BOMBARDIER SD3-60 Maintenance Manual

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AMM21-00-00 1.0.0.0AIR CONDITIONING - DESCRIPTION AND OPERATION

1. General

Refer to Figure 1.

A single air conditioning system supplies conditioned air to the flight and passenger

compartments with separate temperature control for each.

The system derives its hot air from bleeds on both engines but will continue to work, with reduced

performance on a supply from one engine only.

2. Bleed air conditioning

Refer to Figure 1. Refer to Figure 2 (Sheet 1).

Bleed air is taken via fixed orifices from the P2.5 and P3 bleed connections on each engine. At

low power settings, when the P3 bleed pressure is below 35 p.s.i.g., the temperature control

valve (TCV) is fully open admitting P3 bleed air only, to operate the system. At high power

settings, when pressure in the P3 bleed line exceeds 35 p.s.i.g. a pressure switch operates to

initiate modulation control via the solenoid selector valve and temperature sensor (TS), initially

closing the TCV. Due to the absence of P3 pressure, the check valve in the P2.5 bleed line

opens, maintaining system requirements on P2.5 bleed air only. Should the temperature in the

common bleed line fall to below 300° F whilst operating on P2.5 bleed air, a temperature sensor

(TS) will modulate the TCV to open, allowing P3 bleed air to mix with P2.5 thus maintaining the

bleed air temperature above 250° F. To prevent spurious over-pressure warning being caused by

a cold TS, a time delay is included to postpone the opening of the TCV until 10 seconds after the

HA/SOV is selected open.

Downstream of the TS air passes through a hot air shut-off valve (HA/SOV), a venturi and a

check valve to a common line. The check valves in each half system prevent cross-flow between

engines and the dumping of all bleed air, should either duct fracture.

Air in the common line passes to a refrigeration unit consisting of a dual heat exchanger and a

three-wheel air cycle machine (ACM). In the heat exchanger the bleed air is cooled in the primary

section, compressed and then intercooled in the secondary section. The cooling medium in the

heat exchanger is ambient air driven through the heat exchanger by the fan of the ACM. The

NACA inlet for ambient air is located in the fuselage roof fairing. A flap at the top rear is spring-

loaded closed and will open inwards to supplement the supply during static running should the

demands of the ACM cause a partial depression within the fairing. A lip at the rear of the flap (aft

hinge point) provides for aerodynamic assistance of flap closure during flight (in addition to spring

action).

From the secondary section of the heat exchanger, the bleed air is ducted to the turbine inlet and

to one half of a dual bypass valve; the outlets from both units combine and deliver the air to a

water separator. The cooled air from the secondary section expands in the turbine and produces

a low temperature and condensed mixture (fog); it also provides the power to drive the

compressor and the fan. The water separator coalesces the fog into drops which, when

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collected, are delivered as water to an aspirator which sprays into the cooling air stream of the

heat exchanger.

Beyond the water separator, the ducting divides to provide for the various services detailed in

para 4.

3. Bleed air control, indication and warning

A. HA/SOV control and indication

The left and right motorised HA/SOVs are each controlled by ON/OFF switch modules having

integral line indication of valves open/shut condition on the AIR CONDITIONING panel 9P.

Line indication, which is controlled by 'travel limit' switches within each HA/SOV is provided

by coloured strip lights in the cap of each module. On post-mod A8033 aircraft, indication of

engine bleed point is given by P2.5 (Green letters)/P3 (yellow letters) indicators, one for each

engine.

Power supplies for the left and right control switches are respectively taken from the 28V dc

left shedding busbar and the 28V dc ground services busbar (via 5 amp circuit breakers Nos

90 and 211 on distribution panels 1D and 2D). The power supply for indication is taken from

the 28V dc right essential services busbar via 5 amp circuit breaker No. 196 on distribution

panel 2D.

The HA/SOVs will close automatically in the following contingencies:-

(1) When the Reserve Power System is activated for either engine a supply will be made

available from the relevant reserve power relay to the 'close' field of the HA/SOV on that

side.

(2) Each HA/SOV will close under the influence of its control relay (located on control panel

1C-left, 2C right) should the centre duct temperature exceed 525° F or the centre duct

pressure exceed 35 p.s.i.g.

