TWICE AS FAR

 

SWISSAIR 111

CRASH INVESTIGATION

 

 

- THE INVESTIGATION -

 

0THER TESTS

AIR FLOW TEST FLIGHT

AIR FLOW TEST FLIGHT

 

 

Part of the investigation included

understanding the airflow patterns in the Swissair configured MD-11 aircraft

while in flight.

Knowing those patterns could help locate the source of the fire.

Boeing's  experience in these matters revealed that

airflows in the aircraft while at ground level

differed to those while at high altitude.

One reason for this was that

with the aircraft flying at over thirty thousand feet,

 the skin of the aircraft cooled down to minus 60 degrees F.

Plus the plane travelled at a speed of 0.8 mach or about 700 miles per hour,

so any heat on the inside surface of the skin

would quickly dissipate and be lost to the huge heat sink that the aircraft skin had become.

To determine these patterns

there was a need to schedule a  test flight with the appropriate systems in place

to record those internal air flow patterns while at altitude.

As mentioned in the book,

there was considerable opposition to having a police investigator on board the flight.

That opposition not only came from Boeing and the TSB

but from RCMP file supervisors.

 

 

 

This photo shows some of the video recording gear that was used on the test flight.  VHS was the standard for the time as digital recording was still in its infancy.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Some of the smoke generating and accumulation gear that were used on board the test flight.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

One of the scanners that were used to determine the level of smoke, in this case, in the cockpit area.  Several were used, and each had been properly calibrated before the flight.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Once the flight was over and back on the ground, there was time for a group photo of those who had worked the test flight, except of course for the second Boeing photographer who took this photo.  Four TSB members are present along with me, and the rest are all Boeing personnel.  John Garstang is at the photo's left rear with Mark Clitsom beside him and then Vic Gerden as the third from the left of those standing.  Larry Fogg is in the blue, white and red jacket and kneeling on the right of the foreground row.  Jim Foot is standing at rear centre, fifth from the right of those standing just behind the salmon coloured shirt.  I am at the extreme rear of the group, left of centre and behind Gerden's left shoulder, a head above everyone else.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SMOKE INSERTION POINTS

 

Pt #

Details

1

Behind avionics circuit breaker panel

2

Above emergency battery pack (sta. 403)

3

2.1 (1R) door vicinity of door ramp deflector (sta. 428)

4

1.1 (1L) door forward drop ceiling support post (sta. 428)

5

Inboard of Lav B at ceiling support post (sta. 477)

6

Inboard of Lav A at ceiling support post (sta. 477)

7

E & E bay near throttle cable drop.

8

Above cockpit door at emergency battery pack panel with handheld dragger tube.

 

The tests were completed first with the smoke curtain sealed

and then with the curtain opened. 

 

CAMERA POSITIONS

 

Pt #

Details

1

Smoke insertion point 1

2

Smoke insertion point 2

3

Smoke insertion point 3

4

Smoke insertion point 4

5

Smoke insertion point 5

6

Smoke insertion point 6

7

Smoke insertion point 7

8

Above ceiling cockpit bulkhead

9

Above ceiling engine fire S.O. cable drop

10

Below ceiling overhead avionics C/B panel

11

Roaming cameras

 

 

 

 

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ALUMINIUM DROP TEST

ALUMINIUM DROP TEST

 

This video shows the Aluminium Drop Test on ceiling tile and carpet flooring

that took place in the Transportation Safety Board Lab in Ottawa. 

It shows molten aluminium at 1000 degrees F

being dropped on ceiling tile and flooring carpet from the debris wreckage. 

 

 

-- ALUMINIUM DROP TEST VIDEO --

 

 

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EXPLOSIVE WIRES SALT WATER FLOAT TEST

EXPLOSIVE WIRES SALT WATER FLOAT TEST

 

The following is a video of the tests that John Garstang and I performed

to see if the explosive wires that had been found on the beach close to Halifax

could have floated there in salt water.

There was no indication that explosives had been involved in the downing of the aircraft,

but to cover all the bases, it was agreed that the test should be conducted in actual salt water.

Remember that things may float in salt water

yet sink in fresh water due to the difference in buoyancy between the two.

So the test was conducted at Lawrencetown beach, Nova Scotia.

It was found that the blue and white plastic exhibit did float,

but the others did not.

Because they were all found together,

it is reasonable to assume that since three of the four exhibits did not float to the location where they had been found,

then neither did the fourth.

No other similar exhibits were found anywhere else during the beach search.

While the explosive wire issue was merely a side show and not related in any way to the onboard fire,

the matter serves to show how the TSB handled potential criminal matters.

If they reacted in this manner over something totally unrelated to the investigation of the fire cause,

then one can easily believe their denial of Dr Brown's AES results

that linked an incendiary device to the cause of the fire.

