LOT Polish Airlines Flight 007
Encyclopedia
LOT Polish Airlines
Flight 007 crashed near Okęcie Airport
in Warsaw
, Poland
, on 14 March 1980, due to mechanical failure as the crew aborted a landing and attempted to go-around
. All 87 crew and passengers died.
. The aircraft which crashed was the first Il-62 LOT had purchased for this purpose, manufactured in 1971. As all purchased Ilyushins, it was named after a famous Polish historical figure, in this case Nicolaus Copernicus
("Mikołaj Kopernik" in Polish).
, about one minute before the landing, the crew reported to Okęcie Air Traffic Control that the landing gear indicator light was not operating, and that they would go-around
and allow the flight engineer
to check if it was caused by a burnt-out fuse or lightbulb, or if there was actually some problem with the gears deploying. This was a common occurrence among Ilyushin
s and rarely indicated a serious problem.
(11:13:46) Okęcie Air Traffic Control: Flight 007, 5 degrees to the right.
(11:13:52) Okęcie ATC: Flight 007?
(11:13:54) Flight 007: Yes, acknowledged that... One moment, we have some problems with landing-gear-down-and-locked indicator, request a go-around.
(11:13:57) Okęcie ATC: Acknowledged, runway course and altitude 650. [At the moment, "Kopernik" was at altitude 250.]
(11:14:00) Flight 007: Runway course and 650.
This was the last transmission from "Kopernik".
Nine seconds later, the aircraft suddenly entered a steep dive. At 11:14:35, after 26 seconds of uncontrolled descent, the aircraft clipped a tree with its right wing and impacted the ice-covered moat
of a 19th-century military fortress with the speed of about 380 km/h (238 mph) at a 20-degree down angle, 950 meters away from the runway
threshold and 100 meters from a residential area. At the last moment Captain Paweł Lipowczan, using nothing but the plane’s ailerons, managed to avoid hitting a correctional facility for teenagers located at Rozwojowa street. On impact, the aircraft disintegrated; large part of the main hull submerged in the moat, while the tail and parts of the main landing gear landed a few meters further, just before the entrance to the fort. On the scene, a diving team was later trying to recover parts of the aircraft (including some of the engines) from the moat, but it was far too murky; finally, the moat had to be dried to allow the air crash investigation team to recover parts of the disintegrated plane. The body of Captain Lipowczan was found lying on the street about sixty meters from the crash site; other bodies were scattered between the plane parts.
Among the 87 fatalities were Polish singer Anna Jantar
, American ethnomusicologist Alan P. Merriam
, six Polish students returning home from an AIESEC
conference in New York and a contingent of the amateur U.S. boxing team. According to the doctors who arrived at the scene, many of the passengers were apparently asleep when the plane hit the ground, but some of them - including many of the boxers - were supposedly aware that they were about to crash, as they held to their seats so strongly that on impact, the muscles and tendons in their arms became severed. Some reports suggested that some of the boxers actually survived the crash and drowned in the moat, but no evidence for this was presented.
By ironic coincidence, at the time the "Kopernik" crashed, a conference on improvements in air travel safety was being held at Okęcie airport, less than a kilometer away.
In a twist of fate, Ryszard Chmielewski, the flight engineer, was scheduled to fly to Warsaw on that day; because he suffered from jet lag
and insufficient rest after the previous flight, he switched shifts with one of his colleagues and flew out of New York one day later. Seven years later, as a flight engineer and instructor, monitoring the progress of flight engineer Wojciech Kłossek, he was on board of LOT Flight 5055
, which crashed killing all 183 people on board.
While recovering the engines, the inner left engine - engine number 2 - was found to be cut in half, held together only by the fuel lines. When the engine was further examined, the disc of the low pressure turbine was found to be missing; despite extensive search, it was not found at the crash site. Finally, the turbine disc was found about four kilometres (2.5 miles) from the site; it was broken into three similar-sized pieces.
After recovering the cockpit, the throttles of both engine 2 and 3 (inner right) were found to be set to shutdown mode, while on engine 4 (outer right) the thrust was set to maximum. The investigating commission asked the Russians if Il-62 was able to reach the runway with one engine operating; no conclusive answer was received, but calculations based on the official technical data suggested that, while one engine thrust was insufficient for the aircraft to maintain altitude, it was enough to reach the runway and try to land. No explanation was found why the aircraft with one engine operating at maximum power suddenly entered a steep dive.
