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Supporting technical information A98H0003

In-flight entertainment network (IFEN) – Wreckage examination

8 AWG wire

Main power supply wire

None of the recovered segments of the 8 AWG wire exhibited heat or fire damage.

The following wire segments were recovered:

The average measured length of the 8 AWG main power supply cable assembly from terminal strip S3-600 to the CBs installed in the lower avionics CB panel was 488 cm (192 inches). The average measured length from terminal strip S3-674 to the CBs installed in the left-hand mid-equipment CB panel was 97 cm (38 inches). Based on these measurements, 86.5% of the white wire, 84.3% of the orange wire, and 85.6% of the red wire were recovered.

Jumper wire

None of the recovered 8 AWG jumper wire segments exhibited heat or fire damage. The following segments of the orange, white, and red jumper wires were recovered:

Orange
White
Red

12 AWG wire

Identified wire exhibiting heat or fire damage

Lower avionics CB panel to E-Rack 1 location

The following recovered segments were identified as power supply cables for PSU 1, PSU 2, PSU 3, and PSU 4:

The average measured length of the power supply cable assembly from the lower avionics CB panel to E-rack 1 was 1 090 cm (429 inches). The overall length of the identified recovered cable assembly is approximately 102 cm (40 inches) or 9.4%.

Lower avionics CB panel to E-Rack 2 location

The following recovered segment was identified as the power supply cable assembly for PSU 3 and PSU 4:

Identified wire without heat or fire damage

Lower avionics CB panel to E-Rack 1 location

The following recovered segments were identified as the power supply cable assembly for PSU 1 and PSU 2:

The average measured length of the power supply cable assembly from the lower avionics CB panel to E-rack 1 was 1 090 cm (429 inches). The overall length of the identified recovered cable assembly was approximately 8 cm (3 inches) or 0.7%. As the wire segment attached to the plug on the EMI filter box was located within E-rack 1, it was not included in the overall recovered length calculation.

Lower avionics CB panel to E-Rack 2 location

The following recovered segments were identified as the power supply cable assembly for PSU 3 and PSU 4:

The average measured length of the power supply cable assembly from the lower avionics CB panel to E-rack 2 was 3 876 cm (1 526 inches). The overall length of the identified recovered cable assembly was approximately 1 181 cm (465 inches) (including heat- or fire-damaged cable) or 30.5%. As the wire segment attached to the receptacle side of the electrical connector was located within E-rack 2, it was not included in the overall recovered length calculation.

Left-hand mid-equipment panel to E-Rack 3 location

The following recovered segments were identified as the power supply cable assembly for PSU 5 and PSU 6:

The average measured length of the power supply cable assembly from the left-hand mid-equipment panel to E-rack 3 was 2 248 cm (885 inches). The overall length of the identified recovered cable assembly was approximately 1 483 cm (584 inches) or 66%.

Unidentified wire exhibiting heat or fire damage

The following recovered segments of the power supply cable exhibited heat or fire damage:

Unidentified wire without heat or fire damage

The following recovered segments of power supply cable assembly exhibited no heat or fire damage:

Assessment of recovered PSU cable assemblies exhibiting heat or fire damage

The following total recovered lengths were calculated for each colour of PSU power cable wires:

The overall average length of PSU power cable exhibiting heat or fire damage was approximately 451 cm ((461 + 424 + 469)/3) (177.5 inches ((181 + 167 + 184.5)/3)). If all of the wires exhibiting heat or fire damage were located in the same area, then this average length of PSU power cable would fit between approximately STA 383 and STA 506. This measurement does not include the 198 cm (78 inches) of 12 AWG wire that were recovered without insulation and that could not, therefore, be identified by colour.

SDU to galley 1 MTEB cable assembly

The following recovered segments were identified as originating from the SDU to the Galley 1 MTEB cable assembly:

IFT/VES 28V CB and wiring installation

IFT/VES 28V (1 A CB)

The 16 AWG jumper wire was recovered with one end attached to a portion of the F2 CB and the other end attached to the terminal of the "IFT/VES 28V" 1 A CB. Neither the wire nor the CB portions exhibited heat or fire damage.

16 AWG wire

Four segments of tin-coated 16 AWG wire were recovered, each exhibiting an area of melted copper resulting from electrical arcing. Although no wire marking could be distinguished, there was sufficient insulation adhering to these four segments to identify them as portions of wire PN 50013-102, which was installed from the "IFT/VES 28V" 1 A CB to the Galley 8 disconnect. Two segments also had conduit material adhering to them.

These four wire segments were recovered intertwined within the same bundle of wires as the 12 AWG power supply wires that exhibited signs of electrical arcing. PN 50013-102 is the only wire of its type and size within the same area as the 12 AWG wires, located between STA 383 and STA 506.

Relay assembly and galley 8 disconnect

The following recovered components of the relay assembly and Galley 8 disconnect were identified. None exhibited heat or fire damage.

Line replaceable units

E-Rack 1 LRUs

The following recovered components did not exhibit heat or fire damage:

All of the following recovered components exhibited heat or fire damage:

E-rack 2 LRUs

The following components were recovered. None exhibited heat or fire damage.

LRUs from unidentified locations

The following recovered components did not exhibit heat or fire damage.

The following recovered component exhibited heat or fire damage:

LRU fuse testing

All fuses from recovered LRUs were inspected and determined to be in serviceable condition.