Aviation Investigation Report A98H0003

IFEN – Installation

  1. IFEN Installation
  2. Technical Documentation Requirements
    1. HI Drawings
  3. SR Technics QA
  4. CB Installation
    1. Lower Avionics CB Panel
      1. CB Unit 1
      2. CB Unit 2
    2. Left-Hand Mid-equipment Panel
  5. IFEN Wiring
    1. Contract Specifications
    2. FAR 25.1353 Specification
    3. Military Specifications for Wire
    4. McDonnell Douglas Wiring Guidelines
    5. Power Cable Design Specifications
  6. IFEN Installation Observations
    1. Installation of the Main Power Cable and PSU CBs – Lower Avionics CB Panel
      1. Discrepancies
    2. Installation of the 8 AWG Jumper Wires – Lower Avionics CB Panel
      1. Discrepancies
    3. Installation of the PSU Cable – CBs to E-Rack 1
      1. Discrepancies
    4. Installation of the PSU Cable – CBs to E-Rack 2
      1. Discrepancies
    5. Installation of the Main Power Cable – Left-Hand Mid-equipment Panel
      1. Discrepancies
    6. Installation of the 8 AWG Jumper Wires – Left-Hand Mid-equipment Panel
      1. Discrepancies
    7. Installation of the "IFT/VES 28V" 1 A CB and Wiring
      1. Discrepancies
    8. Wiring Installation – SDU to Galley 1 MTEB
      1. Discrepancies
    9. HI EO Observations
  7. STC Inspection Requirement
    1. Conformity Inspection
    2. Compliance Inspection
    3. SBA Conformity/Compliance Inspections

IFEN Installation

All IFEN installation work was accomplished by HI personnel at SR Technics' facilities in Zurich, Switzerland. HI personnel responsible for the installation included an on-site supervisor, a chief inspector, and three working groups. The structures group was responsible for installing the E-racks and other structural items, the cabin group was responsible for installing the cabling, and the electrical group was responsible for assisting with technical problems during the modification and system testing. It was HI's practice to employ contract employees to perform the majority of the installation work and to assign permanent employees to provide QA oversight. HI has indicated that, for the most part, the installation team comprised the same personnel for all of the installations.

The IFEN installation was carried out under HI EO 20016-501 Rev B Interactive Flight Technologies Inc. Entertainment System on Swissair MD-11 Aircraft. This EO was applicable to the occurrence aircraft and provided instructions for the provisioning and modification of the aircraft structure, electrical systems, and interior components required to install the IFT IFEN system. This EO also identified reference materials including the HI installation kit drawings and the MD-11 MM, SRM, WDM, and the IPC. The EO did not identify the applicable revision status of the HI kit drawings or of the supporting documents.

The TSB reviewed HI drawings and various supporting documents pertaining to the installation of the IFEN system cabling and to the design and manufacture of the various power cable assemblies.

MDL 12003-501 (257 Pax) Rev D, dated 24 January 1997, was applicable to HB-IWF at the time of the IFEN system installation. This MDL referenced the following drawings and documents:

  • 20023 Rev N/C (04-18-97) Wiring Drawing (drawing marked "for reference only")
  • 20017 Rev N/C (01-21-97) System Functional Block Diagram
  • 90010 Rev B1 (01-22-97) System Circuit Breaker Installation Kit
  • 90049 Rev C2 (02-05-97) Overhead System Cable Routing Installation Kit
  • 20016 Rev N/C (01-20-97) Engineering Order/Installation Procedure
  • 20032 Rev A (01-21-97) System Electrical Load Analysis

By the time the IFEN system was installed in HB-IWF these drawings had been revised as follows:

  • 20023 Rev B (06-05-97)
  • 20017 Rev B (04-10-97)
  • 90010 Rev B (12-30-96)
  • 90049 Rev D (05-06-97)
  • 20016 Rev B (08-20-97)

It was HI's practice to use the most recent version of drawings for system installations, including the IFEN installation.

Although they were not included in the MDL, the following drawings were identified in the ELA as applicable documents for the ELA for the Swissair MD-11. The TSB determined the drawings to be pertinent to defining the IFEN system configuration.

  • 20042 Rev C (12-31-96) Schematic Circuit Breaker Unit #1
  • 20045 Rev A (12-31-96) Circuit Breaker Unit #2 Schematic

During the IFEN system installation documentation review, (STI) the TSB identified numerous discrepancies in the approved drawings and supporting documentation. SR Technics indicated that they had previously experienced difficulties troubleshooting the IFEN system because the HI wiring diagrams did not always represent the actual installation.

Many discrepancies were noted when the HI wiring diagrams were compared to the IFEN MM. IFT had obtained HI engineering information, including wiring diagrams, to develop the IFEN MM. It was IFT's responsibility to ensure that HI technical documents were consistent with IFT's specifications and documentation.