Detailed analysis of the pieces of the turbine disc found several metallic impurities on the edges of two of them; in one case, they were identified as coming from the engine nacelle, in another, the impurities came from the nacelle, the hull, the control pushers and finally, the electric wires. Also, detailed examination of the surface of the broken disc showed significant evidence of material fatigue.
and elevator
control pushers and destroyed the number 3 engine, causing loss of control over the plane; it also severed power cables for both the flight data recorder
and the cockpit voice recorder
. This caused the last moments of "Kopernik" not to be recorded.
The cut control pushers also explained the sudden steep dive. When they were cut, the horizontal stabilizer, under its own weight, dropped down, causing the nose also to go down. This could be counteracted by the vertical trim; in Il-62s, the switch setting the vertical trim to manual operation was secured by a thin, sharp wire. On Capt. Lipowczan's right hand, small wounds were found, and they were confirmed to be made while Lipowczan was still alive; supposedly, he ripped the security off and tried to control the vertical trim, but it was too late.
In an interview for Polish TV series The Black Series, Capt. Tomasz Smolicz, an experienced airline pilot who flew thousands of hours on transatlantic routes on Ilyushins Il-62 and Il-62M in the 1970s and 1980s (he flew "Kopernik" from Warsaw to New York on 13 March 1980), stated that the planes returning to Warsaw from America usually landed on runway course 155 (155 degrees, south-south-east), and if they landed at or before noon on a sunny day (such as on 14 March 1980), the sun was shining almost directly in their eyes, which were weary after several hours of night flight and constant monitoring of cockpit instruments; this sometimes caused disorientation and confusion if an indicator light actually was lit or not; so, on that day, the landing gear indicator could have actually been lit, but the crew members might have managed to see it incorrectly. During the recovery, the landing gear was found to be properly extended and locked.
jet engine
’s shaft, and weaknesses in the design of its turbine.
During the manufacturing of the low pressure shaft, at a location where its section diameter increases, a sharp, 90-degree step was made, resulting in a sudden diameter change over a very short linear length. In engineering terms, such sharp step instead of a radiused fillet causes a significant concentration of stress. This became a tragic, textbook example of stress concentration increase of a "stepped shaft", which in-turn initiated the formation of micro-cracks through the material core, a phenomenon known as material fatigue. Additionally, the metallurgical analysis found, that alloying impurities were present such as non-metallic inclusions in the alloy of the shaft, in addition to the incorrectly performed heat treatment
process, which further reduced the shaft's ability to carry the torsional loads as designed. The improperly machined engine shaft, coupled with metallurgical alloy impurities, facilitated an accelerated fatigue of this key engine component via unmitigated formation of micro-cracks through the shaft's core, ultimately leading to its failure.
Over time, the magnitude of the structural defects in "Kopernik"'s shaft reached a critical point, and the shaft broke, resulting in the physical separation of the low pressure turbine from the low pressure compressor. As a result, the low pressure turbine explosively disintegrated. Ejected with enormous force, pieces of turbines damaged 3 of the plane's 4 engines and cut through the hull, causing the failure of the vertical and horizontal flight controls (rudder
and elevator
), and a massive failure of numerous systems of the airplane. The sudden loss of control of the flight control surfaces caused a steep, unrecoverable dive, and resulted in a crash, 26 seconds from the time of the original failure.
A press article, released in Poland in 2010 and based on the review of archival documentation kept in IPN
claimed that PRL
authorities contributed to the crash by demanding savings from PLL LOT and excessive exploitation of engines. The article also claimed that, when the engine that disintegrated on 14 March 1980 was earlier found to have an unusually high level of shaft vibrations, the only solution implemented by Polish ground personnel was switching the engine between different Il-62s; also, the turbine disc exhibited evidence of some crude attempts to repair it, against the producer's regulation. Part of the claims of the article was subsequently dismissed by the ground personnel and aviation experts: the mechanics claimed that they reported the high vibration level to the engines' manufacturer, but the only response they received was the paper stating that "the level of vibrations reported does not exceed the levels found by the manufacturers as ordinary." (The Polish TV documentary exhibits those documents in their original form.) Having no technical possibility of getting inside the engine and check it (this also contradicts the claims that the turbine disc was tampered with by the ground personnel), the mechanics decided to switch the suspicious engine between different aircraft, to ensure that it gets on the aircraft where the other three engines are in the best condition so, in case it fails, the aircraft could continue flight on three remaining engines - no one suspected such failure could lead to loss of flight controls and two of three other engines.
