"Fat-Fingers" and Aircraft Incidents and Accidents

We've all done it - type something incorrectly into a computer system with hopefully nothing more resulting than maybe some mild embarrassment, kind of like what the Wachovia Bank clerk probably felt after finding out that he or she typed in a customer's bank account number instead of his account balance when the customer closed his account. The typo indicated that the customer owed the bank $211,010,028,257,303.00.

Sometimes the error causes a bit more than embarrassment, such as when an emergency operator types in the wrong address, which leads to emergency services being delayed in reaching the scene of the incident. When the emergency system design itself compounds the error, as seems the case in an incident in Pittsburgh last year, bad things can sometimes result.

Bad things can also result if the operator making the error happens to be an airline pilot. You may recall that a United Arab Emirates (UAE) aircraft struck its tail on take-off from Melbourne Airport, Victoria, Australia on the 20th of March of 2009.

The Australian Transport Safety Bureau (ATSB) determined that "the pre-flight take-off performance calculations were based on an incorrect take-off weight that was inadvertently entered into the take-off performance software on a laptop computer used by the flight crew."

The aircraft's first officer typed in the aircraft's weight as being 262.9 tonnes; the true weight was 362.9 tonnes.

As a result of this incident and the fact that 12% of worldwide commercial aircraft accidents involving fatalities between 2000 and 2009 involved take-offs, the ATSB undertook a study of aircraft incidents and accidents around the world that "were the result of a simple data calculation or entry error by the flight crew."

The results were published today in a report titled, "Take-off performance calculation and entry errors: A global perspective." You can read a report summary here; the full report in PDF is here.

The ATSB report "... documents 20 international and 11 Australian accidents and incidents (occurrences) identified between 1 January 1989 and 30 June 2009 where the calculation and entry of erroneous take-off performance parameters, such as aircraft weights and ‘V speeds’ were involved."

The report says:

"The most common contributing safety factor identified related to crew actions (39 per cent), including monitoring and checking, assessing and planning, and the use of aircraft equipment. This was followed by absent or inadequate risk controls (31 per cent), mostly centred on poor procedures, non-optimally designed aircraft automation systems, inappropriately designed or unavailable reference materials, and inadequate crew management practices and training. Common local conditions (27 per cent) involved inadequate task experience or recency, time pressures, distractions and incorrect task information."

The report also notes "... that these types of errors have many different origins; with crew actions involving the wrong figure being used, data entered incorrectly, data not being updated, and data being excluded. Furthermore, a range of systems and devices have been involved in these errors, including performance documentation, laptop computers, the flight management computer, and the aircraft communications addressing and reporting systems."

Since there are so many different sources of risk, the reports states that:

"... there is no single solution to ensure that such errors are prevented or captured."

As a result, the ATSB report suggests a number of "error capture systems that airlines and aircraft manufacturers can explore", including "appropriate crew procedures, especially those involving cross-checking; aircraft automation systems and software design involving the entering and checking of data; the provision of, and design of flight documentation and performance charts; and adequate crew pairing that accounts for aircraft-type experience for all crew operating the aircraft."

Even with these error capture systems in place, the ATSB warns that pilots still need: 

"... to ensure procedures are followed even when faced with time pressures or distractions."

You can read an ABC News Australia interview with Martin Dolan, the ATSB's chief commissioner about ATSB's new report here.

In other aircraft safety related news, the Wall Street Journal reports that Air France-KLM SA has agreed to implement the 35 safety recommendations made by an independent safety review team including "in-flight observation of cockpit crews."

Air France, in its news release, said that the independent safety review on flight safety which was set up in December of 2009, six months after the crash of Air France Flight 447 was:

 "... comprised [of] eight acknowledged independent experts of international standing chosen to combine French and Anglo-Saxon mindsets. The review team looked into all the internal operating modes, decision-making processes and practices that might have an impact on the safety of Air France flights, by combining a systematic viewpoint on safety with practical experience in running operations at airlines comparable in size to Air France. On this basis, following an inquiry that ran throughout 2010, the experts made proposals that will serve as drivers for our continuous safety improvement process."

The WSJ story notes that the safety team recommended that Air France release summaries or excerpts of the report's recommendations along with their supporting analysis, but Air France for unspecified reasons declined to do so. This was contrary to what was expected, as indicated in this other WSJ story from yesterday.

Finally, earlier this week a pilot friend of mine sent me a link to a USA Today story noting that for the third time in four years, there were no fatal commercial airline crashes in the US in 2010. The USA Today story quotes statistics Professor Arnold Barnett who specializes in accident statistics at the Massachusetts Institute of Technology's Sloan School of Management as saying:

"In the entire First World, fatal crashes are at the brink of extinction."

The "non-First World", however, still has a ways to go.

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IEEE Spectrum's risk analysis blog, featuring daily news, updates and analysis on computing and IT projects, software and systems failures, successes and innovations, security threats, and more.

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Willie D. Jones
 
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