b737 engineering continuation trainingcbt.altitudeglobal.aero/files/b737 q1 2012.pdf · for...

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B737

ENGINEERING

CONTINUATION TRAINING

DATED: Jan 2012

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FOR REFERENCE ONLY

Contents

1 SAFAIR PROCEDURES REVIEW ................................................................................................. 3

2 TECHNICAL LOG REVIEW OF SECTOR RECORD PAGES (SRP) AUTHORIZED BY ALT ENGINEERS . 3

3 SIRS TRENDS ............................................................................................................................ 3

4 B737 MOR LISTING FOR 2011/2012 ......................................................................................... 3

5 MEDA INVESTIGATION SUMMARY .......................................................................................... 4

6 MEDA TRENDING .................................................................................................................... 4

7 B737 TECHNICAL NOTES REVIEW ............................................................................................. 4

8 B737 AIRWORTHINESS DIRECTIVES ......................................................................................... 5

9 B737 MODIFICATIONS ............................................................................................................. 5

10 B737 SYSTEM REVIEW ............................................................................................................. 5

11 SAFAIR ALL WEATHER OPERATIONS ........................................................................................ 5

12 SAFAIR RVSM OPERATIONS ..................................................................................................... 5

13 ESDS ........................................................................................................................................ 6

14 ATTACHMENT 1 – MOR LISTING .............................................................................................. 6

15 ATTACHMENT 2 – ADDITIONAL INFORMATION ..................................................................... 11

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1 Safair Procedures Review For clear and precise instructions on how SAFAIR require their Technical Logs to be completed, refer to the following: SAFAIR CAME.

2 Technical Log Review of Sector Record Pages (SRP) Authorized by ALT Engineers

No SRP data as yet: From February 2010, the ALT library has been doing a 100% sample of all the documentation received. It can be seen in which month so far and which line station is responsible for the highest discrepancies. Information gathered shows no trend between new or long serving ALT engineers, meaning that these errors are made by all. More detail can be found in the Part 145 Continuation Training. Remember to tick the CDCCL blocks, when CDCCL maintenance tasks are done.

3 SIRS TRENDS Please see Part 145 Continuation for further details, including a graph representing all of the SIRS on the Maintenance Error Management System file (MEMS).

4 B737 MOR Listing for 2011/2012 Current MOR’s outstanding for the B737 – see Attachment 1 hereto.

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FOR REFERENCE ONLY

5 MEDA Investigation Summary All aircraft types: 2006: 2 MEDA Investigations 2007: 2 MEDA Investigations 2008: 1 MEDA Investigations 2009: 8 MEDA Investigations 2010: 11 MEDA Investigations 2011: 5 MEDA Investigations B737: 2012: None reported at this time.

6 MEDA Trending

7 B737 Technical Notes Review Below is a listing of all recently issued Safair Technical notes for the B737. The list runs from earliest date to the last one being the most recent Technical Note received. No B737 Technical Notes as yet.

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FOR REFERENCE ONLY

8 B737 Airworthiness Directives Below is a listing of FAA & EASA Ad’s issued in 2011. AD No. Description

US-2011-24-12 Fuselage - Chem-Milled Steps - Ispection / Repair / Modification

2011-0223 Hydraulic Power – Main Cargo Door (MCD) Hydraulic System & Control Panel – Modification Doors – MCD & Surround Structure – Replacement / Modification

US-2011-23-05 Fuselage - Frame and Frame Reinforcement - Inspections, Repair, Optional Terminating Action

9 B737 Modifications No new MOD’S at this time.

10 B737 System Review No system review this quarter.

11 Safair All Weather Operations Check SAFAIR CAME if applicable.

12 Safair RVSM Operations Check SAFAIR CAME if applicable.

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13 ESDS ALT Engineers are reminded to take all precautions when handling Static Sensitive equipment. Always keep the item in its protective static packaging and only remove the item when you are grounded to the aircraft, using the static strap found in the aircraft. The removed equipment must be placed into the protective static packaging before you remove the static strap, and leave the aircraft. ALT Line Station Procedures give further information on this topic. THIS SUBJECT WILL ALSO BE COVERED IN MORE DETAIL IN THE EWIS COURSE

14 Attachment 1 – MOR Listing Type: B737 Location: Bologna Occ Num: 201114222 Series: 400 Reporter: BA Date: 09 Nov 2011 Engine: CFM 56 Repref: 879864 Flt Phase: Landing Regn: G-DOCW Operator: BA Status: Closed On Receipt Classification : Occurrences Events : A/c Maintenance NR2 engine thrust reverser locked out due to fault. When reverse selected it was discovered that reverse thrust not available on NR1 engine either. Firm use of manual brakes bought a/c to a stop. On inspection of C/B panel it was discovered that the C/B for the wrong engine had been pulled resulting in both engines having no reverse thrust. Inspection of panel revealed that the thrust reverser C/Bs are not labelled LH/ RH or nr1/nr2

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Type: B737 Location: Nottingham East Midlands Occ Num: 201114239 Series: 500 Reporter: bmibaby Date: 15 Nov 2011 Engine: CFM 56 Repref: O2695-11 Flt Phase: Maintenance Regn: G-BVZE Operator: bmibaby Status: Closed On Receipt Classification : Occurrences Events : A/c Maintenance

A/c Technical Occurrence Nr2 engine thrust reversers system locked out incorrectly. A/c had maintenance carried out before flight where the reverser system had been locked out iaw AMM. On arrival the system was to be reinstated, however the links and locking pins in the module were found not to have been fitted. Type: B737 Location: Nottingham East Midlands Occ Num: 201114196 Series: 300 Reporter: bmibaby Date: 15 Nov 2011 Engine: CFM 56 Repref: 02675-11 Flt Phase: Parked Regn: G-TOYH Operator: bmibaby Status: Closed On Receipt Classification : Occurrences Events : A/c Equipment / System Malfunction

A/c Maintenance MEL maintenance items not carried out.

