SLATS POSITION INDICATING - DESCRIPTION AND OPERATION

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1. General
The upper display unit of the Electronic Centralized Aircraft Monitoring (ECAM) system shows the slat position. The display unit shows the slat position together with the flap position and the direction of their movement. A full description of the flap position indicating data is given in (Ref. AMM D/O 27-55-00-00).

The Instrumentation Position Pick-Off Unit (IPPU) 4CN monitors the movement of the mechanical transmission system. It thus monitors the operation and position of the slats.

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2. Component Location

Component Location

FIN	FUNCTIONAL DESIGNATION	ZONE	ATA REF
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6001CM	SLAT-PCU	147	27-84-51
4CN	IPPU-SLAT	148	27-85-11

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3. System Description

Indication of the Slat Positions ** ON A/C NOT FOR ALL

Indictaion of the Slat Positions ** ON A/C NOT FOR ALL

The IPPU is attached to the slat Power Control Unit (PCU). An intermediate gear transmits the movement from the output shaft of the differential gearbox to the IPPU. The IPPU sends the slat position data to the Flight Warning Computers (FWC1, FWC2). The FWCs send the data to the Electronic Instrument System (EIS). The EIS shows the position of the slats on the upper display unit of the ECAM system.

The upper display unit uses the shape of a wing to show the slat and flap positions. A grey symbol shows the fixed center section of the wing. Green indications show the correct position of the slats and flaps. When the slats and flaps are fully retracted, the green symbols are shown on the two sides of the center section of the wing.
White points show the position of the slats on the display. The white points are not shown when the slats and flaps are fully retracted (clean configuration). The indication S, which is usually green, shows the slat part of the display. The indication is not shown when the aircraft is in the clean configuration.

The upper display unit also shows:

the position of the flap and slat control lever
the position of the slat surfaces
the direction and limit of the slat surface movement
when the slat alpha-lock/speed baulk-function is in operation
when the slat locking function is engaged
when a system failure has occurred.

White points show the position of the slats on the display. The white points are not shown when the slats and flaps are fully retracted (clean configuration). The indication S, which is usually white, shows the slat part of the display. The indication is not shown when the aircraft is in the clean configuration.

The upper display unit also shows:

the position of the flap and slat control lever
the position of the slat surfaces
the direction and limit of the slat surface movement
when the slat alpha-lock/speed baulk-function is in operation
when the slat locking function is engaged
when a system failure has occurred.

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4. Power Supply

Slat Position Indicating - Schematic

431XP ESS BUS and 231XP BUS 2 supply 26V AC:

431XP ESS BUS supplies circuit breaker 1CN
231XP BUS 2 supplies circuit breaker 2CN
1CN supplies 26V AC to IPPU connector A
2CN supplies 26V AC to IPPU connector B.

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5. Interface
Not Applicable

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6. Component Description

A. Instrumentation Position Pickoff-Unit (IPPU) FIN: 4-CN

The IPPU has:

a splined input shaft
a spring-loaded locking plate
reduction gears
a reduction gear housing
two synchro transmitters which operate independently
a synchro cover
an electrical connector assembly
a cover plate.

When the IPPU is removed, the spring-loaded locking plate holds the splined input shaft from the removed IPPU. When the IPPU is installed, the mount of the IPPU pushes the locking plate away from the shaft splines. The input shaft moves the reduction gears which are in the reduction gear housing. The reduction gears turn the two synchro transmitters which are below the synchro cover.

The electrical connector assembly is installed on the reduction gear housing. The electrical connector assembly has two connectors, one for each synchro transmitter. The connectors are identified as A and B. The cover plate is installed over an opening in the reduction gear housing. There is a window in the cover plate to monitor adjustment of the IPPU to zero.

The IPPU is the same as the Feedback Position Pick-Off Unit (FPPU) and a full description is given in (Ref. AMM D/O 27-81-00-00).

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7. Operation/Control and Indicating

Indication of the Slat Positions ** ON A/C NOT FOR ALL

Indictaion of the Slat Positions ** ON A/C NOT FOR ALL

Slat Position Indicating - Schematic

When the slats move, the upper ECAM display unit (Ref. AMM D/O 31-66-00-00) shows:

the FLAP indication in cyan
the position indication of the flap and slat control lever as 0, 1 (1 + F when the flap auto-command function is engaged), 2, 3 or FULL in cyan
the correct slat position by green triangles
the new slat position by blue triangles.

