Precisely so the real question is why have malaysian Airlines not released maintenance records for 9M-MRO?

Was MH370 still fitted with low pressure oxygen hoses part numbers 57034-81220, 57034-81320, or 57034-91100?

Boeing Alert Service Bulletin 777-35A0027 Revision 1, dated April 19, 2012 requires replacement of low pressure oxygen hoses with non conductive low pressure hoses located in the flight deck within 18 months.

The original hose looks like this with an anti-kink spring embedded in the plastic.



Boeing Tests of used hoses found that often at either end engineers had spliced hoses into couplings with severed spring wire able to connect electrically to the rest of the aircraft through the coupling itself. In cases where this happened the hose in effect became like an electric bar heater. Findings of tests indicated when exposed to 28VAC at 5amps and temperatures over 604-620 degrees F the hose would rupture.

Those conditions might not occur for months of normal operation but in the event of electrical shorting or surges the amperage would rise sharply along with the temperature of the hose.