Issue No. 20 – July 2008
Issue No. 20 July 2008
Page 1
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 Operators 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 to EMBRAER Customers.
Earlier editions of E-JETS NEWS publication can be found at Flyembraer Portal at
http://www.flyembraer.com
- Login (enter username and password);
- Select “Maintenance” and then “Technical Support”;
- Select “E-Jets NEWS for Operators”;
- 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 addressed to:
E-JETS NEWS
Tel: +55 12 3927 7075
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.
Issue No. 20 July 2008
Page 2
CF34-10E Aft Engine Mount Wear – Update
Effectivity: EMBRAER 190
There are some field reports received by EMBRAER concerning aft engine mount wear as presented in E-Jets NEWS Release No. 12 and No. 14, as shown in the pictures below.
Observed wear on engine Aft Mount related to thermal blanket
As an interim solution, GE recommends that the blanket be “lightly tapped with a rubber mallet, to provide more clearance.” Wear limits were also revised (EMM Revision May/08) to provide more flexibility, as regards the wear limits and blending procedures to the operators. Revised limits are in CF34-10E Engine Manual, 71-00-20 Aft Engine Mount and inspection 001 (4. Visual inspection, subtask 71-00-20-220-802, F. All other areas for: wear).
As a final solution, a thermal blanket design change to create more clearance was proposed and is being analyzed by GE.
Design change details and field introduction forecast will be informed in a further edition.
Control Column Light Oscillation with AP Engaged – Update
Effectivity: EMBRAER 170 / 190
As previously informed in E-jets NEWS Release No. 12, EMBRAER received some reports of control column oscillation during flight, when the Auto Pilot is engaged and Vertical Mode Speed is enabled.
FOL 170-2007-066, Rev.1, was revised to inform that the root cause was identified as an occasional synchronism loss between the FGCS controls in the VS (Vertical Speed) mode. This asynchrony may result in the oscillation of the control column with no EICAS message associated and eventually with an autopilot disengagement.
EMBRAER recommends that, in the case of control column oscillation during flight, pilots (after ensuring that the airplane is not in a pre-stall condition) disengage the VS mode and then reengage any Vertical Navigation mode desired (FPA, FLCH …), even the VS, again. For further information, please refer to FOL 170-2007-066 rev1. The solution will be addressed through Load 23.
EMBRAER 190 MLG Internal Nitrogen Leakage – Update
Effectivity: EMBRAER 190
According to E-Jets NEWS No. 15, EMBRAER informed that a new type of seal will be tested and, after the results are received, the implementation plan will be informed.
The Greene Tweed seal (AGT seal 2000A1751K01) was submitted to a cycling test. Nearing completion of the tests (20,000 cycles), no signs of leakage were noted. Then, it will be released as a final solution to the fleet.
AMM, IPC and SB are expected to be released until Oct/2008 as FOC on attrition, that is, MLG overhaul or retrofit for units where leakage is suspected to be present.
Issue No. 20 July 2008
Page 3
“TAIL STRIKE PROT FAIL” CAS Message Being Displayed – Update
Effectivity: EMBRAER 190
As previously informed in the E-Jets NEWS Release No. 15, EMBRAER received some reports of “TAILSTRIKE PROT FAIL” CAS message occurrence without the RA in MMEL 34-31-00.
This message is being triggered by a momentary loss of communication between the RA and TX/RX Antennas.
SNL 190-27-0038 will be revised to inform the FIM TASK to check the cable connections between RA (RA 1 and 2) and TX / RX Antennas. In addition, there no need for any further maintenance action or operational check.
It is important to emphasize that the “TAILSTRIKE PROT FAIL” message is inhibited on the ground with none of both engines running.
New Horizontal Stabilizer Actuator Control Electronic PN 416500-1005 – Update
Effectivity: EMBRAER 190
This article is aimed at informing that Service Bulletin 190-27-0016 (Installation of new Horizontal Stabilizer Actuator Control Electronics, HS-ACE PN 416500-1005) has been revised only to update the aircraft effectivity.
