Show 37: Analysis of Second Interim AAIB
Report Concerning the Crash
of a British Airways 777
Title: Crash of British Airways 777 at Heathrow on 17 January 2008 - Update 2
Date: 25 January 2008; Length: 6:38
This second update includes information from the AAIB's interim report of 23 January 2008. You can listen to or watch the podcast at the following links:
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Accident investigation details
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0:30: Accident overview
0:55: Role of the Air Accidents Investigations Branch (AAIB)
1:10: Review of information provided by the initial AAIB report
1:48: Review of information from the second report from 23 January 2008
2:22: Overview of ongoing AAIB actions and areas of interest
3:55: Suggestions for evaluating news about the accident
4:40: Suggested accident-related resources
5:17: Suggested tool for analyzing and understanding aviation safety data
5:52: Credits and copyright information
Hello, and welcome to the Conversation at AirSafe.com, sponsored by Speedbrake Publishing. I'm your host Dr. Todd Curtis, the creator of AirSafe.com, your reliable source of airline safety and security information since 1996.
In this Conversation, I’d like to discuss the latest official update from the investigation into the crash of a British Airways 777 at London’s Heathrow Airport on the 17th of January 2008.
Although the aircraft was substantially damaged by the crash, there was only one serious injury among the 136 passengers, and no serious injuries among the 16 crew members.
This was a scheduled international flight from Beijing, China to London, England. The flight was routine until about two miles from touchdown. The engines would not respond to commands to increase thrust, and as a result the aircraft touched down about 1000 feet short of the runway.
The Air Accidents Investigation Branch of the UK’s Department of Transport is the lead agency in this investigation. They released an initial report about their investigation on the 18th of January, a day after the accident, and a second update on the 23rd of January.
In the initial report, the AAIB stated that the flight was normal and uneventful until the aircraft was on final approach for runway 27L.
At about 600 feet above the ground, the autothrottle system commanded an increase of engine thrust to maintain the aircraft’s flight path angle.
The engines did not respond to this command, and also did not respond when the crew manually commanded an increase in thrust.
During a standard approach, the aircraft is flown at a shallow three degree flight path angle.
The pilot flying, in this case the first officer, increased the flight path angle after the engines failed to respond to thrust commands.
The aircraft cleared the airport’s perimeter fence before landing in a grassy area short of the runway.
The second AAIB update from the 23rd of January provided additional details about the behavior of the aircraft:
- During final approach, the engines initially responded to autothrust commands to increase thrust.
- The right engine thrust reduced about three seconds after this command, and about eight seconds later, thrust on left engine reduced to similar levels.
- The engines continued to produce thrust above flight idle but below the commanded level.
- Recorded data indicate there was adequate fuel, and that the autothrottle and engine controls performed as expected prior to, and after, reduction of thrust.
The AAIB continues to look at all scenarios that could explain thrust reduction, as well as scenarios that would explain the lack of response to throttle level inputs. The AAIB is also performing a detailed analysis and examination of the complete fuel flow path from the aircraft tanks to the engine fuel nozzles. The AAIB is also closely cooperating with Boeing, Rolls-Royce, and British Airways, all of whom also have representatives within the investigation team.
The investigation is still in its earliest stages, and many possible explanations for the accident still exist:
- The investigation may exclude some possibilities, but further investigation may reveal others.
- Given the current direction of the investigation, it is more likely that there may be issues with multiple systems involving failures, unexpected behaviour, or inadequate, inappropriate, or missing procedures.
- Keep in mind that a system failure may occur in many ways, including situations where the system performs as expected, but fails to achieve a desired result.
The observations made in the previous podcast about the challenges facing the AAIB in analyzing this accident are still relevant.
- Accidents that occur because of system-related problems are usually a combination of technological and human factors issues.
- It may be difficult to recreate the conditions associated with the accident, in part because some relevant environmental or system conditions may not be well understood.
- System-related problems may be due to subtle and complex interactions within and between systems and their human operators. Understanding those interactions can be a long and difficult process.
The suggestions made in the previous podcast about how to evaluate what is being published about the investigation are also still valid.
If you are interested in following what is said about the investigation online or in the news media, keep this in mind: prior to the completion of the investigation by the AAIB, those outside of the investigation, including aviation safety experts and the largest news media organizations, will have access only to a fraction of the relevant information.
The AAIB will likely provide several more updates prior to publishing a final report, and these updates represent the most authoritative source of information about the ongoing investigation.
Finally, take the time to read between the lines and figure out what is fact and what is speculation.
If you are interested in following the 777 investigation, or if you are interested in other aviation safety or security issues, you can check out the following resources:
- For more on the 777 Investigation, visit 777.airsafe.org.
- If you want to provide feedback about this podcast, visit feedback.airsafe.org.
- For other airline safety and security podcasts, visit podcast.airsafe.org.
- Background information about the site and the site’s creator Dr. Todd Curtis is available at media.airsafe.org.
I’ll be back with some final thoughts after this brief message (commercial break).
Well, it looks like that's all the time we have for today.
Before we end this Conversation, I'd like to remind all my listeners that this podcast is produced by The AirSafe.com Foundation, a nonprofit organization that supports a number of efforts to further the public's understanding of aviation safety and aviation security.
For information about the Foundation or to make a tax deductible donation, please visit Airsafe.org.
For more information about airline safety, you can find us at AirSafe.com. That's a-i-r-s-a-f-e.com.
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Thanks for listening, and we'll see you next time.
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Dr. Todd Curtis is the author of the book Parenting and the Internet (Speedbrake Publishing, 2007) and is also the host of the podcast of the same name. For more information about the podcast, visit the Speedbrake.com podcast. For more on the book, visit books.speedbrake.com.
http://www.airsafe.com/podcasts/show37.htm -- Revised: 10 February 2008