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Supporting technical information A98H0003

In-flight entertainment network (IFEN) – Review

IFEN – Review

The TSB reviewed the IFEN wiring installation on Swissair's fleet of 15 MD-11 aircraft to become familiar with the IFEN installation and how it functioned

Observations on the IFEN installation

Although the following observations are specific to the IFEN installation, discrepancies with aircraft wiring were also noted including contact between wire bundles, coiling and stowing methods that do not comply with the MD-11 WDM, clamping and fastening techniques, and protective wrapping practices.

The following observations focus on the IFEN main power supply cable, the PSU cables, and the 16 AWG wire routed to the Galley 8 disconnect panel.

HI installation practices

HI has stated that even though the company was not working in the USA, it was following the FAR 145 repair station requirements and performing installations and inspections in the same manner as it would have if the company were installing the IFEN system in the USA.

A number of observations pertaining to the installation of the IFEN system wiring appear to contradict the guidelines or "best practices" that are presented in reference documents such as the FAA ACs and the aircraft manufacturer's approved manuals, including the following examples:

Wire routing from the lower avionics CB panel to the conduit used over galley 2

The four PSU cables and the 16 AWG wire were routed rearward along the lower avionics CB panel and were attached with nylon, self-locking cable ties to the main power supply cable. This large wire bundle was then cable-tied to the DC bus bar at the lower avionics CB panel, and in some installations, was held in place by a clamp near the rear of the panel. The wire bundle was then directed upward until it separated into two smaller bundles. The main power supply cable looped downward toward a conduit along the right side of the fuselage and the four PSU cables and the 16 AWG wire continued upward as a single bundle near the avionics disconnect panel.

Table: Wire bundle installation from the lower avionics CB panel to the forward edge of the conduit
HB- Aircraft SN IFEN Install Date Conduit Wire Bundle RouteFootnote 1 Wire Support PositionFootnote 2 SleevingFootnote 3
Upper Centre Lower
IWC 48445 19 November 1996 Outboard Forward Y N U/K  
IWD 48446 19 December 1996 Outboard Forward U/K N N Between the upper and centre wire support
IWG 48452 24 January 1997 Outboard Forward U/K Y U/K  
IWO 48540 3 April 1997 Outboard Aft Y Y Y Between the upper and centre wire support
IWN 48539 14 April 1997 Outboard Aft Y Y Y  
IWE 48447 30 April 1997 Centre Aft U/K U/K U/K  
IWP 48634 5 August 1997 Centre Aft U/K Y Y  
IWA 48443 20 August 1997 Centre Forward U/K Y U/K  
IWF 48448 9 September 1997 N/A N/A N/A N/A N/A  
IWI 48454 22 October 1997 Centre Forward U/K U/K U/K Between the upper support and the conduit entrance
IWH 48453 11 November 1997 Centre Forward U/K Y U/K Between the upper and centre wire support
IWB 48444 26 November 1997 Centre Forward Y Y U/K  
IWM 48457 21 December 1997 Centre Forward Y Y U/K Between the upper and centre wire support
IWQ 48541 12 January 1998 Centre Forward U/K Y U/K  
IWK 48455 22 January 1998 Centre Forward U/K Y U/K Between the upper and centre wire support
IWL 48456 26 February 1998 Outboard Forward Y Y U/K Between the upper support and the conduit entrance

In one installation, it could not be determined whether the wire bundle was fastened to the upper wire support. If it was not fastened, then the routing was such that the bundle could have come into contact with this support.

Wire routing from the rear of the conduit to approximately STA 515

The installation of the wire bundle from where it exited the conduit to approximately STA 515 also varied between aircraft. The wire bundle was clamped to existing aircraft wire bundles where it exited the conduit. It was then routed and clamped either above or below the centre support for the R1 flapper door ramp deflector, and either above or below the wire support brackets across the forward cabin drop-ceiling. At some of the clamping locations, spacers were installed to separate the wire bundles. Some of the wire bundles also had protective sleeving installed where it passed under the centre support for the R1 flapper door ramp deflector.

