By Fred Vallance-Jones, Robert Cribb and Tamsin Mcmahon
The Hamilton Spectator
(Jun 10, 2006)
When the pilot of an Air Georgian business jet flying to
Toronto started to lose cabin pressure in 2003, he did what
crews are trained to do.
He shoved the plane into an emergency descent.
With just minutes of oxygen available in the emergency
supply, he had to get the plane down to breathable air --
But in a nearly catastrophic twist, the manoeuvre meant
to save lives instead sent the seven-passenger Cessna
Citation plane swooping into the path of a Delta Air Lines
Only a sophisticated collision avoidance system prompted
the Delta pilot to take evasive action, saving as many as
The cause of the depressurization was later discovered to
be a faulty door seal -- a problem that had been showing up
sporadically in joint U.S.-Canadian data on the Cessna since
1996, yet had never been addressed by Canada's airline
regulator, Transport Canada.
It's one example that highlights what experts say is a
major issue in the airline industry: Many safety problems
have been found only after they killed people, leading to
so-called "tombstone improvements."
Experts say the industry needs to do a better job
identifying trends in mechanical problems that, however
small, can lead to a plane going down.
Transport Canada says it doesn't see any disturbing
overall trends in mechanical problems since 2000.
But a joint investigation into airline safety by The
Hamilton Spectator, Toronto Star and The Record of Waterloo
Region found the same kinds of maintenance problems can crop
up time after time -- with no permanent fixes.
The investigation also revealed that many types of
mechanical malfunctions have been rising, even though the
number of takeoffs and landings has decreased.
The newspapers analysed more than 50,000 incident reports
made to Transport Canada and obtained through an access to
The data show an aviation system susceptible to a wide
array of problems, including planes that get too close to
each other in the sky, that have put more than 80,000
passengers at risk over the past five years.
In 2004, there were close to 1,800 mechanical incidents
Incidents of depressurization were up 23 per cent from
2000 to 2004.
The most serious -- forcing emergency descents like in
the Air Georgian case -- are rarer, with 10 last year
involving commercial planes, according to the Transportation
Safety Board (TSB), which investigates airline incidents.
The air leak in the Air Georgian plane was first noticed
by a passenger who heard a whistling sound coming from the
door, says a TSB incident report.
The whistle turned to a roar, with pressurized air
sluicing past a faulty door seal. The noise was so loud the
pilots couldn't hear the urgent calls from air traffic
controllers to stop losing altitude, and when they did, it
was too late to prevent the near collision.
The Transport Canada incident report later said the plane
had originated in the Turks and Caicos Islands where it was
exposed to high humidity. Then, at a stopover in Georgia, it
was raining. All that water seeped into the door seal and
froze at a high altitude, leading to the depressurization
and the Cessna's emergency landing.
Neither Mississauga-based Air Georgian nor Delta would
comment on the emergency.
Cessna indicated to Air Georgian that "they have had a
few like incidents reported before" and recommended checking
the door seals in high humidity conditions, the incident
U.S. data show as early as 1996 there had been sporadic
reports of Cessna Citation door seals failing because of
water, including three that forced emergency descents. All
of the emergency descents involved Canadian planes, although
the data don't reveal who the operators were.
Loss of cabin pressure can quickly lead to
unconsciousness for crew and passengers, turning aircraft
into ghost planes that careen to the ground when they run
out of fuel.
Professional golfer Payne Stewart was killed in just such
a crash in 1999 and a depressurized Helios Airways 737
crashed into a mountain in Greece last year killing 121.
Halifax aviation consultant Alex Richman says that --
ironically -- had there been a crash between the Cessna and
the Delta airliner, the door seal problem would have got a
lot more attention than it did.
The system to fix mechanical defects is flawed, Richman
"As much attention has to be paid to rare events as is
paid to frequent events," Richman said.
Richman says a lot of problems go undetected.
"The fatal accident rate has decreased markedly, but has
remained constant the last 10 years and more attention has
to be paid to the precursors and the less severe problems
which may lead to an accident," says Richman, an
epidemiologist who once practised in New York City and now
puts his medical background to work analysing aviation data
and flagging emerging problems for commercial clients.
Many of the mechanical incidents in the Transport Canada
data had the potential to be disastrous -- including
disintegrating tires tearing into wings and fuselages, fiery
engine failures and critical parts falling off aircraft.
Unscheduled landings caused by mechanical problems have,
conservatively, affected at least 50,000 passengers in
Canada since 2000, the analysis shows.
