay. Maintenance
access is through the baggage bay doors. The
components include the batteries, PDU's ,
generator control unit and a maintenance test
panel.
The standard 28 VDC ground power
connection is located in the right
I
Fuel
Systems
• Single point
pressure refuelling
for fast
turnarounds
• Jet pumps for low
maintenance costs
Two-tank system
The fuel system consists of two integral
wing tanks each with its own engine
supply, venting and contents
measurement sub-systems. Usable
capacity is 727 i mperial gallons (873
USG, 3306 litres).
Pressure refuel/defuel
Refuelling is accomplished by overwing
gravity feed on each wing or by single
point pressure refuelling from a
connection on the right wing leading
edge outboard of the nacelle. Defuelling
is also available via the single point
system or by gravity drain. The single
point system is automatic and will
completely fill the tanks or fill to a preselected level measured from the fuel
quantity measuring system.
32
Low maintenance jet pumps
Normal operation of the fuel system is
t hrough jet pumps, and requires no
additional electro-mechanical pump
when the engines are running, so
Jetstream 41 fuel pump life is greatly
extended. Electrical boost pumps are
provided for engine start, cross feeding
and to act as stand-by pumps.
Tank crossfeed to the opposite engine is
provided, but tank-to-tank crossfeed is
not available. Fuel quantity
measurement is by a capacitance probe
system with magnetic level indicators
available in each cell for verification.
Fuel low level warning is provided.
Fuel quantity, fuel flow/fuel used
i ndications form part of the flight deck
LED engine instrumentation display.
These can be readily converted before
i nstallation from imperial to metric
units.
I
Hydraulic
System
• Components
located in
dedicated bay for
easy maintenance
• Variable delivery
pumps for low
maintenance
• Permaswage piping
for easy, effective
assembly and
repair
Hydraulic power is used to operate the
flaps, spoilers, landing gear, wheel brakes
and nosewheel steering. In addition, an
emergency hydraulic system with its own
supply of hydraulic fluid is available for
flaps and landing gear. Mineral based
hydraulic fluid conforming to MIL-H-5606
i s specified as standard. As an option, the
system could be configured for synthetic
hvdro-carbon based oil to MIL-H-83282.
With the exception of the main pumps,
emergency handpump and selector,
components of the hydraulic power
generation system are located in a
hydraulic hay in the ventral fairing.
Normal system, 2000 psi
The system has a single 2000
psi supply pressurised by two
engine-driven pumps. A
nitrogen charged accumulator
stores fluid pressure within
t he system to compensate for
any pressure loss when a
hydraulic service is selected.
'The pumps are pressure
regulating, variable delivery
t ype. They are sealed to
prevent contamination of the
engine oil system and have
ease drain return pipes with
i n-line filters to return any
l eakage flow to the main
reservoir.
Emergency
systems
An emergency system hand
pump and selector valve are
i nstalled under the flight deck
floor between the crew seats.
I hydraulic fluid is supplied to
.
4
t he pump from an emergency cell in the
hydraulic reservoir. The selector valve has
t hree positions: normal, flaps and landing
gear.
The normal position allows fluid to be
pumped into the normal system via a nonreturn valve for maintenance operations:
t he remaining two positions allow the
flaps or landing gear to be lowered
t hrough their respective emergency
systems.
Ice and Rain
Protection
• Developed through
comprehensive
flight testing
• Pneumatic, clam
shell boots de-ice
wing and
empennage
• Electric anti-icing
of propellers,
elevator horns,
pitot heads, static
plates and stall
vanes
During its
certification
programme
Jetstream 41 was
subjected to
comprehensive
flight testing in
icing conditions
to show good
compliance with
J AR/FAR 25,
appendix C for
forming
operation in ice-
conditions.
Pneumatic, hot
air, and electrical
systems are used
for ice and rain protection which have the
capacity to give the required protection even
with one engine shut down. The wing
outboard leading edges can be illuminated at
night by a lamp in each nacelle to aid
detection of ice accretion. Protection to the
fuselage is provided by replaceable Kevlar
panels in the propeller plane should any ice
be thrown due to delayed operation of the
propeller anti-icing system.
Pneumatic system, clam shell boots
Airframe de-icing of wing and empennage
leading edges is achieved with a pneumatic
boot system which connects paired boots in
three pneumatic circuits. The hoot on the
outer wings and horizontal tailplane are of
` clam shell' design which gives an enhanced
de-icing action. The system is supplied with
high temperature, high pressure air from the
HP bleed port on both engines. When the
system is off, some of the manifold air is
dumped through ejector valves to create a
vacuum which holds down the rubber hoots,
thus maintaining smooth aerofoil surfaces.
The boots are divided between three circuits,
each with its own control valve. A single
press of the de-icing 'CYCLE' switch starts a
double cycle operation via a timer unit, over
a six second period. In the event of a timer
failure, each de-icing boot circuit (:all be
36
cycled separately with an associated manual
switch.
Electrical systems
DC electric anti-ice protection is provided
for the propellers, elevator horns, pitot
heads, static plates and stall ident vanes.
The OAT probe and the ice detector also
have de-icing elements. Two independent
200V AC inverters power one of two anti-ice
elements of indium trioxide film on each of
the main windshield panels.
Engine
Anti-icing protection to the intake cowling
and inlet air entry ducts is provided by HP
bleed air controlled by an electrically
operated bleed valve. In addition, should an
engine flame-out due to excessive ice or
water ingestion, the negative torque sensor
will quickly sequence an auto-ignition
switch to effect a relight before the engine
spools down.
Rain protection
A two speed wiper system with automatic
parking is installed for the main windshield
panels. This is augmented by windshield
washers and demisters.
Servicing
And Handling
• Easy ground
handling for rapid
turnarounds
• Small turning
circle for ground
manoeuvrability
• MSG-3
maintenance
philosophy for low
man hour input
MSG-3 maintenance system
Jetstrearn 41 maintenance requirements have
been developed using the MSG-3 concept.
Working groups have assessed all the
maintenance-significant items using a logic
analysis with a clear distinction between
economics and safety which also covers the
detection of hidden functional failures. New
regulations covering damage tolerance
philosophy and supplemental structural
i nspections of high time airframe are
i ncorporated.
The resulting Maintenance Review Board
report contains only those tasks that provide
a genuine retention of the inherent designed
level of safety and reliability or provide an
economic benefit to the operator.
The principal maintenance intervals are at
300 hours (A check) and :300( hours
( C check). An equalised maintenance
programme based on a 150 hour interval has
been developed.
Steering Committee Reviews
The Joist ream 41 i ndustry steering committee
comprising manufacturers, operators and
advisors from the regulatory authorities
meets regularly to review the maintenance
programme in the light of aircraft
developments and operational experience.
Easy ground handling
The logical arrangement of services allows
for easy ground handling and rapid
turnarounds if required.
And Suppliers
Vendors
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