World Library  
Flag as Inappropriate
Email this Article

Lufthansa Flight 2904

Article Id: WHEBN0008107688
Reproduction Date:

Title: Lufthansa Flight 2904  
Author: World Heritage Encyclopedia
Language: English
Subject: Aviation accidents and incidents in 1993, Indian Airlines Flight 427, China Eastern Airlines Flight 5398, History of Poland (1989–present), Indian Airlines Flight 491
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Lufthansa Flight 2904

Lufthansa Flight 2904
Wreckage of Flight 2904 on 15 September 1993
Accident summary
Date 14 September 1993
Summary Overshot runway, pilot error
Site Warsaw, Poland
Passengers 64
Crew 6
Injuries (non-fatal) 68
Fatalities 2
Survivors 68
Aircraft type Airbus A320-211
Operator Lufthansa
Registration D-AIPN

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.

Description of the incident

Illustration of time elapsed between touchdown of the first main strut, the second, and engagement of brakes.

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.[1] 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 (37 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 (37 km/h) and the increased speed the airplane hit the ground at approximately 170 knots (310 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 start to deploy, these systems depending on oleo strut (shock absorber) compression. The wheel brakes, triggered by wheel rotation being equal to or greater than 72 knots (133 km/h) began to operate about 4 seconds later.

The residual length of the runway (left from the moment when braking systems had begun to work) was too short to enable the aircraft to stop on the remaining runway. 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 (133 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 training captain (seated in the right seat) 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."[1]

Causes of this accident

The main 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 airport; accompanied by intensive variation of wind parameters as well as by heavy rain on the runway itself.

One additional cause was the lack of current wind information at the tower. For that reason no up-to-date wind information could be transmitted to the crew.

Further additional causes were certain design features of the aircraft. Computer logics prevented the activation of both ground spoilers and thrust reversers until a minimum compression load of at least 6.3 tons was sensed on each main landing gear strut, thus preventing the crew from achieving any braking action by the two systems before this condition is met.

Details about the design features of the aircraft

To ensure that the thrust-reverse system and the spoilers 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 at least one of the following two conditions is true:

  • there must be weight of at least 6.3 tons on each main landing gear strut
  • the wheels of the plane must be turning faster than 72 knots (133 km/h)

The thrust reversers are only activated if the first condition is true. There is no way for the pilots 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 combined required to trigger the sensor was not reached. Point two was not fulfilled either due to 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.

Illustration of distance relative to main strut touchdown. The striped line marks 1400 m, which divides the runway in half. Red indicates the landing gear have not touched down, blue indicates hydroplaning, and green indicates wheels on the ground.

As a result of the accident, Airbus Industrie changed the required compression value from 6.3 tons to just 2 tons per main landing gear.

Notable passengers

  • Dr. Franz Bertele, the German ambassador to Poland, and his wife received slight injuries[1]
  • Marcin Bronikowski, well known Polish opera singer, baritone, received slight back injuries[1]

References

  1. ^ a b c "Jet breaks up in Poland; 2 dead, 45 hurt." Associated Press/Houston Chronicle. Wednesday 15 September 1993. Section A, Page 11, 4 Star.

External links

  • Accident description at the Aviation Safety Network
  • "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 Web 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.

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.