Technical Documentation Requirements

The agreement between IFT and HI, entered into on 30 July 1996, outlined the following requirements for technical documentation with which HI was required to comply:

  • Ensure the accuracy and consistency of HI technical documentation with the applicable IFT or Swissair source specifications, documents, and drawings.
  • Prepare an installation block diagram illustrating basic LRU to LRU system connections.
  • Prepare all structural, cabling, and equipment installation drawings.
  • Prepare a detailed installation work-scope, based on HI installation drawings and test documents, that provides written installation instructions sufficient to install all parts manufactured or purchased by HI and all equipment supplied by IFT. The work-scope must contain test plans to verify that the IFT IFEN system does not interfere with the existing aircraft systems.
  • Prepare a system wiring diagram illustrating the entire system wiring definition, equipment pin assignments, grounds, and so on. This drawing must specify aircraft effectivity by assigned aircraft registration numbers.
  • Prepare a system schematic diagram, showing the entire system connectivity and LRU internal functionality. This drawing must specify aircraft effectivity by assigned aircraft registration numbers.
  • Prepare a master drawing and a data list of all IFT and HI drawings and documents that affect the configuration and certification of the existing Swissair aircraft.
  • Prepare all mechanical and cabling assembly and detail drawings.
  • Create task cards for all installation activities including aircraft specifics, such as tail number, type, and so on.

HI produced task cards that provided installation information. These cards were to be used in conjunction with the STC EO. A tally sheet listing all of the task cards was used as a tracking device and a master sign-off sheet for the task cards. Once all of the task cards were completed and accounted for, HI signed off the EO and issued an FAA Form 337 to SR Technics. Each task card identified the aircraft type and registration information.

HI Drawings

The Statement of Work contained in the agreement between IFT and HI outlined the requirements for structural, cabling, and equipment installation drawings. IFT required HI to provide and prepare all structural, cabling, and equipment installation drawings as CAD electronic files using AutoCAD® 12.0, or a later version. Additionally, IFT required HI to provide the installation drawings in both electronic and paper formats.

HI's approved procedures required each drawing to undergo the following quality control review process prior to being approved and released for use:

  • The CAD operator ensures that the drawing accurately and correctly reflects the design information.
  • An independent reviewer assesses the drawing to ensure that it complies with HI's published drawing practices and to verify that the information is correct.
  • An engineer assesses the drawing.
  • The project engineer assesses the drawing.

The approval box on the first page of the drawing requires that each of these steps be signed off, including the name of each signatory and the date. These four approval boxes on the HI drawings reviewed by the TSB had been signed off and dated.

Standard CAD drawing practices allow a CAD operator to simply "cut/copy and paste" information between drawings and most other documents produced in electronic format, thereby minimizing the potential for errors when transferring information. This practice enables information to be copied from one drawing to sub-assembly drawings, installation drawings, IFEN MM figures, WDM supplements, and installation instructions.

SR Technics QA

The agreement between Swissair and SR Technics, dated September 1996, required SR Technics' QA department to inspect the installation work accomplished by HI. (STI) SR Technics performed detailed QA inspections on the first three aircraft to assess HI's work. As SR Technics became more confident in the quality of HI's work, the company relied on their normal "D check" QA procedures.

CB Installation

The HI system design specified the use of jumper wires between CBs as a means of supplying power to each adjacent CB.

CB identifications and ratings, as described below, are based on information obtained from HI drawings applicable to the MD-11 IFEN system installation.

Lower Avionics CB Panel

Each of the four installed PSUs were powered by a three-phase CB located on the lower avionics CB panel, grouped under the heading "IFE/VES, 115 VOLTS AC POWER (3ø)."

The "IFT/VES 28V" 1 A CB was located on the lower avionics panel, grouped under the heading "DC BUS." This CB provided 28 V DC power to the IFEN system relay assembly located above Galley 8. Removal or loss of this 28 V DC power caused an "On/Off" relay, located within the relay assembly, to supply a ground that disabled the output of the PSUs.

The IFEN CB placards on the lower avionics CB panel did not conform with the aircraft manufacturer's standard for CBs. According to the standard, the electrical bus (1, 2, or 3) that was the originating source of power was to be identified on the placard. The IFEN system placards did not identify the electrical bus that provided the power for the PSUs.

Table: CB Installation

CB Identification Rating (A) CB Power Source CB Panel Location
RACK1 PS1 15 Terminal Strip S3-600 (115 V AC Bus 2) F7
RACK1 PS2 15 RACK1 PS1 CB F9
RACK2 PS3 15 RACK1 PS2 CB F11
RACK2 PS4 15 RACK1 PS3 CB F13
"IFT/VES 28V" 1 SLAT CONTROL PWR B CB (28 V DC-2) F1

CB Unit 1

CB Unit 1 was mounted to the underside of E-rack 1 in Bay 1 and received 48 V DC from PSU 1 and PSU 2. The following CB identifications and ratings are based on HI Drawing 20042 Rev C.

Table: Power Supply 1

CB Identification Rating (A) CB Power Source
MOD 2 20 PSU 1
SDU 1 7.5 MOD 2 CB
SDU 5 7.5 SDU 1 CB
DAU 1 7.5 PSU 1
MOD 1 5 DAU 1 CB
SDU 4 15 MOD 1 CB
CC 1 1 SDU 4 CB
CC 2 1 CC 1 CB
CC 3 1 CC 2 CB
CC 4 1 CC 3 CB
CC 5 1 CC 4 CB
CC 6 1 CC 5 CB

The TSB identified the following discrepancies:

  • The drawing identified the SDU 1 CB as B1-7050; however, the IFEN MM identified this CB as B1-7043.
  • The drawing identified the CC 1-CC 6 CBs as 1 A; however, the IFEN MM, Figure 119 identified these CBs as 0.5 A.
  • The drawing identified the SDU 5 CB as 7.5 A; however, the IFEN MM, Figure 119 identified this CB as 15 A.
  • The drawing identified a "MOD 2 CB"; however, the IFEN MM identified a "MOD 1-2" CB.
  • The drawing identified the MOD 2 CB as 20 A; however, the IFEN MM, Figure 119 identified the MOD 1-2 CB as 5 A.