Information regarding MOD 2 improvements has not been included in the revision. However, SNL 190-27-0039 describes all the technical modification incorporated in the new MOD 2 units and how to identify the Mod in the HS-ACE.
The SNL is now available on the Flyembraer website.
Wing Anti-Ice Valves Inop – Update
Effectivity: EMBRAER 190
As an update of E-Jet NEWS Release No. 18, analysis of some cases of A-I WING FAIL observed during last winter concluded that the RH Slat A-I valve actuator supply port may freeze. Consequently, the valve does not open when necessary.
EMBRAER 190 RH installation is more susceptible to such events, mainly during the first flight of the day, after a cold soak condition. Hamilton Sundstrand has performed tests and concluded that a heated tube is necessary to warm up the actuator servo supply chamber, thus avoiding ice formation.
This solution is still under validation process, which may be finished by Jul/08. A new Service Bulletin is expected to be issued after the completion of this analysis. The figure below shows the modification proposal.
Issue No. 20 July 2008
Page 4
EGPWM Retrofit to PN 7028419-1904 – Update
Effectivity: EMBRAER 170 / 190
As previously informed in E-Jets NEWS release No. 17, an incompatibility between SBs 170-34-0021/190-34-0012 and the AIPC was detected.
EMBRAER would like to highlight that those Service Bulletins DO NOT need to be accomplished anymore, once they were superseded by the AIPC revision.
Also, no further action is required for those service bulletins that have already been accomplished.
TAT Failure (PN 102AW1AF)
Effectivity: EMBRAER 170 / 190
EMBRAER released SNL 170-34-0021 and SNL 190-34-0019, informing about the TAT failure and evidences of overheating and/ or burnt harness/ connector.
EMBRAER recommends that the operators follow the instructions described in the mitigation action paragraph to prevent the occurrence of such event.
TCAS Operational Test
Effectivity: EMBRAER 170 / 190
TCAS operational test must be executed according to the procedure described in AMM TASK 34-43-00-710-801-A / SUBTASK 710-001-A.
It was verified that there is a test available on the TCAS / XPDR MCDU page, but it may generate incorrect results and must not be used.
SNLs 170-34-0022 and 190-34-0020 bring further information about this issue.
Hydraulic Temperature Switch Installation
Effectivity: EMBRAER 170
When performing the installation of the hydraulic temperature switch, special attention is required regarding the presence of a safety hole in the tee fitting.
For the first deliveries of EMBRAER 170s, the installation of the temperature switch was in a different configuration and it was not required to apply a lock wire to these switches. Thus, for these aircraft, the tee fitting has no safety hole. The current configuration otherwise requires a safety wire and the tee fitting has an appropriate safety hole.
AMM TASK 29-33-02-400-801-A Hydraulic Temperature Switch – Installation was not reflecting such differences, so it has been recently revised. This new task is expected to be available for customers in the next AMM scheduled revision, expected for August/2008.
Issue No. 20 July 2008
Page 5
SNL FWD/ AFT Cargo Door Jamming Due To Foreign Object
Effectivity: EMBRAER 170 / 190
EMBRAER has issued SNLs 170-52-0021 and 190-52-0015 informing about cargo door jamming events and maintenance actions.
It was detected that loose pieces of luggage or cargo door nets not properly attached to the floor fittings may interfere as foreign objects with the locking mechanism.
Therefore, FIM tasks 52-31-00-810-801-A (Forward-Cargo-Door does not open) and 52-32-00-810-801-A (Aft-Cargo-Door does not open) will be improved to also include the removal of the internal cargo door lining from the outside, using the access through the maintenance panel.
Refer to the mentioned SNLs for detailed information.
Thrust Reverser Fire Seal - GE SB 78-0050 release
Effectivity: EMBRAER 170
Recently, GE has issued SB 78-0050 (Replacement of the Fire Seals in the Lower Area) to improve durability of both Lower Rear Seal and Drain Mast Seal.
The redesign changed the type of junctions between seals, the junction locations and the shape of the seals. Design improved seals were introduced on Thrust Reverser SN 430.