The initiating circuitry for the control relays is taken from a temperature sensor and an

over-pressure switch situated upstream of the primary heat exchanger in the centre duct.

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Air Conditioning Schematic

Figure 1

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When either the temperature or pressure switch settings are exceeded the respective

switch contacts make to:-

(a) illuminate the BLEED air caption on the centralised warning panel and the duct

OVERHEAT or OVER PRESSURE light on panel 9P as appropriate.

(b) energise the control relays which 'lock on' providing a supply to the 'close' field of the

HA/SOV.

NOTE: The system is reset by tripping and resetting circuit breakers Nos 90 and 211 on

respective distribution panels 1D and 2D when warning lights are extinguished i.e.

bleed air temperature or pressure has returned to normal.

B. Spar box overheat warning

A thermostat is located in the centre-wing spar box bay left and right at station 68.80. Should

the ambient temperature at either position rise to 110°C, possibly as a result of a leak in

either the air-conditioning or aerofoil bleed air piping, the contact of the thermostat will close

to illuminate:-

(1) The BLEED caption on the centralised warning panel 1P.

(2) The SPAR BOX OVERHEAT lights on panel 9P and the Anti-icing Services Panel 4P.

Power supplies for operation are taken from the 28V d.c. right essential services busbar,

via C/B No. 196 on distribution panel 2D.

NOTE: Upon receipt of a warning, the crew adopt a drill to determine and isolate the source of

seepage.

C. Duct low pressure warning

Warning of duct low pressure is afforded by three LP switches, two of which sense the

pressure of the bleed air ducting immediately downstream of the venturi in each half system

and the other sensing the pressure in the common (centre) duct upstream of the primary heat

exchanger.

Each switch 'breaks' on a rising pressure not greater than 6 p.s.i.g. and 'makes on' a falling

pressure less than the break pressure but not less than 5 ± 0.25 p.s.i.g.

Power supplies for signalling operation are taken from the 28V d.c. right essential services

busbar via C/B No. 196 on distribution panel 2D.

The LP switch in each half system is wired in parallel with the LP switch in the centre duct

and becomes operational only when the HA/SOV is fully open ie. the valve's limit switch has

tripped (open) providing power to operate the LP circuit control relay.

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With flow in both half systems, should the pressure at any of the three LP switches fall below

the make pressure, a supply will be completed to illuminate the BLEED caption on the

centralised warning panel and the DUCT LOW PRESSURE warning light on panel 9P.

When there is flow in one half system only, the warning lights will illuminate should either the

LP switch in that half system or in the common duct fall below the make setting.

D. Duct overpressure warning

A high pressure switch is tapped into the centre duct upstream of the primary heat

exchanger. The HP switch makes on a rising pressure of 35 ± 1 p.s.i.g. and breaks on a

falling pressure less than the make pressure but not less than 29 p.s.i.g.

NOTE: To avoid initial surge activation of overpressure warning, a 3 second interval should be

observed between ON selection of both engine bleeds.

Should the make pressure be operationally exceeded as a result of a system malfunction a

supply will be completed to illuminate the BLEED caption on the centralised warning panel

and the duct OVER PRESSure light on panel 9P. Power supplies for operation are taken from

the 28V dc right essential services busbar via C/B no. 196 on distribution panel 2D.

Upon a receipt of a warning, the crew adopt a drill to identify and isolate the faulty HA/SOV.

4. Air conditioning services

NOTE: On 300F series aircraft (post-mod A8593), all reference to passenger compartment

services are to be ignored.

- Pre Mod A8593 Air Conditioning Control Panel 9P - Refer to Figure 2 (Sheet 1).

- Post Mod A8593 Air Conditioning Control Panel 9P - Refer to Figure 2 (Sheet 2)).

The deleted services on Figure 2 (Sheet 2) are inhibited.

A. Flight compartment conditioned air

A cold air tapping is taken from downstream of the water separator and is connected to a hot

bleed air junction controlled by an electrically operated, single/dual (-300F series aircraft

bypass valve. The junction forms an ejector type mixer and is connected to a distribution duct

which supplies two floor level distributors located on the left and right of the flight

compartment. The conditioned air enters the flight compartment through a series of holes in

the forward faces of each floor level distributor. The air flow is controlled by manually

operated butterfly valves located at the aft end of each distributor. The valves are identified

CABIN HEAT - ON/OFF.