Table: Power Supply 2

CB Identification Rating (A) CB Power Source
VOD 1 20 PSU 2
SDU 3 7.5 VOD 1 CB
SDU 2 7.5 PSU 2
SDU 6 15 SDU 2 CB
SP_MOD[1] 2.5 SDU 6 CB
CFS 4 SP_MOD CB
CTIU 1 CFS CB
HDU 1 1 CTIU CB
HDU 2 1 HDU 1 CB

The TSB identified the following discrepancies:

  • The drawing identified both SDU 2 and SP_MOD CBs as B1-7043.
  • The drawing identified an "SP_MOD"; however, the IFEN MM, Figure 119 showed "14 CH MOD" and the written description stated "13-Ch MOD." HI has since verified that "SP_MOD" is the same as "13-Ch MOD."
  • The drawing identified the CTIU CB as B1-7046; however, the IFEN MM identified this CB as B1-7045.
  • The drawing identified the SDU 2 CB as B1-7043; however, the IFEN MM identified this CB as B1-7050.
  • The drawing identified B1-7045 as the "CFS" CB; however, the IFEN MM identified it as "CFS2."
  • The drawing identified the HDU 1 and HDU 2 CBs as 1 A; however, the IFEN MM, Figure 119 identified these CBs as 0.5 A.

CB Unit 2

CB Unit 2 was mounted to the underside of E-rack 2 in Bay 7 and received 48 V DC from PSU 3 and PSU 4. CB identifications and ratings are based on HI Drawing 20045 Rev A.

Table: Power Supply 3

CB Identification Rating (A) CB Power Source
MOD 1 5 PSU 3
SDU 11 15 MOD 1 CB
SDU 12 15 SDU 11 CB
SDU 9 20 PSU 3
SDU 17 5 SDU 9 CB
MOD 2 5 SDU 17 CB
NSU 3 MOD 2 CB

IFT indicated that the NSU received power from PSU 4 in accordance with Drawing 20067 Rev N/C. WDM Supplement 20023 Rev D for the IFEN system installation refers to Drawing 20067 for the CB schematic Unit 2. Although this drawing is identified as applicable only to the B747 aircraft, IFT has advised that the drawing is an accurate representation of the Product 99 configuration as installed in the occurrence aircraft. The TSB has not identified any other drawings or documentation that support the use of Drawing 20067. However, there are numerous documents that support the use of Drawing 20045 Rev A.

  • Drawing 12003-501
  • Drawing 20032 Rev A
  • Drawing 20045
  • Drawing 80008
  • IFEN MM
  • QA Final Inspection Checklist for PN 80008-101
  • FAA Form 8130-3 for the E-Rack Installation Kit
  • Drawing 90043-504
  • Drawing 20023 Rev F

An inspection of two CB Unit 2 panels removed from Swissair aircraft revealed that the wiring for the NSU CB was installed as per Drawing 20045.

The TSB identified the following discrepancies:

  • The drawing identified the SDU 9 CB as B1-7064; however, the IFEN MM identified this CB as B1-7054.
  • The drawing identifies B1-7061 as the "MOD 1" CB; however, the IFEN MM identified it as "MOD #2-1" and the IFEN MM, Figure 120 shows it as "MOD 1-2."
  • The drawing identifies B1-7066 as the "MOD 2" CB; however, the IFEN MM identified it as "MOD #2-2" and the IFEN MM, Figure 120 showed it as "MOD 2-."

Table: Power Supply 4

CB Identification Rating (A) Power Source
SDU 8 20 PSU 4
SDU 10 15 SDU 8 CB
DAU 2 7.5 PSU 4
VOD 2 20 DAU 2 CB
HDU 3 1 VOD 2 CB
HDU 4 1 HDU 3 CB
CC 8 1 HDU 4 CB
CC 9 1 CC 8 CB
CC 10 1 CC 9 CB
CC 11 1 CC 10 CB
CC 12 1 CC 11 CB

At the time of the accident, PSU 4 was installed and powered in HB-IWF, although it was not used to supply electrical power to any of the components in the 61-seat IFEN configuration.

The TSB identified the following discrepancies:

  • The drawing identified the SDU 8 CB as 20 A; however, the IFEN MM, Figure 120 identified this CB as 15 A.
  • The drawing identified the HDU 3, HDU 4, CC 8, CC 9, CC 10, CC 11, and CC 12 CBs as 1 A; however, the IFEN MM, Figure 120 identifies all of these CBs as 0.5 A.

Left-Hand Mid-equipment Panel

The left-hand mid-equipment panel was located between STA 854 and STA 896, approximately 50 inches to the left of the aircraft's centreline. The PSU 5 and PSU 6 three-phase CBs were grouped under the heading "IFT/VES 115VAC POWER RACK 3." The following CB identifications and ratings are based on HI Drawing 90010 Rev B.

Table: Left-Hand Mid-equipment Panel

CB Identification Rating (A) CB Power Source
PSU 5 15 Terminal Strip S3-674 (115 V AC)[2]
PSU 6 15 PSU 5
IFT/Printer 115 V 2 PSU 6 CB
IFT VDU 28 V 1 AISLE LIGHTS CONTROL (28 V DC)

The TSB identified the following discrepancies:

  • The drawing identified B1-7033 CB as "IFT/VDU"; however, the IFEN MM identified this CB as "VDU."
  • The WDM identified the AISLE LIGHTS CONTROL CB as B1-1065; however, the IFEN MM identified this CB as B1-1063.