A/c received after first flight of the day. Carried forward defect for generator nr2 inoperative, ref MEL 24-1-A. Maintenance actions not carried out with drive still connected and bulbs still in.

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FOR REFERENCE ONLY

Type: B737 Location: Belfast (BEL) Occ Num: 201114185 Series: 300 Reporter: Jet2.com Date: 10 Nov 2011 Engine: CFM 56 Repref: 01717-11 Flt Phase: Parked Regn: G-CELY Operator: Jet2.com Ltd Status: Closed On Receipt Classification : Occurrences Events : A/c Maintenance Rudder flange bolt inspection Airworthiness Directive cycle limit over ran by 31 cycles. Airworthiness Directive AD2003-26-01. Task accomplished with no findings. Type: B737 Location: Belgrade Occ Num: 201114064 Series: 300 Reporter: Jet2.com Date: 09 Nov 2011 Engine: CFM 56 Repref: 01706-11 Flt Phase: Maintenance Regn: G-CELS Operator: Jet2.com Status: Closed On Receipt Classification : Occurrences Events : A/c Maintenance Post maintenance acceptance check found all PSUs dropped down, lanyards broken, four PA system speakers damaged and a total of 19 oxygen hoses showing signs of rodent damage.

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Type: B737 Location: Prestwick Occ Num: 201114485 Series: n/k Reporter: Maint Org Date: 18 Nov 2011 Engine: UNKNOWN Repref: PAML-009-11 Flt Phase: Not Applicable Regn: EI-DCJ Operator: Ryanair Status: Closed On Receipt Classification : Occurrences Events : A/c Maintenance Lower Anti-collision light cable harness assembly found chafed to the core. During C Check, the lower anti-collision light assembly was found fitted the wrong way round. This caused the cable loom to be routed incorrectly, rubbing on the structure and damaging the cable. Type: B737 Location: Luton (LUT) Occ Num: 201113657 Series: 300 Reporter: Thomson Airways Date: 31 Oct 2011 Engine: CFM 56 Repref: O3372-11 Flt Phase: Not Applicable Regn: G-THOO Operator: Thomson Airways Status: Closed On Receipt Classification : Occurrences Events : A/c Maintenance Engine fire bottle squibs not electronically tracked. During maintenance to replace engine fire bottle squibs, it was discovered that the squibs found fitted were not as specified and were overdue for replacement. Arrangements made for replacements.

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Type: B737 Location: Faro Occ Num: 201108219 Series: 300 Reporter: Thomson Airways Date: 17 Jul 2011 Engine: CFM 56 Repref: 01839-11 Flt Phase: Initial Climb Regn: G-THOP Operator: Thomson Airways Status: Closed Classification : Occurrences Events : A/c Maintenance

A/c Structure Failure / Malfunction Leak from L5 (Eyebrow) window replacement panel.

A leak was evident from the L5 window replacement panel in the climb. The level of noise generated at FL360 was intense and at times affected flight deck communication. The pressurisation was checked and confirmed to be normal. The flight continued. This case has been going on for considerably longer than this event. Reporter feels the retro-fit of the panel to the eyebrow windows has not been well designed. Apart from getting rained on during approach, several pressure leaks before this have occurred. There is also a possibility that the leak has allowed water ingress and the onset of corrosion. CAA Closure: The root cause of this occurrence is that not enough sealant was applied to the surface or edge of the pre-installed gasket as required by the engineering order during installation of the blank. The organisation believe this to be a single defect and not a technical issue. Type: B737 Location: Edinburgh (EDI) Occ Num: 201014537 Series: 300 Reporter: Titan Airways Date: 09 Nov 2010 Engine: CFM 56 Repref: 11-0303 Flt Phase: Maintenance Regn: G-ZAPV Operator: Titan Airways Status: Closed Classification : Occurrences Events : A/c Maintenance

Defective flight deck window supplied. CAA Closure: Third party maintenance provider organised to replace nr1 RH

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FOR REFERENCE ONLY

window. Over a three day period the engineering company attempted to install the window but during pressure test it would leak. On investigation it was found that the window did not have a seal installed for mating the surface window to airframe. A replacement window sourced and fitted. Operator audited third party maintenance company due to time taken for task to be carried out. Further audit carried out by CAA to verify issues raised by operator. No issues were identified.

15 Attachment 2 – Additional Information This section includes some information taken from My Boeing Fleet which we hope will be of interest. In some cases, the specific subjects may not be applicable to cargo aircraft. However, it is an indication of what is in the pipeline for the future.

SERVICE LETTER Commercial Aviation Services

CUSTOMER SUPPORT ENGINEERING BOEING COMMERCIAL AIRPLANES P.O. BOX 3707 SEATTLE WASHINGTON 98124-2207

BOEING PROPRIETARY

737-SL-78-030-B ATA: 7831B20

21 December 2011 SUBJECT: THRUST REVERSER BLOCKER DOOR HINGE COMPONENT

MODEL: 737-300 to -500

APPLICABILITY: All 737-300 to -500 Airplanes

REFERENCES: a) Maintenance Manual 78-31-06

b) Illustrated Parts Catalog 78-31-07

c) Component Maintenance Manual 78-31-23

EXPORT COMPLIANCE STATEMENT:

Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 730-774). An export license may be required before it is used for development, production, or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws.