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A temperature sensor and a duct overheat switch are located in the common duct to the flight

compartment. The temperature control is described in para 6.

NOTE: Except for -300F series aircraft, conditioned air from the passenger compartment

system is available through two gaspers located on the flight compartment aft

bulkhead. See para 4.C.

B. Windshield and side window demisting

Two tappings are taken from the flight compartment conditioned air duct and routed to a

manually controlled butterfly valve located at either side of the flight compartment on the

forward face of station 74 at rear window height. The valves are identified DEMIST - ON/OFF

and control the demist air flow to the flight compartment side windows and windshields.

C. Passenger compartment conditioned air

A cold tapping is taken from downstream of the water separator and is connected to a mixing

box. Hot bleed air is also connected to the mixing box through one half of an electrically

controlled dual bypass valve.

The mixing box forms an ejector type mixer and supplies conditioned air to a distribution duct.

The temperature of the conditioned air is determined by the amount of bleed air allowed to

enter the mixing box via the dual bypass valve.

The distribution duct delivers warm conditioned air to the left and right floor level distributors

or cold conditioned air to the left and right ceiling level distributors. The conditioned air enters

the passenger compartment through a series of holes in the face of each distributor.

The distribution of conditioned air to either the floor level distributors or the ceiling level

distributors is controlled by two manually operated valves located on the left and right of the

flight compartment aft bulkhead. Each valve has two positions:-

(1) SUMMER - with the control lever in this position the duct to the floor level distributors is

blocked off and cold conditioned air is delivered to the ceiling level distributors.

(2) WINTER - with the control lever in this position the duct to the ceiling level distributors is

blocked off and warm conditioned air is supplied to the floor level distributors.

Two tappings are taken from the common duct to the passenger compartment and are

connected to two gaspers, one located on the right and one on the left of the flight

compartment aft bulkhead. The gaspers provide a secondary source of air conditioning

for the flight compartment.

D. Compartment Anti-Fog System

NOTE: On 300F series aircraft (post mod A8593) subsequent reference to passenger

compartment

in the following text is to be read as flight compartment.

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In hot, humid conditions, with the air conditioning system operating in the full cooling mode

fogging may appear in the passenger compartment.

This condition ensues when the passenger compartment duct sensor detects an actual

temperature several degrees higher than that at the water separator inlet, modulating both

portions of the dual by-pass valve to close. This may cause the water separator to freeze,

thus activating its integral by-pass and permitting turbine delivered fog from the ACM to enter

the compartment.

In this contingency the ANTI-FOG ON/OFF switch (panel 9P) which series-links a 33K.ohm

resistor with the duct sensor and passenger compartment controller is selected ON.

This will bring the duct sensed temperature, in the full cooling mode to approximate more

closely to that of the water separator.

The sensor will then signal the low temperature limiting circuitry of the controller to modulate

the dual by-pass valve such that the water separator inlet temperature remains above 35° F.

The ANTI-FOG ON/OFF switch should not be switched ON in normal conditions, so that, in

the heating mode, the passenger compartment duct temperature upper limit of 160° F (71°)

remains effective and full advantage of the cooling mode is available when fog would not

ensue.

E. Individual ventilation

(1) Passenger compartment

Individual ventilation is provided by air outlets (gaspers) located on the passenger

service units (PSUs). The PSUs are located above the seats on each side of the

passenger compartment. The right hand side PSUs have double gasper installations.

Each gasper comprises a manually operated butterfly valve which is opened and closed

by a knurled ring located on the bottom of each gasper.

Two cold air tappings are taken from downstream of the water separator. One tapping is

connected, via a flap valve, to the right gasper system and the other is connected, via a

second flap valve, to the left gasper system. The flap valves prevent feed back from the

gasper fans.

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Control Panel 9P (Pre-mod A8593)

Figure 2 (Sheet 1)

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Control Panel 9P (Post-Mod A8593)

Figure 2 (Sheet 2)

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(2) Flight compartment

Two gaspers, one for the left side and one for the right side, are located on the main

instrument panel 1P and provide cool, conditioned air for the flight compartment.

Pre Mod A8593

The cool air for the flight compartment gaspers is tapped from the left and right supply to

the passenger compartment. The tappings are taken downstream of each flap valve and

are connected to the associated gasper via a collector box. The collector box prevents

ingress of water and/or condensation when the gasper boost system is in operation. See

para 4.F.(2).

