flight control issues

7/29/2019 Flight Control Issues

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Flight control issueson A330/A340

A330/A340 Operational Liaison Meeting


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2Flight control issues on A330/A340

Content

Alpha lock Ground spoilers extension during taxi

Rudder travel limit faults


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A330/A340

ALPHA LOCK



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ALPHA LOCK: Background Two A340 operators have reported an

ALPHA LOCK message flashing on ECAM

during SLATS/FLAPS retraction to CLEAN

after take-off.

In both cases, SLATS/FLAPS retraction toCLEAN configuration was initiated at therecommended (S) speed.

In one case, misinterpretation of thesituation (SLATS jam) led to an IFTB.


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ALPHA LOCK descriptionDesign objective

The purpose of the ALPHA LOCK function is to

prevent slat retraction to CLEAN configuration

at low speeds or high angles of attack.

This function is necessary due to the large

reduction in the stall AOA (-5) when SLATSretract from configuration1 to CLEAN.


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ALPHA LOCK descriptionArchitecture

ADIRU1/2/3 SFCC1/2

Corrected AOA

CAS


7/367Flight control issues on A330/A340

ALPHA LOCK activation

Note: ALPHA LOCK fu nct ion is inhib i ted w hen SLATS have star ted to retract to 0

SLATS/FLAPS lever selected from 1 to 0

SLATS retraction inhibited

AND

AOA > 8.5ORCAS < 148 Kt



ALPHA LOCK deactivation

SLATS/FLAPS lever selected from 1 to 0

SLATS retraction to 0

AND

AOA < 7.6ANDCAS > 154 Kt



A330 ALPHA LOCK settings

180

Wings level (Conf 1)

140150160170190200210220230240250

200 210 220 230Weight (T)

CAS

(Kt)

VFE

V lock

S speedV lock( = 8.5)

V lock out( = 7.6)




140150160170180190200210220230240250

200 210 220 230Weight (T)

CAS

(Kt)

VFE

V lock

20 bank angle (Conf 1)

S speed

V lock( = 8.5)V lock out( = 7.6)




140150160170180190200210220230240250260270

200 210 220 230 240 250 260 270Weight (T)

CAS

(Kt)

VFE

V lock

Wings level (Conf 1)

S speed V lock( = 8.5)

V lock out( = 7.6)




140150160170180190200210220230240250260270

200 210 220 230 240 250 260 270Weight (T)

CAS

(Kt)

VFE

V lock

20 bank angle (Conf 1)

S speed

V lock

( = 8.5)V lock out( = 7.6)



ALPHA LOCK: Conclusions

ALPHA LOCK function is a protection featurewhich can be activated following a normal

procedure.

The ALPHA LOCK message flashing on

ECAM is not a failure warning (SLATS jam).

In case of ALPHA LOCK activation, continue

acceleration to the selected CLIMB speed to

allow SLATS retraction.


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GROUND SPOILERS

EXTENSION DURING TAXI




Ground spoilers extension during taxiEvent Description

Two A330 operators have recently reported

sudden aircraft braking during low speed taxi.

Both events were caused by an automatic

Ground Spoilers extension while Auto Brake

MAX was engaged.



Ground spoilers extension during taxiEvent Analysis

Results of the DAR readout for one of the tworeported cases are:

Initial conditions:Aircraft was in low speed taxi for take-off (2 Kt),configuration 1+F, GND SPLR armed, throttlelevers on IDLE and Auto-Brake MAX armed.

Event:

Simultaneous and spurious RA1 & RA2 spikesabove 30 ft activate the automatic GND SPLRextension, which subsequently triggers MAX

Auto-Brake.



Ground spoilers extension during taxiAuto Brake function descriptionAuto Brake function

When an Auto Brake mode (LO, MED or MAX) is

armed, braking will be applied as soon as the

Ground Spoilers are extended.