ECCN: 9E991

SUMMARY:

The purpose of this service letter is to notify operators of the availability of an improved thrust reverser blocker door anti-rotation bracket (clip) P/N 315A1500-25 that has been created to resolve damage problems caused by the current design 315A1500-10 and similar previous design anti-rotation brackets (clips).

BACKGROUND:

Operator inspections of installed thrust reverser assemblies disclosed worn blocker door hinge joints on numerous in–service airplanes. Boeing investigation determined that the blocker door hinge component wear resulted from the rotation of the hinge bolt on the unclamped (floating) hinge installation.

737-SL-78-030-B

21 December 2011 Page 2 of 3

Export Controlled ECCN: 9E991 BOEING PROPRIETARY

Boeing implemented a design change which added an anti–rotation clip, P/N 315A1500–539, to the hinge bolt on the floating hinge installation. Additionally, the hinge clevis sleeve bushings on both hinge installations were replaced with Karon–coated bushings, P/N KJB247004B, for improved hinge joint wear life. These improvements have been incorporated in production on airplanes Line Position 2527 and on. Line Position 2527 was delivered in September 1993.

After introduction of the anti–rotation clip, reports from operators and Boeing experience revealed that the tabs on the clip can be deformed or broken during installation. The design of the rotation clip was revised (clip, P/N 315A1500–539, was replaced by clip, P/N 315A1500–10) to delete the tab which had contacted the bolt head. In addition, the installation of the bolt and nut through the blocker door was reversed to improve tool access and reduce damage to the clip during installation. These improvements were incorporated on airplanes Line Position 2764 and on. Line Position 2764 was delivered in September 1995.

BOEING ACTION:

Boeing has designed and released a new anti-rotation clip P/N 315A1500-25 that will not contact the bull nose fairing.

The references a), b) and c) manuals will be revised to include the new clip and installation orientation. This information will be included in each of the next revisions.

SUGGESTED OPERATOR ACTION:

Boeing recommends that operators procure the new hinge bolt anti-rotation bracket P/N 315A1500-25 for installation during future blocker door maintenance activity. Once released, follow the revised installation procedure in the AMM for installation of the new anti-rotation bracket. Boeing wishes to note that the direction of the bolt is reversed from its original orientation.

WARRANTY INFORMATION:

Boeing warranty remedies are not available for the subjects discussed in this service letter.

INTERCHANGEABILITY:

315A1500, to show P/N 315A1500-25 is a one way replacement for P/N 315A1500-10 and P/N 315A1500-23.

PARTS AVAILABILITY:

The improved anti-rotation bracket is available through normal Boeing spares channels.

737-SL-78-030-B



GDS:cmm

Original: Dated: 30 September 1993. Revision A: Dated: 10 May 1999. Revised to include new anti-rotation clip P/N 315A1500-

10. Revision B: Revised to include new anti-rotation clip P/N 315A1500-25. Attachment I: Blocker Door Orientation with Old Anti-Rotation Clip Attachment II: New Anti-Rotation Clip Installation

THIS PAGE IS LEFT INTENTIONALLY BLANK

BOEING PROPRIETARY

ATTACHMENT I To: 737-SL-78-030-B


BOEING PROPRIETARY

Blocker Door Orientation with Old Anti-Rotation Clip

THIS PAGE LEFT BLANK INTENTIONALLY BLANK

BOEING PROPRIETARY

ATTACHMENT II To: 737-SL-78-030-B


NOTE: The direction of the bolt is reversed from its original orientation in View C.

315A1500-25 Anti-Rotation Clip Installation


FLEET SUPPORT ENGINEERING BOEING COMMERCIAL AIRPLANES P.O. BOX 3707 SEATTLE WASHINGTON 98124-2207

BOEING PROPRIETARY

737-SL-32-057-C ATA: 3210-40

23 November 2011 SUBJECT: MAIN LANDING GEAR LOWER TORSION LINK FRACTURES

MODEL: 737-100/-200/-300/-400/-500 (737CL)

APPLICABILITY: All 737-100/-200/-300/-400/-500 Airplanes

REFERENCES: a) Maintenance Manual 32-11-00/ 601, Torsional Free Play Inspection

b) Maintenance Manual 32-11-81/501, Main Gear Damper Adjustment

c) Maintenance Manual 32-11-51/601, MLG Torsion Links-Inspection/Check

d) 737-100/-200 Maintenance Planning Data (MPD), D6-17594

e) 737-300/-400/-500 Maintenance Planning Data (MPD), D6-38278

f) Maintenance Manual 32-11-81/401, Main Gear Damper Installation



ECCN: 9E991

SUMMARY:

Boeing occasionally receives reports of broken torsion links and damaged shimmy damper pistons on 737 Classic airplanes. These events have been attributed to excessive wear or looseness in the main landing gear torsion link apex joint. This looseness can make the shimmy damper ineffective and can allow for a shimmy event to occur.

This service letter is provided to advise operators of recommended maintenance practices to prevent main landing gear torsion link and shimmy damper piston fractures.