IFEN Wiring

All of the IFEN cables were custom-made and supplied as part of the installation kit. The CFS, CCs, VODs, and aircraft interface units were connected to the NSU via two twisted-pair cables each. The wiring for both the BDN and the LAN was physically combined in one cable connected to the SDU. The SEB-to-SEB cabling consisted of a single daisy-chained cable that was routed in the seat track between seat groups. This cable was shielded, using both foil and braid shielding for maximum protection from EMI, and was composed of one coaxial cable (to carry broadband data), two shielded twisted-pairs (to carry LAN data), and two power conductors (to distribute power to the seat groups). The SEB-to-SEB cable was terminated in quick-disconnect shielded connectors.

Contract Specifications

The Statement of Work contained in the agreement between IFT and HI included the following wiring specifications:

  • All cabling shall be installed per FAR 25.1353 and the installation of cables and harnesses shall meet the applicable requirements of the Boeing or McDonnell Douglas documents.
  • Cabling shall be clamped every 20 to 22 inches and wherever the cable routing changes direction.
  • HI shall meet the separation requirements between IFEN system cabling and existing cabling that are heavy transmitters of electrical power.
  • Cable and harness design and assembly shall follow the guidelines of Boeing and McDonnell Douglas as applicable.
  • Cabling installation drawings shall contain the aircraft station, left or right buttock line, and waterline of each cable run and disconnect location.
  • System cabling interfaces to aircraft power and existing systems will be defined by the airline customer and will be communicated to HI.
  • Single wire used in all cables and harnesses shall meet the requirements of MIL-W-22759.[3]
  • Multiple twisted conductors used in all cables and harnesses shall meet the requirements of MIL-C-27500.
  • Coaxial wire used in cables or harnesses shall meet the requirements of MIL-C-17.

FAR 25.1353 Specification

FAR 25.1353 includes the following specifications:

  • Electrical equipment, controls, and wiring must be installed so that operation of any one unit or system of units will not adversely affect the simultaneous operation of any other electrical unit or system essential to the safe operation.
  • Cables must be grouped, routed, and spaced so that damage to essential circuits will be minimized if there are faults in heavy, current-carrying cables.

Military Specifications for Wire

MIL-W-22759 specifies the use of fluoropolymer-insulated single conductor electrical wires made with tin-, silver-, or nickel-coated conductors of copper or copper alloy as specified by the applicable specification sheet.

MIL-W-27500 covers the requirements for special purpose cables and electrical power cables including the basic wire size and type, number of wires, and shield and jacket styles, as specified.

MIL-C-17 specifies the use of flexible and semi-rigid cables with solid and semi-solid dielectric cores, with single, dual, and twin inner conductors.

McDonnell Douglas Wiring Guidelines

McDonnell Douglas wiring guidelines are described in both the MD-11 MM and the WDM.

The MD-11 MM, Chapter 20, "Standard Practices—Airframe," includes a section on electrical and electronic components. Standard practices included in this chapter include inspection, repair, installation, servicing, and test procedures, among others.

The WDM, Chapter 20, "Standard Practices," describes generic manufacturing and repair practices applicable to all MDC commercial aircraft, including how to terminate wires, how to install connectors, splices, wire harnesses, wire bundles and grounding straps, how to terminate electrical shields and ground wires, and how to install and maintain electrical and electronic conductors and termination points.

These practices are similar to the wiring guidelines described in the following FAA ACs:

  • AC 43.13-1A Acceptable Methods, Techniques, and Practices—Aircraft Inspection and Repair
  • AC 65-15A Airframe and Powerplant Mechanics Handbook

MDC also published additional wiring information, including DPS 1.834-7 Fabricating and Installing Wire Harnesses—Commercial. This proprietary manufacturing document provides extensive information relating to wire manufacturing and installation, including the following procedures:

  • Selecting the size of the plastic strap
  • Routing of wires to mod blocks
  • Grouping and routing wire
  • Using the appropriate bend radius and slack in cables
  • Protecting installed wire bundles

Because DPS 1.834-7 was proprietary, HI did not identify it as a reference document.

Power Cable Design Specifications

In accordance with contract agreements between IFT and HI, the main power supply cable was to be designed and manufactured to conform with MIL-C-27500. This specification included a requirement to use white, blue, and orange circuit identification colours. HI's Cable Assembly A/C[4] Power to Circuit Breaker drawing identified the main power supply cable as PN 60005-101, supplied by Whitmore Wire & Cable. HI Drawing 60005 Cable A/C Power required this cable to be manufactured using three M16878/5-BNL wires, extruded PTFE-insulated wires rated at 200°C, 1 000 V. The wire colours were identified as white, red, and orange. MIL-DTL-16878 included the following specifications:

  • B: Copper-coated conductor material
  • N: 8 AWG
  • L: 133 strands of wire

The wire could be either tin, silver, or nickel coated. When a material is not specified, a material can be used that will enable the insulated wire to meet the performance requirements of the specification.

