You don’t need me to tell you how devastating
a fire can be, especially if that fire is on board an aeroplane. For example your
House was on fire, you can escape. If you are travelling on an airplane and
an uncontrollable fire breaks out, you have nowhere to go. You are at the mercy of the skill
of the pilots and clock to ensure your survival. Some of the most horrific air disasters that
have ever occurred have involved inflight fires. Perhaps amongst the most devastating
and terrifying cases in this category is the disaster we’re discussing today.
The era of history that we know as the Cold War, a lot of images probably spring to mind. The
city of Berlin, today the German Capital, was pretty much at the epicenter of a division between
East and West. The city itself was divided in two, the West side of the city, an exclave of West
Germany within the east. A wall separated the two. This split was in part a result from the events
of the Second World War. After the war the Soviet Union occupied the Eastern half of the city and
indeed East Germany as a whole, aside from West Berlin. The Soviet Union wanted to expand their
sphere of influence. East Germany became a puppet state like other countries in Eastern Europe
East Germany for this era of history was a separate country from the rest of Germany. It
had all the things you’d expect a different country to have. Its own government, its own
infrastructure, its own currency and of course to lead onto our topic today, its own airline.
The East German airline was called Interflight or in German Interflug. Interflug operated
between the years of 1958 and 1991 and were based out of what was known as the time as Berlin
Schönefeld airport. As East Germany was under the influence of the Soviet Union, the aircraft they
operated were Czech, Russian and Ukrainian made.
The Soviet Union throughout the 1950s
and 1960s, much like other countries were developing their own aviation technology
as things transitioned into the jet age. In 1963, the Soviet Union unveiled what was at
the time, the largest passenger plane ever made. A four rear mounted engine jetliner called the
Ilyushin IL-62. It was infact one of only two planes to feature this configuration of engine and
tail structure, the other being the Vickers VC-10. For its time this was a huge plane.
Though it was a narrow body jetliner it was quite long standing at over 53
meters in length. The plane could carry close to two hundred passengers with a range
of 6000 miles, making it the ideal plane for long range flights for carriers in the East. 292
of these Soviet airliners were built. Many were flown for Aeroflot, but many were also in the
hands of air carriers across the Soviet World. Air Koryo of North Korea, supposedly still has
two of these planes in passenger service today.
Needless to say that Interflug also operated the
plane in its time. They started receiving their IL62s in 1970 and their first Ilyushin was DM-SEA,
the accident aircraft. The plane would operate for little over two years before its deadly
fate, which brings us to August 14th, 1972.
It was a Monday, also a very warm summers day
in Berlin. This Ilyushin IL62 was sitting on the ground at Berlin Schönefeld airport. It had
just arrived in from a flight from Moscow and preparations were being made for a journey
that afternoon down to Burgas in Bulgaria. One thing to highlight before we go further is in
relation to the accident flight’s flight number. Most sources do not seem to include this
information. That could be because in this specific case this rather simple piece of
information seems to be a bit conflicting. One source (an old German Documentary) did mention
that the flight number was 450 (four-fifty). Though I have no reason to suspect this
is false, I have also seen multiple people reference a flight number of 742. The
thing is, regardless I was not able to cross reference this information with other
written sources so for the sake of this video the plane will be referred by an abbreviated
version of its registration, Echo Alpha.
The IL62 required 4 pilots to fly. 51-year-old
Captain Heinz Pfaff was one of the most experienced pilots around flying the Ilyushin.
By the time of the disaster he had acquired over 8,000 flight hours. Sat next to him was his
co-pilot, 35-year-old Lothar Walther, an experienced pilot in his own right with over 6,000
hours logged. Also on board was a Flight Engineer Ingolf Stein aged 32. Finally there was the
navigator on board, 38-year-old Achim Filenius. Interestingly, the Navigator was a man who
was involved in another Interflug aviation incident in 1963. A non-fatal incident
which was the result of malfunctioning landing gear forcing a belly landing.
The flight to Burgas was carrying primarily East German holiday makers to the sunny
Bulgarian Coast. 148 passengers boarded the flight with a further four flight attendants
in the cabin for a total of 156 people on board. Down below, ground handlers were loading
passenger luggage into the cargo compartments., but this was the only thing being loaded.