737-SL-32-057-C

23 November 2011 Page 2 of 4


Revision C of this service letter recommends bleeding the dampers periodically to remove air from the system that can reduce the effectiveness of the damper.

BACKGROUND:

The shimmy damper is installed at the main landing gear torsion link apex joint and is intended to hydraulically damp out resonant oscillations in the gear that could otherwise lead to a shimmy event. Periodic adjustments are required to compensate for normal wear and prevent excessive looseness in the apex joint.

Operators have reported numerous main landing gear shimmy events and torsion link fractures on model 737CL airplanes. Typically, the torsion link fractures by ductile overload across the larger of the two lightening holes. In some cases, the shimmy damper piston also fractures.

An investigation of several fractures determined that excessive play was present at the torsion link apex joint, rendering the shimmy dampers ineffective. In some other cases, the investigation determined that the shimmy event was caused by insufficient bleeding of the damper after the damper or the landing gear was installed. Air within the damper will reduce the damper’s effectiveness. Loss of proper damping resulted in torsion link loads in excess of design, followed by ductile fracture.

The upper and lower torsion link lugs on the inner and outer cylinders and their attach points are also subject to wear on the bushing inner diameters and flanges faces. Regularly scheduled maintenance is necessary to ensure that the torsion link joints remain within serviceable wear limits, and that the reference a) torsional free play is within limits.

BOEING ACTION:

The reference a) maintenance manual provides instructions for main landing gear torsional free play inspection. Adjustment of the shimmy damper and the torsion link apex joint is necessary prior to performing the torsional free play inspection.

The reference b) maintenance manual provides instructions for the adjustment of the torsion link apex joint and shimmy damper.

The reference c) maintenance manual provides wear limits for the interface of the thrust washers and the spherical shaped bushings common to the lower torsion link apex lug. After tightening the apex nut, the minimum allowable distance across the outer faces of the thrust washers is 2.700 inches. A dimension less than 2.700 inches indicates the bushings and thrust washers need replacement. Wear on the non-spherical side of the thrust washers also occurs and is not accounted for in the face to face measurement of the installed spherical washers. Periodic disassembly of the joint should be performed in order to fully inspect these washers and to look for unusual wear on the damper piston rod. See Figures 1 and 2.

737-SL-32-057-C



The reference d) and e) MPD documents recommend a functional check of MLG torsional free play at specified intervals. However operators may benefit from performing these checks on a more frequent basis.

The reference f) maintenance manual provides a procedure for bleeding air out of the damper assembly.


To reduce the likelihood of a main landing gear shimmy event, Boeing recommends the following steps which are in addition to the tasks currently specified in the MPD’s:

1) Adjust the main landing gear torsion link apex joint per the reference b) maintenance manual at frequent intervals, such as at each C-check or annually.

2) After adjusting the apex joint per item 1) above, measure across the faces of the thrust washers. If a dimension of less than 2.700 inches is obtained, there is excessive wear and the joint should be disassembled. Any worn parts should be replaced.

3) Disassemble the apex joint and examine the spherical cup washers, the damper piston, and the spherical bushings in the torsion link for wear at frequent intervals, such as every 2C-check. Figures 1 and 2 show common areas of wear. Any measurable wear at these locations is cause for replacement of parts.

4) Bleed any air entrained in the hydraulic fluid or trapped within the damper at frequent intervals, such as every C-check, per the reference f) maintenance manual.

Some operators have initiated a program where the torsion links, shimmy damper and associated hardware are replaced at scheduled intervals, such as each C-check or a 2-C check. Other operators may wish to consider this practice to help prevent unscheduled maintenance and/or shimmy events.

ESTIMATED LABOR HOURS:

An estimated 1 labor hour is required for each landing gear to adjust the torsion link apex joint and measure across the faces of the thrust washers. If the torsion link apex joint requires disassembly, an additional estimated 1.5 labor hours is required per joint to examine and replace worn parts. An estimated 0.5 labor hour is required to bleed each damper.


Boeing warranty remedies are not available for the subjects discussed in this service letter.

737-SL-32-057-C



RDL:cmm

Original: Dated: 5 July 1994. Revision A: Dated: 18 September 2006. Updated several sections of the service letter to

reflect current status. Revision B: Dated: 27 April 2011. Clarify recommended actions. Add Figures 1 and 2. Revision C: Added recommendation to bleed dampers per AMM Attachment: Figure 1: Shimmy Damper Piston – Example of excessive wear at the location

common to Spherical Thrust Washer, due to incorrect adjustment of the Apex Joint, and Figure 2: Examples of wear on the non-spherical side of the Thrust Washers

Attachment I To: 737-SL-32-057-C


BOEING PROPRIETARY

FIGURE 1

SHIMMY DAMPER PISTON – EXAMPLE OF EXCESSIVE WEAR AT THE LOCATION COMMON TO SPHERICAL THRUST WASHER, DUE TO INCORRECT ADJUSTMENT OF

THE APEX JOINT

Attachment I To: 737-SL-32-057-C



FIGURE 2

EXAMPLES OF WEAR ON THE NON-SPHERICAL SIDE OF THE THRUST WASHERS



BOEING PROPRIETARY

737-SL-32-177-A ATA: 3209-00

11 January 2012 SUBJECT: INSTALLATION OF TITANIUM PROXIMITY SENSOR P/N 80-207-

01 ON WING LEADING EDGE AND LANDING GEAR MODEL: 737-100 through -500

APPLICABILITY: All 737-100 through -500 airplanes

REFERENCES: a) IPC 27-88 (737-300/400/500) and IPC 27-80 (737-100/200) Leading

Edge Flap and Slat Position Indicating b) IPC 32-09 Landing Gear Safety Sensors

c) IPC 32-61 Landing Gear Position Indicating and Warning System



ECCN: 9E991

SUMMARY:

The purpose of this service letter is to inform operators regarding availability of an improved proximity sensor P/N 80-207-01 which may replace the current 1-899-15, -26 and -29 sensors at selected locations. Typical locations per reference a), b) and c) IPC chapters and Tables 1 and 2.