Operational integration

The IFEN system was presented to cabin and flight crews (via communications materials, such as reference guides and AOM bulletins) as a system requiring very little interaction on their parts. Although the MD-11 flight crews did not receive formal training on the IFEN system, they were provided with some basic information about the system in the Swissair AOM bulletins

Swissair AOM bulletins

AOM bulletins were periodicals written and published by Swissair Operational Engineering that were used to provide information specific to technical and operational matters closely related to the volumes of the AOM. The following AOM bulletins included references to the IFEN system.

AOM bulletin 74/97

AOM Bulletin 74/97 New Inflight Entertainment System, issued on 21 February 1997, was the first bulletin to refer to the IFEN system. The purpose of the bulletin was not to describe the system in detail, "because it should not have any impact in our cockpit work," but to provide some general background information. The bulletin described an estimated weight increase of more than 1 000 kg for the complete system and stated that the only technical concern of which the flight crew should be made aware was that in the event that the system became unstable, the crew was to "pull the 28 V DC CB F-1 on [the] avionics panel" to shut the system down.

AOM bulletin 76/97

AOM Bulletin 76/97 Inflight Entertainment System, issued on 21 March 1997, noted that there had been reports of an increase in temperature in the economy class on certain HB-IWG flights.Footnote 4 The temperature increase was attributed to the IFEN system producing more heat than expected, especially with a full load of passengers. The bulletin noted that the problem was under investigation, but until a permanent solution could be developed a temporary solution could be implemented—in the event of an increase in cabin temperature, the flight crew was instructed to select the ECON switch to the OFF position, thereby producing colder air in the cabin. The flight crew was also cautioned that if this action did not succeed in lowering the cabin temperature within four hours, the IFEN system would have to be shut down.

AOM bulletin 79/97

AOM Bulletin 79/97 Inflight Entertainment System (IFEN), issued on 26 June 1997, provided additional information on the continuing problem of increased cabin temperature when the IFEN system was in use. The bulletin identified two deviations from the previously published procedures (AOM Bulletin 76/97):

  1. There were several reports that the flight crew did not switch on the IFEN system on a PBR fuel flight in order to avoid a possible ECON OFF condition.
  2. There were reports of the flight crew selecting the ECON switch to the OFF position at the beginning of the flight as a preventive measure.

This bulletin provided the following IFEN directives:

  1. When the IFEN system is technically available, it must be turned on for the duration of the flight.
  2. In the event that the high temperature in the cabin does not decrease within one hour after take-off, the ECON switch must be selected to the OFF position.
  3. If the ECON switch has been selected to the OFF position and the temperature has not decreased within four hours, the IFEN system must be shut down and an aircraft log entry must be made.
AOM Bulletin 83/98

AOM Bulletin 83/98 Parking Check, issued on 23 March 1998, stated that the instruction to pull the IFEN CB on the avionics panel had been incorporated in the Flight Parking checklist.Footnote 5 It also mentioned that the ON/OFF switch, which was to be installed on the M/C panel, would not be available until the fourth quarter of 1998. Once the switch was installed, there would no longer be a requirement to pull the CB.

The following additional procedural information was also provided:

  1. Once the flight is terminated, pull the CB and leave it in this position. This allows the system time to cool down.
  2. The next flight crew must push in the CB as part of the cockpit preparation.

It was noted that if the CB was found pushed in upon the cockpit preparation, it was to be assumed that the ground engineer had pushed it in and that, therefore, "an initial pull/push of the CB shall not be done."

AOM Bulletin 86/98

AOM Bulletin 86/98 IFE On Transit Stations, issued on 10 July 1998, discussed the "well-established" procedure of pulling the IFEN CB after the flight to reset any screens that had experienced problems during the flight. Pulling the CB resets the entire IFEN system; therefore, any movies in progress will also reset. It was determined that this procedure was undesirable during a stopover because of the difficulties it created with passengers who were using the IFEN system. Since the M/C is the only person aware of the number of passengers using the IFEN system, it was decided that "Whenever the [M/C] thinks a reset after landing will annoy too many passengers, he will report to the cockpit before the aircraft has come to a complete stop after taxi in and then we will not pull the IFE CB."

Info flash no. 6

On 29 October 1998, Swissair Operational Engineering issued Info Flash No. 6, IFEN (Interactive Flight Entertainment Network) to all Swissair pilots, which announced the decision to deactivate the IFEN system on both the MD-11s and B-747s.

