Operator E-jets News Rel 07

Issue No. 07 – June 2007

Issue No. 07 June 2007

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From the Editor

E-JETS NEWS is a publication that presents EMBRAER 170/190 aircraft technical items. This newsletter, compiled by EMBRAER Fleet Technical Center (EFTC), brings the latest developments and shares in-service knowledge and maintenance best practices. It also provides troubleshooting tips to optimize aircraft utilization and efficiency in daily operation.

E-JETS NEWS addresses Operator’s concerns with maintenance support and dispatchability of EMBRAER 170/190 aircraft. It has relevant information to be shared with the technical departments, such as Engineering and Maintenance. Recipients are encouraged to distribute this newsletter within EMBRAER Customers.

Earlier editions of E-JETS NEWS publication can be found at CIS / Aerochain at

http://www.aerochain.com

- Login (enter username and password);

- Select “Technical Services” and then “EMBRAER Customer Services”;

- Select “Maintenance Support”;

- Select “E-JETS NEWS;

- Click on desired E-JETS NEWS.

If any additional information regarding the in-service items covered in the E-JETS NEWS is needed, please contact the local EMBRAER Field Service Representative. General questions or comments about the E-JETS NEWS publication can be address to:

E-JETS NEWS

Tel: +55 12 3927 5762

Fax: +55 12 3927 5996

E-mail: [email protected]

PROPRIETARY NOTICE

The articles published in E-JETS NEWS are for information only and are an EMBRAER S/A property. This newsletter must not be reproduced or distributed in whole or in part to a third party without EMBRAER’s written consent. Also, no article published should be considered authority-approved data, unless specifically stated.


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CF34-10E Engine Center Vent Tube – Update

Effectivity: EMBRAER 190

According to E-Jets NEWS release No. 4, EMBRAER received a report of deformed CF34-10E Center Vent Tube (CVT) in the EMBRAER 190 fleet, which was observed during the aircraft look-around inspection. The CVT was removed from the aircraft and GE started the investigation process with tests and mechanical analysis.

The misshaped condition observed on the CVT raised up some theories for root cause investigation, as listed below:

• Vibration

• Handling damage

• Detonation

• Overpressure due to engine malfunction

• Tensile load due to thermal expansion

• Deflagration

• Superheated steam

After tests and analyses performed with the deformation symmetry observed on the CVT, two most probable root causes were described:

• Superheat steam: Ice/water trapped in the centerbody cavity could be heated to 300 deg Fahrenheit which could raise the pressure enough to cause this event. Estimated time and weather conditions of reported event suggests heavy ice storm on February 14

th, 2007;

which may have caused ice/snow accumulation.

• Deflagration: Vaporized oil/fuel/air mixture auto ignites at high cavity temperatures, causing cavity pressure rise.

No more events have been reported, but CVT’s thickness and/or material change are being considered by GE.

Thrust Reverser CF34-8E Core Cowl UV Degradation: Data Collection Survey – Update


EMBRAER was informed about a wear over the bronze mesh of the composite material located on the structure of the engine core cowl (refer to E-Jets NEWS Release No. 3). After an analysis, it was discovered that this kind of wear is a consequence of Ultra Violet radiation. This radiation degrades the superficial epoxy resin that covers the mesh. Thus, the resin is eroded by the airflow and the mesh becomes exposed.

The final solution is under certification by Aircelle (pending a few tests). It will consist in adding a protective paint layer on the exposed area of the core cowl.

The service bulletin is being worked in parallel with validation tests and certification. Field plan is expected to be finalized by December 2007 as the production introduction (targeted to Thrust Reverser s/n #450).

CF34-8E Combustor Liner – Update


EMBRAER was informed about an engine removal due to cracks in the combustor liner (refer to E-Jets NEWS Release No. 6). After borescope inspection, damage exceeding limits described on EMM (Subtask 72-00-00-220-065 (Page 843) – For the inspection limits, refer to Table 803) was found.

Preliminary investigation on the removed engine indicated no impact on engine operability. In High Pressure Compressor, significant deposits were observed along leading edges of all blades and vanes from stage 4 and up, not silt-like, as found in hot section. This may lead this issue to be environment-related. Some components and materials are still under investigation and EMBRAER is following up this issue with GE. The final findings and root causes will soon be properly communicated.