P/N 80-207-01 is built on a Titanium enclosure with a sealed wire entry to prevent moisture ingress which may lead to corrosion of internal components. The new sensor may be used in all Leading Edge and Landing Gear positions (except uplock) subject to new installation requirements to protect against potential corrosion due to dissimilar metals effects.

BACKGROUND:

Review of operator reports reveal numerous schedule interruptions traced to discrepant P/N 1-

737-SL-32-177-A

11 January 2012 Page 2 of 3


899-29 proximity sensors. Attempts to improve the performance by means of minor improvements in the design have not yielded significant improvement in removal rates. As a result, a new sensor design was developed which focused on providing a sealed enclosure to prevent the ingress of moisture and contaminants and to improve component manufacturability.

DISCUSSION:

The new sensor is Boeing P/N 10-61226-45 (CRANE/ELDEC P/N 80-207-01) which may replace the 10-61226-15, -26 and -29 (CRANE/ELDEC 1-899-15, -26 and -29) sensors at locations listed in Tables 1 and 2. For corrosion protection, CRES washers are required in locations where the washer is in direct contact with the sensor as identified in Figure 2. Further, wet installation of fasteners is required with BMS 3-28 sealant. In addition, sensor installation requires faying surface seal with BMS5-95 sealant. The process is similar to that outlined per SWPM 20-20-00.

Door sensors, airstair lock pin sensor and MLG uplock sensor will not accommodate the new -45 design due to interference with the wire entry barrel at those locations.

Differences between the -15, -26 and -29 sensors and the -45 sensors include dimensional and material changes. The use of a titanium case has driven the need for specific installation requirements to prevent corrosion of the mating surfaces due to dissimilar metals effects.

The titanium sensor also requires use of an environmental sealant on mating surfaces to prevent corrosion.

BOEING ACTION:

Boeing and Crane/ELDEC have completed the design and certification of the P/N 10-61226-45 Crane/ELDEC P/N 80-207-01 solid Titanium (Ti) encased proximity sensor.

Boeing will modify the AMM installation instructions to account for each location’s specific requirements as discussed in this Service Letter. This includes AIR/GND and Landing Gear Indication ATA chapters 32-09 and 32-61 and LE Flap/Slat Status ATA chapter 27-88 (27-80 for 737-100/-200).


Operators may wish to replace the -15, -26 or -29 sensor with the new -45.

Sensor replacement should be accomplished per AMM procedures. Components required for the installation are summarized in attachments to this SL for convenience. Figures “1” and “2” illustrate the installation of the various components for each sensor location on Landing Gears and on Leading Edge Slats and Flaps. The typical installation and component location is

737-SL-32-177-A



illustrated in Figures “1” and “2” as follows:

Figure 1: Titanium Proximity Sensor 80-207-01 Figure 2: Typical Ti Sensor Installation Table 1: Landing Gear Locations Table 2: Flap and Slat Locations


Approximately 2.75 labor hours is required per sensor to replace and test an existing sensor with the new 80-207-01 titanium sensor.


Boeing warranty remedies are not available for the actions suggested given in this service letter.

INTERCHANGEABILITY:

P/N 80-207-01 is two-way interchangeable with P/N 1-899-29 subject to installation hardware and process requirements, as discussed above in the “DISCUSSION” section.

CMC / EICAS MESSAGE (S):

N/A

SCE:cmm

Original: Dated: 28 April 2011. Revision To add locations in Table 2 for 737-100/-200 that were omitted in the original

release. Attachment: Figures Illustrating the Installation and Tables detailing the Components required

for installation at each location.

THIS PAGE INTENTIONALLY LEFT BLANK.

