FLAPS POSITION INDICATING - DESCRIPTION AND OPERATION

** ON A/C NOT FOR ALL

1. General
The upper display unit of the Electronic Centralized Aircraft Monitoring (ECAM) system shows the flap position. The display unit shows the flap position together with the slat position and the direction of their movement. A full description of the slat position indicating data is given in (Ref. AMM D/O 27-85-00-00).

The Instrumentation Position Pick-Off Unit (IPPU) 3CN monitors the movement of the mechanical transmission system. It thus monitors the operation and position of the flaps.

** ON A/C NOT FOR ALL

2. Component Location

Equipment on Flap Power Control-Unit - Component Location

FIN	FUNCTIONAL DESIGNATION	ZONE	ATA REF
** ON A/C ALL
6201CM	FLAP-PCU	147	27-54-51
3CN	IPPU-FLAP	148	27-55-11

** ON A/C NOT FOR ALL

3. System Description

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

Flap Position Indicating - Schematic

The IPPU is attached to the flap 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 flap 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 flaps 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 flaps on the display. The white points are not shown when the flaps and slats are fully retracted (clean configuration). The indication F, which is usually green, shows the flap 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 flap surface
the direction and limit of the flap surface movement
when the flap locking function is engaged
when the flap auto-command function is engaged
when a system failure has occurred.

White points show the position of the flaps on the display. The white points are not shown when the flaps and slats are fully retracted (clean configuration). The indication F, which is usually white, shows the flap 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 flap surfaces
the direction and limit of the flap surface movement
when the flap locking function is engaged
when the flap auto-command function is engaged
when a system failure has occurred.

** ON A/C NOT FOR ALL

4. Power Supply

Flap Position Indicating - Schematic

The 431XP ESS BUS and the 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.

** ON A/C NOT FOR ALL

5. Interface
Not Applicable

** ON A/C NOT FOR ALL

6. Component Description

A. Instrumentation Position Pickoff-Unit (IPPU) FIN: 3-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 27-51-00-00).

** ON A/C NOT FOR ALL

7. Operation/Control and Indicating

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

Flap Position Indicating - Schematic

When the flaps move, the upper 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 flap position by green triangles
the new flap position by blue triangles.

When the flaps 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 flap position go out of view.

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

the F 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 flap symbol in green
a cyan symbol below the related white point of the new flap position selection.

When the flaps reach their new position:

the flap 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 flaps do not move to the correct position:

the F indication changes from white to amber
the flap 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 flap position selection.

A. Flap Protection

(1) Flap Lock

If the Wing Tip Brakes (WTB) lock the flap transmission system (e.g. in an asymmetry condition (Ref. 27-51-00)):

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

(2) System Failure

If the SFCCs send a failure message to the EIS, or the System Data Acquisition Concentrators (SDAC1, SDAC2) (Ref. AMM D/O 31-54-00-00) send a SFCC failure message:

the white F indication changes to amber
the green flap index changes to amber.

(3) Flap Lock

If the Wing Tip Brakes (WTB) lock the flap transmission system (e.g. in an asymmetry condition (Ref. 27-51-00)):

the white F indication changes to amber
the flap symbol changes 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 flap position selection.
an amber F LOCKED message comes on above the F indication.

(4) System Failure

If the SFCCs send a failure message to the EIS, or the System Data Acquisition Concentrators (SDAC1, SDAC2) (Ref. AMM D/O 31-54-00-00) send a SFCC failure message:

the white F indication changes to amber
the flap symbol changes from green to amber.

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

(1) No Position Data

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

the green index of the flap system goes out
two amber crosses come on at the flap 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 flaps at the DMC input:

the flap position symbol goes out
the white points showing the flap positions go out
two amber crosses come on at the flap 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.

** ON A/C NOT FOR ALL

8. BITE
Not Applicable

[Rev.10 from 2021] 2026.04.01 06:55:16 UTC