SB 78-0050 is recommended to be accomplished when one of the lower seals are removed from the Thrust Reverser or when they are not repairable, as per Engine Manual TASK 78-31-05-300-801 (Repair of the Lower Rear Seal, Repair 001).
The fire seals located in the upper area of the Inner Fixed Structure (IFS) will be addressed by a follow-on SB, as upper and lower seals can be replaced independently.
Audio Control Panel (ACP) Dimming Function
Effectivity: EMBRAER 170 / 190
EMBRAER has received some reports of ACPs lights flickering but without losing their functionality.
Further analysis revealed that such behavior can be caused by the position of the rotary knob of the cockpit lights panel. This rotary knob controls a potentiometer, provided with a non-linearity in its course, causing the symptom observed.
SNLs: 170-23-0006 and 190-23-0005 contain further details about this issue.
Issue No. 20 July 2008
Page 6
G3 Smoke Seal/ Ventilation Tube Installation
Effectivity: EMBRAER 170 / 190
EMBRAER has been inquired about the different configurations of the smoke seal installation located behind Galley G3, in the aft avionics compartment. See below examples of typical installations:
Due to certification and smoke penetration requirements, the configurations may vary between EMBRAER 170/175/190/195 models as per table below:
Model Effectivity Installation
MSN 001 to 129
Smoke Seal only 170
MSN 130 and on
Ventilation Tube only
175 All 175 Ventilation Tube only
190 All 190 Smoke Seal + Ventilation tube
195 All 195 Smoke Seal + Ventilation tube
If this difference is noted during checks/ maintenance activities, please be advised of the mentioned information about each aircraft model and effectivity.
Engine-Driven Pump (EDP) Ball Attenuator Removal
Effectivity: EMBRAER 190
As previously informed in E-Jets NEWS Release No. 15 and in releases No. 7, 9 and 12 under the article title, “Engine-Driven Pump (EDP)-03 Removals”, modifications on Engine-Driven Pump (EDP) were introduced since the beginning of EMBRAER 170/ 190 operation, to address external leakage issues.
After the retrofit of EDP 51164-01 and 51164-02 to 51164-03 and 51164-04, cases have still been reported concerning cases of leakage in the EDP -03 at the interface of the port cap and front housing split line due to damage of the larger face seal.
Aircraft prototype and laboratory tests indicated that the EDP discharge ball attenuator installation is causing a magnification of the pressure ripple level in the tubing between the EDP and the ball attenuator. Excess ripple is thought to be a major contributor to the damage in the port cap/ front housing split line seal.
The solution of relocating and resizing the attenuator was discarded because it requires a substantial design modification, requiring an installation recertification.
After good results on the E170 (refer to E-Jets NEWS Release No. 15) and extensive testing on the E190, attenuator removal on the E190 was reassessed:
• Ripple is substantially minimized during cruise phase.
• Passenger cabin noise level measured on a production aircraft configuration was negligible.
The final solution for the EDP external leakage is to retrofit EDP -01 and -02 to -03 or -04, and apply SB 190-29-0020 HYDRAULIC POWER - REMOVAL OF ENGINE-DRIVEN-PUMP (EDP) PRESSURE ATTENUATOR OF No. 1 AND No. 2 HYDRAULIC SYSTEMS.
Issue No. 20 July 2008
Page 7
CF34-10E Engine, Commanded In Flight Shut Down (IFSD) Event Due to Engine Hardware Failure
Effectivity: EMBRAER 190
The EMBRAER 190 fleet has recently experienced a commanded engine IFSD during the takeoff phase.
It was reported that there is a loud noise just after the landing gears are commanded to the up position and the ITT from engine number two reached approximately 1100°C.
The flight crew elected to shut the engine down and decided to return to departure airport. A controlled approach was performed with no emergency declaration and without any incident or injuries.
After landing, an engine visual inspection was performed and no signs of FOD were observed.
The N1 shaft was locked and metal debris were found in the engine exhaust area. The VSV system was inspected and no damage or any discrepancy was reported.