jet engine, air is sucked from the front of the engine by the low pressure compressor. After passing the compressor, air is divided into two channels, outside and inside. From the inside channel, air travels into the high pressure compressor, after which it enters the combustion chamber. Each step from the low to high pressure compressor increases air pressure. In the combustion chamber, air is mixed with fuel and then ignited. As combustion occurs, ultra high pressure gases exit the rear of the combustion chamber, pass both turbines, mix with air from the outside channel, then exits the engine’s rear — generating engine thrust for the aircraft. On their way, the ultra high pressure gases meet a high pressure turbine and a low pressure turbine, and the angle of their blades forces both turbines to spin. Since the turbines are connected by a common shaft to the compressors, as both turbines spin, both compressors are forced to spin also. The spinning of the compressors is needed for engine work, as their rotation sucks air into the engine, as well as further pressurizing it once it is inside (as air passes through each step of the compressors).
As the #2 engine's low pressure shaft failed in the engine due to metal fatigue, the low pressure turbine become suddenly physically separated from the low pressure compressor, freeing the turbine. Because the engine combustion chamber was still producing power, the suddenly freed turbine spun out of control with such enormous speed that within a fraction of a second, the centrifugal force
caused the turbine to disintegrate explosively. Pieces of turbines were ejected in all directions with the speed of artillery shells.
; after that, the engines were taken back to the USSR.
The Polish commission report also called for some modernizations in the Il-62 project, most notably doubling the flight controls, so that if one system failed the plane would still be controllable. At the time, redundant controls of this kind were in general use in American and European-made airliners. This issue was never addressed by the Russians; none of their Ilyushin
s of all types had installed an alternate controls.
A small statue dedicated to the boxers who perished in the accident - a trigonal prism
made of bronze, with a knocked-out boxer statue at the top, is located at the grounds of Warsaw sport club Skra Warszawa. An identical statue is located at the United States Olympic Training Center in Colorado Springs. The statues were funded by Thomas Kane of Printon Kane and Company and AIBA
and designed by American sculptor Auldwin Thomas Schonberg.
The graves of the "Kopernik" crew are located at the Powązki Military Cemetery in Warsaw. One of the streets adjacent to the crash site bears the name of Captain Paweł Lipowczan.
LOT Polish Airlines
Polskie Linie Lotnicze LOT S.A. , trading as LOT Polish Airlines, is the flag carrier of Poland. Based in Warsaw, LOT was established in 1929, making it one of the world's oldest airlines still in operation. Using a fleet of 55 aircraft, LOT operates a complex network to 60 destinations in Europe,...
Flight 007 crashed near Okęcie Airport
Warsaw Frederic Chopin Airport
Warsaw Chopin Airport is an international airport located in the Włochy district of Warsaw, Poland. Poland's busiest airport, Warsaw Chopin handles just under 50% of the country's air passenger traffic....
in Warsaw
Warsaw
Warsaw is the capital and largest city of Poland. It is located on the Vistula River, roughly from the Baltic Sea and from the Carpathian Mountains. Its population in 2010 was estimated at 1,716,855 residents with a greater metropolitan area of 2,631,902 residents, making Warsaw the 10th most...
, Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
, on 14 March 1980, due to mechanical failure as the crew aborted a landing and attempted to go-around
Go-around
A go-around is an aborted landing of an aircraft that is on final approach.- Origin of the term :The term arises from the traditional use of traffic patterns at airfields. A landing aircraft will first join the circuit pattern and prepare for landing in an orderly fashion...
. All 87 crew and passengers died.
