Sub,iectATA 27 ~ELEVATOR MECHANICAL CONTROL LINKAGE # CHECK FOR CORRECT IN

: UNCOUPLING UNIT

De AOT-Dispatch, AIRBUS [mailto:Airbus ..AOT-Dispatch@airbus.com]

Envoye jeudi 18 novembre 2010 10:01

Objet : ATA 27 -ELEVATOR MECHANICAL CONTROL LINKAGE # CHECK FOR CORRECT

INSTALLATION OF THE PITCH UNCOUPLING UNIT

FROM AIRBUS CUSTOMER SERVICES TOULOUSE

ALL OPERATORS TELEX - ALL OPERATORS TELEX

SUBJECT; ATA27 - ELEVATOR MECHANICAL CONTROL LINKAGE - CHECK FOR

CORRECT

INSTALLATION OF THE PITCH UNCOUPLING UNIT

OUR REF: AOT 27A6068 rev 01 dated 18 November 2010

OUR PREVIOUS REF: AOT 27A6068 dated 18 November 2010

O.REASON FOR REVISION

The attached file was not the good version.

I.AIRCRAFT AFFECTED

All A300-600 in-service aircraft.

Elevator Control

Linkage Elevator Control

Unit

Linkage

2.REFERENCED DOCUMENTATION

- Ref.l: IPC 27-31-07 Figure 16 Item 100:

Mechanism Assy, Locking, pitch uncoupling

- Ref.2: IPC 27-31-07 Figure 16 Item 110:

Rod Assy, Control

- Ref.3: Aircraft Maintenance Manual (A~M) 27-30-00 Figure 001: General

Description

- Ref.4: Illustrated parts Catalog (IPC) ~7-31-01 Figure 02 Item 190:

Control Install pitch Captain - Bellcrank Assy, Pitch control

- Ref.5: IPC 27-31-07 Figure 04 Item 60: Detent Bellcrank and Lever -

Bellcrank Assy, Override Unit

- Ref.6: AMM 27-31-00 Page Block 501 section 2. (1) Operational test,

To check correct operation of pitch uncoupling solenoid

- Ref.7: Maintenance Planning Document (MPD) task number 273100-01-1·

Operational Check Of Pitch Control Uncoupiing Using "TEST-OK"

Facility On Lateral Panel

- Ref. 8: AMM 27-31-00 Page Block 501 section 3. (2): Functional test of

pitch control uncoupling and coupling

- Ref.9: MPD task number 273100-02-1: Functional Check Of Pitch Control

Uncoupling And Coupling

- Ref.IO: AMM 27-31-33 Page Block 401: Pitch Uncoupling Unit-Removal

!Installation

3.REASON

1
3.1 FACTS

During routine maintenance check on an A300-600, one operator found the

pitch uncoupling unit Ref.l installed at an incorrect location, i.e.

inverted with the rod assembly Ref.2.

After complete inspection of its fleet, the operator identified the

same

incorrect installation on another aircraft.

3.2 SYSTEM DESCRIPTION

The inputs from the control columns are transmitted to the elevators by

dual control channels, each channel routed along one side of the

fuselage.

Refer to Ref.3. The left and right control channels are interconnected

at

two points by two detent bellcranks, one forward bellcrank Ref.4

beneath

the flight compartment floor, the other rear bellcrank Ref.5 between

the

two elevators.

The two elevator control channels can be uncoupled during the takeoff

and

landing phases in the event of jamming of one control channel, by means

of

the two detent bellcranks Ref.4 and Ref.5.

A pitch uncoupling unit Ref.l prevents any inadvertent uncoupling of

the

two elevator control channels after the take-off, in order to prevent

asymmetrical loads being applied to the structural attachments of the

trimmable horizontal stabilizer.

The pitch uncoupling unit solenoid (4CF) is energized if airspeed is

higher

than 30 kts and lower than 195 kts. The two elevator control channels

can

then be uncoupled in the event of jamming.