As part of the maintenance action, a borescope inspection was performed and internal damage in the HPT was found. A complete borescope inspection was not possible because some access ports were stuck. The engine was removed and sent to engine shop for repair and root cause investigation.
Initial Investigation shows HPT blade airfoil separation as the primary cause for IFSD. The root cause is still unknown and investigation is in progress. No action in the field is recommended at this moment.
Metal debris on exhaust area
Metal debris on exhaust area
HPT area, Internal damages
HPT area, Internal damages
Issue No. 20 July 2008
Page 8
APU Troubleshooting
Effectivity: EMBRAER 170 / 190
In order to achieve better APU system troubleshooting capabilities, EMBRAER and Hamilton Sundstrand have developed the APU FADEC Software Version 3.0, APU FADEC Hardware Version 3.0 and the Electronic Starter Controller Version 2 (ESC 2).
The new functionalities include fault modeling logic changes as well as new hardware for closed-loop monitoring of the Brushless Starter Generator (BSG) and the Fuel Module.
As other support tools for APU troubleshooting, EMBRAER will issue an SNL with preventive maintenance recommendations.
Additionally, the FIM tasks have been revised to include the FADEC 3.0 SW fault isolation logic and to align the troubleshooting procedures to the reported field fixes of the faults.
Catalytic Oxidation of Carbon Brakes due to Runway De-icing (RDI) Fluids
Effectivity: EMBRAER 170 / 190
On March 13th, 2008, EASA issued a Safety Information Notice (SIN) 2008-19 concerning the Catalytic Oxidation of Carbon Brakes due to Runway De-icing (RDI) Fluids.
FAA issued an equivalent document on June 06th, 2008: Special Airworthiness Information Bulletin (SAIB) NM-08-27.
The intention is to advise registered owners and operators of Transport Category Airplanes equipped with carbon brakes and operated to/ from airports where RDI fluids are used, that the use of carbon brakes in aircraft since the 1980s and the concurrent switch to more environmental friendly organic salt RDI fluids have led to a concern that is possibly safety-related, and that corrective actions may impose additional costs.
These Notice/ Bulletins were issued for information only.
Nevertheless, upon performance of scheduled maintenance of the landing gear wheels, it was recommended to carry out a detailed visual inspection of the wheel carbon heat pack for obvious damage, distortion, missing elements or corrosion. Complete information can be found at:
• EASA SIN 2008-19:
http://www.easa.eu.int/ws_prod/c/c_sin.php
• FAA SAIB NM-08-27:
http://rgl.faa.gov
Brake carbon disk failures due to catalytic oxidation are in fact one issue that has particularly affected EMBRAER 170. However, the EMBRAER 190 is also subject to the same condition. During EOC USA 2008, the update regarding this issue was informed as shown below:
Interim Solution
• MABS SB 90000583-32-04 recommends inspection at each tire change after 1000 cycles brake life, not exceeding 1400 cycles;
• Improved anti-oxidation coating for the brake pressure plate
Final Solution
• New anti-oxidation coating for all disks
Implementation Plan
• EMBRAER 170:
• Pressure plate coating already implemented by brake PN 90000583-2
• All disks coating: Dec/2008
• EMBRAER 190:
• Pressure plate coating to be implemented in Nov/2008
• All disks coating: Jan/2009
• Implementation FOC on attrition
Issue No. 20 July 2008
Page 9
MFS PCU/ FCM/ YOKE LVDT SNSR Correlated With “FLT CTRL NO DISPATCH”
Effectivity: EMBRAER 170 / 190
EMBRAER received some field reports from operators concerning the occurrence of FLT CTRL NO DISPATCH messages with the following associated maintenance messages on the CMC at the same time:
• L MID MFS PCU/FCM4/YOKE LVDT SNSR
• L INBD MFS PCU/FCM3/YOKE LVDT SNSR
• L OUTBD MFS PCU/FCM1/YOKE LVDT SNSR
• R MID MFS PCU/FCM4/YOKE LVDT SNSR
• R INBD MFS PCU/FCM3/YOKE LVDT SNSR
• R OUTBD MFS PCU/FCM1/YOKE LVDT SNSR
This scenario happens when the aircraft equipped with Load 19 is in flight with Calibrated Air Speed (CAS) near 180 knots and Speed Brake handle off of the "stowed" position, thus the Spoiler Command Response Monitor is simultaneously triggered on FCM 1, 3 and 4. It is important to note that CAS 180 knots is the minimum speed for Speed Brake actuation.
