The search for the cause of the fire that brought down Swissair Flight 111 on
the evening of September 2, 1998, killing all 229 people aboard, took over four
years and cost $39 million. It was one of the most exhaustive airline crash
investigations ever mounted. In this interview, airline safety expert David
Evans takes an authoritative look at the investigation and what he calls a
"confederacy of complacency" in the airline industry regarding safety
improvements following this and other major accidents. The interview was
conducted in October 2003 at the offices of Air Safety Week, a widely
respected airline safety newsletter that Evans edits.
NOVA: What was known in the immediate aftermath of the crash?
Evans: Well, based on the conversations between the pilots and air traffic
control, the initial indications were that they had some sort of a smoke event
on the airplane. We know that the crew had declared a Pan, which is a technical
problem on the airplane that affects safety. And moments before the final
crash, they declared a Mayday. What was initially known was a loss of
control.
NOVA: So the crew knew there was a fire?
Evans: If we look at what the crew was experiencing as they were flying along
on this nighttime flight, we have to note that smoke and fire events on
aircraft can be seductive. I mean, you've got a sort of a whiff of something,
and then you're going through a procedure, trying to determine where this smoke
is coming from. In pilots' parlance, the situation is known as Smoke and Fire
of Unknown Origin.
I think that the final horror of their grim situation may not have been fully
appreciated until the fire in the attic space over the cockpit burned its way
through the ceiling panel, and Captain [Urs] Zimmermann was showered with the
charred effects of the fire, the burned plastic, the sudden blast of heat. At
that point, I think that that eruption of hot gas and possibly flame into the
cockpit pushed him out of his seat, because we do know that he was not in the
captain's left seat at the moment the airplane collided with the water.
NOVA: How useful were the black boxes in the subsequent inquiry?
Evans: The cockpit voice recorder and the flight data recorder lost power about
six minutes before the airplane finally crashed. These devices, the so-called
black boxes, which are actually painted orange, are really the Rosetta Stones
for an accident investigation, because they enable investigators to recreate
the sequence of cascading failures, what the crew was doing, what they were
saying to each other, and also the wealth of systems data that is captured on
modern black boxes.
“Clearly we had an uncontrolled, uncontained, runaway fire on this
airplane.”
It's of interest that in the course of this investigation, the Transportation
Safety Board of Canada (TSB), which had primary responsibility for the
investigation, issued safety recommendations calling for improved black-box
capability and an independent power supply so that if the aircraft lost
electrical power, they would keep on catching any data that was there to be
had. They also called for dual installation, so that you'd have a fully
redundant cockpit voice and flight data recorder capability located both in the
nose and in the aft part of the airplane.
NOVA: Have those recommendations been acted upon?
Evans: The TSB issued its recommendations for improved black boxes some three
years ago now. Those recommendations, primarily calling for a two-hour
recording capability so that they would have a better capability in the future
for reconstructing accident scenarios, have not yet been acted upon by the
authorities. Those recommendations have simply dropped into a regulatory black
hole.
Working the evidence
NOVA: Without the black-box data, how did the TSB pursue its investigation?
Evans: The absence of good flight and cockpit voice recorder data obviously
increases the difficulty of the investigation. Let's say on a scale of
difficulty from zero to 10—zero being pretty straightforward, 10 being
extraordinarily difficult—if you've got the black boxes and good data
from them, the level of difficulty might be on the order of a four or five.
Without the black boxes, you're talking a nine or 10 level of difficulty and
trending towards unsupportable conclusions.
It really pushed the investigators back into sort of a secondary mode. They
began looking at other sources of data: What could they capture from the
non-volatile memory chips in the engines' digital recorders? How else could
they look at this in terms of the physical evidence?
NOVA: What did they focus on?
Evans: Well, the investigators began focusing on the source of the smoke,
because where there's smoke, there's fire. And clearly we had an uncontrolled,
uncontained, runaway fire on this airplane.
NOVA: Did the mountain of evidence retrieved from the seafloor help them
pinpoint the source of the fire?
Evans: Well, in the horribly grim circumstances of this tragedy, the one small
footnote of good news perhaps, from an investigative standpoint, was that the
airplane impacted into water, which had the effect of immediately dousing the
fire and freezing in time the evidence that would be so crucial to unraveling
the mystery. Had the airplane crashed on land, we probably would have just had
a smoking, black, smeared piece of earth with some tiny pieces of aluminum and
wire. It would have been much more difficult.
As it was, the investigators were able to recover the heat-damaged, charred
wires, which were obviously burned from either electrical arcing or a runaway
in-flight fire of some kind. Those wires led them to pursue the scenario of a
runaway, uncontained, in-flight fire of electrical origin.
NOVA: What was known at the one-year anniversary of the crash?
Evans: By the one-year anniversary, the bulk of the wreckage had been
recovered. The notion of an electrically stoked fire on the airplane had been
pretty well established. The investigators were now facing a major effort to
recreate the circumstances surrounding the fire: how it got started, how it
took root, how it was able to ultimately bring this airplane down.
“I was thinking at the time: These things are flying firetraps.”