The aircraft
LOT initiated their transatlantic routes in the early 1970s, for which it decided to purchase the newly introduced Ilyushin Il-62Ilyushin Il-62
The Ilyushin Il-62 is a Soviet long-range jet airliner conceived in 1960 by Ilyushin. As successor to the popular turbo-prop Il-18 and with capacity for almost 200 passengers, the Il-62 was the largest jet airliner when it first flew in 1963. It entered Aeroflot service on 15 September 1967 with...
. The aircraft which crashed was the first Il-62 LOT had purchased for this purpose, manufactured in 1971. As all purchased Ilyushins, it was named after a famous Polish historical figure, in this case Nicolaus Copernicus
Nicolaus Copernicus
Nicolaus Copernicus was a Renaissance astronomer and the first person to formulate a comprehensive heliocentric cosmology which displaced the Earth from the center of the universe....
("Mikołaj Kopernik" in Polish).
Crash
On its final flight, the aircraft was piloted by Captain Paweł Lipowczan and First Officer Tadeusz Łochocki. Flight 007 was scheduled to depart from Kennedy International Airport at about 19:00 local time on 13 March 1980, but it was delayed because of a heavy snowstorm. It finally departed at 21:18, and after nine hours of an uneventful flight, it was approaching Warsaw Airport at 11:13 local time. During their final approachFinal approach (aviation)
A final approach is the last leg in an aircraft's approach to landing. In aviation radio terminology, it is often shortened to "final".In a standard airport landing pattern, which is usually used under visual meteorological conditions , aircraft turn from base leg to final within one to two miles...
, about one minute before the landing, the crew reported to Okęcie Air Traffic Control that the landing gear indicator light was not operating, and that they would go-around
Go-around
A go-around is an aborted landing of an aircraft that is on final approach.- Origin of the term :The term arises from the traditional use of traffic patterns at airfields. A landing aircraft will first join the circuit pattern and prepare for landing in an orderly fashion...
and allow the flight engineer
Flight engineer
Flight engineers work in three types of aircraft: fixed-wing , rotary wing , and space flight .As airplanes became even larger requiring more engines and complex systems to operate, the workload on the two pilots became excessive during certain critical parts of the flight regime, notably takeoffs...
to check if it was caused by a burnt-out fuse or lightbulb, or if there was actually some problem with the gears deploying. This was a common occurrence among Ilyushin
Ilyushin
Open Joint Stock Company «Ilyushin Aviation Complex» , operating as Ilyushin or Ilyushin Design Bureau, is a Russian design bureau and aircraft manufacturer, founded by Sergey Vladimirovich Ilyushin. Ilyushin was established under the Soviet Union. Its operations began on January 13, 1933, by...
s and rarely indicated a serious problem.
(11:13:46) Okęcie Air Traffic Control: Flight 007, 5 degrees to the right.
(11:13:52) Okęcie ATC: Flight 007?
(11:13:54) Flight 007: Yes, acknowledged that... One moment, we have some problems with landing-gear-down-and-locked indicator, request a go-around.
(11:13:57) Okęcie ATC: Acknowledged, runway course and altitude 650. [At the moment, "Kopernik" was at altitude 250.]
(11:14:00) Flight 007: Runway course and 650.
This was the last transmission from "Kopernik".
Nine seconds later, the aircraft suddenly entered a steep dive. At 11:14:35, after 26 seconds of uncontrolled descent, the aircraft clipped a tree with its right wing and impacted the ice-covered moat
Moat
A moat is a deep, broad ditch, either dry or filled with water, that surrounds a castle, other building or town, historically to provide it with a preliminary line of defence. In some places moats evolved into more extensive water defences, including natural or artificial lakes, dams and sluices...
of a 19th-century military fortress with the speed of about 380 km/h (238 mph) at a 20-degree down angle, 950 meters away from the runway
Runway
According to ICAO a runway is a "defined rectangular area on a land aerodrome prepared for the landing and take-off of aircraft." Runways may be a man-made surface or a natural surface .- Orientation and dimensions :Runways are named by a number between 01 and 36, which is generally one tenth...
threshold and 100 meters from a residential area. At the last moment Captain Paweł Lipowczan, using nothing but the plane’s ailerons, managed to avoid hitting a correctional facility for teenagers located at Rozwojowa street. On impact, the aircraft disintegrated; large part of the main hull submerged in the moat, while the tail and parts of the main landing gear landed a few meters further, just before the entrance to the fort. On the scene, a diving team was later trying to recover parts of the aircraft (including some of the engines) from the moat, but it was far too murky; finally, the moat had to be dried to allow the air crash investigation team to recover parts of the disintegrated plane. The body of Captain Lipowczan was found lying on the street about sixty meters from the crash site; other bodies were scattered between the plane parts.