BOEING PROPRIETARY

ATTACHMENT To: 737-SL-32-177-A


BOEING PROPRIETARY

Figure 1. Titanium Proximity Sensor 80-207-01

ATTACHMENT To: 737-SL-32-177-A 11 January 2012

Page 2 of 2


Figure 2. Typical Installation/ Component Arrangement

Titanium Sensor

Aluminum Mounting Interface-

Structure or Bracket

Bolt- Wet Install- BMS3-38

Washer- Bolt Side

Washer- Nut Side

Lock Nut

Typical Landing Gear Ti Sensor Installation

Refer to Attached Installation Tables for Mounting Hardware Details

Fay Surface Seal- BMS5-95

Bolt thru Top Bolt thru Bottom

ATTACHMENT To: 737-SL-32-177-A


BOEING PROPRIETARY

Wire Diagram

Equip # 737-100/-200 737-300/-400/-500 AIR/GROUND Sensor Nomenclature

326401 S00071 X X

LEFT MAIN LANDING GEAR DOWNLOCK

326401 S00073 X X

RIGHT MAIN LANDING GEAR DOWNLOCK

326401 S00075 X

NOSE LANDING GEAR DOWNLOCK

326401 S00076 X

NOSE LANDING GEAR UPLOCK

323101 S00105 X X

LANDING GEAR GROUND SAFETY

323101 S00106 X X

LANDING GEAR AIR SAFETY

326401 S00301 X X

SECONDARY RIGHT LANDING GEAR DOWNLOCK

326401 S00302 X X

SECONDARY LEFT LANDING GEAR DOWNLOCK

326401 S00333 X

SECONDARY NOSE LANDING GEAR DOWNLOCK

323101 S00805 X X

NOSE GEAR AIR/GROUND PROXIMITY

326401 S00845 X

NOSE GEAR DOWN

326421 S00853 X

SECONDARY NOSE GEAR DOWN

Table 1 – Sensor Locations and Applicability – Landing Gear Locations

ATTACHMENT To: 737-SL-32-177-A 11 January 2012

Page 2 of 2


Wire Diagram

Equip # 737-100/-200 737-300/-400/-500 AIR/GROUND Sensor Nomenclature

278111 S00162 X X WING LEADING EDGE SLAT 1 FULL EXTEND

278111 S00163 X X WING LEADING EDGE SLAT 1 EXTEND

278111 S00164 X WING LEADING EDGE SLAT 2 FULL EXTEND

278111 S00165 X WING LEADING EDGE SLAT 2 EXTEND



278111 S00168 X X WING LEADING EDGE FLAP 1 RETRACT

278111 S00169 X X WING LEADING EDGE FLAP 1 EXTEND









278112 S00178 X WING LEADING EDGE SLAT 5 FULL EXTEND

278112 S00179 X WING LEADING EDGE SLAT 5 EXTEND



NOTE: For -200 non-advanced: Slats 2,3,4,5 extend sensor not applicable. For -100 non-advanced: Slats 3 & 4 extend sensor not applicable.

Table 2 – Sensor Locations and Applicability – Flap and Slat Locations


FLEET SUPPORT ENGINEERING BOEING COMMERCIAL AIRPLANES P.O. BOX 3707 SEATTLE WASHINGTON 98124-2207

737-SL-32-121-C

ATA: 3231-10 4 October 2011

SUBJECT: LANDING GEAR CONTROL LEVER IMPROVEMENTS

MODEL: 737-100 through -900

APPLICABILITY: -All 737-100 through -500 airplanes line number 1 through 3132.

-All 737-600 through -900 airplanes line number 1 through 3099 (Airplane line number 3099 was delivered in November 2009).

REFERENCES: a) 737 OHM 32-34-02 (For 737-100 through -500 levers)

b) 737 OHM 32-34-08 (For 737-100 through -500 levers)

c) 737 OHM 32-34-37 (For 737-600 through -900 levers)

d) 737 AMM 32-31-11/401

e) SRP 737NG-32-0164

f) Service Bulletin 737-32-1422

SUMMARY:

Various operators have reported experiencing intermittent illumination of the green and red landing gear indication lights during landing gear extension. These problems are often traced to high friction or binding in the landing gear control lever slide mechanism or faulty lever position switches. This service letter informs operators of lever assembly improvements and maintenance actions that can help eliminate these occasional lever problems.

Revision B to this service letter clarifies recommendations for cleaning and lubricating the landing gear control lever assembly.

Revision C to this service letter provides information about another cause of landing gear lever problems that can be addressed by implementation of a Boeing service bulletin.

BACKGROUND:

Some operators have indicated that when the landing gear control lever is moved to the DOWN position, the red and green landing gear indication lights illuminate simultaneously. Troubleshooting has shown that the problem is often due to:

737-SL-32-121-C

4 October 2011 Page 2 of 4

1) High friction in the lever slide mechanism, or 2) Faulty position switches in the lever assembly, or 3) Landing lever control aft quadrant bottoming out before the gear lever reaches the down

position.

The high friction causes the lever to stay in the extended (pulled) position when it is moved to the DOWN detent. Ultimately, this prevents the handle from actuating the electrical position switches in the lever housing that extinguishes the red lights.

To lower the friction in the lever, some operators lubricate the sliding surfaces of the control lever. However, experience shows that the higher friction condition can re-occur if the lubrication becomes contaminated with dust or other debris.

In an effort to permanently resolve the problem, operators may wish to disassemble the lever assemblies and slightly increase the diametrical clearance between the lever slide tube and the bushings in the mating lever components. Increasing the clearance between these parts significantly reduces the friction when the lever is extended or pulled as described above.

Boeing also discovered that there is a possibility that the aft quadrant of the landing gear control system on 737-600 through -900ER airplanes may bottom out (hit its stop) prior to the landing gear lever reaching the bottom of the DOWN detent in the lever module. This can occur under adverse tolerance conditions or if the cable system is out-of-rig. If this bottom-out condition occurs, the landing gear selector valve will be in the down position to extend the landing gears (causing the green lights operate normally and come on) but the landing gear lever may not easily drop into the detent, thereby not actuating the gear lever down switch (causing the red lights to stay on). The reference e) Service Related Problem (SRP) was initiated to resolve the problem of the aft quadrant hitting its stop when the gear lever is down

BOEING ACTION:

Boeing has revised the reference a) and c) overhaul manuals to allow the following modifications to the landing gear lever assemblies:

1. Allow the optional use of P/N 257T1111-4 bushings in place of bushings P/N BACB10D165. The new bushings have a slightly smaller inside diameter to facilitate a line-reaming process.

