Lufthansa Flight 2904
Encyclopedia
Lufthansa
Flight 2904 was an Airbus A320-200
which overran the runway, in Okęcie International Airport
on 14 September 1993. It was a flight from Frankfurt
, Germany
to Warsaw
, Poland
.
Lufthansa Flight 2904 was cleared to land at Okęcie International Airport
Rwy 11 and was informed of the existence of wind shear
on the approach.http://www.rvs.uni-bielefeld.de/publications/Incidents/DOCS/ComAndRep/Warsaw/warsaw-report.html To compensate for the crosswind
, the pilots attempted to touch down with the aircraft banked slightly to the right. Additionally they landed with a speed about 20 knots (39.2 km/h) faster than usual. According to the manual, this was the correct procedure for the reported weather conditions. But the weather report was not up to date. At the moment of touch down, the assumed crosswind
turned out to be a tailwind
. Due to the tailwind of approximately 20 knots (39.2 km/h) and the increased speed the
airplane hit the ground at approximately 170 knots (333.2 km/h) and far beyond the normal touch down point. The aircraft's right gear touched down 770 m from the runway 11 threshold
. The left gear touched down 9 seconds later, 1525 m from the threshold. Only when the left gear touched the runway
did the ground spoilers and engine thrust reversers
deploy, these automatic systems depending on oleo strut (shock absorber
) compression. The wheel brakes, triggered by wheel rotation being equal to or greater than 72 knots (141.1 km/h) began to operate after about 4 seconds. Seeing the approaching end of the runway and the obstacle behind it, the pilot steered the aircraft off the runway to the right. The aircraft departed the runway at a speed of 72 knots (141.1 km/h) and rolled 90 m before it hit the embankment and an LLZ aerial with the left wing. A fire started in the left wing area and penetrated into the passenger cabin
. Two of 70 occupants died in this accident, including the co-pilot who died on impact and one passenger who was unable to escape because he lost consciousness as a result of the smoke in the cabin.
Marcin Bronikowski, a passenger, told Warsaw
Radio ZET
station that the incident occurred "in a fraction of a second after landing" and that "there was even hand-clapping after the landing."
; accompanied by intensive variation of wind parameters as well as by heavy rain on the runway itself.
s are only activated in a landing situation
, the software has to be sure the airplane is on the ground even if the systems are selected mid-air. The spoilers are only activated if either of these conditions are true:
The thrust reversers are only activated if the latter condition is true. There is no way for the pilot to override the software decision and activate either system manually.
In the case of the Warsaw accident neither of the first two conditions was fulfilled, so the most effective braking system was not activated. Point one was not fulfilled, because the plane landed inclined (to counteract the anticipated crosswind). Thus the pressure of 12 tons on both landing gears required to trigger the sensor was not reached. Point two was also not fulfilled because of a hydroplaning effect
on the wet runway.
Only when the left landing gear touched the runway did the automatic aircraft systems allow the ground spoilers and engine thrust reversers to operate. Due to the braking distances in the heavy rain the aircraft could not stop before the end of the runway. The computer did not actually know the aircraft had landed until it was already 125 meters beyond the half way point of runway 11.
Lufthansa
Deutsche Lufthansa AG is the flag carrier of Germany and the largest airline in Europe in terms of overall passengers carried. The name of the company is derived from Luft , and Hansa .The airline is the world's fourth-largest airline in terms of overall passengers carried, operating...
Flight 2904 was an Airbus A320-200
Airbus A320
The Airbus A320 family is a family of short- to medium-range, narrow-body, commercial passenger jet airliners manufactured by Airbus Industrie.Airbus was originally a consortium of European aerospace companies, and is now fully owned by EADS. Airbus's name has been Airbus SAS since 2001...
which overran the runway, in Okęcie International 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....
on 14 September 1993. It was a flight from Frankfurt
Frankfurt
Frankfurt am Main , commonly known simply as Frankfurt, is the largest city in the German state of Hesse and the fifth-largest city in Germany, with a 2010 population of 688,249. The urban area had an estimated population of 2,300,000 in 2010...
, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
to 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...
.
Description of the incident
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....
Rwy 11 and was informed of the existence of wind shear
Wind shear
Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and direction over a relatively short distance in the atmosphere...
on the approach.http://www.rvs.uni-bielefeld.de/publications/Incidents/DOCS/ComAndRep/Warsaw/warsaw-report.html To compensate for the crosswind
Crosswind
A crosswind is any wind that has a perpendicular component to the line or direction of travel. In aviation, a crosswind is the component of wind that is blowing across the runway making landings and take-offs more difficult than if the wind were blowing straight down the runway...
, the pilots attempted to touch down with the aircraft banked slightly to the right. Additionally they landed with a speed about 20 knots (39.2 km/h) faster than usual. According to the manual, this was the correct procedure for the reported weather conditions. But the weather report was not up to date. At the moment of touch down, the assumed crosswind
Crosswind
A crosswind is any wind that has a perpendicular component to the line or direction of travel. In aviation, a crosswind is the component of wind that is blowing across the runway making landings and take-offs more difficult than if the wind were blowing straight down the runway...
turned out to be a tailwind
Tailwind
A tailwind is a wind that blows in the direction of travel of an object, while a headwind blows against the direction of travel. A tailwind increases the object's speed and reduces the time required to reach its destination, while a headwind has the opposite effect...
. Due to the tailwind of approximately 20 knots (39.2 km/h) and the increased speed the
airplane hit the ground at approximately 170 knots (333.2 km/h) and far beyond the normal touch down point. The aircraft's right gear touched down 770 m from the runway 11 threshold
Displaced threshold
A displaced threshold is a runway threshold located at a point other than the physical beginning or end of the runway. The portion of the runway so displaced may be used for takeoff but not for landing...