Among the 87 fatalities were Polish singer Anna Jantar
Anna Jantar
Anna Jantar-Kukulska was a popular Polish singer and mother of Natalia Kukulska.Born in Poznań as Anna Maria Szmeterling, she graduated from Adam Mickiewicz University in Poznań. She began her career in 1968 with the song Po ten kwiat czerwony. A year later she became the lead vocalist of the band...
, American ethnomusicologist Alan P. Merriam
Alan P. Merriam
Alan Parkhurst Merriam was an ethnomusicologist during the last half of the twentieth century. He is remembered primarily for his book, The Anthropology of Music, in which he promotes the study of music from an anthropological perspective and with anthropological methods.In , Merriam proposed a...
, six Polish students returning home from an AIESEC
AIESEC
AIESEC is a global youth organisation that develops leadership capabilities through their internal leadership programmes and engaging students and graduates in international student exchange and internship programmes for profit and non-profit organisations. Its international office is in...
conference in New York and a contingent of the amateur U.S. boxing team. According to the doctors who arrived at the scene, many of the passengers were apparently asleep when the plane hit the ground, but some of them - including many of the boxers - were supposedly aware that they were about to crash, as they held to their seats so strongly that on impact, the muscles and tendons in their arms became severed. Some reports suggested that some of the boxers actually survived the crash and drowned in the moat, but no evidence for this was presented.
By ironic coincidence, at the time the "Kopernik" crashed, a conference on improvements in air travel safety was being held at Okęcie airport, less than a kilometer away.
In a twist of fate, Ryszard Chmielewski, the flight engineer, was scheduled to fly to Warsaw on that day; because he suffered from jet lag
Jet lag
Jet lag, medically referred to as desynchronosis, is a physiological condition which results from alterations to the body's circadian rhythms; it is classified as one of the circadian rhythm sleep disorders...
and insufficient rest after the previous flight, he switched shifts with one of his colleagues and flew out of New York one day later. Seven years later, as a flight engineer and instructor, monitoring the progress of flight engineer Wojciech Kłossek, he was on board of LOT Flight 5055
LOT Polish Airlines Flight 5055
LOT Polish Airlines Flight 5055 crashed in the Kabaty Woods nature reserve on the outskirts of Warsaw on May 9, 1987. The aircraft was an Ilyushin Il-62M bearing the name Tadeusz Kościuszko...
, which crashed killing all 183 people on board.
| Nationality | Passengers | Crew | Total |
|---|---|---|---|
| 42 | 10 | 52 | |
| 28 | 0 | 28 | |
| 4 | 0 | 4 | |
| 3 | 0 | 3 | |
| Total | 77 | 10 | 87 |
Investigation
The militiamen quickly surrounded the site and removed any spectators; recovery of airplane pieces started soon. Both the cockpit voice recorder and flight data recorder were found quickly; unfortunately, the recording suddenly stopped nine seconds after the last transmission, 26 seconds before the crash.While recovering the engines, the inner left engine - engine number 2 - was found to be cut in half, held together only by the fuel lines. When the engine was further examined, the disc of the low pressure turbine was found to be missing; despite extensive search, it was not found at the crash site. Finally, the turbine disc was found about four kilometres (2.5 miles) from the site; it was broken into three similar-sized pieces.
After recovering the cockpit, the throttles of both engine 2 and 3 (inner right) were found to be set to shutdown mode, while on engine 4 (outer right) the thrust was set to maximum. The investigating commission asked the Russians if Il-62 was able to reach the runway with one engine operating; no conclusive answer was received, but calculations based on the official technical data suggested that, while one engine thrust was insufficient for the aircraft to maintain altitude, it was enough to reach the runway and try to land. No explanation was found why the aircraft with one engine operating at maximum power suddenly entered a steep dive.