2. Add a requirement to line-ream the inside diameter of the P/N 257T1111-4 and/or P/N BACB10D165 bushings to 0.7925/0.7935 inches diameter. The line-ream requirement and the larger bore size decrease the possibility of bushing misalignment and the amount of friction at the bushing-lever slide interface.

737-SL-32-121-C


For 737-600 through -900ER airplanes line number 1282 and subsequent, the lever assembly part number was changed from 273A3301-6 to 273A3301-8 in production. The new part number incorporates the above noted changes and several other minor design improvements. These two lever assembly part numbers are interchangeable on all 737-600 through -900ER airplanes. A Boeing service bulletin was not issued to provide retrofit instructions to incorporate all of the new design changes into the 273A3301-6 lever assembly, therefore it is not possible to completely modify the older part number to the new part number.

To resolve the problem of the aft quadrant hitting its stop when the gear lever is down, Boeing changed the pitch diameter of the aft cable quadrant from 4.0 inches to 4.2 inches to improve system overtravel when the landing gear lever is in the down position. This change prevents the quadrant from contacting its stop before the landing gear lever is in the fully down position. This change was incorporated into production at airplane line number 3100, which was delivered in November, 2009. Boeing issued the reference f) service bulletin to provide inspection and retrofit instructions for airplane line numbers 3099 and earlier.


For operators experiencing landing gear extension and retraction indication problems, we suggest the following actions:

1) Verify that the position switches in the lever assembly are correctly installed and adjusted [see Figure 502 in reference a) OHM or Figure 101 in the reference c) OHM]. The switches should actuate before the lever reaches the bottom of the detent. An incorrectly installed or marginally adjusted switch could also result in similar landing gear indication problems.

2) Ensure that the position switches in the lever assembly are functioning correctly. Since switch operation can be intermittent, consider replacing the switches whenever the lever assembly is out of the airplane for repair/overhaul.

3) At a convenient maintenance or overhaul opportunity, disassemble the lever assembly and line-ream (or hone) the lever drum/crank bushing bores to 0.7925/0.7935 inches [see Figure 3 in the reference a) OHM or Figure 601 in the reference c) OHM]. Optionally, operators can install new P/N 257T1111-4 bushings prior to the line-ream (or hone) step. These bushings have a slightly smaller inner diameter to facilitate the line-ream process.

4) On all 737 lever assemblies, we recommend that operators clean the sliding surfaces of the lever slide mechanism periodically since dirt and debris are likely to increase friction in the lever. Operators can clean the lever sliding mechanism with electrical contact cleaner. Approved electrical contact cleaners are listed in the Standard Wiring Practices Manual (SWPM) 20-60-01. These cleaners include isopropyl alcohol and methyl alcohol. Getting this product in a spray container is preferred since it is more likely to penetrate into the close

737-SL-32-121-C


tolerance clearance area of the sliding elements of the landing gear lever. Move the lever in and out while applying the cleaner for better penetration. Limited access to clean the sliding portion of the lever assembly is available through the cockpit fascia panel.

5) On affected 737-600 through -900ER airplanes, perform the inspection specified in the reference f) service bulletin and if needed, replace the aft control quadrant.

While lubricating the lever may temporarily solve a friction problem, Boeing does not generally recommend lubricating the lever components while it is installed in the airplane for two reasons: First, the excessive lubrication tends to accumulate dust and dirt which will eventually increases friction. Second, the lubrication can drip or spray onto electrical components and/or the lever latch solenoid mechanisms which can lead to other lever malfunctions. Instead, Boeing recommends cleaning the sliding surfaces as noted above if it is not convenient to remove the lever assembly from the airplane.


We estimate that it will take approximately 2.0 labor hours to accomplish the bushing modifications once the landing gear lever is removed from the airplane.

Please refer to reference f) Boeing Service Bulletin for the estimated labor to inspect and/or replace the aft control quadrant.


Boeing warranty remedies are not available for suggested operator actions 1) through 4) discussed in this service letter.

Boeing Industry Support Information for suggested operator action 5) is provided in the reference f) Boeing Service Bulletin.

RDL:cmm Original: Dated: 7 April 2003 Revision A: Dated: 6 October 2005. Changed lubrication recommendation and

added cleaning recommendation Revision B: Dated: 17 January 2008. Clarified lubrication recommendations,

improved text in several areas and deleted unnecessary attachment Revision C: Added information regarding SRP 737NG-32-0164.

MAINTENANCE TIP Commercial Aviation Services


BOEING PROPRIETARY

737 MT 46-017 757 MT 46-015747-400 MT 46-015 767 MT 46-015

747-8 MT 46-007 777 MT 46-031787 MT 46-008

19 January 2012

SUBJECT ELECTRONIC FLIGHT BAG (EFB) – FREQUENT ‘WINDOWS OR ADC FAILURE’ FAULTS

APPLICABILITY All Airplanes Equipped with Boeing Class 3 EFBs

REFERENCES a) AMM Tasks for EFB Software Crossload (See Attachment) b) AMM Tasks for EFB Windows Reimage (See Attachment)

CONDITION Boeing recommends that maintenance personnel follow the recommended action provided in this maintenance tip when the flight crew submits a maintenance log write up similar to the following examples:

EFB IS UNSERVICEABLE

EFB APPLICATIONS UNSERVICEABLE

EFB WINDOWS APPLICATIONS UNSERVICEABLE

RECOMMENDED ACTION

The estimated time required for maintenance personnel familiar with EFB maintenance to perform the steps in this maintenance tip is provided in the following table. In most cases, it is not required to complete all of these steps to resolve the intermittent WINDOWS OR ADC FAILURE faults.