Cabin crew

There was no mandatory formal training program on the IFEN system for the cabin crews.

There was no mandatory formal training program on the IFEN system for the cabin crews.

The M/C was provided with an IFEN System Quick Reference Guide, which was to be used in conjunction with the general Troubleshooting Guide. A description of the IFEN system was provided to the cabin attendants through Inflight and Directive, monthly information bulletins. Directive, which superceded Inflight, was the medium through which new instructions and procedures were provided to the cabin crew prior to having them incorporated into the applicable documents (e.g., checklists). Every flight attendant was required to read and know the directives. Additionally, the Swissair Product Centre was a venue for crew members to become familiar with new tools, services, or both, such as the IFEN system. IFT provided a mock-up of the IFEN installation that was used to demonstrate all of the available features of the installed system.

Although there were no cabin checklist procedures specific to the IFEN system, it was the cabin crew's practice to shut down the system between 10 and 20 minutes prior to landing. Activation and deactivation of the system was accomplished by using a "swipe" card at an MVD. Even with the system deactivated, the PSUs would be electrically powered as long as aircraft power was available. PSU 48 V DC output power is collectively removed from all the PSUs only by pulling the "IFT/VES 28V" 1 A CB. Complete shutdown of the IFEN PSUs requires that each 15 A CB be pulled.

IFEN quick reference guide

This guide was written to complement the Pre-, In-, and End-of-Flight check sheets. The guide provided basic information on how to prepare the system for operation, disable the games of chance at the end of the flight, and shut down the system. The guide required that the M/C report all failures on the IFEN reporting sheet and, if there was a severe problem with the system, that the M/C contact Maintenance Control. If a problem was encountered with the system and it did not automatically reboot after 15 minutes, the cabin crew was to carry out the following procedures:

  1. Disable the system.
  2. Pull the CB and wait 30 seconds.
  3. Push the CB.
  4. Wait 10 minutes before enabling the system again.

Although it was not specified, the CB to be pulled was the "IFT/VES 28V" 1 A CB, located in the lower avionics CB panel.

Inflight and directive publications

The IFEN system was first introduced in October 1996 in Swissair's Inflight publication and was described as "the world's most advanced interactive inflight system." Inflight and Directive publications that included information relating to the IFEN system are summarized below.

Inflight 10/96

The IFEN article provided an overview of what the system would provide and an initial list of aircraft that would be fitted with the system. The article identified three steps to help guide the cabin crews through the introductory phase:

  1. If the cabin crews had any questions not covered in the IFEN article overview, they were to be forwarded in writing. If the question(s) had not already been foreseen, they would be included in the general training program and they would be answered on the "Questions and Answers Wall."
  2. A training support video tape was offered to all cabin crew members.
  3. At the grand opening of the IFE Product Palace Exhibition on 6 November 1996, a display set of seats would be set up with a working IFEN system installed to provide the opportunity to browse through the whole selection of entertainment choices.
Inflight 12/96

The IFEN article announced that the first MD-11 aircraft (HB-IWD) would be operating with the new entertainment system by 25 December 1996 and provided a proposed installation schedule for the remaining MD-11s. The article also stated that information and documentation would be made available starting on 9 December 1996.

Inflight 1/97

The IFEN article stated that due to additional technical problems with the hardware and software, the introduction of the system would be postponed until 24 January 1997 and that HB-IWG would be the first aircraft in operation with the new system. A nine-minute general overview video would be made available as of 27 December 1996. An instruction manual would also be made available to the M/C and flight attendants during the opening of the exhibition, which had been postponed until 13 January 1997.

Inflight 2/97

The IFEN article stated that HB-IWG would be equipped and ready for customer use on 25 January 1997. Training was being offered at the product palace on a voluntary basis. The video would also be available for anyone to take home if they were interested in doing so. The instruction document would first be made available to the respective crews and would then be distributed to each person's post box by approximately 12 February 1997.

Inflight 4/97

The IFEN article listed some system deficiencies, including the following:

The latest system updates were made available through the Product Centre and all cabin crew personnel were invited to "Just step in—sit down. Inform yourself about the latest status."