Airlines and cargo operators point out these kinds of
failures are rare when compared to the thousands of daily
One of the jobs of Transport Canada -- and the Federal
Aviation Administration in the U.S. -- is to avoid potential
disasters by making sure endemic failures are fixed.
It collects what are known as "service difficulty
reports" from airlines -- who are obligated to report
problems -- and puts them in a database.
The regulators look for patterns in the data, then send
advisories or, in the case of the most serious problems,
airworthiness directives to manufacturers and operators. The
directives contain mandatory repairs to be completed within
a set period of time.
Critics maintain the system isn't up to the job of
detecting problems in today's evermore-sophisticated planes.
"As the airplanes are getting more complex, our system
for managing these more complex aircraft hasn't kept pace,"
said John Eakin, a Texas aviation consultant who has studied
aviation safety data for 15 years. He entered the field
after being trapped in a helicopter that crashed in 1984.
One example of the technological gap between planes and
the safety system comes from the flight of an Air Transat
Airbus A310 in March 2005.
Its rudder snapped off after the plane left Cuba for
Quebec City. The pilots were able to maintain control and
limp back to Cuba.
The rudders are made of composites -- new-age materials
held together by glue-like substances. Composites are
stronger and lighter than the aluminum traditionally used in
aircraft, but how they age and decay is not fully
The incident remains under investigation by the
Transportation Safety Board, but after problems were found
in a similar Federal Express aircraft in November 2005, the
TSB issued urgent recommendations for stepped-up rudder
Service difficulty reports on such incidents are supposed
to be filed with Transport Canada or the FAA within days of
But Eakin says not only do some carriers fail to report
service difficulties as required, but the data itself is of
Like Richman, Eakin also advocates more investigation of
incidents that don't lead to calamity.
"Incidents are so much more valuable than the accidents,"
he says. "Usually, at least, there is a live pilot to talk
to. But incidents don't get investigated."
In Canada, the TSB only investigates about 50 air
occurrences a year and, as in the U.S., most of those are
the more dramatic ones.
Still, the TSB has had its own concerns about aircraft
In its 2000-2001 annual report, the board raised a number
of "significant air safety issues" related to maintenance.
"Accidents and incidents involving maintenance procedures
and logbook-keeping, human errors on the part of aircraft
maintenance engineers, and the inadequate supervision of
maintenance apprentices have risen significantly in recent
years," the report said.
While technological advancements have improved
reliability, it added, they have also added complexity that
requires attention to detail and expertise from the people
tasked with maintenance.
The board has not pursued the issue since, said Nick
Stoss, TSB director of air investigations.
Airlines do have their own internal systems for tracking
One of those systems is run by Halifax-based CanJet
airlines. It feeds all inflight problems in its small fleet
of Boeing 737s into a computer system.
"The software package has a built-in feature that will
flag us in the event a defect of the same category is raised
three times in 15 flights," said James Penwell, CanJet's
director of maintenance.
"If three defects are reported (in one or more planes),
it will flag us to say, 'Guys, it's time to take a look
CanJet was to upgrade to a more sophisticated system this
month, and also has access to Boeing's in-house database of
in-service defects. Air Canada has an even more
sophisticated system that downloads flight data
automatically from its Airbus planes.
Some of the more common mechanical problems include
hydraulic malfunctions and reports of smoke in the cabin or
They each account for about 100 Transport Canada incident
reports a year.
In October 2004, a First Air Boeing 727 had just pulled
away from the gate in Ottawa when oily hydraulic fluid began
leaking from a pinhole leak in a hose and was sprayed into
the plane's heating system.
Panicked travellers gasped and grabbed for pillows to
protect their mouths and eyes from the burning mist.
Dianna Patryluk of Cape Dorset, Nunavut, watched
helplessly as the choking wave surged toward her.
"People behind us were already panicking before it got to
"And then, when I say it was burning, it was your throat
that was burning and it felt like it was closing up."
The plane had just pulled from the gate in Ottawa for a
routine shuttle to Iqaluit on Baffin Island. "It really did
feel like you weren't going to get out of there," said
Eventually, the passengers were hustled off using the
back stairs. Several were treated by paramedics, but
Patryluk says she still has problems with her eyes.
First Air plays down the drama, saying mechanical
"These are mechanical parts we are dealing with, and
mechanical parts -- no matter how stringent an airline
maintenance procedure is -- mechanical parts do fail from
time to time" said Jim Balingall, an airline spokesperson.
"That aircraft was evacuated without incident and the
passengers were treated according to our emergency response