Detailed analysis of the pieces of the turbine disc found several metallic impurities on the edges of two of them; in one case, they were identified as coming from the engine nacelle, in another, the impurities came from the nacelle, the hull, the control pushers and finally, the electric wires. Also, detailed examination of the surface of the broken disc showed significant evidence of material fatigue.
Sequence of events
Finally, when the control pushers were found to be cut in half, it was proven that the cut was not caused by the crash, and some traces of the metal alloy the turbine disc was made of was found on the surface of the cut, the sequence of events became clear. The disaster started when "Kopernik" was instructed to climb to a higher flight level. When the necessary thrust was applied to all four engines, the low-pressure turbine of the number 2 engine disintegrated explosively after 9 seconds. One piece of the turbine disc got ejected upwards, not causing any significant damage; the second piece shot into the engine number 1, damaging it seriously; finally, the third piece of the disc shot into the hull, severed the rudderRudder
A rudder is a device used to steer a ship, boat, submarine, hovercraft, aircraft or other conveyance that moves through a medium . On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane...
and elevator
Elevator (aircraft)
Elevators are flight control surfaces, usually at the rear of an aircraft, which control the aircraft's orientation by changing the pitch of the aircraft, and so also the angle of attack of the wing. In simplified terms, they make the aircraft nose-up or nose-down...
control pushers and destroyed the number 3 engine, causing loss of control over the plane; it also severed power cables for both the flight data recorder
Flight data recorder
A flight data recorder is an electronic device employed to record any instructions sent to any electronic systems on an aircraft. It is a device used to record specific aircraft performance parameters...
and the cockpit voice recorder
Cockpit voice recorder
A cockpit voice recorder , often referred to as a "black box", is a flight recorder used to record the audio environment in the flight deck of an aircraft for the purpose of investigation of accidents and incidents...
. This caused the last moments of "Kopernik" not to be recorded.
The cut control pushers also explained the sudden steep dive. When they were cut, the horizontal stabilizer, under its own weight, dropped down, causing the nose also to go down. This could be counteracted by the vertical trim; in Il-62s, the switch setting the vertical trim to manual operation was secured by a thin, sharp wire. On Capt. Lipowczan's right hand, small wounds were found, and they were confirmed to be made while Lipowczan was still alive; supposedly, he ripped the security off and tried to control the vertical trim, but it was too late.
In an interview for Polish TV series The Black Series, Capt. Tomasz Smolicz, an experienced airline pilot who flew thousands of hours on transatlantic routes on Ilyushins Il-62 and Il-62M in the 1970s and 1980s (he flew "Kopernik" from Warsaw to New York on 13 March 1980), stated that the planes returning to Warsaw from America usually landed on runway course 155 (155 degrees, south-south-east), and if they landed at or before noon on a sunny day (such as on 14 March 1980), the sun was shining almost directly in their eyes, which were weary after several hours of night flight and constant monitoring of cockpit instruments; this sometimes caused disorientation and confusion if an indicator light actually was lit or not; so, on that day, the landing gear indicator could have actually been lit, but the crew members might have managed to see it incorrectly. During the recovery, the landing gear was found to be properly extended and locked.
Causes of disaster
According to the Polish government's Special Disaster Commission, the crash was caused by defects in materials, faults in the manufacturing process of the Kuznetsov NK-8Kuznetsov NK-8
The NK-8 was a low-bypass turbofan engine built by the Kuznetsov Design Bureau, in the 20,000 lbf thrust class. It powered production models of the Ilyushin Il-62 and the Tupolev Tu-154A and B models.-External links: - NK-8...
jet engine
Jet engine
A jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
’s shaft, and weaknesses in the design of its turbine.
During the manufacturing of the low pressure shaft, at a location where its section diameter increases, a sharp, 90-degree step was made, resulting in a sudden diameter change over a very short linear length. In engineering terms, such sharp step instead of a radiused fillet causes a significant concentration of stress. This became a tragic, textbook example of stress concentration increase of a "stepped shaft", which in-turn initiated the formation of micro-cracks through the material core, a phenomenon known as material fatigue. Additionally, the metallurgical analysis found, that alloying impurities were present such as non-metallic inclusions in the alloy of the shaft, in addition to the incorrectly performed heat treatment
Heat treatment
Heat treating is a group of industrial and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical. Heat treatments are also used in the manufacture of many other materials, such as glass...
process, which further reduced the shaft's ability to carry the torsional loads as designed. The improperly machined engine shaft, coupled with metallurgical alloy impurities, facilitated an accelerated fatigue of this key engine component via unmitigated formation of micro-cracks through the shaft's core, ultimately leading to its failure.