DESCRIPTION STEP NUMBERS

ESTIMATED COMPLETION

TIME

COMMENTS

Review EFB Fault Log for WINDOWS or ADC FAILURE events

1 and 2a 2 minutes

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747-400 MT 46-015 767 MT 46-015747-8 MT 46-007 777 MT 46-031

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Page 2 of 5


DESCRIPTION STEP NUMBERS

ESTIMATED COMPLETION

TIME

COMMENTS

RESTART Windows

2b 10 Minutes Only required if Steps 1 and 2a indicate an isolated WINDOWS OR ADC FAILURE condition.

Reinstall Windows OS and DELETE TEMP

3 through 5 25 Minutes Only required if Steps 1 and 2 indicate an intermittent WINDOWS OR ADC FAILURE condition. May be deferred to a convenient maintenance period.

Reimage Windows 6 45 Minutes Only required if performing Steps 3 through 5 does not resolve the issue after returning the EU to service. May be deferred to a convenient maintenance period.

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1. Determine if the reported condition is due to a WINDOWS OR ADC FAILURE fault.

a) From the EFB MAIN MENU page, navigate to the FAULT LOG page (SYSTEM PAGE->EFB MAINTENANCE->FAULT LOG).

b) If a WINDOWS OR ADC FAILURE event is recorded in the fault log at a time that could correspond to the flight crew reported EFB issue, continue to Step 2. If not, this maintenance tip does not apply. Note any EFB faults that correspond with the flight crew report and refer to the Fault Isolation Manual for further guidance.

2. Review the FAULT LOG to determine if additional WINDOWS OR ADC FAILURE faults are logged within the last 30 days.

a) If additional WINDOWS OR ADC FAILURE faults are logged, proceed to Step 3.

b) If not, the WINDOWS OR ADC FAILURE is an isolated fault. In this case, RESTART the EU from the SYSTEM page. All of the EFB Windows applications should complete their startup (all application buttons on the EFB MAIN MENU appear gray) within 10 minutes and the EU can be returned to service.

3. Reinstall the WinOS software by crossloading the WinOS software from the offside EFB per Aircraft Maintenance Manual Task identified in Ref /A/. During this step, execute Step 4 below before exiting LOAD MODE on the target EFB.

Note: The WinOS software part number will have one of the following part number formats:

BFBXX-W2KT-XXXX, or

ACZXX-8241-XXXX

4. Perform a DELETE TEMP operation on the target EFB.

a) From the LOAD MODE page, select DISK UTILITIES.

b) Select DELETE TEMP and then select CONFIRM.

5. When the DELETE TEMP operation is completed, the DISK UTILITIES page will be displayed. Select the ‘Back’ function key on the EFB Display Unit and then select REBOOT TO

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MAIN. Once the EU completed its startup (all application buttons on the EFB MAIN MENU appear gray), the EU can be returned to service.

6. If an EU continues to exhibit intermittent WINDOWS OR ADC FAILURE faults after performing Steps 4 and 5 and returning the EU to service, Boeing recommends that the operator REIMAGE WINDOWS on the EU, per Aircraft Maintenance Manual Task identified in reference b). Once the EU is reimaged, it is recommended that the Windows software be restored by performing a crossload from the offside EU, per Aircraft Maintenance Manual Task identified in reference a).

BACKGROUND Due to a WINDOWS OR ADC FAILURE fault, flight crews may encounter a condition where all of the EFB Windows application buttons on the MENU page are displayed with a black background and cyan border and text. An amber FAULT is displayed on the top left hand of the EFB Display Unit, and the fault message APPLICATION FAILURE is displayed on the SYSTEM page. As a result, flight crews may submit a log write-up indicating that the EFB or the EFB Windows applications are unserviceable.

In some cases, the use of the RESTART function temporarily corrects the condition, but WINDOWS OR ADC FAILURE events persist after the EU is returned to service.

MAINTENANCE MANUAL ACTION

The applicable FIM task will be revised in the next available revision.

CMC / EICAS MESSAGE

N/A

EXPORT COMPLIANCE STATEMENT


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SAH: pjp

Attachment: AMM Tasks for EFB Software Crossload and AMM Tasks for EFB Windows

Reimage.

ATTACHMENT To:

737 MT 46-017 757 MT 46-015747-400 MT 46-015 767 MT 46-015

747-8 MT 46-007 777 MT 46-031 787 MT 46-008



AMM Tasks for EFB Software Crossload:

AMM Task Name Major Model AMM Task Number

Electronic Unit - Crossload Software Installation 777 46-11-03-470-801





Crossload EU Software 767 46-11-02-472-023

Electronic Flight Bag Crossload - Software Installation

787 DMC-B787-A-46-11-07

AMM Tasks for EFB Windows Reimage

AMM Task Name Major Model AMM Task Number

Reimage Windows Partition 777 46-11-03-470-804

EFB - Re-image the Windows Partition 737 46-11-00-470-802

EFB - Re-image the Windows Partition 747 46-11-00-470-802

EFB Windows Partition Reimage 747 46-11-00-470-802

Re-image the Windows Partition 757 46-11-00-472-005

Re-image the Windows Partition 767 46-11-00-472-026

Reimage the Windows Partition - Software Operation

787 DMC-B787-A-46-11-07

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