In accordance with contract agreements between IFT and HI, the power cable for each of the power supplies was to be designed and manufactured to conform with MIL-C-27500. This specification included a requirement for white, blue, and orange circuit identification colours. HI's Cable Assembly Circuit Breaker to Rack Disconnect drawing identified the power cable for each of the power supplies as PN M27500A12TE3U00. MIL-C-27500 included the following information:

  • M27500: Cable specification
  • A: Identification method of cable wire and shield coverage (white, blue, orange wire)
  • 12: Conductor size (12 AWG)
  • TE: Basic wire specification (MIL-W-22759/16)
  • 3: Number of wires in cable (3)
  • U: Shield type and material (no shield)
  • 00: Jacket type (no jacket)

The cable was manufactured by twisting the three wires together and securing them with cable ties.

IFEN Installation Observations

The HI EO contained "Accomplishment Instructions" for installing the IFEN kit. Installation activities included aircraft preparation, kit installation, close-up, and return-to-service. Each activity was subdivided into specific tasks that described the required action, the parts required, and in some instances, the applicable reference documents. The mechanic or technician was to acknowledge completion of a task by signing (initialling) in the appropriate signature box adjacent to the task description. The completed tasks were to be subsequently reviewed by an approved inspector; if the inspector determined that the completed tasks were acceptable, the inspector was to sign (initial) in the signature box adjacent to the task description.

Upon fulfillment of the Accomplishment Instructions, HI prepared FAA Form 337, which confirmed that the IFT IFEN system had been installed in accordance with the applicable HI MDL. HI used FAA Form 337 to assure SR Technics that all work performed by HI was completed in accordance with the FARs and complied with the approved IFEN STC.

The STC EO section entitled "System Cable Routing Installation" contained the following "Notes":

  • Maintain adequate distance from existing wiring.
  • Ensure a minimum bend radius of 5X-cable thickness.
  • Reference standard practices AC 43.13-1A.

Installation of the Main Power Cable and PSU CBs – Lower Avionics CB Panel

Installation information for the main power supply cable and the PSU CBs located in the lower avionics CB panel included Drawings 20023 Rev B, 90049 Rev D, 90010 Rev B, and 50000 Rev C. The HI drawings included the following information:

  • The main power cable assembly, PN 50000-201, had an overall length of approximately 240 inches and contained wires WW55-9000-8WH, -8RD, and -8OR.
  • Wire WW55-9000-8WH was terminated at the "A" terminal of the B1-7025 CB.
  • Wire WW55-9000-8RD was terminated at the "B" terminal of the B1-7025 CB.
  • Wire WW55-9000-8OR was terminated at the "C" terminal of the B1-7025 CB.
  • The main power cable assembly originated at S3-600 and terminated at the B1-7025 CB.
  • The B1-7025 CB was identified as the "Rack 1 PSU1" CB.
  • The main power cable assembly was to be routed outboard from S3-600 to the right side of the fuselage then directed upward through an existing conduit that had been used for routing the 8 AWG bus feed.[5]
  • The main power cable assembly was to be clamped to existing cable runs.
  • Within the avionics compartment, the main power cable assembly was to be supported with nylon clamps in five locations and routed with existing feeder cables.

The HI EO contained the following information:

  • Locate the CB panel above the observer's station.
  • Install four 15 A CBs in each of the following positions: 7, 9, 11, and 13.
  • Route wire harness assembly 50000-201 from S3-600 at STA 380 to the newly installed 15 A CBs.
  • Terminate cable ends of wire harness assembly 50000-201 at B1-7025.

The WDM identified S3-600 as a terminal strip located in the avionics compartment at STA 380.

Discrepancies

The TSB identified the following discrepancies:

  • The installation drawings did not specify the conduit to be used.
  • The installation drawings did not define the specific routing and installation of the cable assembly from the rear of the lower avionics CB panel to the right side of the fuselage.

Installation of the 8 AWG Jumper Wires – Lower Avionics CB Panel

Installation information for the jumper wires for the 15 A power supply CBs located on the lower avionics CB panel included Drawings 20023 Rev B, 60005 Rev A, 90049 Rev D, 90010 Rev B, and 50000 Rev C. The HI drawings included the following information:

  • The PN for the jumper wires was 50000-301.
  • Cable assembly PN 50000-301 contained cable PN 60005-101 and had an overall length of approximately 54 inches.
  • Cable PN 60005-101 consisted of three twisted 8 AWG wires—white, red, and orange.
  • Wire studs were to be crimped to the cable assembly during
    installation.[6]
  • The white 8 AWG jumper wire was to be installed between corresponding "A" terminals of each of the four 15 A CBs.
  • The red 8 AWG jumper wire was to be installed between corresponding "B" terminals of each of the four 15 A CBs.
  • The orange 8 AWG jumper wire was to be installed between corresponding "C" terminals of each of the four 15 A CBs.

The HI EO contained the following information:

  • Determine the exact lengths of the 50000-301 jumper assemblies that bus the PSU 1-4 CBs.
  • Terminate the jumper assemblies as per the drawing.
  • When connecting the B1-7025 bus side, connect the 50000-201 along with the jumper assemblies.

Discrepancies

The cable assembly drawing for PN 50000-301 defined a specific length and shape (54 inches, twisted 8 AWG wires) for the jumper wire; however, the EO indicates that the exact length is to be determined upon installation. It was HI's installation practice to use a single wire for each jumper since, owing to space limitations, it was not possible to install the 54-inch, twisted cable between adjacent CBs.