When the slats reach their new position:

the FLAP indication changes from cyan to white.
the position indication of the flap and slat control lever changes from cyan to green.
the blue triangles of the slat position go out of view.

If the slats/flaps do not move freely, the FLAP indication changes from cyan to amber.
When the slats move, the upper display unit (Ref. AMM D/O 31-66-00-00) shows:

the S indication in white
the position indication of the flap and slat control lever as 0, 1 (1 + F when the flap auto-command function is engaged), 2, 3 or FULL in cyan
the slat symbol in green
a cyan symbol below the related white point of the new slat position selection.

When the slats reach their new position:

the slat symbol is shown around the related white point
the position indication of the flap and slat control lever changes from cyan to green
the cyan symbol below the related white point goes out of view.

If the slats do not move to the correct position:

the S indication changes from white to amber
the slat symbol changes from green to amber
the position indication of the flap and slat control lever stays cyan
the cyan symbol stays below the related white point of the slat position selection.

A. Slat Protection

(1) Slat Lock

If the Wing Tip Brakes (WTB) lock the slat transmission systems (for example in an asymmetry condition (Ref. 27-81-00)):

the white S indication changes to amber
the slat index changes to amber
an amber S-LOCKED message comes on above the set position indication.

(2) Slat Lock

If the Wing Tip Brakes (WTB) lock the slat transmission systems (for example in an asymmetry condition (Ref. 27-81-00)):

the white S indication changes to amber
the slat symbol changes to amber
an amber S LOCKED message comes on above the S indication
the position indication of the flap and slat control lever stays cyan
the cyan symbol stays below the related white point of the slat position selection.

(3) Alpha-Lock/Speed Baulk

The Alpha-Lock/Speed Baulk function prevents the retraction of the slats when the aircraft is operating outside specified flight parameters (Ref. AMM D/O 27-81-00-00). If the flap and slat position lever is moved to the 0 position and the function operates (for example if the Corrected Angle of Attack (CAoA) is too large or the Computed Air Speed (CAS) is too low):

the flap index stays green and moves to the retracted position if it is not already in this position
the cyan selected position point on the flap side of the wing display goes off if it is on
the green slat index stays at position 1 and flashes, the cyan position selected point stays on
the cyan 0 set position indication under the grey wing center-section stays on
a green flashing A-LOCK message comes on at the slat side of the indication.

(4) Alpha-Lock/Speed Baulk

The Alpha-Lock/Speed Baulk function prevents the retraction of the slats when the aircraft is operating outside specified flight parameters (Ref. AMM D/O 27-81-00-00). If the flap and slat position lever is moved to the 0 position and the function operates (for example if the Corrected Angle of Attack (CAoA) is too large or the Computed Air Speed (CAS) is too low):

a green flashing A LOCK message comes on above the S indication
the green slat symbol stays at position 1 and flashes
the cyan position selected symbol stays on
the position indication 0 of the flap and slat control lever stays cyan.

(5) System Failure

If the SFCCs send a failure message to the EIS, or the System Data Acquisition Concentrators (SDAC1 and SDAC2) send a SFCC failure message:

the white S indication changes to amber
the green slat index changes to amber.

(6) System Failure

If the SFCCs send a failure message to the EIS, or the System Data Acquisition Concentrators (SDAC1 and SDAC2) send a SFCC failure message:

the white S indication changes to amber
the slat symbol changes from green to amber.

B. No Data at the Data Management Computer (DMC) Input

(1) No Position Data

When no valid positional data is available for the slats at the DMC input:

the green index of the related slat system goes out
two amber crosses come on at the slat side of the display
the cyan lever position indication comes on
the cyan dot which indicates the lever configuration comes on.

(2) No Configuration Indication

When no valid configuration data is available from the DMC two amber crosses replace the lever position indicator.

(3) No Position Data

When no valid position data is available for the slats at the DMC input:

the slat position symbol goes out
the white points showing the slat positions go out
two amber crosses come on at the slat side of the display
the position indication of the flap and slat control lever changes from green to cyan.

(4) No Configuration Indication

When no valid configuration data is available from the DMC, two amber crosses replace the lever position indicator.

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8. BITE
Not Applicable

[Rev.10 from 2021] 2026.04.01 07:04:35 UTC