. The left gear touched down 9 seconds later, 1525 m from the threshold. Only when the left gear touched 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...
did the ground spoilers and engine thrust reversers
Thrust reversal
Thrust reversal, also called reverse thrust, is the temporary diversion of an aircraft engine's exhaust or changing of propeller pitch so that the thrust produced is directed forward, rather than aft. This acts against the forward travel of the aircraft, providing deceleration...
deploy, these automatic systems depending on oleo strut (shock absorber
Shock absorber
A shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy. It is a type of dashpot.-Nomenclature:...
) compression. The wheel brakes, triggered by wheel rotation being equal to or greater than 72 knots (141.1 km/h) began to operate after about 4 seconds. Seeing the approaching end of the runway and the obstacle behind it, the pilot steered the aircraft off the runway to the right. The aircraft departed the runway at a speed of 72 knots (141.1 km/h) and rolled 90 m before it hit the embankment and an LLZ aerial with the left wing. A fire started in the left wing area and penetrated into the passenger cabin
Aircraft cabin
An aircraft cabin is the section of an aircraft in which passengers travel. At cruising altitudes of modern commercial aircraft the surrounding atmosphere is too thin to breathe without an oxygen mask, so cabins are pressurized at a higher pressure than ambient pressure at altitude.In commercial...
. Two of 70 occupants died in this accident, including the co-pilot who died on impact and one passenger who was unable to escape because he lost consciousness as a result of the smoke in the cabin.
Marcin Bronikowski, a passenger, told 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...
Radio ZET
Radio Zet
Radio ZET – Polish commercial radio station. The current owner of the station is Eurozet. The editor-in-chief of Radio ZET is Mateusz Kirstein. The Radio started broadcasting on 28 September 1990, being the first private radio station in Warsaw.-History:...
station that the incident occurred "in a fraction of a second after landing" and that "there was even hand-clapping after the landing."
Causes of this accident
The cause of the accident was incorrect decisions and actions of the flight crew. Some of the incorrect decisions were taken when information about windshear was received by the crew. The windshear was produced by the front passing over the airportAirport
An airport is a location where aircraft such as fixed-wing aircraft, helicopters, and blimps take off and land. Aircraft may be stored or maintained at an airport...
; accompanied by intensive variation of wind parameters as well as by heavy rain on the runway itself.
Details about the design features of the aircraft
To ensure that the thrust-reverse system and the spoilerSpoiler (aeronautics)
In aeronautics, a spoiler is a device intended to reduce lift in an aircraft. Spoilers are plates on the top surface of a wing which can be extended upward into the airflow and spoil it. By doing so, the spoiler creates a carefully controlled stall over the portion of the wing behind it, greatly...
s are only activated in a landing situation
Landing
thumb|A [[Mute Swan]] alighting. Note the ruffled feathers on top of the wings indicate that the swan is flying at the [[Stall |stall]]ing speed...
, the software has to be sure the airplane is on the ground even if the systems are selected mid-air. The spoilers are only activated if either of these conditions are true:
- there must be weight of over 12 tonTonThe ton is a unit of measure. It has a long history and has acquired a number of meanings and uses over the years. It is used principally as a unit of weight, and as a unit of volume. It can also be used as a measure of energy, for truck classification, or as a colloquial term.It is derived from...
s on each main landing gear strut - the wheels of the plane must be turning faster than 72 knots (141.1 km/h)
The thrust reversers are only activated if the latter condition is true. There is no way for the pilot to override the software decision and activate either system manually.
In the case of the Warsaw accident neither of the first two conditions was fulfilled, so the most effective braking system was not activated. Point one was not fulfilled, because the plane landed inclined (to counteract the anticipated crosswind). Thus the pressure of 12 tons on both landing gears required to trigger the sensor was not reached. Point two was also not fulfilled because of a hydroplaning effect
Hydroplaning (road vehicle)
Aquaplaning or hydroplaning by the tires of a road vehicle, aircraft or sometimes roller coaster occurs when a layer of water builds between the rubber tires of the vehicle and the road surface, leading to the loss of traction and thus preventing the vehicle from responding to control inputs such...
on the wet runway.
Only when the left landing gear touched the runway did the automatic aircraft systems allow the ground spoilers and engine thrust reversers to operate. Due to the braking distances in the heavy rain the aircraft could not stop before the end of the runway. The computer did not actually know the aircraft had landed until it was already 125 meters beyond the half way point of runway 11.
Notable passengers
- Dr. Franz Bertele, the German ambassador to Poland, and his wife received slight injuries
- Marcin Bronikowski, well known Polish opera singer, baritone, received slight back injuries
Flight number
Lufthansa stopped using the number 2904 for this flight and re-numbered to 3302, whilst others on the same route were re-numbered to 3300 and 3304, respectively. In November 2010, the Frankfurt-Warsaw route received the flight numbers 1346, 1348 and 1350 as part of a general re-numbering of the entire European network. As of October 27, 2011, the number 2904 is again used (Berlin to Nurnberg flight).External links
- "Report on the Accident to Airbus A320-211 Aircraft in Warsaw on 14 September 1993" (Archive) - Main Commission Aircraft Accident Investigation
- Appendices (Archive) - Prepared for the World Wide WebWorld Wide WebThe World Wide Web is a system of interlinked hypertext documents accessed via the Internet...
and edited by Marco Gröning - He scanned a photocopy of the report using Deskscan II. The sizes of most of the images of the figures were around 450KB-600KB. Gröning used Paint Shop Pro 4.12 shareware to enhance the images, working over them by hand. This allowed him to reduce the images by an order or magnitude or more without compromising readability. Gröning said that in some cases this enhanced the readability.
- Appendices (Archive) - Prepared for the World Wide Web