Among the miscellaneous items in the cargo, deicing fluid was stored at the very rear
of the aircraft in compartment number 4.
Leaving the gate in Berlin, Echo Alpha
took to the skies just before 4:30 in the afternoon on August 14th, 1972. In
just a few hours the plane would be in Bulgaria. Captain Pfaff was at the flight
controls of the massive Ilyushin jet. The first roughly 13 minutes or so of the flight
as the plane climbed were completely normal.
The first sign of trouble for the pilots was
first reported at 4:43. The aircraft was climbing through 29,000 feet or in meters as these pilots
would have been using, 8,900 meters. The pilots had noticed an issue with the plane’s elevator
trim function. Trim on aircraft allows a pilot to adjust small tabs on the flight control surfaces.
Trim can be used to apply a certain level of deflection force on say the elevators in this
case to help maintain a desired pitch. It can make controlling an airplane a lot easier and pretty
every plane has elevator pitch trim. In fact the art of trimming is one of the first things a
new pilot is taught to do in flying school.
The pilots of out Interflug flight had
noticed the pitch trim was unresponsive. In attempting to troubleshoot the problem, the
plane’s course deviated 10 degrees to the east. Without further context, this alone was not
a cause for distress but urgent enough that the pilots deemed it was necessary to return
to Berlin. So at this point the pilots began to turn their plane around and communicated with
controllers about their situation. The thing is, the pilots in this moment had no idea how bad of a
situation had just surfaced. To them, they thought they had a failed trim function. In the back of
the plane, it was a completely different story.
Let’s back up. We need to talk a bit more
about the design of the Ilyushin Il62. As previously mentioned, this is a pretty long
aircraft. Like almost every other plane you have likely ever been on, the passenger cabin is
pressurized with the comfortable cabin atmosphere sealed inside an air tight chamber. But there was
additional space on the IL62 behind the cabin in a void space, an unpressurized chamber not visible
to the passenger’s or even flight attendant’s.
Many electrical cables ran through this void
space. Everything from cables relating to the cabin lighting to the coffee machines used by the
flight attendants. Also back here were critical lines relating to the aircraft’s flight controls.
But there was still even more in this area than the plane’s electrics The tail section is where
all four of the plane’s engines are located. When the plane was designed, it was decided that to
connect hot air from the engines to the aircraft’s air conditioning system, they would use that
same space behind the cabin to transport hot air. The air coming through here from the engines
reached temperatures around 300 degrees Celsius.
So what happened on this flight, is
that a leak had occurred in these hot air tubes within this space in the rear of the
plane. It’s believe the leak was going on for considerable time before things got critical.
At temperatures around 300 degrees, the heat weakened the insulation of the nearby electrical
wiring. Once the internal wiring was exposed, a catastrophic electrical failure occurred.
Short circuiting created super-heated arcing events. Reports suggest that the temperature of
this arcing reached around 2000 degrees Celsius.
For reference lava or magma, that is liquid
rock from volcanoes, ranges in the region little over half of that in temperature. 2000
degrees is also a little under half way to the temperature of the surface of the sun. Sparks
with a temperature in the region of 2000 degrees ignited the magnesium Alloys of the aircraft
structure. Such arcing was believed to have also occurred in the lower cargo deck. A fire erupted
in the tail and cargo sections of the aircraft.
The one thing that was not fitted in this
space was smoke or fire detection equipment. So out of sight an inferno was allowed to consume
the tail section of the plane. The pilots had no idea this was even happening just yet. As the
fire consumed the tail section of the plane it began to spread. Smoke poured into the passenger
cabin. As the inferno spiralled even more out of control it began to affect the aircraft’s flight
controls, which was probably when the pilots first noticed an issue, the flight controls pertaining
to the elevator were being destroyed by the fire.