Post Mod A8593

From the two tappings in the water separator outlet duct, cold air is ducted to either side

of the aircraft to individual gaspers positioned in the flight deck. There is no gasper ram/

fan system.

F. On-ground ventilation

On-ground ventilation, with engines shut down, may be taken from any of the following

independent sources.

(1) Main Fan

The fan, situated within the fuselage roof between stations 74 and 137 supplies ambient

air via a tapping in the main ducting immediately downstream of the water separator. A

shut-off valve in the fan duct prevents back flow through the fan when the normal air

conditioning is operating.

(a) Shut-off valve

The shut-off valve idented HR6, is actuated by a split field (open-shut) series wound

motor, incorporating limit switches which prevent overtravel and control an indicator

module displaying line indication of valve open/shut condition.

(b) Power supplies and control

Electrical power is derived from the 28V dc ground services busbar (right) via a 5

amp circuit breaker No. 211 (for shut-off valve operation) and a 25 amp circuit

breaker No. 212 (for fan operation) on distribution panel 2D.

Control is by a three position switch ON-RAM-OFF on AIR CONDITIONING panel

9P.

The control circuitry is such that, following an ON selection at the control switch,

power will not be available to drive the fan until the control valve is fully opened (limit

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switch tripped). The fan circuit is also subject to the overriding authority of the

landing gear weight switch and is operational on ground only.

In flight, the control valve may be opened (RAM selection) as a boost to the bleed air

flow or to provide an alternative supply of air at ambient conditions following a total

loss of bleed air.

(2) Gasper boost system (Pre-Mod A8593 only)

Refer to Figure 1

A gasper boost unit is sitted on either side of the aircraft within the fuselage roof structure

between stations 89 and 146 and is employed to increase flow from the gaspers when

the aircraft is on the ground or to provide gasper supply in periods of flight (take-off and

landing) when normal air conditioning is unavailable (engine bleeds OFF).

(a) Left installation

The left sub-system is served by an intake scoop mounted on the fuselage side wall

at station 89. The supply ducting, fitted upstream of the collector box incorporates a

gasper boost control valve, a fan and a flap valve.

The flap valve is employed to prevent back-flow when the fan (which is utilised for

ground use only) is operating.

Beyond the collector box, flexible distribution ducting is routed through the fuselage

sidewall to the flight and passenger compartment gaspers, located respectively on

main instrument panel 1P and the passenger service units.

A branch pipe from the flight compartment distribution duct incorporates a flap valve

which closes when the boost system is in use and open to permit 'aircraft en-route'

delivery of conditioned air when the basic air-conditioning system is operating.

(b) Right installation

The right sub-system is similar to the left, except that two fans are fitted in series to

ensure that adequate delivery velocity is available from the double gasper

installations on this side.

(c) Gasper boost shut-off valves

The valves, idented 1HM4 - left and 2HM4 - right are actuated by a split field (open -

shut) series wound motor and incorporate limit switches to prevent over-travel.

Indicator modules on panel 9P are controlled by the limit switches and display line

indication of the appropriate valves open/shut condition.

For valve control aspects - refer to para 4.F.(2)(e).

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(d) Power supplies and controls

Power supplies are derived from the 28V dc Ground Services Busbar via 5 amp

circuit breakers Nos 209 and 211 (for boost control valve operation) and a 15 amp

circuit breaker No. 210 (for fan operation) on distribution panel 2D.

Control is by a three position switch ON-RAM-OFF on the AIR CONDITIONING

panel 9P.

(e) Operation

With power made available (para (d)) and the aircraft on the ground, selection of the

control switch on panel 9P to ON will operate all three fans and provide appropriate

'on line' indication when each boost shut-off valve has reached the fully open

position (limit switch tripped). Fan inducted ambient air will then be available to the

gaspers.

The fans will operate throughout the take-off run until the supply is interrupted by

weight switch action when the aircraft becomes airborne. Operationally the switch is

left at ON (thus admitting ram air via the open boost valves) until conditioned air is

again made available i.e. engine bleeds are opened. The switch is then selected

OFF providing subsequent 'off line' indication when the valve is fully closed (limit

switch tripped).

