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Supporting technical information A98H0003

In-flight entertainment network (IFEN) – Installation

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:

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

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.

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:

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 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:

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_MODFootnote 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:

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.

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:

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:

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)Footnote 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:

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:

FAR 25.1353 specification

FAR 25.1353 includes the following specifications:

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:

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:

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/CFootnote 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:

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:

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":

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 HI EO contained the following information:

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

Discrepancies

The TSB identified the following discrepancies:

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 HI EO contained the following information:

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:

The HI EO contained the following information:

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

Discrepancies

The TSB identified the following discrepancies:

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:

The HI EO contained the following information:

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

Discrepancies

The TSB identified the following discrepancies:

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 HI EO contained the following information:

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 wWires – 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 HI EO contained the following information:

Discrepancies

The TSB identified the following discrepancies:

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:

The HI EO contained the following information:

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

Discrepancies

The TSB identified the following discrepancies:

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 HI EO contained the following information:

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:

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:

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.