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RAT FAIL CAS Message - Update

Effectivity: EMBRAER 170 / 190

As an update of the topic in reference showed in E-jets NEWS Release No. 3 (RAT FAIL message due to MAU2 reset) and Release No. 5 (RAT FAIL Being Caused by SPDA Micro Active/Standby Out Of Synchronism), EMBRAER would like to inform that SNLs 170-24-0022 and 190-24-0016 were issued and contain detailed information about those issues. These SNLs also include information about some improvements regarding the RAT FAIL CAS message that will be incorporated on SPDA Block 11. Find some of them listed below:

1) RAT GCU PBIT will be inhibited in the SPDA MICRO/COMM standby module. This will avoid spurious messages during the SPDA transfer control;

2) TRUEC Enable Disagreement logic will be improved in order to avoid latching the "RAT FAIL" CAS message on the ground;

3) In order to correlate transitory condition of the TRUEC Enable Disagreement, a new CMC maintenance message will be created.

CMC LDI INFORMATION


EMBRAER has released revision 1 of SNL 170-45-0005 and revision 2 of SNL 190-45-0005. These documents provide information about the CMC LDI changes and also about the known spurious messages that may show on the Central Maintenance Computer (CMC).

These SNLs will be revised whenever either a new CMC LDI version is released or new spurious maintenance messages are identified.

EMBRAER 170 / 175 DUNLOP TIRE 20 PR


In June 2007, EMBRAER certified the new Dunlop main bias tire to be used on the EMBRAER 170/175 Main Landing Gear Wheel Assembly. The new Dunlop tire is a 20 PR (plies) tire while the old one is 18 PR (plies), what means that the new tire has a strength carcass.

The external dimensions of the mounted tire like diameter, shoulder diameter, width, including growth dimensions were not modified. The tire tread compound is maintained with the same raw material specification of the Dunlop 18 PR.

The 18 PR tire and wheel assembly PN is 90000582WT.

The 20 PR tire and wheel assembly PN is 90000582WTA.

See below the maximum weight comparison between both tires:

Dunlop

18 PR

Dunlop

20 PR

Weight Lb / Kg 93.1 / 42,2 100 / 45,4

The tire inflation pressure will remain the same for Dunlop 18 PR and Dunlop 20 PR.

The 20 PR Tire (PN DR31020T) was certified with full inter-mixture with 18 PR tire (PN DR31018T); therefore, the aircraft could be fitted with any combination of 18 PR tire and 20 PR tire in the main landing gear leg.


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CF34-10E Oil Puddle in the Exhaust Chevron Nozzle after engine shutdown. Oil Puddle Limits Revised


There are some CF34-10E engines that may have aft-sump oil leakage and accumulation in the exhaust chevron nozzle.

The CF34-10E Engine Manual (EM) has been revised and provides a new acceptable limit of 9 inches (229 mm) wide and 6 inches (152 mm) long within 15 minutes of engine shutdown.

If the oil puddle on exhaust chevron nozzle is found out of the above limits, it is recommended that the local GE field representative be contacted for immediate technical instructions.

GE currently recommends that operators clean out the exhaust nozzle whenever oil or water puddles in the nozzle.

Additional details on aft-sump leakage limits can be found in the:

• CF34-10E EM 72-00-00, Testing 001, subtask 72-00-00-760-170, K. (3), Page 1322;

• EMBRAER 190 Operational Bulletin: O.B. No. 170- 014/05.(Expected to be revised in June 2007)

The root causes have been defined by GE as scavenge pump timing and aft sump size.

Aft sump hardware will be modified to reduce the amount of oil stored in the sump after engine shut down.

A test is being performed by GE to validate the proposed solution. Initial tests indicate that the amount of oil stored in the sump has been reduced by 40%.

Modifications include the implementation of an air/oil seal screen and removal of an air/oil separator nozzle. After solution validation tests are performed, implementation plan details will be informed.

Figure 1 – Aft Sump area Leakage

Figure 2 – Oil Puddle in the Exhaust Chevron Nozzle

New Engine Bleed Low-Pressure Check Valve


EMBRAER would like to clarify the following items, regarding the new low-pressure check valve (LPCV) -4:

- The new part number suffix -4 is the final fix for Airworthiness Directive (AD) DAC 2005-09-03.


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- Due to a shortage of new parts, EMBRAER SB 170-36-0011 (190-36-0006) only shows aircraft serial numbers which were factory-incorporated.