Brakes can be released by:

Retracting the spoilers (Ground Spoilers disarm lever)or

Disengaging the Auto-Brake (pushbutton or brake

pedal)


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ACTIVATION CONDITIONS

PRE-SELECTION

Ground spoilers extension during taxiGround Spoiler logic descriptionWith PRIM standard M11 (A330-300)

GROUND

SPOILERS

EXTENSION

Ground Spoilers Lever armed AND

all throttles at IDLE

wheel speed from both MLG > 72 Kt

OR

both MLG compressed confirmed 2 sec

(condition maintained 3.3 sec)AND

Radio Height < 6ft

OR

1 throttle in REV ANDthe other not more than IDLE


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Ground spoilers extension during taxiGround Spoiler logic descriptionWith PRIM standard M12 (A330-300) and for all A330-200

Logic modification to avoid GND SPLR retraction in case ofbounce above 6 ft during landing

ACTIVATION CONDITIONS

PRE-SELECTION

GROUND

SPOILERS

EXTENSION

Ground Spoilers Lever armed ANDall throttles at IDLE

wheel speed from both MLG > 72 Kt

OR

OR

1 throttle in REV AND

the other not more than IDLE

both MLG compressed confirmed 2 sec

AND

Radio Height < 6ft

Condition

maintained

6.3 sec

PRIM modification


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Ground spoilers extension during taxiGround Spoiler logic description The new logic introduced in PRIM M12 and on

all A330-200 aircraft is more sensitive to Radio

Altimeter spikes, only on ground during taxi

No increased risk of undue ground spoilers

extension in flight

A340 aircraft is not affected by this new logic


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Ground spoilers extension during taxiCorrective actions SHORT TERM ACTIONS

August 99, OIT/FOT ref. SE-E/999.0104/99 issuedrequesting to arm the Ground Spoilers just beforetake-off

A330 FCOM and QRH will be updated accordingly

LONG TERM ACTIONS

New PRIM standard M13/P5 (valid for A330-300and A330-200) is developed; available for retrofit inFebruary 2000


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A330/A340

RUDDER TRAVELLIMIT FAULTS



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Rudder Travel limit faultsSystem description The Rudder Travel Limitation system protects the

aircrafts structure against excessive loads, by speed-scheduling the maximum rudder deflection.

TLU law (A340)

05

101520253035

100 155 160 180 220 250 270 300 330CAS (Kt)

TLU

()

30

3.5

TLU=Travel Limitation Unit


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Rudder Travel limit faultsSystem descriptionTLU display on ECAM

Rudder trim

TLU in High speed position

Rudder electrical stops


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Rudder Travel limit faultsSystem descriptionRudder Travel Limitation System

Rudder Limitation Unit

Pedal Limitation Unit


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Rudder Travel limit faultsSystem description

Reconfiguration

TLU

Back-up function = TLU full opening at SLATS extension

SEC2

SEC1

Channel 2

Channel 1

ECAM warning:F/CTL RUD TRV LIM1 FAULT

ECAM warning:F/CTL RUD TRV LIM FAULT


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Rudder Travel limit faultsBackground Since mid-98, several cases ofRUD TRV LIM

1(2) FAULT ECAM message have been

reported on ground during the F/CTL check.

One case (A330-300) ofRUD TRV LIM FAULT

occurred in flight where the TLU remained in

high speed (closed) position during approach

and landing. The TLU back-up function (full

opening at slat extension) did not operate. The aircraft involved in these events were all

fitted with the latest SEC standard L14/M11.


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Rudder Travel limit faultsGround events:Analysis

The TLU were removed from aircraft and testedby AI and the manufacturer.

On some of them, electronic card deterioration

was observed. This deterioration was due topremature wear induced with SEC L13/M10 prior

to the installation of the new SEC L14/M11.

On others, the unit inspection did not identify any

faulty or deteriorated components.


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Rudder Travel limit faultsGround events: Corrective actions OIT (SE-E/999.0048/99/VHR) issued in April 99

requested removal of TLU at first occurrence of aRUD TRV LIM 1(2) FAULT message for inspectionby Airbus and supplier.

All removed TLU units for which the failure is

confirmed will be fitted with a new electronic card.The qualification tests for these new electronic cardshave been upgraded.

