The Auto-Ignition of a Saturated Oxygen level in a confined space at Cruise altitude
Heat of an external fire can build pressure in a container and cause it to rupture. Containers are equipped with a pressure relief device (aka enriching the air around it). (Exceptions may exist where authorized by DOT.) No part of the container should be subjected to a temperature higher than 125°F (52°C). Smoking, flames, and electric sparks in the presence of enriched oxygen atmospheres are a potential explosion hazard
Note:
52°C IS a VERY LOW max danger point - electrical equipment / transformers heatsinks can exceed temperatures well above 300-400°C - and locally, a lot higher. .
from the assertion in the email below:
"Further, the flash point was not affected by oxygen concentration …… "
A very designedly confusing way in which to express the obvious fact that the SU-GBP flight deck on the ramp at Cairo was open to the elements, unpressurized and unsealed.
Of course at 35,000 feet, the very opposite situation applies and a significant oxygen leak will over time reach an enrichment level of saturation that can support a DDT event, once there is a combustion source….usually an arc or spark.
In similar vein, the result of an overpressure against an oxygen blowtorch weakened hull is greatly enhanced by the cabin pressurization force already acting upon the hull. At cruise height it’s like pricking an inflated balloon (whereas on the ramp, it’s like pointlessly pricking a deflated balloon).
NASA is the authority on auto-ignition temperatures and these certainly do depend upon the environmentals (oxygen enrichment levels, cabin pressure (very dry air), uniform mixing due airflows and a very confined space).
As soon as the oxygen blowtorch weakened hull experiences the overpressure of a DDT at cruise height and blows out, the aircraft instantly depressurizes and the DDT event is very quickly over, past and finished, thus limiting the peripheral damage to systems – …. i.e. the fire is totally out and the airplane can fly on, courtesy of multiple levels of redundancy and a very sophisticated flight control system that not only has multiple levels of redundancy, but also supplies instantaneous rectifying responses to any accelerometer detected divergences. i.e. within reason, but obviously flight into very turbulent air or Cumulo-nimbus will always induce an “upset” of some magnitude (but self-rectified once out of the cloud build-up and back in smoother air on a necessarily different heading). The ITCZ explains why this happened North of the Equator’s equatorial band and didn’t happen on its southerly tracking) Why? Because the ITCZ reaches its seasonal Northern-most latitudinal travel in the month of March.
As I’ve said before, the scenario is not unlike an electrical short in a vapour-filled fuel-tank, except that the explosive power of a highly-combustible fuel vapour is very much in contrast with the combustion-supporting role (only) of non-flammable oxygen at an enrichment level of (or approaching) ”saturation”.
Feel free to forward this explanation on to Bert. (and include the link to my MH370 causation theory )
http://www.iasa-intl.com/folders/mh370/An_MH370_Analysis-of-Likelihoods.htm or https://bit.ly/2J1mR8U or http://tinyurl.com/or9bzf2
see also: http://www.iasa-intl.com/folders/mh370/Its_a_Ripley's.htm
Regds
John S
From:
JOHN KING <john.king19@comcast.net>
Sent: Wednesday, January 22, 2020 2:27 AM
To: John Sampson <phoebus@iinet.net.au>
Subject: AIT lower ?
Thanks for the new URL.
Notice on page 65 (bottom of page), it says "Further, the flash point was not affected by oxygen concentration …… "
Bert Werjefelt (Visionsafe) said his Lab reported the same - 'auto ignition temperatures (AITs) are not changed by oxygen concentrations'.
The opposite was claimed in the VJ Final Report and repeated in a FOIA to me back then.
Does your MH370 scenario presume this ?
JK
--
On January 20, 2020 at 9:14 PM John Sampson <phoebus@iinet.net.au> wrote:
JK
SU-GBP (Flt MS667) Report is downloadable from:
https://www.baaa-acro.com/sites/default/files/import/uploads/2013/11/SU-GBP.pdf
JS
From:
John Sampson <phoebus@iinet.net.au>
Sent: Tuesday, January 21, 2020 10:07 AM
To: 'JOHN KING' <john.king19@comcast.net>
Subject: RE: Boeing Doc / missing link
http://tinyurl.com/lxg34rl Final SU-GBP Report
Final SU-GBP Report has actually been removed from the Egyptian EMCA website (i.e. not just a wrong or DEAD link).
http://www.civilaviation.gov.eg/accident/Reports/B777_SU-GBP_cockpit_fire_accident final Report responding to boeing comments 019-09-2012a.pdf
Appreciate it if you are able to locate another copy JK.
Not a working link on Harro Ranter’s aviation-safety.net or Wikipedia either…….
Egyptians are the original missing link……
Probable causes for the accident can be
reached through:
1. Electrical fault or short circuit resulted in electrical heating of flexible
hoses in the flight crew oxygen system. (Electrical Short Circuits; contact
between aircraft wiring and oxygen system components may be possible if multiple
wire clamps are missing or fractured or if wires are incorrectly installed).
2. Exposure to Electrical Current.
Follow-up / safety actions
EMCA issued 2 Safety Recommendations
Issued: 01-SEP-2012 To: SU-GBP (1)
Inspect, and if necessary repairing the captain\'s and first officer\'s oxygen light plate wiring. (as per Service Bulletin 777-33-0042)
Issued: 01-SEP-2012 To: SU-GBP (2)
Replace low pressure oxygen hoses with non-conductive low pressure oxygen hoses located in the flight deck (as per Service Bulletin 777-35A0027)