- The above mentioned SBs will be revised in July 2007 to include the rest of the fleet as soon as Hamilton Sundstrand (HS) is able to keep up with the orders.

- As a consequence, after the SB revision, the AD will also be revised to add the new valve as the final evolution of old -3 ones.

- Once the -4 check valves are installed in the aircraft, operators have to comply with the MRB, which requires a functional test to be performed every 3000FH.

Wing Anti-Ice Valve (WAIV) Grounding Wire


EMBRAER has been questioned about the possibility of the LH/RH WAIV control circuit grounding wire getting loose, disconnected and/or broken due to its present installation. Such event might bring the A-I WING FAIL message on the CAS, caused by a failure of the valve's control circuit, as sensed by the AMS controller. An inspection on a production line aircraft showed the following:

- The control circuit grounding wire (GS) is connected with the valve's frame grounding harness.

- The cable is too long, being prone to getting unintentionally disconnected, or jammed in the valve's access panel.

This scenario is already covered by the applicable FIM. Production line aircraft will have a dedicated GS connector and a shorter, better-routed, grounding wire.

YAW Tendency Due To Misrigging of the Rudder Surface


EMBRAER has received field reports concerning rudder surface slightly out of the neutral position. An Electronic Rigging was performed to address this issue.

The rudder surface deviation generally happens after a pilot report informing an unusual yaw tendency in flight that is counteracted by a yaw trim command.

Performing the rudder surface rigging according to AMM Task AMM TASK 27-20-00-820-801-A with the rudder surface in neutral position slightly out of zero (the system allows a maximum of 2.4 degrees out of neutral rigging) to the left or to the right will cause an offset. This offset from the neutral position at high speeds has an influence in the yaw tendency.

As described in AMM TASK 27-20-00-820-801-A, before doing the electronic rigging procedure, the rudder surface must be manually aligned until it is centered in the rudder fairing. Also, it is important to make sure that the Rudder Trim is at neutral position.

When a rigging procedure is performed, it supersedes the previous one. In this case, if you have done the rigging procedure with the rudder surface not aligned with the rudder fairing, a yaw tendency will be verified.

Engine-Driven Pump (EDP) -03 Removals


In October 2006, EMBRAER issued SBs 170-29-0011 and 190-29-0007 replacing the actual EDP with a new one 51164-03 to reduce the occurrences of external leakage and increase the reliability of the pump. The retrofit campaign is ongoing and around 60% of fleet has the new part number.


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Until May 2007, seven units of new EDP 51164-03 were returned to Parker.

Three units were “No Fault Found”:

• One unit removed during troubleshooting because of a system pressure fault. A defective ground wire causing a low pressure indication on the hydraulic system synoptic page was identified.

• Two units removed because of system leakage, pump determination, no fault found.

One unit ran dry for over an hour. It is suspected to have had an internal failure of the barrel assemble from running dry, resulting in high case pressure, causing system leakage and depletion.

Three units found leaking at the split line. Upon disassembly, the large face seal was found damaged resulting in an external leakage. EDP split line seal is under investigation.

P-ACE Mod A


An improved P-ACE Mod A was released introducing a current driver to the Digital/ Analog converter circuit to prevent increase of current in the component at low temperature manufacturing test. This is a component issue and does not affect the field operation.

P-ACE -802 and -822, will be released with mod A modification already incorporated. Therefore, all operators will install it through service bulletin application.

The letter A will be marked on the identification plate.

Improper installation position of the Fuel Restrictor causing fuel imbalances and spillages during pressure refueling


Due to some fuel spillage occurrences and successive fuel imbalance problems during pressure refueling on two aircraft, an operator troubleshot the fuel system of both aircraft using the manual pressure refueling procedure and, as a result, considerable fuel imbalance was noticed again.

Based on troubleshooting results, EMBRAER decided to perform a deeper investigation on the refueling line during the aircraft MODLINE downtime.

Inspection detected an inversion on the fuel restrictors’ installation position. The LH restrictor was installed in the RH tank and vice-versa, affecting significantly the flow and pressure of fuel delivered to both tanks.

Correct installation of fuel restrictors may solve fuel spillages and imbalances found during pressure refueling of the affected aircraft.