Installation of the PSU Cable – CBs to E-Rack 1

Installation information for the PSU cables from the CBs in the lower avionics CB panel to E-rack 1 included Drawings 20023 Rev B, 90049 Rev D, 90010 Rev B, and 50001 Rev E. The HI drawings included the following information:

  • Cable assembly PN 50001-101 contained PSU 1 and PSU 2 cables.
  • The PSU 1 and PSU 2 cables were identified as M27500A12TE3U00.
  • The PSU 1 cable included wires WW55-9001-12WH, -12BL, and -12OR.
  • The PSU 2 cable included wires WW55-9003-12WH, -12BL, and -12OR.
  • The overall length of cable assembly PN 50001-101, from cannon plug to CB terminal lugs, was approximately 37 feet.
  • Cable assembly PN 50001-101 was routed above Galley 2, continued rearward along the upper right side of the fuselage, and terminated at E-rack 1 at "MS[7] 647.0".
  • Cable assembly PN 50001-101 originated at the line-out terminals of the B1-7025 and B1-7026 CBs and terminated at plug[8] P1-7141, which connected to receptacle[9] R5-7141 at E-rack 1.
  • Cable assemblies PN 50001-101 and PN 50001-201 (PSU 3 and PSU 4) were to be clamped together and attached to an existing wire support. The support was located aft of "MS 401.0" and between longerons L7 and L10 on the right side of the fuselage.

The HI EO contained the following information:

  • Obtain power wiring cable PN 50001-101.
  • Locate the A Zone E-rack 1A disconnect at "MS 647.0" as per the drawing.
  • Route and clamp power wires following the right-hand overhead runs to the "MS 401.0" aft cockpit wall conduits.
  • Locate harness assembly PN 50001-101 and terminate to the line side of the CBs.

The MD-11 IPC provided the various wire support PNs and their STA locations.

Discrepancies

The TSB identified the following discrepancies:

  • Drawing 20023 identifies PSU 1 cable wires as WW55-9001-12WH, -12BL, and -12OR; however, Drawing 90010 identifies these wires as WW58-9446-12WH, -12OP, and -12BL.
  • Drawing 20023 identifies PSU 2 cable wires as WW55-9003-12WH, -12OR, and -12BL; however, Drawing 90010 identifies these wires as WW58-9447-12WH, -12OR, and -12BL.

Installation of the PSU Cable – CBs to E-Rack 2

Installation information for the PSU cables from the CBs in the lower avionics CB panel to E-rack 2 included drawings 20023 Rev B, 90049 Rev D, 90010 Rev B, and 50001 Rev E. The HI drawings included the following information:

  • Cable assembly PN 50001-201 originated at the line-out terminals of the B1-7027 and B1-7028 CBs and terminated within Plug P5-7142 at E-rack 2.
  • Cable assembly PN 50001-201 contain PSU 3 and PSU 4 cables.
  • The PSU 3 and PSU 4 cables were identified as M27500A12TE3U00.
  • The overall length of cable assembly PN 50001-201, from cannon plug to CB terminal lugs, was approximately 130 feet.
  • The PSU 3 cable included wires WW56-9001-12WH, -12BL, and -12OR.
  • The PSU 4 cable included wires WW56-9003-12WH, -12BL, and -12OR.
  • Cable assembly PN 50001-201 was routed above Galley 2, continuing rearward along the upper right side of the fuselage, crossing over to the left side of the fuselage at "MS 1239.00" and continuing rearward until it terminated at E-rack 2 at "MS 1393.00".
  • Cable assemblies PN 50001-101 and 50001-201 were to be clamped together and attached to an existing wire support. The support was located aft of "MS 401.00" and between longerons L7 and L10 on the right side of the fuselage.
  • Cable assembly PN 50001-201 was to be clamped and attached to existing wire supports located at "MS 695.00," "MS 755.00," "MS 6-70.00," and "MS 1199.00" between longerons L7 and L10 on the right side of the fuselage.
  • Cable assemblies PN 50001-201 and 50001-301 were to be clamped together and attached to an existing wire support at "MS 1239.00" between longerons L7 and L10 on the right side of the fuselage.
  • Cable assembly PN 50001-201 was to cross over the crown of the fuselage at "MS 1239.00" and be clamped to the aircraft structure.
  • Cable assemblies PN 50001-201 and 50001-301 were to be clamped together and attached to an existing wire support at "MS 1239.00" between longerons L7 and L10 on the left side of the fuselage.
  • Cable assembly PN 50001-201 originated at the line-out terminals of the B1-7027 and B1-7028 CBs and terminated within Plug R5-7142.

The HI EO contained the following information:

  • Obtain power wiring cable 50001-201.
  • Locate the C Zone left-hand E-rack 2A disconnect at "MS 1473.0" as per the drawing.
  • Route and clamp the power wires following the left-hand overhead runs to "MS 1239.0".
  • At "MS 1239.0," route and clamp the wires to the right-hand overhead by crossing over the aircraft crown as per the drawing.
  • Route and clamp the wires FWD to the mid-equipment panel "MS 859.0" as per the drawing.
  • Locate harness assemblies 50001-201 and terminate to the line side of the CBs.

The MD-11 IPC provided the various wire support PNs and their STA locations.

Discrepancies

The TSB identified the following discrepancies:

  • Drawing 20023 identified PN 50001-201 terminating in R5-7142; however, Drawing 90010 identifies this cable terminating in P1-7142.
  • The wire support location "MS 6-70.00" was not clearly defined.