 

 

-- EXPLOSIVE WIRE FLOAT TEST VIDEO --

 

 

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SEAWATER TEST WIRES

SEAWATER TEST WIRES

 

RETRIEVAL RESULTS

 

 

During the Auger Electron Spectroscopy (AES) testing of the debris short circuited wires,

Dr. Brown requested that new sample wires be created as a known test series.

The main purpose was to determine what would happen to short circuited wire beads

under various controlled conditions.

Various types of aircraft wire samples were created

according to a prearranged plan

and submerged in seawater for thirty days.

These photos show those wires upon retrieval after thirty days of exposure to seawater.

 

 

 

Exhibit #1-12740 is the pallet containing the aluminium frame piece with the attached wires.

It was retrieved after thirty days of seawater submersion, as were the other two pallets.

The pallets had not drifted, and everything on them was intact upon retrieval.

The only thing changed was that the ballast weights were cut out when lifted to the side of the boat.

This allowed for a lighter pallet when it came time to lift them up onto the wharf.

 

 

 

 

Exhibit #1-12741 was the pallet with the aluminium frame piece and the magnesium rudder pedal. 

Again everything was intact, and the wires were still in contact with the magnesium pedal.

 

 

 

 

The rudder pedal had deteriorated only slightly

during its thirty day submersion.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pallet exhibit #1-12743 held the ten wires without any other metal strips.

 

 

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SMARTFIRE COMPUTER PROGRAM

 

SMARTFIRE SOFTWARE IN THE SWISSAIR 111 INVESTIGATION

PREFACE

During the writing of the book Twice As Far, I knew that this software had been utilized.  However, after reviewing this report, it was determined that the program was of no value in this fire investigation for the reasons shown here.  Therefore, it was merely a ‘red herring’ that would have added unnecessary layers to the story.  Too much reliability and accuracy is applied to software programs in the belief by many that because it is a computer program, it must be reliable and accurate.  However, any computer is run by a program, and that program is written by humans.  In this case, this program requires the input of measurements and details that have been determined through questionable circumstances that themselves are unlikely to be reliable and accurate.

ASSESSMENT OF REPORT

As part of the investigative process, the Transportation Safety Board utilized Smartfire, a Computational Fluid Dynamics software program that could determine fire properties and fire progression in a structure.  They looked to Fire Safety Engineering Group at the University of Greenwich in the United Kingdom as it had been used in that country on several major fires.  However, the program was not compatible with the drafting data of the aircraft that had been created for this investigation.  The TSB had used North America’s standard CAD program while the British standard was different.  Because of the volume of CAD data, it was simpler to rewrite the program to accommodate the TSB.  This was advantageous to the FSEG company as they wanted to break into the North American market with their Smartfire software.  Because they did not wish to absorb the cost of rewriting the program, the TSB agreed to pay for the rewrite.  This would allow the program to be utilized for this investigation plus any other fire investigation in North America. 

Eventually, the software was used to produce a fire scenario, and their report is available on the web at https://www.fire.tc.faa.gov/2004Conference/files/materials/F.Jia,M.Patel&%20E.Galea_Simulating_the_Swissair_Flight_111_in-flight_fire.pdf

The company and their results were also mentioned in the final TSB report for this crash as being highly successful.

A review of their report at the above site provided an insight into some potential problems with the project.  Had this matter ever gone to court, it is quite possible that an examination of the mater would have provided numerous arguments.

Since the FSEG company was eager to break into the North American market, they needed a successful experience with a major investigative group in a prominent and important investigation.  The TSB’s Swissair 111 investigation met those requirements.  If they could then be successful, the TSB would be their route to that North American market.

Several avenues for argument could be raised in court.

1.      With the TSB paying for the rewriting of the software, the company now became indebted to the TSB.  After that amount of expense, a failure would have been the death knell for the software in North America.

2.      A line in their report is as follows: ‘It is worth noting that CFD techniques are not error free;’.  The paragraph continues further with ‘Thus it is important to understand the limitations of such simulations.’

3.      A further line: ‘the key goal of the study undertaken was to validate and/or determine the probability that a scenario is “likely” . . . . The rigours of such a complex simulation are quite demanding . . . .’

4.      Yet another line: ‘. . . software was used to predict the “possible” behaviour of airflow as well as the spread of fire and smoke within SR 111.’

5.      Now this line: ‘This assisted investigators in assessing fire dynamics for cause and origin determination.'

This last line is important because of a further area of the report.  In truth, the cause and origin determination was provided to the company as a start-point for their fire modelling scenarios.

6.      ‘SMARTFIRE thus became the first CFD fire model to be used in an air crash investigation. The official TSB report acknowledged the technology’s successful debut in ‘helping to develop better insight into and understanding of the fire’.

7.      ‘A research version of the SMARTFIRE V3.0 [2,3] software was used to perform the fire simulations in this study.’

This, therefore, was not a standard, well established software version, but an experimental version.

8.      ‘Within SMARTFIRE the user can define a range of scalar variables, which can be used to represent the transport of products such as toxic gases and smoke.’