EMBRAER will issue a new Service Bulletin for each E-Jet family with instructions to open the wing fuel tanks to inspect refueling line for any evidence of fuel restrictors’ improper installation and, if necessary, to return the system to the correct configuration.

These Service Bulletins will be issued after the validation tests that are being performed.

The operators will also be informed of this issue through a Service Newsletter. Service Bulletins are not issued in order to receive instructions for troubleshooting and correction.


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Flap – Torque Limiter Trip Indicator – Indication


EMBRAER has received reports from the field regarding a wrong indication of the torque limiter trip indicator on the flap actuator.

Flaps Actuator location

Scenario 1 = According to figure 1, this position indicates the normal position for the flap torque limiter.

Figure 1 – Normal Position

Scenario 2 = When the torque limiter trip indicator is in the trip position and the trip pin is tripped as per figure 2, maintenance action is required as per FIM TASK 27-51-00-810-802-A.

Figure 2 – Torque limiter

Scenario 3 = When the torque limiter trip indicator is in the set position and the trip pin is tripped as per figure 3 in the next page. This scenario may occur due to the trip pin not getting fully out of the torque limiter or getting fully out of the torque limiter without pushing the torque limiter trip indicator to the trip position. Therefore, it is necessary to accomplish FIM TASK 27-51-00-810-802-A.


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Scenario 4 = When the torque limiter trip indicator is in the trip position and the trip pin is not tripped as per figure 4. This condition may occur due to the vibration of the aircraft during landing. If this scenario occurs, accomplish AMM TASK 27-51-01-210-801-A. If a CMC message appears, do the applicable FIM TASK.


Note: A SNL regarding this subject will be issued and the FIM TASK will be revised.

RAM Air Inlet Duct Acoustic Attenuator Screen


EMBRAER has received reports informing that the ram air inlet duct acoustic attenuator screen was found damaged on some EMBRAER 170/190 aircraft.

This may cause loose material from the damaged screen to obstruct the dual heat exchanger inlet and expose the duct structural material of the ram air inlet duct.

Aircraft tests have revealed that the acoustic treatment of the internal duct surface is not required to maintain proper noise attenuation. Thus, EMBRAER released SBs 170-21-0031 and 190-21-0018 in June 2007 to rework the duct and remove the acoustic attenuator screen. Also, EMBRAER released SNLs 170-21-0027 and 190-21-0022 to address this issue.

Aircraft S/N 17000170 and 19000088 and on have an equivalent factory-incorporated modification. AIPC has already been revised in order to allow the use of the improved duct bearing new part number. A SNL will be issued to inform the operators about this subject.

“HYD 1 (2) ELEC PUMP FAIL” Spurious CAS messages


Service Newsletters 170-29-0005 and 190-29-0004 were issued in the beginning of June 2007 to inform about the occurrences of spurious HYD 1 ELEC PUMP FAIL and HYD 2 ELEC PUMP FAIL messages that are displayed simultaneously on EICAS when there is a failure in the flap or slat system. The SNLs indicate the scenarios where the messages are considered spurious or not. Correction to these spurious messages will be introduced in the Primus EPIC Field Loadable Software System for EMBRAER 170/175 and EMBRAER 190/195, Load 23.


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SLAT Harness Skew Sensor - Troubleshooting


Two scenarios (hard and intermittent failures) in which the “SLAT FAIL” message may show on the EICAS, correlated with one or more slat harness skew sensors maintenance messages displayed on the CMC have been identified.

For those two scenarios (hard and intermittent failures), SNLs 170-27-0039 and 190-27-0031 were issued to help during the troubleshooting, thus, all FIM procedures will be updated and revised accordingly in the next revision, scheduled for August 2007.

Slat Skew Sensors and harness location

MAU2 NIC3 [CORE] FAULT caused by Nose Wheel Steering Control Module


EMBRAER will issue SNLs 170-31-0012 and 190-31-0011 to inform the operators about nose wheel steering control module failures triggering “MAU2 NIC3 [CORE] FAULT” maintenance message.

EMBRAER will revise FIM TASK 31-41-00-810-89F-A to suggest NWSCM removal as first action to troubleshoot “MAU2 NIC3 [CORE] FAULT”. There is no need to replace NWSCM in order to identify whether the module is responsible for triggering the maintenance message. If the module is faulty its sole removal will clear the maintenance message.