I think with respect to the impact on the families, the one-year anniversary
is one of particular symbolism and perhaps personal pain. There's no closure in
terms of the investigation. Who knew that this investigation would ultimately
drag out to four years or more to put together all the factors, all the latent
hazards, all the circumstances surrounding this tragedy? So at the one-year
point, major safety themes were emerging, but we were a long way from closure
in the form of justifiable conclusions.
NOVA: And what was happening at this point in the investigation?
Evans: At this point the investigators had an airplane that began life as four
million parts flying in close formation, and now they had recovered virtually
the equivalent of those four million parts, and those parts were in bins. They
had a major challenge: what I would call forensic reconstruction of what
occurred on the airplane. They determined to try and reassemble the cockpit.
They created a steel frame, or skeleton, on which to mount recovered pieces of
the airplane. They also began focusing in on the forward part of the cabin,
including the attic space, the forward galley, and the cockpit, and on putting
the pieces together—the panels, the aluminum, the wires, the electrical
components—to try and recreate how this case progressed from an
electrical incident to a major accident.
If we look at the amount of flammable material that the investigators recovered
from the airplane and, to their dismay, finding how much of it was
burned—the oxygen-line end caps, the thermal acoustic insulation
blanketing, and other material—I was thinking at the time: These things
are flying firetraps. I mean, how is it that we can put 200-plus people in an
airplane with all this flammable material? This is the tinder waiting for the
match. And the match, as we now know, was the electrical arcing. [Editor's
note: The investigators concluded that electrical arcing—a discharge of
electricity from a damaged cable—triggered a fire in the plane's
insulation materials. The arcing occurred in the attic space just above and aft
of the cockpit, possibly in bundles of wiring in that space.]
Taking action—and not
NOVA: Had this kind of fire ever been reported before?
Evans: Behind every major aviation accident is a history. In the case of
Swissair Flight 111 and the thermal acoustic insulation blankets, the Chinese
had experienced a number of cases of in-flight fire and damage in which the
blankets had burned. And the Chinese authorities had contacted our Federal
Aviation Administration (FAA) and advised them "Guys, you may have a
flammability problem here." Action taken: None.
NOVA: What action did the TSB, for its part, take when this danger of fire
became clear?
Evans: Well, by December of 2000, the Safety Board of Canada felt like it was
dealing with a major problem: the vulnerability of aircraft to in-flight fires.
And they had a press conference at which they expressed publicly their
concerns—to wit, that collectively in the industry we have not done an
adequate job of reducing the flammability and providing greater protection
against in-flight fire.
NOVA: Did the TSB add this potential danger to its list of official
recommendations?
Evans: Yes. The TSB has issued a number of very important recommendations to
improve the safety of this airplane and of all airplanes. Those recommendations
have been transmitted to the Canadian regulatory authorities and to our
National Transportation Safety Board, which is the comparable accident
investigation body to the Canadians'. Our Safety Board, to its great credit,
has fully endorsed the Canadian recommendations and has sent them on to the
FAA, which is the regulatory authority responsible for this airplane.
NOVA: Has the FAA endorsed the recommendations?
Evans: In terms of what the FAA is doing, let me cite the great British Prime
Minister Disraeli: "We are making haste slowly."
Lessons
NOVA: So what would you say is the legacy of this case?
Evans: The legacy of this case is enormous, because we have a continuing
problem with in-flight smoke and fire. I like to say that if the cabin of a
modern jetliner was a restaurant, it would not get an occupancy permit, because
you've got people in a confined space with no fire detection or suppression,
and they're sitting on top of high-powered electrical circuitry and a big load
of fuel. You have all this in very close proximity.
“We have what I would call a confederacy of complacency with respect
to in-flight fire detection and suppression.”
Now, if we look at, say, rest homes, the mobility of old folks is likewise
limited. Yet to get an occupancy permit for your parents' rest home, the
builders and developers had to demonstrate that every square inch of that
nursing home is covered by detection and suppression. We can look up in this
office space here, and we can see the nozzles for the fire-protection system.
You know that if we have an electrical fire in this building, we're going to be
doused with a spray of water. We are fully protected, and yet we can get out
quickly also. When you're in a jetliner at 30,000 feet, you're not getting out.
You've got to fight it long enough to get the airplane on the ground.
Now, what do we have in the airline industry? We have what I would call a
confederacy of complacency with respect to in-flight fire detection and
suppression. The National Transportation Safety Board has said that we need an
integrated firefighting philosophy on airplanes. Yet we've got spaces that we
don't have access to that are not protectable by fire detection or suppression.
So the hazard continues to this day.
NOVA: Do you think the apparent industry inaction on this front is due to a
cavalier attitude about the value of human lives?
Evans: No. There is a phrase within the industry to the effect that "If you
think safety is expensive, try an accident." So I don't see that at work here.
What I do see are a combination of forces: complacency, bureaucratic inertia,
"It's too hard," "We're not making money now," things of this nature.
What strikes me is that so many of these accidents about which I have written
over the years had precursor events that, had action been taken with alacrity,
if we had not been in the Rip Van Winkle mode of regulatory torpor, could have
been prevented. So the issue to me is not whether you can fly for a thousand
years before you're going to be involved, statistically speaking, in an
aircraft accident. The question is: How many of these accidents were avoidable
and preventable? I haven't seen one yet where structure and systems were
involved where it wasn't avoidable and preventable beforehand. And therein lies
the tragedy. Therein lies the culpability.
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