Inflight 8/97

The IFEN article noted that some unsolved problems with the system still existed, which resulted in additional work for the cabin crews. Further software and improvements were anticipated throughout the summer that were expected to improve the system's reliability.

Inflight 9/97

The IFEN article stated that the latest software updates and corrections to the hardware had improved the system's reliability. Cabin crews were again asked to visit the Product Centre to receive the latest information and "hands-on training."

Directive 11/97

The IFEN article stated that the software update installed in mid-September had greatly improved the system's reliability. The cabin crew was advised that in the event of single-seat lock-ups, the CB could be pulled then pushed in again after 30 seconds. The cabin crew was advised to contact the cockpit crew prior to taking any action. The crew was also instructed to report all malfunctions on the IFEN troubleshooting form. The article reported that a number of customer service complaint letters had been received regarding flight attendants' lack of knowledge on certain issues. As a result, it was again recommended that they visit the Product Centre to further inform themselves about the IFEN system.

Directive 12/97

The IFEN article described new procedures relating to the IFEN system. In the event of single-screen problems, it was left to the discretion of the M/C to decide whether to disable or enable the system from the management terminal, which takes approximately five minutes. If this procedure was unsuccessful, the system would need to be rebooted in the following manner:

  1. Disable the system at the management terminal.
  2. Pull the CB. Wait 10 minutes for the hard disk drive to cool and for data to be transferred.
  3. Push in the CB.
  4. Provide maintenance with detailed reports of what was done and what did not work.
Directive 1/98

The IFEN article reminded cabin crews about the services offered by the Product Centre. It also noted that an IFT specialist would be available to answer questions every Wednesday.

Directive 4/98

The IFEN article stated that there was no technical reason not to use the IFEN system during transit stops, provided that the cabin is cooled appropriately to keep the seat electronics boxes from heating up. The cabin crew was again reminded to provide detailed information when reporting discrepancies.

Directive 5/98

This was the last Directive to mention the IFEN system. The IFEN article announced new procedures for rebooting the system:

  1. Pull the CB in the cockpit for 30 seconds only.
  2. Wait 10 minutes before enabling the system again, allowing sufficient time for data to transfer.

Maintenance personnel

All servicing and maintenance of the IFEN system was carried out by SR Technics personnel. IFT's on-site representative provided troubleshooting guidance and technical assistance as required. Servicing the IFEN system included obtaining transaction data and adding new software builds. Maintaining the system's products to the latest standards included troubleshooting and replacing the LRUs.


IFT presented a seven-day IFEN training course, starting on 2 January 1997, at their facilities in Phoenix to seven SR Technics technicians. They also provided an advanced training session at SR Technics facilities in February 1998. Seventeen SR Technics personnel, including five who had participated in the seven-day course, attended the advanced training session. Training documents included the IFEN system wiring diagrams and the IFEN MM. Certificates were issued to attendees who successfully completed each of these training programs. IFT also provided on-the-job training during each installation and throughout the year on an ongoing basis.

IFT issued the Supplemental Training and Information document on 1 January 1998. It was intended for use by individuals already familiar with the IFEN system and focused on providing a more in-depth understanding of the following items:

Although HI was not responsible for supplying any formal training, they did provide SR Technics personnel with some basic on-the-job instructions during the IFEN installations.

IFEN maintenance manual

IFT produced the IFEN MM using HI engineering data, including electrical drawings produced in CAD format. It was IFT's responsibility to ensure that HI technical documents were consistent with IFT's specifications and documentation.

The purpose of the manual was to define basic maintenance procedures and practices for maintenance personnel working on the IFEN system. The procedures enabled maintenance personnel to quickly inspect the IFEN system and included procedures for inspecting selected IFEN components, performing certain post-flight checks, reporting failures to IFT or its representatives, performing periodic preventive maintenance, and returning failed components to IFT. The manual was not intended to provide in-depth system- or component-level maintenance. All component-level maintenance was to be performed by IFT.

The Swissair IFEN MM, Rev B, issued on 2 September 1997, identified HB-IWF (the occurrence aircraft) as an MD-11-056 aircraft equipped with 12 first-class and 49 business-class seats. The MD-11-056 designation was used to reference applicable documentation.