3.3 INVESTIGATIONS

The incorrect installation will not be detected during the

accomplishment

of the pitch uncoupling Operational test AMM Ref.6, required every 2000

Flight Hours (FH) or 36 months (MO) as per MPD Ref.7. This test only

validates the condition of the pitch uncoupling solenoid.

The incorrect installation can only be detected during the

accomplishment

of the pitch uncoupling Functional test as per AMM Ref.B, required

every

18000 FH or 120 MO as per MPD Ref.9.

Both aircraft identified with the incorrect installation had never

passed

the Functional test since their entry into service.

2
3.4 CONSEQUENCES

Would the pitch uncoupling unit Ref,l be inverted with the rod

assembly Ref.2, the pitch uncoupling duririg the takeoff and landing

phases

in the event of jamming is no more possible.

3.5 AIM

Airbus recommends to perform the actions defined in this AOT to ensure

a

reliable function of the elevator control columns by means of a one

time

visual inspection, to check the correct installation of the pitch

uncoupling unit Ref.l and to restore the system if needed.

It is anticipated that this AOT will be rendered mandatory by an EASA

Airworthiness Directive.

4.SHORT TERM ACTION

4.1 PLANNING AND MANPOWER

Airbus requires that, on A300-600 and A300-600ST, the correct pitch

uncoupling installation is visually checked on aircraft on which the

pitch

uncoupling Functional test Ref.S has never been performed since

original

aircraft delivery.

This functional test is required every IS000FH or 120MO as per MPD

Ref.9.

This AOT is applicable only to aircraft wnich have not accomplished

this

MPD Ref. 9 yet.

On applicable aircraft, the visual inspection must be accomplished

within

30 days from the AOT issuance date.

The visual inspection represents 2.00 man-hours, with an addition of

4.00

man-hours in case of necessary corrective actions.

4.2 INSPECTION / CORRECTIVE ACTIONS

On applicable aircraft, the following procedure shall be applied:

- Visually check that the pitch uncoupling unit Ref.l is installed at

the right location as per AMM Ref.IO.

- If the installation is correct:

a No further action is required.

3
- If the installation is not correct:

o Remove and re-install at the correct location the pitch

uncoupling unit and the rod assembly, as per AMM Ref.10.

Perform the necessary adjustments so that riggings are correct.

a Perform the Functional test of the pitch uncoupling unit as

per

AMM Ref.8.

4.3 DATA REPORTING

Report the inspections findings to the Aitbus contact point given in

paragraph 7.

4.4 MATERIAL AND TOOLING

Neither specific material nor tooling is required for these actions.

S.FURTHER ACTION

A revision of the pitch uncoupling replacement task AMM Ref.lO has been

launched by Airbus in order to clarify which test is required after

replacement.

6.AOT APPROVAL

The technical content of this AOT has bee~ approved under EASA Design

Organization Approval EASA.21J.031.

7.REPORTING / ACKNOWLEDGEMENT

Operators are requested to acknowledge receipt of this AOT within 48

hours

after receipt to:

MIle Laetitia BONNET, SEEL

Phone number: +33 (O}S 67 19 24 40

Fax number: +33 (OJ 5 61 93 32 73

E-mail· Laetitia.bonnet@airbus.com

This acknowledgement can be made through the Airbus RCSR office when

available.

Questions about the technical content of this AOT, and inspection

results,

with or without findings, are to be sent to Airbus Customer Services,

Engineering and Technical Support, attention of:

Mr. Stephane ROBINAUD, SEEL6

Phone number: +33 (0)5 67 19 08 81

Fax number: +33 (0)5 61 93 32 73

E-mail: stephane.robinaud@airbus.com

Best regards,

4
E. VAN AELST

VICE PRESIDENT A300 PROGRAMME

CUSTOMER SERVICES DIRECTORATE

5