TWICE AS FAR

 

SWISSAIR 111

CRASH INVESTIGATION

 

 

 

- EXTRACT FROM FILE NOTES -

 

 

FOR

- 2001 DEC 02 -

 

From Wikipedia, the free encyclopedia

01-12-02          .. 

At lunch, I had a chance to discuss a few things with Don.  He told me that he had a recent email he had sent to John GARSTANG and Vic GERDEN that included a telephone conversation he had held with Dr. QUINTIERE.  QUINTIERE had expressed his concern about the ability of the Metallized Mylar to create the burn damage that had occurred in our aircraft.   I asked Don if he would send me a copy of it, and he agreed.  Later this evening, he advised that he had indeed done so this afternoon, and it should be on my email when I get back to the hangar.  It was, and is attached.

From: "Enns, Don"              To: 'Tom Juby'

Subject: FW: Re[2]: FW: SR111 Fire/Explosion Group Meeting 27/11/01; Foll

Date:  Sun, 2 Dec 2001 18:48:23 -0500

FYI                > -----Original Message-----

> From:           Enns, Don       > Sent: Tuesday, November 20, 2001 2:43 PM

> To:    Gerden, Vic; Vance, Larry; Garstang, John

> Subject:        FW: Re[2]: FW: SR111 Fire/Explosion Group Meeting 27/11/01;

> Vic  For your information.

> This is some of the input to phase two of our fire test plan.  Dr. Quintiere's main concern was that this would not be an accurate fire scenario for SR111.  As you can see below it is not meant to be, but it is good that we still have this much interest by the top experts in the field.  I told Dr. Quintiere that he would be welcome to join us for the burn test if he wanted.

> It was also noteworthy that during our conversation Dr. Quintiere volunteered that he did not think there would be enough heat generated solely by the thin film insulation to do the damage that we see.  A similar opinion had been expressed earlier by Dr. Lyon who, after the first burn test asked if we thought that the "few grams" of Mylar in the aircraft would be sufficient to generate the heat required to do structural damage to the aircraft.

> Don

            In addition, Dr. LYON had made the comment to Don ENNS that Dr. QUINTIERE and he are the two top experts in the world in the field of aircraft material fires.  Now, keeping this in mind, they have both expressed a considerable amount of doubt in the ability of Metallized Mylar and the associated materials in the top area of the aircraft to create the damage that has been found. 

            One other area that Don and I discussed centered on the oxygen level in the aircraft during the fire.  I asked if anyone has determined the percentage of O2 that likely was in the air at any point during the fire.  Normal O2 is about 21%.  At altitude, air is thinner so there are fewer molecules available to sustain the oxidation rate, even though the percentages are the same.  What effect might this have had on the Metallized Mylar fire, or any fire in the aircraft?  The air pressure is normally set to about an altitude of about 5500 ft, so this may not have a great effect, if any at all.   Now, with the aircraft being a sealed environment except for the replacement air via the re-circulation fans (about 30% replacement), to what level would the O2 fall at various stages of the fire?  If the re-circ fans are shut down (which apparently, they were for a considerable period of time), does this also shut down the intake of fresh air?  With a 30% replacement rate, just what volume/rate of air does this amount to and how much fresh O2 actually does comes in?  In addition, if the oxygen line did rupture, what effect will this have on the overall volume of O2 in the aircraft, with a line pressure of nearly 2000 PSI, but only about 80 cu feet in the tank when full?  If the ambient oxygen level is low, will this raise the level and by how much?  The aircraft has a massive volume, and just what effect will a burst line have, and how fast?  I suggested to Don that the various parties involved would research this, as O2 levels will have a definite effect on the condition of the passengers, which in turn will have a possible effect on any settlements.  These findings can/will also be used to argue the amount of burning as well as the rates of fire.  If the O2 levels fell below 14%, the fire should go out.  Did this happen at any time pre-crash?  The O2 line may have ruptured, and while the overhead cockpit light and the wires in the bathtub show various amounts of heat and some burning, they are not totally destroyed as would be expected in a long-term pure O2 fire.  How long would the O2 flow last?  But the melting of the end cap on the oxygen line would take a lot of heat.  With this amount of heat passing by the O2 line, where then did it go, as it would not all be transferred to the oxygen line?  We have evidence of molten material on the cockpit carpet, so this would account for some of it.  Once the material is burnt to create the heat to melt the end cap, what then burnt to melt the rest of the aluminium frames? A lot of questions, and Don and John appear to be the only persons to do the work.  John is far too busy with other things, and even Don is too busy with other areas.  Yet it is one of many important series of questions that demands answers.  Don expressed the hope that Dr. GALEA will be able to supply some or most of the answers.  So, these are all questions that are yet to be answered.  However, John has run into sever problems with regards to the computer fire modelling.  It seems that another company from Waterloo, Ontario has bid on the process, and there is a question as to their capabilities.  John may have to go through considerable delays now with this.  There is a question of expertise.

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