CF34-8E Nacelle Seals


During visual inspections in the field, damage has been found in the transcowl fire seals, mainly at the rear seal (refer to picture - pink seal).

Temporary repair procedures and fly-by periods are provided by EMBRAER after case by case analysis. A definitive repair (for the rear seal) has already been developed by Aircelle, and it consists in a Technical Instruction. The repair instructions will be included in EMM (revision expected for July 31

st, 2007)

and in CMM. Repair kits will be available in August 2007 and parts can be ordered directly from Aircelle at:

[email protected]

Phone: +33 1 64 14 80 33

The final solution is a redesign of all seals, which will introduce smooth curvatures to make them more robust. They are expected to be introduced from thrust reverser SN #430, to be delivered by EMBRAER by early 2008.

Transcowl Fire Seal Location (pink Seal)


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Add Heat Valve Operational Test


The add heat valve is used to control temperatures at the condenser inlet and outlet locations, within the air conditioning pack. It was verified that its built-in test (IBIT) is not fully effective in case the shut-off valve fails in the open position. In order to correct troubleshoot the add heat valve, EMBRAER has developed a new test procedure (TASK 21-51-20-710-801-A - Add Heat Valves - Operational Test) that is available in the AMM revision released in June 2007.

Additionally, EMBRAER recommends that this task be performed every 600 FH, or whenever there is a PACK 1(2) FAIL CAS message, while the add heat valve IBIT correction is not available.

An IBIT including add heat valve open and close fail positions will be introduced in the AMS software Black Label version 9. SNLs 170-21-0026 and 190-21-0021 were released in June 2007 to cover this subject.

Un-commanded dry motoring upon APU start


EMBRAER has recently been informed about an event involving one EMBRAER 190 aircraft which resulted in an un-commanded dry motoring.

A field report stated that during the APU start, there was an un-commanded dry motoring of engine #2. Thrust lever was found to be at idle and start/stop switch was at the off position. Maximum N2 speed observed was 25% and N1 displayed zero. EMBRAER, GE, and Honeywell have prioritized this issue and are working on the tear down of the removed LRUs to make shop findings available for analysis.

EMBRAER will keep operators informed about the investigation progress until there is a definition as to the root cause and solution for this event.

Pylon Movable Fairing


A crack running along the chemically milled area edges, generated by vibration loads, has been found in the pylon movable fairing.

The fly-by is available in SRM and the repair procedure, which will be included in the next revision of SRM that will be released in July 2007, is already available in IC2006-190/1393.

For the fleet, a solution has already been developed and a SB will be available in August 2007. The solution consists in the installation of a reinforcement (Figure 2). For in-production aircraft, with effectivity starting from SN 19000110 onwards, the solution consists in the installation of a reinforcement and the elimination of the chemically milled area.

Figure 1 – Pylon Movable Fairing Cracks

Figure 2 – Reinforcement installation (stringers)


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Acronyms

AD = Airworthiness Directive

AIPC = Aircraft Illustrated Parts Catalog

AMM = Aircraft Maintenance Manual

ANAC = Agência Nacional de Aviação Civil (Brazilian Civil Aviation Authority)

AOM = Airplane Operations Manual

APU = Auxiliary Power Unit

CAS = Crew Alerting System

CMC = Central Maintenance Computer

CMM = Component Maintenance Manual

CVT = Center Vent Tube

DLS = Data Load System

EDP = Engine-Driven Pump

EMM = Engine Maintenance Manual

FIM = Fault Isolation Manual

IBIT = Initiated Built in Test

ITEM = Illustrated Tool and Equipment Manual

LDI = Loadable Diagnostic Information

LH = Left-Hand

LPCV = Low-Pressure Check Valve

LRU = Line Replaceable Unit

MMEL = Master Minimum Equipment List

MRB = Maintenance Review Board

NWSCM = Nose Wheel Steering Control Module

OB = Operational Bulletins

P-ACE = Primary Actuator Controls Electronics

PIL = Parts Information Letters

PN = Part Number

RAT = Ram Air Turbine

RH = Right-Hand

SB = Service Bulletin

SN = Serial Number

SNL = Service Newsletter

SRM = Structural Repair Manual

UV = Ultra Violet

WAIV = Wing Anti-Ice Valve

Note: All abbreviations used in EMBRAER Maintenance Manuals can be found in the Introduction to AMM Part II.

Operator E-jets News Rel 07

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