Over time, the magnitude of the structural defects in "Kopernik"'s shaft reached a critical point, and the shaft broke, resulting in the physical separation of the low pressure turbine from the low pressure compressor. As a result, the low pressure turbine explosively disintegrated. Ejected with enormous force, pieces of turbines damaged 3 of the plane's 4 engines and cut through the hull, causing the failure of the vertical and horizontal flight controls (rudder
Rudder
A rudder is a device used to steer a ship, boat, submarine, hovercraft, aircraft or other conveyance that moves through a medium . On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane...
and elevator
Elevator (aircraft)
Elevators are flight control surfaces, usually at the rear of an aircraft, which control the aircraft's orientation by changing the pitch of the aircraft, and so also the angle of attack of the wing. In simplified terms, they make the aircraft nose-up or nose-down...
), and a massive failure of numerous systems of the airplane. The sudden loss of control of the flight control surfaces caused a steep, unrecoverable dive, and resulted in a crash, 26 seconds from the time of the original failure.
A press article, released in Poland in 2010 and based on the review of archival documentation kept in IPN
IPN
IPN may refer to:* Intuit PaymentNetwork* Independent Practitioners Network* Infectious pancreatic necrosis, disease in fishes* Instant Private Network, type of VPN...
claimed that PRL
PRL
PRL may refer to:* Parameter Request List, a DHCP option* Parti Réformateur Libéral, a former Belgian political party* Penn Eastern Rail Lines* Pennine Radio Limited...
authorities contributed to the crash by demanding savings from PLL LOT and excessive exploitation of engines. The article also claimed that, when the engine that disintegrated on 14 March 1980 was earlier found to have an unusually high level of shaft vibrations, the only solution implemented by Polish ground personnel was switching the engine between different Il-62s; also, the turbine disc exhibited evidence of some crude attempts to repair it, against the producer's regulation. Part of the claims of the article was subsequently dismissed by the ground personnel and aviation experts: the mechanics claimed that they reported the high vibration level to the engines' manufacturer, but the only response they received was the paper stating that "the level of vibrations reported does not exceed the levels found by the manufacturers as ordinary." (The Polish TV documentary exhibits those documents in their original form.) Having no technical possibility of getting inside the engine and check it (this also contradicts the claims that the turbine disc was tampered with by the ground personnel), the mechanics decided to switch the suspicious engine between different aircraft, to ensure that it gets on the aircraft where the other three engines are in the best condition so, in case it fails, the aircraft could continue flight on three remaining engines - no one suspected such failure could lead to loss of flight controls and two of three other engines.
The engine shaft’s explosive disintegration
In the Kuznetsov NK-8Kuznetsov NK-8
The NK-8 was a low-bypass turbofan engine built by the Kuznetsov Design Bureau, in the 20,000 lbf thrust class. It powered production models of the Ilyushin Il-62 and the Tupolev Tu-154A and B models.-External links: - NK-8...
jet engine, air is sucked from the front of the engine by the low pressure compressor. After passing the compressor, air is divided into two channels, outside and inside. From the inside channel, air travels into the high pressure compressor, after which it enters the combustion chamber. Each step from the low to high pressure compressor increases air pressure. In the combustion chamber, air is mixed with fuel and then ignited. As combustion occurs, ultra high pressure gases exit the rear of the combustion chamber, pass both turbines, mix with air from the outside channel, then exits the engine’s rear — generating engine thrust for the aircraft. On their way, the ultra high pressure gases meet a high pressure turbine and a low pressure turbine, and the angle of their blades forces both turbines to spin. Since the turbines are connected by a common shaft to the compressors, as both turbines spin, both compressors are forced to spin also. The spinning of the compressors is needed for engine work, as their rotation sucks air into the engine, as well as further pressurizing it once it is inside (as air passes through each step of the compressors).