One of the returned TLU units (on which no failure

was identified) has been instrumented and will befitted on A340 MSN 1 for flight tests in Oct/Nov 99.The objective is to identify the origin of the failure in areal operating environment (vibrations, loads,temperature ).


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Rudder Travel limit faultsInflight Event:Analysis

This event was the result of a t r ip le fai lure:

Double TLU failure (degraded electronic

card as in the ground events).

First reported case ofnon functioning of theback-up TLU opening at slat extension.

Inspection of the unit identified a number offaulty relays which could explain the failure of

the back-up function.


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Rudder Travel limit faultsInflight Event:Corrective actions

The actions launched in the context of theground events are valid also for the inflight

case since the dual TLU failure had the same

origin.

Review by the TLU supplier of the component

qualification tests to identify a possible quality

drift.

Due to their similarities, review and harmonisethe A330 and A340 procedures for RUD TRV

LIM FAULT and RUDDER JAM.


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Rudder Travel limit faultsRUD TRV LIMIT FAULT Procedure The revised procedure for A340 and A330

approach and landing will be:

F/CTL RUD TRV LIM FAULT

RUD WITH CARE ABV 160 KTMAX X WIND FOR LDG: 15 KT

STS

STATUS

RUD WITH CARE ABV 160 KT

MAX X WIND FOR LDG: 15 KT

APPR PROC

-GPWS FLAP MODE OFF

-FOR LDG USE FLAP 2

-APPR SPD 160 KT

-APPR SPD VLS+10 KT

AT LDG ROLL:

DIFF BRAKING ... AS RQRD

INOP SYS

RUD TRV LIM

Appears if TLU closed at high speed

In case of One Engine INOP When All Engines Operative


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Rudder Travel limit faultsRUDDER JAM Procedure The Revised A330/A340 Procedure will be

FOR APPROACH

AVOID LANDING WITH CROSSWIND from the side where the

rudder is deflected

FOR LANDING ...... USE FLAP 2

GPWS FLAP MODE .... OFF

APPR SPEED .... VLS+10

SPEED AND TRAJECTORY .. STABILISE ASAP

In case of Engine Out:

APPR SPEED ......160 KT

LDG DIST PROC APPLY

ON GROUND

DIFFERENTIAL BRAKING.. ...USE ASAP


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Rudder Travel limit faultsRevised Procedures

These procedures will be included in:

A340 FWC L8 due for certification in April 2000

A330 FWC K5 due for certification in June 2000

FCOM and QRH will be updated accordingly.


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Rudder Travel limit faultsRUDDER TRAVEL LIMIT FAULTA/C

QRH

FCOM

ECAM

RevisedProcedures

A340CONF 2VREF+15

CONF 2Vapp = VLS+10Max X-wind: 15 kt

CONF 2Vapp = VLS+10Max X-wind: 15 kt

FCOM/ECAMCONF 2

AEO: VLS+10 (VREF+15)OEI: Vapp = 160 ktMax X-wind: 15 ktDifferent. braking as required

A330CONF 2VREF+20

CONF 2Vapp = VLS+10

Max X-wind: 15 kt

CONF 2Vapp = VLS+20

Max X-wind: 15 kt

FCOM/ECAMCONF 2

AEO: VLS+10 (VREF+20)OEI: Vapp = 160 ktMax X-wind: 15 ktDifferent. braking as required


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Rudder Travel limit faultsRUDDER JAMA/C QRH FCOM Revised Procedures

A340 CONF 2Avoid X-windUse differential braking

CONF 2

Avoid X-windUse differential braking

FCOM/QRHCONF 2

AEO: VLS+10 (VREF+15)OEI: Vapp min = 160 kt

Avoid X-windUse differential braking asap

A330 CONF 2OEI: VLS+20 (VREF+25)


CONF 2OEI: VLS+20


FCOM/QRHCONF 2

AEO: VLS+10 (VREF+20)OEI: Vapp min = 160 kt

Avoid X-windUse differential braking asap

flight control issues

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