As I understand this statement, the TSB was able determine what values could be used in the program, and as such, they could adjust those variables to arrive at a predefined conclusion if they so desired.

9.      ‘The fire simulations in this study were performed using a special version of the SMARTFIRE V3.0 software with features developed particularly for this project.'

         'Due to the highly complex nature of the geometry in the aircraft, some of “small” features and components had to be either approximated or removed from the geometry to make the SMARTFIRE computer files manageable. The approach to simplify complex geometry is a common CFD practice.’

Again, this was not an off-the-shelf standard version, but a special version.  There would have been no actual testing to determine the accuracy of the results.  For these results to be accepted in a court of law in this country, the results would have to be verifiable.  Since this was a one and only experience, there was nothing with which to compare it to determine its accuracy.

10.    ‘Several simulations were performed to ensure that the airflow pattern observed in the model, with the aid of minor changes to the inlet conditions, was similar to that observed in actual aircraft during airflow flight tests.’

         ‘The TSB provided estimated MD-11 cockpit airflow values (e.g., conditioned air supply rates into and out of the cockpit) that were obtained from the Boeing Company for the flight condition that best represented the occurrences. These airflow values were used to set the initial airflow conditions at the various flow components in the CFD model. The model was then run and the velocity vectors and flow rates were studied at different locations within the virtual aircraft. Some adjustments were made to the flow rates until the model’s velocity vector values closely matched those calculated from the flight test video recordings. The airflow patterns in the computer model were then compared to the smoke release flow patterns recorded on the flight test video recordings. The airflow patterns in the computer model were determined to be consistent with those observed experimentally.

The problem with these two statements is that the airflow flight test provided test results in a non-fire scenario.  Obviously, we were unable to determine actual airflow results consistent with a fire scenario without creating a similar fire in the aircraft.  But how can these non-fire scenario results be considered as accurate for a real fire scenario.  Any experienced fire fighter will agree that as soon as the fire begins, the airflows will change dramatically and unpredictably.

11.    ‘The fire ignition site, as provided by TSB, was prescribed with the aid of a volumetric heat source. The source was adjusted so as to sustain the combustion of the material over a short duration. This was necessary to allow the material to reach a critical temperature to allow flame propagation. In the simulation, the fire spread after initial ignition, was only allowed to spread once the neighbouring cell reached the ignition criterion.  This allowed the heat release to be predicted by the amount of surface that was ignited as a result of the flame spread, if the ignition criteria were met. This approach eliminates use of the more complex route of predicting flame propagation via chemical reaction.’

Several things are a problem with this statement.  First, the TSB provided what they thought was the ignition point.  In other words, it was the location determined by Jim Foot with his wire placement of the short-circuited wires.  How he came to these conclusions and his lack of expertise to do so has been described in the book.  His opinion of the source of the fire would never be presented in a court of law in this country as he had no qualifications to make that determination.  Next, the source point was adjusted to provide the required outcome, and fire spread was allowed only when the burning area reached a certain ignition criterion, or temperature.  Yet, in the FAA burn tests, the temperatures failed to reach anything of significance.  The flame slowly progressed along the Mylar material without providing any significant heat.  In the third test, fire spread was due to sparks from short-circuited wires.  There is no indication that this was included in the scenario, and how can anyone or any software predict that outcome.  Furthermore, some of the materials were likely damp due to condensation on the cold surfaces of water vapour exhaled by the passengers.  To what amount is not known, and it seems this was not included in the computer calculations. 

12.    ‘The main scenario considered for simulation was that the fire started within the confines of a relatively small area above the right rear cockpit ceiling, just forward of the cockpit rear wall near STA 383. The TSB determined that it was most likely that the fire started from a wire arcing event that ignited the nearby MPET-covered insulation blankets. These MPET-covered insulation blankets are easily ignited and were prevalent in the area. Of all the wires and cables that were located in the area of interest, the only arc-damaged wire that could be positioned in that area with relative accuracy were a pair of In-Flight Entertainment Network (IFEN) Power Supply Unit (PSU) cables. Although it is possible that other wires from this localised area that were not recovered might also have arced, the only arcing event that is known to have occurred within that area is the forward arc on TSB Exhibit 1-3791, located just forward of STA 383. The TSB requested that this location be used as the fire initiation site.

          A heat release rate, to sustain the fire at the fire ignition site, was prescribed, as CFD simulations cannot predict arcing type ignition sources. To achieve this, it was necessary to ascertain what fire load was required to sufficiently heat the MPET in a small-localised area, so as to create a small self-propagating fire at the initiation site. This method of igniting the fire was agreed to by the TSB.’

There we have it.  A predetermined source as directed by the TSB based on a scenario that they had decided upon.  The software, utilizing this source point and the TSB’s special parameters, was then used to confirm the source point.  Just how objective is that.  This would never stand the test of court. 

Once again, the TSB has shown its inability to examine the evidence objectively. 

 

 

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