00-12-13 0700
Morning routine.
….
TSB packed all their equipment into
the moving truck today, except for
John’s office, and the truck pulled
out at noon.
I photocopied the last of my notes
up to this morning and put them in
the binder for the file. The
photocopier is now gone, so anything
more will be done at the last all at
once.
Larry FOGG decided to run a yellow
polypropylene rope in the frame in
place of the IFEN wires, so gave him
a hand with the MD-11 tour to show
the routing on the aircraft that was
photographed. This doesn’t
necessarily mean that this was the
routing on HB-IWF, but it would be
close. Then had a chance to
ask him some questions about the
materials present. He feels
that the green canvas-like and
rubber-like material above each of
the doors in not very flammable.
This has yet to be checked, but if
so, then it reduces the fire load on
the slide panels above the door.
Then, I asked if the wire runs were
anywhere near being accurate.
He pointed out a clamp on the right
side at the waterfalls that is where
it is supposed to be, but there is
no way of knowing if the wires
pulled through the clamp at the time
of the crash. However, they
are likely within a foot of being
accurate. We discussed the
amount of burning on the wires on
the right-hand side, and it seems
that this run of wires has undergone
considerable heat, burning off the
outer coating, leaving the Kapton
material surrounding the copper
wire. This material does not
burn, so it is deceiving to see it
with the covering.
The wire run on the left-hand side
appears to largely be unburnt,
apparently protected by the
fibreglass fourth duct to the fifth
zone. I had considered that
this duct would be consumed and add
to the fire load, but it would
appear that it did not as the wires
are intact.
Another point to consider is the
fact that the ducts are wrapped in
fibreglass insulation, and then
covered with the Metallized Tedlar
or Mylar material, a single wrap.
So, there is only one layer of
Metallized Mylar to burn, plus any
tape that is added. At two
places, there is another wrap of
insulation covered both sides with
Tedlar or Mylar, usually Metallized
Mylar. So this fact actually
reduces the fire load. Of
course, the hull insulation is
actually four layers of Metallized
Mylar, with two layers of fibreglass
insulation. However, how much
of this failed to burn and floated
away not to be found.
So the bottom line here is that the
amount of fuel above the ceiling
that actually burnt is unknown, and
is highly variable. The 1R
forward door drum shows heat damage
and melting to one area, yet the
plastic on the wires is untouched in
other areas. At the same time,
according to FOGG, the frayed wire
ends going up and down from the drum
are show heat damage and
embrittlement.
This afternoon, the
security-engineering people were in
to reset the alarm in my two rooms.