Apollo 204 Review Board Appendix D - NASA's History Office

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h:pec been or are under study as possible i!_-niiion sources. These possible c_mrces are:
('1) G"s Chronmtograph CaMe (l'nclos_'rc 5-4, Sot'rce No. 3, Coordhmt"s G-15).
(2_ Biomedical Adapter "'()ctotms" C:dml (EnCh_|||'e 5-4, Source No. 20, Coordinates E-I";_.
(3) Arcing in and under tl_e Carl,on l)io×kie and Odor ,.\b_rber Compartme'_t (Ii:nclosure
5-4.. Source No. 15 and 16, Coordinatc-_ L-11 and I.,-1.t).
(4) Wires in Channel tI {Enclosure 5-,1, Source No. 19, Coordinatc_, F-17).
(5) Wire bct_ween Inverter No. 3 and Junction Box C-15-1A-52 (Enclosure 5-4,' Source 17,
CcoFdirh_ttCs G- l,b). "
(6) DC power to Cnnnectorj-185 (Enclosure 5-,t-, Source No. 3, Coordinates G-15)•
(7) AC t>ov.'et to Suit Comprcssc_r No. 1 and No. 2 (Not located in Enclosure 5-4).
(8) Suit Biomedmal-Adapter I tarncss (Not located in Encrosure 54).
(9) Cabie t larn_s to Cabin Fans (Not located in Enclosure 5-4).
(1% Cable ttarncss 'o ECU Instz-amentation Power Supply and its mating harness.
i. A detailed study of lhe disposition of tt',e gas chromatograph cable harness and connector before
and during the fire was made (Enclosure 5-23). From observational evidence of photographic enlarge-
ments and the c0nditiou of the connector it has been ascertained that the gas chromatograph cable
did not reside on the aft bulkhead befo, e the fire started, where it was found after the fire, but was
in or near the gas chromatograph bay. Metallurgical arid spectrographic studies of the 115 VAC wires,
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nlCr_Cl
as well as laboratory cxl)ciin:cnl-s, indicates tilac tlic ntcil, iltg of the copper wire within t}_.c '-: ' slitcatl).
Was a result of external heating, which burneci away the Teflon insulation, with subsequent shorting of
115 VAC lines. The resuhs of these events caused molten copper to exude through discontinuities
in the nickel sheath• Therefore, as based upon these Findings, the has chromatograph cable harness and
connector cg.lliltOt be coP, s[clclcd as &II ignitioa source.
j. The Biomedical Adapter "Octopus" cable and connector were studied visually by microscopic
c×amination. Several are:,s were obsctxcd ti_.,tt ind!catcd possible arcing along tile twisted ,,,'ire pahs
of the cable harness. These areas we..'e replicated and submitted to electron microsccpic examination
at a magnification of "_ppioxhnate!y 5000 diameters. The photomicrog-raphs of the suspicious areas
indicated point source melting and defects in the metal surfaces produced by low cner_.%, intermittent
arcing. Based upon the degree of inching and the depth and length oi these defects it was determined
t}:a" ibis type of arcing could not raise the temperature of the Teflon to a spontaneous ignition level.
In addition, ti:e number and condition of arc spots along a length of twistect pair of wires inciicated
that the Tc.qon insulation had been burned from the cable harn_s prior to arcing. Investigation of
the shielded cable did net reveal any suggestions of arcing; therfore, it is concluded that the wiring
i:: *he "'Octopus" cable ha-'ness did not provide a primary ignition source. X-ray examination, re-
, ,'.'.:_, c, ;_::¢! conli:'luity chccl-:s of the ;'Octopv's'" cable connectors we:e ncg-_tivc and showcd no anomalic;.
k. "I hc cable harness to the ECU Instrumcl:tation sensor power supply contained botia 28VDC Bus
A .m.'l 2RV!.)C Bus B to provide redundant power." Because of the.redundancy, a short in the power
conductor.of one Bus would not be revealed by the telemetery data from these instruments. Whether
,:r :mr a short occurred cannol be determined because cf extensive destruction of the wire bundle
_,_'. .t?.e li:_erin_ fire in this area.
!:: , :,'.,-r to ;,rc_,.id,_ cla:q_v in :,5_.' !,:'_ the d-'_r:_'gcd" ::r'.'a i:'a the lower },:ft ha_',d area (-Y, +Z)
• ".:' v..l£cc:s a_Te co\or pla'e to C-iS-lY.-;2 :':id adjacent wiring, the 1)C; power cabin to connector
.i'l_5 and tile Gas Chromatograph Cable Harness, the Flight Q.ual Recorder, and the extreme left
La::d !,_tt;ons of the 'Patch and Auxiliary Electronic Ccntrol Assemblies (ECA's).
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(I1 The abraided wire and adjacent cover in front of Junction Box C-15-1A-52 was investigated
_o detennine _;hether this wire had shorted to the panel and to assess the results if arcing had
occarred.. Both _he wire and the panel were submitted to microscopic and metallurgical examination
:'_ determhae the extent of arcing and therma / profile. Microscopic cxmnination of the wire revealed
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