As the #2 engine's low pressure shaft failed in the engine due to metal fatigue, the low pressure turbine become suddenly physically separated from the low pressure compressor, freeing the turbine. Because the engine combustion chamber was still producing power, the suddenly freed turbine spun out of control with such enormous speed that within a fraction of a second, the centrifugal force
Centrifugal force
Centrifugal force can generally be any force directed outward relative to some origin. More particularly, in classical mechanics, the centrifugal force is an outward force which arises when describing the motion of objects in a rotating reference frame...
caused the turbine to disintegrate explosively. Pieces of turbines were ejected in all directions with the speed of artillery shells.
Aftermath
The Polish government's Special Disaster Commission sent its findings on the cause of the accident to Moscow. In response, Russian engineers and scientists stated that the reasons given were implausible and that the turbine disintegrated because of engine failure, contrary to what was stated in the Polish report. (This could partially be attributed to a grudge Russian engineers held against Poles, who purchased their Ilyushins but replaced their radionavigational systems with separately purchased, more modern American ones.) Many years later it was revealed that after Flight 007's crash, all Il-62s used by Russian officials and VIPs had their engines discreetly replaced with newer ones. At one occasion, Polish governmental Il-62M had had specially installed newer engines for a joint Polish-Russian governmental trip to BeijingBeijing
Beijing , also known as Peking , is the capital of the People's Republic of China and one of the most populous cities in the world, with a population of 19,612,368 as of 2010. The city is the country's political, cultural, and educational center, and home to the headquarters for most of China's...
; after that, the engines were taken back to the USSR.
The Polish commission report also called for some modernizations in the Il-62 project, most notably doubling the flight controls, so that if one system failed the plane would still be controllable. At the time, redundant controls of this kind were in general use in American and European-made airliners. This issue was never addressed by the Russians; none of their Ilyushin
Ilyushin
Open Joint Stock Company «Ilyushin Aviation Complex» , operating as Ilyushin or Ilyushin Design Bureau, is a Russian design bureau and aircraft manufacturer, founded by Sergey Vladimirovich Ilyushin. Ilyushin was established under the Soviet Union. Its operations began on January 13, 1933, by...
s of all types had installed an alternate controls.
A small statue dedicated to the boxers who perished in the accident - a trigonal prism
Prism (geometry)
In geometry, a prism is a polyhedron with an n-sided polygonal base, a translated copy , and n other faces joining corresponding sides of the two bases. All cross-sections parallel to the base faces are the same. Prisms are named for their base, so a prism with a pentagonal base is called a...
made of bronze, with a knocked-out boxer statue at the top, is located at the grounds of Warsaw sport club Skra Warszawa. An identical statue is located at the United States Olympic Training Center in Colorado Springs. The statues were funded by Thomas Kane of Printon Kane and Company and AIBA
International Boxing Association
The International Boxing Association is a for-profit organization that sanctions professional boxing matches and awards world and subordinate championships.- Origins :...
and designed by American sculptor Auldwin Thomas Schonberg.
The graves of the "Kopernik" crew are located at the Powązki Military Cemetery in Warsaw. One of the streets adjacent to the crash site bears the name of Captain Paweł Lipowczan.
See also
- List of notable accidents and incidents on commercial aircraft
- List of Poland disasters by death toll
- LOT Polish Airlines Flight 5055LOT Polish Airlines Flight 5055LOT Polish Airlines Flight 5055 crashed in the Kabaty Woods nature reserve on the outskirts of Warsaw on May 9, 1987. The aircraft was an Ilyushin Il-62M bearing the name Tadeusz Kościuszko...
External links
- Planecrash Info accident report
- Polish press article (polish language)
- Wikipedia map disaster site
- Materials publicized on Polish version of Wikipedia dedicated to same subject
Plane pictures
- http://aviation-safety.net/photos/displayphoto.php?id=19800314-1&vnr=1&kind=PC
- http://www.planepictures.net/netshow.php?id=425406
Disaster site pictures
- Planecrashinfo.com photo and report
- http://republika.pl/blog_ft_239514/338340/tr/kopernik.jpg
- http://republika.pl/blog_ft_239514/338340/tr/kopernik1.jpg