(3) Recirculation/Ground inlet fan (pre-mod A8593 only)

The fan, which is situated within the fuselage roof between stations 137 and 179 may be

used in the recirculation or ground inlet modes in hot, humid conditions to augment the

movement of air within the passenger compartment.

(a) Recirculation

In the recirculation mode the fan draws air through the kicking strip ducts and

delivers it back to the passenger compartment via the high level ducts. Recirculation

may be selected on in flight to supplement the normal air conditioning.

(b) Ground inlet

In the ground inlet mode the fan draws ambient air through a grille in the fuselage

roof and delivers it directly to the high level ducts. This facility is for ground use only

and should not be selected on in flight.

(c) Control valves

The valves, idented 2H53 (recirculation) and 1H53 (ground air) are actuated by split

field (open-shut) series wound motors and incorporate limit switches to prevent

over-travel. Indicator modules on Panel 9P are controlled by the limit switches and

display line indication of the appropriate valves open/shut condition.

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(d) Power supplies and controls

Electrical supplies are derived from the 28V dc ground services busbar via a 5 amp

circuit breaker No. 208 (for control valve operation) and a 10 amp circuit breaker No.

207 (for fan operation) on distribution panel 2D. Control is by a GND AIR - RE-CIRC-

OFF switch on panel 9P.

(4) Ground connection

When in extreme climatic conditions, conditioned air may be supplied to the aircraft via a

ground connection using a suitable Ground Service Unit (G.S.U.).

The ground connection is tapped into the right vertical duct between stations 74 and 89,

15.6 in. above the water line.

Air is delivered from the G.S.U. with the right S/W valve set at WINTER and the left S/W

valve set at SUMMER. Conditioned air is then delivered to the pass. compt. via the right

kicking strip and left high level duct. An orifice plate contained in the ground connection

prevent the aircraft from being over-pressurised by the G.S.U.

5. Extraction system

A. Passenger compartment

The majority of passenger compartment air is extracted via a grille on top of the galley unit

and is ducted to an under-floor louvred outlet in the aft baggage compartment, where it is

discharged overboard.

A portion of the passenger compartment air is extracted through grilles above the forward-

facing overhead lockers at the rear, passes through the toilet compartment and aft bulkhead

grilles to be discharged through a separate underfloor outlet in the aft baggage compartment.

B. Flight compartment

Air is extracted from the compartment via a grille positioned on the upper left hand side of the

rear bulkhead from which flexible ducting is routed to a louvred outlet on the aircraft bottom

skin below the left side of the pass. compt. A similar louvred outlet on the opposite side

provides extraction for the equipment bays below the flight compartment floor.

6. Temperature control (Flight and passenger compartment)

NOTE: On 300F series aircraft (post-mod A8593) passenger compartment conditioned air

distribution is inhibited; ducting is blanked and the supply re-directed to the flight

compartment services.

The temperature controller hitherto associated with the passenger compartment is used in

conjunction with the dual bypass valve and flight compartment temperature sensors to

control flight compartment temperature. Flight Attendants Panel 12P is not fitted on - 300F

series aircraft.

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The passenger compartment automatic temperature control system consists of a controller

(electronic analogue type computer) a temperature selector and two temperature sensors, one

within the compartment and the other in the supply duct. The controller compares the selected

temperatures with the compartment and duct sensed temperature and modulates the dual by-

pass valve accordingly. A similar system in the flight compartment modulates the single bypass

valve.

The AUTO TEMPerature selector switch on the pilot's control panel 9P is duplicated on the flight

attendant's panel 12P and becomes operational by the flight attendant only when the AUTO

CONTROL PILOT/ATTD'T switch (9P) is selected to ATTD'T.

The duct temperature sensors in the flight and passenger supply ducts downstream of the hot

line connections additionally signal the temperature controllers to limit respective duct

temperatures throughout the conditioning range of operation (auto mode) to between 35° F (2°

C) and 160° F (71° C).

The lower limit is of particular importance with regard to the passenger compartment controller,

ensuring that delivery air to the water separator is maintained above freezing point.

If a failure occurs and the upper temperature limit is exceeded, an overtemperature switch in the

appropriate duct will illuminate the BLEED air caption on the centralized warning panel and the

associated duct OVERHEAT light on the AIR CONDITIONING services panel 9P.