The Spoiler Command Response Monitor may have been triggered due to a small difference on the airspeed calculated by FCM lanes A and B while CAS was near 180 knots. This difference could cause only one lane to disable the Speed Brake command to its MFS PCU. Whenever this occurs, the “SPDBRK LEVER DISAG” message must be triggered on the CMC.
The extracted FHDB (some columns were hidden) shows an example of described scenario:
INHIBITED SPDBRK LEVER DISAGACTIVE FLT CTRL NO DISPATCHACTIVE FLT CTRL NO DISPATCH L MID MFS PCU/FCM4/YOKE LVDT SNSRACTIVE FLT CTRL NO DISPATCH L INBD MFS PCU/FCM3/YOKE LVDT SNSRACTIVE FLT CTRL NO DISPATCH L OUTBD MFS PCU/FCM1/YOKE LVDT SNSRACTIVE FLT CTRL NO DISPATCH R MID MFS PCU/FCM4/YOKE LVDT SNSRACTIVE FLT CTRL NO DISPATCH R INBD MFS PCU/FCM3/YOKE LVDT SNSRACTIVE FLT CTRL NO DISPATCH R OUTBD MFS PCU/FCM1/YOKE LVDT SNSR
This issue was fixed on Load 21 through the modification of Speed Brake interlocks condition logic.
IDG Disconnect Procedure
Effectivity: EMBRAER 170 / 190
EMBRAER Operations Team has issued FOL 170-2008-028, informing about DDPM revision regarding the procedure used to disconnect the IDG when the aircraft is dispatched with an IDG inoperative (For operators under authority certification that allows one IDG on MEL).
The dispatch with one IDG (MEL item 24-21-01 Engine Driven Generator) inoperative requires that this IDG be disconnected before the release of the airplane. The following procedure must be followed for the correct disconnection of the affected IDG on ground:
Issue No. 20 July 2008
Page 10
For operators under TCCA authority certification, the AMM/RMM will be revised to show the procedure above. It will be made available in the next schedule revision (July/08 footer date).
Acronyms
ACP = Audio Control Panel
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
BSG = Brushless Starter Generator
CAS = Crew Alerting System
CMC = Central Maintenance Computer
CMM = Component Maintenance Manual
DLS = Data Load System
EDP = Engine-Driven Pump
EICAS = Engine Indicating and Crew Alerting System
EIPC = Engine Illustrated Parts Catalog
EMM = Engine Maintenance Manual
ESC = Electronic Starter Controller
FADEC = Full Authority Digital Electronic Control
FCM = Flight Controls Module
FGCS = Flight Guidance Control System
FHDB = Fault History Database
FIM = Fault Isolation Manual
FOL = Flight Operations Letter
HPT = High Pressure Turbine
HS-ACE = Horizontal Stabilizer Actuator
Control Electronics
IDG = Integrated Drive Generator
ITT = Interstage Turbine Temperature
IFSD = In-Flight Shut down
LDI = Loadable Diagnostic Information
LRU = Line Replaceable Unit
LVDT = Linear Variable Differential-Transducer
MFS = Multi-function Spoiler
MLG = Main Landing Gear
MMEL = Master Minimum Equipment List
OB = Operational Bulletins
PCU = Power Control Unit
PN = Part Number
SB = Service Bulletin
SN = Serial Number
SNSR = Sensor
SNL = Service Newsletter
TR = Thrust Reverser
T/S = Troubleshooting
VSV = Variable Stator Vane
Note: All abbreviations used in EMBRAER Maintenance Manuals can be found in the Introduction to AMM Part II.