Installation of the Main Power Cable – Left-Hand
Mid-equipment Panel

Installation information for the main power supply cable and PSU CBs located in the left-hand mid-equipment panel included drawings 20023 Rev B, 60005 Rev A, 90049 Rev D, 90010 Rev B, and 50000 Rev C. The HI drawings included the following information:

  • The main power cable assembly, PN 50000-202, had an overall length of approximately 72 inches and contained wires WW57-9000-8WH, -8RD, and -8OR.
  • Wire WW57-9000-8WH was terminated at the "A" terminal of the B1-7029 CB.
  • Wire WW57-9000-8RD was terminated at the "B" terminal of the B1-7029 CB.
  • Wire WW57-9000-8OR was terminated at the "C" terminal of the B1-7029 CB.
  • The main power cable assembly originated at S3-674 and terminated at the B1-7029 CB.
  • The B1-7029 CB was identified as the "PSU 5" CB.

The HI EO contained the following information:

  • Locate the left-hand mid-equipment panel at approximately STA 859.0 and drill holes for CBs.
  • Install the two 15 A CBs using the new hardware provided with the kit.
  • Locate wire harness assembly 50000-201 and route it from S3-674 to the newly installed B1-7029 CB.
  • Terminate cable ends of 50000-201 at S3-674 and B1-7029 with hardware provided with the kit.
  • Connect terminal ends of S3-674 as per the drawing.

The WDM identified S3-674 as a terminal strip located in the left-hand mid-equipment panel.

Discrepancies

The HI EO identified the cable assembly as PN 50000-201; however, Drawing 90010 identifies it as PN 50000-202.

Installation of the 8 AWG Jumper Wires – Left-Hand
Mid-equipment Panel

Installation information for the jumper wires located in the left-hand mid-equipment panel included drawings 20023 Rev B, 90049 Rev D, 90010 Rev B, and 50000 Rev. The HI drawings included the following information:

  • The PN for the jumper wires was 50000-301.
  • Cable assembly PN 50000-301 contained cable PN 60005-101 and had an overall length of approximately 54 inches.
  • Cable assembly PN 50000-301 consisted of three twisted, 8 AWG wires—white, red, and orange.
  • Wire studs were to be crimped to the cable assembly during installation.
  • The white 8 AWG jumper wire was to be installed between corresponding "A" terminals of each of the two 15 A CBs.
  • The red 8 AWG jumper wire was to be installed between corresponding "B" terminals of each of the two 15 A CBs.
  • The orange 8 AWG jumper wire was to be installed between corresponding "C" terminals of each of the two 15 A CBs.

The HI EO contained the following information:

  • Locate jumper assembly 50000-301 and connect it to the bus side of B1-7029 along with cable 50000-202. Connect the opposite end of 50000-301 to B1-7025.
  • Locate and connect the 500001-301 wire assembly to the line side of B1-7029 and B1-7030 as per Drawing 90010, Sheet 5.

Discrepancies

The TSB identified the following discrepancies:

  • The EO requires the opposite end of jumper PN 50000-301 to be connected to CB B1-7025; however, this CB is located in the lower avionics CB panel (PSU 1).
  • The EO identifies PN 500001-301; however, 500001-301 is an invalid PN.
  • The EO does not state to terminate the jumper assemblies as per Drawing 50000.

Installation of the "IFT/VES 28V" 1 A CB and Wiring

Installation information for the "IFT/VES 28V" 1 A CB and the wire to the Galley 8 disconnect panel included drawings 20023 Rev B, 50013 Rev F, 90049 Rev D, and 90010 Rev B. The HI drawings included the following information:

  • Jumper cable assembly PN 50013-102 was to be installed between the line-in terminal of the existing CB B1-31 and the line-in terminal of the "IFT/VES 28V" 1 A CB.
  • PN 50013-102 had an overall length of 36 inches and was identified as a white, 16 AWG wire.
  • PN 50013-102 was a single MIL-W-22759/16-10-9, 10 AWG, white wire.
  • Wire WW56-9101-16WH originated at the line-out terminal of the "IFT/VES 28V" 1 A CB and terminated within Plug P1-7302, which connected to receptacle R5-7302 at the Galley 8 disconnect bracket.
  • Wire WW56-9101-16WH was a 16 AWG wire.
  • Wire WW56-9101-16WH originated at the "IFT/VES 28V" 1 A CB and was routed rearward along the right side of the aircraft until it crossed the aircraft crown at approximately "MS 750".
  • AC Systems to the Galley 8 disconnect cable assembly is PN 50013-101.
  • The relay assembly, PN 80010-101, was attached to a mounting plate installed on the left-hand side of the fuselage, at approximately Longeron L4 at STA 755-775.

The HI EO contained the following information:

  • Locate the cockpit CB panel above the observer's station.
  • Install the "IFT/VES 28V" 1 A CB in position 1.
  • Locate the 28 V DC wire and connect it to the line side of the "IFT/VES 28V" 1 A CB. Provide the bus to the CB in position 2 using 16 AWG wire.

The WDM identified B1-31 as the "SLAT CONTROL PWR B" CB, located at position F1.

Discrepancies

The TSB identified the following discrepancies:

  • Drawings 90010 and 20023 identified jumper wire PN 50013-102 as 16 AWG; however, Drawing 50013 identified this wire as 10 AWG wire.[10]
  • The EO instruction "Locate 28V DC wire and connect to line side of 28V DC CB" did not identify the wire.