NOTE: The passenger compartment overtemperature switch operates when the duct temperature

reaches 185° F to 195° F (85° C to 90° C) and the flight compartment switch at 235° F to

245° F (113° C to 118° C).

Receipt of an overheat warning is a signal to select the affected systems mode switch on panel

9P from AUTO to MANUAL (thus isolating the controller). Operation of the appropriate bypass

valve (dual or single) will then be subject to the control of the associated HOT/COOL manual

control switch on panel 9P; this switch is held momentarily in the required position to modulate

the relevant bypass valve.

On aircraft post Service Bulletin SD360-21-13, crew indication of the ambient temperature in the

passenger compartment is provided by a temperature gauge on panel 9P. Refer to 21-61-00,

pb1.

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AMM21-00-01 2.0.0.0GASPER BOOST SYSTEM - MAINTENANCE PRACTICES

1. Adjustment/Test

A. Function check the system

(1) Provide electrical power and close C/B No. 209, 210 and 211 on distribution panel 2D.

Refer to 12-09-03, pb301.

(2) With the control switch OFF/RAM/ON on panel 9P set at OFF, check that the left and

right gasper boost valves are shut (indicator modules display off-line).

(3) Select control switch to RAM and check that both valves (indicator modules display in-

line).

(4) Fully open gasper units on flight compartment panel 1P and along the left and right sides

of passenger compartment.

(5) Advance control switch to ON and check that all three fans are activated i.e. balanced

delivery velocity of inducted air is available between the left and right hand sides of the

compartments at corresponding lateral positions.

(6) Check fan flight inhibiting circuitry as follows:-

WARNING: ENSURE THAT GROUND LOCKING PINS ARE FITTED TO THE LANDING

GEAR, PREVENTING RETRACTION, SHOULD THE SELECTOR SWITCH BE

OPERATED INADVERTENTLY DURING OPERATION (D).

(a) Gain access to TB74, situated in the right landing gear bay (Stn.316), by removing

the access panel from the bulkhead.

(b) With fan selected ON, connect a switchable 28V d.c. power supply (control switch

open) to the coil of the weight switch relay via terminal No.2 on TB74.

(c) Close the power supply control switch, thus energising the coil of the weight switch

control relay and check that flow from the gaspers has ceased - fans deactivated.

(d) Disconnect power supply and replace access panel.

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AMM21-00-06 3.0.0.0HEAT EXCHANGER - MAINTENANCE PRACTICES

1. Removal/Installation

Refer to Figure 201.

A. Remove a heat exchanger.

(1) Remove access panels 240 AR, 240 BR, 240 AL, 240 BL, 240 CL, 240 DL and 240 EL

on forward fairing. Refer to 6-30-00, pb1.

(2) Remove detachable fairing structure between frame stations 74 and 179.8. Note

positions and method of attachments for subsequent re-installation.

(3) Disconnect ducting as follows:-

(a) Heat exchanger to air cycle machine (detail C)

(b) Heat exchanger to compressor inlet (detail A)

(c) Heat exchanger to turbine and by-pass valve (detail A).

(d) Compressor to heat exchanger (detail A)

(e) Engine supply duct to heat exchanger (detail B)

(4) Disconnect drain tube from heat exchanger.

(5) Detach heat exchanger and channel assemblies where secured to vertical support posts.

(6) Remove unit complete with channel assemblies.

NOTE: Slacken adjacent ducting as necessary to negotiate removal of heat exchanger

noting positions for re-tightening during subsequent re-installation.

B. Install a heat exchanger

NOTE: Operation (1) only applies if unit is not that previously removed (para 1.A.).

(1) Remove the four bolts, nuts and washers which secure the channel assemblies, gasket

and duct to the top of the heat exchanger and fit these items to the replacement unit.

(2) Install heat exchanger with top channel assemblies to support posts and attach using

bolts nuts and washers.

NOTE: At aft inboard corner two vertical bolt positions to be left redundant until forward

fairing is installed.

(3) Connect drain tube to heat exchanger and tighten jubilee clip.

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Heat Exchanger - Removal/Installation

Figure 201

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(4) Refer to Figure 201. Make the following ducting connections with reference to the

appropriate detail using new 'O' ring seals where required.

(a) Heat exchanger to air cycle machine (detail C).