As smoke poured into the cabin the Flight
attendants made the situation known to the pilots. By this point the time was 4:51 and the
plane was heading Northbound back to Berlin. Several minutes had passed since the pilots
first reported what they thought was a flight control issue to the ground. Now they were
dumping fuel to prevent an overweight landing, a mayday distress call was not issued at this
time. The pilots were likely still not aware of how bad the situation was or was about to get.
The fire in the tail section was believed to have made its way to where the Deicing fluid
was stored in the cargo hold. The De-icing fluid loaded in this compartment was highly
flammable. Aviation de-icing fluid according to the FAA has a flashpoint of around 65 degrees
Celsius or 150 degrees Fahrenheit. The Deicing fluid was now acting as a fuel for the fire.
We don’t have a whole lot of information about what happened on board the plane over
the next few minutes. To my knowledge there was not recorded flight data. There’s
no indication as to whether this plane had any flight recorders to begin with. It is likely
that the fire entered the rear passenger cabin, burning away the cabin flooring, seating,
luggage compartments and galley and lavatories. The inferno was raging at such a high temperature
it began to melt and destroy the aircrafts skin.
Captain Pfaff as the time went on would
have experienced increasing difficulty in controlling his aircraft. Multiple
turns were made as the plane descended; they were progressively losing control. 4:59,
less than one minute to impact with the ground. Only now did the pilots send out a distress
call, they reported flight control problems, an on board fire and that they were
beginning an emergency descent.
As the pilots fought for control of the
plane, the fire had eaten its way through the structural integrity of the aircraft to
a critical point. The Tail section of the plane broke away from the fuselage. From this
moment, the plane was completely unflyable. The pilots and all 156 people on board, never
stood a chance. At this time, The massive jet was flying over the town of Königs Wusterhausen, just
a few miles south of Berlin. Bystanders on the ground later noted debris failing from the sky.
Parts of the plane, luggage and people falling to the ground through the opening in the aircraft.
According to a German Newspaper the aircraft was only a few hundred meters above the ground
as the plane roared over the town. The remains of the massive jet entered an uncontrollable
nose dive. In the final descent the fuselage experienced excessive structural stress and part
of the front fuselage was ripped from the plane.
Seconds later, at just after 5pm what was
left of the plane crashed into a wooded area in the town of Königs Wusterhausen
just 6 miles south of Berlin Schönefeld. Everyone is dead. If they had just a few more
minutes, it might have been possible they could have made it to the airport. Although there
is no telling how the plane may have behaved during that turn for final. The aircraft in such a
poor structural state may have broken apart then.
The Interflug disaster was and still is to this
day, the worst air disaster in German history. The horrific nature of the crash, prompted
immediate action and Interflug’s IL62 was temporarily grounded. Following an
investigation, the critical design flaw in the tail of the aircraft was noticed.
The findings of the investigation were relayed back to the Soviet Union and IL62 planes were
to be retrofitted with a revised design and all further manufactured planes of the type were going
to reflect these changes. The changes included additional fire detection and prevention equipment
in the offending space. A small window was added at the rear of the cabin so one can physically
observe with their own eyes what was going on back there. Recommendations were made for periodic
physical inspections of the space for damage.
Because this accident involved a Soviet
airliner, the investigation into this disaster certainly wasn’t without its fair share of Soviet
Shenanigans. The plane’s manufacturer Ilyushin, despite making the aforementioned changes, never
conceded there was a problem with the Il62s design. The Soviet establishment was not willing
to admit that there were technical shortcomings in their aircraft and only quietly implemented those
changes in time. The Soviet Union kept quiet about the crash. The truth behind the disaster,
and what we know today was only uncovered following the reunification of Germany.
For what it’s worth, there were no accidents of this nature involving the IL62 ever again. The
plane has largely been retired from passenger service with the previously mentioned Air Koryo
holding onto their aircraft and some do still remain in government, military and freighter roles
today. Some of Interflug’s own iL-62s actually survived the test of time and are now on display,
including this plane in Leipzig which has now actually been converted into a restaurant.
Patreon Outro
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will be another video coming next Saturday. I was really happy with how this one turned out.
Sources were a bit limited as an English speaker, this video certainly wouldn’t be the
same without modern text translation that’s for sure. German sources
had so much extra information.
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