Dear TSB, an inquiry for your experts.....
My interest is in Deflagration to Detonation Transition (DDT) in
an oxygen-enriched atmosphere in a confined space (such as a sealed
flight deck). The question becomes whether or not it is possible for the
colourless/odourless oxygen concentration (stemming from an undetected
leak) to reach trigger levels for DDT despite the aircon swap-out rate
within a sealed flight deck
at cruise
altitude - with the ignition being provided by wiring faults
(such as arcing of windshield heating terminals). The wild card in this
equation would of course be the rate at which flight crew supplementary
oxygen was leaking into the flight-deck and
(similar to Carbon Monoxide poisoning), causing an undetectable
elevation towards the oxygen enrichment levels required for DDT
(believed to be approx 87%)..
This was
earlier postulated as a possible premise for the MH370 accident and the
later MS804 (Egyptair A320) (see the main document and menu
at https://bit.ly/2J1mR8U or
http://tinyurl.com/or9bzf2
)
An EXEC SUMMARY (never updated) is at
http://tinyurl.com/gqpnwcn
A recent development is the French BEA's finding that Egyptair's Flight
MS804 was downed by a flight-deck fire.... and the reluctance of Egypt
to fully conduct a competent wreckage recovery and accident
examination/investigation. (see link #27 below)
^^^^^^^^^^^^^^^^^^^^^
Scenario for
MH370
would be ignition (wiring flaw
or windscreen heater terminal sparking proximate to a flexible oxygen LP
line or hose) creating a weak point in the close adjacent fuselage
(think focused oxygen lance).....
or just look again at
this image. Remember that
oxygen doesn't burn, the
oxygen outflow just intensely supports combustion and adds to the
ever-rising oxygen enrichment level.
Once oxygen enrichment from the leak reached the trigger level of 87%,
and a DDT occurred, the DDT's overpressure would be reinforced by the
existing cabin pressure differential and cause a flight-deck holing to
atmosphere (at that weakened point) and
consequential explosive decompression of the entire fuselage.... and an
extinction of the fire.
##############################################################################
26. The Oil-Rig Worker's Sighting (valid or invalid?) => link
|
|
|
Windshield Heating Terminal arcing |
27. French BEA Finding is that a Cockpit fire quickly took down A320 Flt MS804 in the Mediterranean => link
28. An Inquiry into Deflagration to Detonation Explosions (to TSB of Canada) => link
______________________________________________________________________
Relevant TSB Links
http://www.tc.gc.ca/eng/canutec/articles-confined-456.htm
Confined Space hazards
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The main concern with oxygen concentrations above 23% is the possibility
that materials which would normally not ignite at normal oxygen levels,
would be prone to combustion. Oxygen-rich atmospheres may be found in
tanks that previously contained oxidizing compounds (e.g. hydrogen
peroxide, sodium chlorate etc. ) which have decomposed, often when
heated, to release oxygen.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Service Difficulty Alert - Transport Canada
www.tc.gc.ca/eng/civilaviation/certification/continuing-alert-2009-05-184.htm
100/200/440)
All RJ aircraft with third crewmember oxygen systems installed
INSPECTION OF THIRD CREWMEMBER OXYGEN HOSE While parked at the gate,
following the application of ground power, a CL-600-2B19 model CRJ-200
aircraft suffered a fire in the vicinity of the JB1 junction box
assembly. The fire was fed by oxygen from a breach of the third
crewmember oxygen
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
www.tc.gc.ca/eng/tdg/newsletter-menu-spring2011-1112.htm
May 13, 2011 ... that lead to the inadvertent loading of the chemical
oxygen generators in the cargo hold. A fire ensued, engulfing
combustible materials nearby, and was proliferated by the generation of
oxygen gas. The aircraft crashed in the Florida Everglades and everyone
on board perished. Measures had not been in place or communicated to
ensure that air operator personnel
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Ignition Sources
While conducting the 1200 hour inspection of the R/H windshield, "the
Anti Static Coating" on the G200 was found unserviceable and did not
meet the specifications required in the manufacturer’s maintenance
manual. The windshield required replacement and upon removal found that,
one of the power cables arced to the aircraft’s structure due to poor
insulation on the terminal end. The windshield and terminal end of the
power cable were replaced.
Transport Canada Comments:
The operator ensured that the adequate clearance between the terminals
and aircraft structure was obtained.
DHC 8 100 series
SDR # 20090604007
____________________________________________________________
Relevant Links
Links below from menu at
http://tinyurl.com/or9bzf2 (
https://bit.ly/2J1mR8U )
Link #16
http://www.iasa-intl.com/folders/mh370/BusinessAustralian.htm#theTheoryPreface
Link #17 (a and b)
https://en.wikipedia.org/wiki/EgyptAir_Flight_804
http://tinyurl.com/kwpo8ao
Link#24
http://www.iasa-intl.com/folders/mh370/BusinessAustralian.htm#DDTdescriptor
Link #25
http://www.iasa-intl.com/folders/mh370/YouJustNeverKnow.docx
Link #27
http://www.iasa-intl.com/folders/mh370/MS804cause_FrenchBEA.htm
***********************************************************************
Comments above passed to:
canutec@tc.gc.ca
http://www.tc.gc.ca/eng/canutec/contact-438.htm
as an inquiry for feasibility as a scenario for Flts MH370 and MS804