Wiring Installation – SDU to Galley 1 MTEB

Installation information for the SDU to Galley 1 MTEB cable assembly included Drawings 20023 Rev B, 50020 Rev E, 90049 Rev D, and 90010 Rev B. The HI drawings included the following information:

  • The SDU/MTEB cable assembly was PN 50020-114.
  • Cable assembly PN 50020-114 had an overall length of approximately 1 380 inches.
  • Cable assembly PN 50020-114 originated at Galley 1 MTEB and terminated at the SDU.
  • The SDU attached to Longeron L10 at STA 1451, adjacent to E-rack 2.
  • Cable assembly PN 50020-114 was routed rearward above Galley 1, turned outboard at the rear of the forward entrance door, and continued rearward along the upper left side of the fuselage.
  • Upon exiting Galley 1, cable assembly PN 50020-114 was to be routed upward and clamped and attached to an existing wire support on the upper left side of the fuselage between longerons L7 and L10 and at Longeron L12.
  • Cable assembly PN 50020-114 was to be routed with the existing bundle from the Galley 1 MTEB to Longeron L12.
  • Cable assembly PN 50020-114 was to be clamped with three additional cable assemblies and attached to an existing wire support on the upper left side of the fuselage at "MS 755.00," Longeron L12.

The HI EO contained the following information:

  • Route the cable assy to the MTEB disconnect.

Discrepancies

The installation drawing did not show cable installation details between "MS 755.00" and the SDU.

HI EO Observations

In addition to the above-noted discrepancies, the TSB made the following observations on the HI EO:

  • The EO Accomplishment Instructions were not identified by aircraft type, registration, or SN.
  • The note to "maintain adequate distance from existing wiring" did not clearly define the separation requirements.
  • Within the EO, "System Cable Routing Installation" section, there was a specific requirement to "coil and stow cables" as per Drawing 90049. This drawing, however, included an instruction to "coil and stow cables during -511 / -521 installation," but did not specify the practice to be followed. The MD-11 MM, Chapter 20, "Standard Practices—Airframe," provided specific instructions for coiling and stowing cables based on the size of the bundle and the type of vibration (low, medium, or high) to which it will be exposed.

STC Inspection Requirement

The STC application process requires two types of inspections: conformity and compliance. SBA, as the applicant of the STC, provided an LOI, dated 19 August 1996, to the FAA. The LOI included the following statements:

Parts conformity will be conducted at Hollingsead facilities in Santa Fe Springs and IFT facilities in Phoenix, AZ.

Installation conformity inspection and compliance inspection tests and walk-through will occur at Swissair facilities in Zurich, Switzerland.

To obtain an STC, the applicant must perform the required conformity and compliance inspections. Once an STC is approved, there is no further requirement for the STC holder to perform conformity or compliance inspections. When an approved STC is subsequently incorporated, it is the aircraft owner or operator's responsibility to ensure that the incorporation conforms with the STC's documentation. Swissair relied on SR Technics to ensure that this commitment was met. SR Technics relied on the FAA Form 337 submitted by HI as proof that the STC was incorporated in accordance with the STC's approved documentation.

Conformity Inspection

The purpose of a conformity inspection is to verify that an aircraft component or modification that is to be part of an STC conforms to the specifications that have been submitted to the FAA to define the modification. These inspections require the inspector to physically compare the component or the modification to the engineering drawings and specifications and verify that the two match.

The STC applicant is required to perform a conformity inspection prior to the official FAA inspection. This requirement ensures that the parts were manufactured and installed in accordance with the most recent revision of the descriptive data, which the applicant attests by signing FAA Form 8130-9 Statement of Conformity.

The FAA delegated its responsibility for conformity inspections to SBA.

Compliance Inspection

The purpose of a compliance inspection is to verify that a particular component or modification to an existing design meets the requirements of the applicable FAR or CARs through physical inspection of the component, installation, or aircraft. These inspections are accomplished through a combination of specification review and physical inspection of the hardware.

The FAA delegated its responsibility for compliance inspections to SBA.

SBA Conformity/Compliance Inspections

SBA authorized IFT as an agent for SBA to sign FAA Form 8130-9 for parts manufactured by IFT. SBA performed the conformity inspections on the IFT-manufactured parts and completed FAA Form 8130-3 Airworthiness Approval Tag.

SBA authorized HI as an agent for SBA to sign FAA Form 8130-9 for parts manufactured by HI. SBA performed the conformity inspections on the HI-manufactured parts and completed FAA Form 8130-3 Airworthiness Approval Tag.

SBA representatives were on site at SR Technics' facilities to perform the STC conformity and compliance inspections of the IFEN installation on the prototype aircraft.


[1]    The source documentation does not define "SP_MOD."

[2]    115 V AC was supplied by the left, mid-cabin AC ground service bus.

[3]    HI used MIL-W-22759/16 wire, an extruded ETFE copolymer insulation, medium weight, tin-coated copper conductor, rated at 150°C, 600 V because it was commonly used throughout the industry and was available within their inventory.

[4]    "A/C" means aircraft.

[5]    There are five conduits installed between STA 366 and STA 374, two of which contain 8 AWG bus feeds. The forward-most conduit contained the right emergency AC Bus Phase A, B, and C wires. The second conduit contained the 8 AWG battery direct bus wire.

[6]    HI drawings identify wire terminals as "wire studs."

[7]    HI uses MS to refer to "manufacturers' station."

[8]   &nbsp"P" identifies a plug.

[9]    "R" identifies a receptacle.

[10]    HI indicated that it installed a 10 AWG wire.

Date modified :
2012-07-27