(b) Compressor to heat exchanger (detail A) using seal Pt. No. 56A 460 225.

(c) Engine supply duct to heat exchanger (detail B).

(d) Heat exchanger to turbine by-pass valve (detail A) using seal Pt. No. 56A 460 175.

(e) Heat exchanger to compressor inlet (detail A) using seal Pt. No. 56A 460 250.

(5) Refit fairing detachable structure between frame stations 74 and 179.8 securing as noted

during removal operations.

(6) Install access panels 240 AR, 240 BR, 240 AL, 240 BL, 240 CL, 240 DL and 240 EL on

forward fairing.

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SD3-60 AIRCRAFT MAINTENANCE MANUAL

AMM21-00-11 4.0.0.0AIR CYCLE MACHINE - MAINTENANCE PRACTICES

1. Servicing

A. Check oil level in sump

(1) Open access panel 240 DL in forward fairing on fuselage roof.

(2) By the use of a mirror inspect the oil level sight plug, situated on the forward side of the

air cycle machine beneath the outlet ducting, to ensure that the sight bulb is full of oil.

(3) Close access panel 240 DL.

B. Replace oil in sump

(1) Remove access panel 240 DL in forward fairing on fuselage roof.

(2) Break locking wire of filler plug, adjacent to oil level sight plug, and remove filler plug and

pre-formed packing. Retain filler plug and discard packing.

(3) Siphon-drain sump through filler plug orifice.

(4) Fill sump to filler port level with Exxon 2380 oil.

NOTE: Exxon 2380 oil per MIL-L-23699 is the recommended lubricant for maximum

service life. If not available MIL-L-7808G is suggested for use in cooler climates

and other oils per MIL-L-23699 for operation in warmer climates.

(5) Install filler plug and new pre-formed packing 69494 K11 and tighten to 15 to 25 lb.in.

torque.

(6) Wire lock plug to sump.

(7) Replace access panel 240 DL.

2. Removal/Installation

A. Remove an air cycle machine (ACM)

Refer to Figure 201.

(1) Open circuit breaker No. 196 on right distribution panel 2D.

(2) Remove access panels 240 AL, 240 CL, 240 DL and 240 EL in forward fairing on

fuselage roof.

(3) Disconnect bayonet type electrical connection from over temperature switch.

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(4) Disconnect the following ducts at the air cycle machine:-

- ACM turbine outlet (detail A)

- Heat exchanger to compressor inlet (detail A)

- Compressor outlet to heat exchanger (detail A).

- ACM turbine inlet (detail B).

- ACM to heat exchanger (detail C).

(5) Remove split pins, nuts, washers and bolts holding ACM to mounting platform, and

retain.

(6) Remove bushes from inboard attachment holes and retain.

(7) Lift ACM clear and remove from aircraft.

NOTE: Slacken adjacent ducting as necessary to negotiate removal of ACM noting

positions for re-tightening during subsequent re-installation.

B. Install an air cycle machine

NOTE: Operation (1) only applies if unit is not that previously removed in para 2.A.

(1) If ACM is unserviceable, transfer turbine outlet elbow and attachments to replacement

ACM, using HYLOMAR jointing compound Part No. SQ32.

NOTE: Alternatively a gasket, Hamilton Standard Part No. 753443-2 may be substituted

for the jointing compound;

(2) Align ACM with attachment holes in mounting platform and fit bushes to the two inboard

holes, with the bush flanges on the outboard side. All bolts to be entered from outboard

side, washers fitted under nuts, nuts tightened and split pinned.

(3) Refer to Figure 201. Make the following duct connections with reference to the

appropriate detail using new 'O' ring seals as required:-

- ACM to heat exchanger (detail C).

- ACM turbine inlet (detail B) using seal Part No. 69494-J-132.

- Compressor outlet to heat exchanger (detail A).

- Heat exchanger to compressor inlet (detail A).

- ACM turbine outlet (detail A).

(4) Reconnect bayonet type electrical connection to over temperature switch.

(5) Replace access panels 240 AL, 240 CL, 240 DL and 240 EL.

(6) Close circuit breaker No. 196 on right distribution panel 2D.

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BOMBARDIER SD3-60 Maintenance Manual

BOMBARDIER SD3-60 Maintenance Manual

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