Showing posts with label SPEED CALCULATION ERRORS. Show all posts
Showing posts with label SPEED CALCULATION ERRORS. Show all posts

Sunday, January 1, 2012

TAKE OFF PERFORMANCE ERRORS

Srinivas Rao | 4:01 PM | | | | | Best Blogger Tips





The Australian Transport Safety Bureau(ATSB) final report of Emirates EK407  tail strike has been released, pointing towards human error in keying of wrong weight and speeds thereof, which resulted in  the aircraft failing to accelerate correctly before over rotating close to the end of the runway and striking the tail several times before becoming airborne and returning to land safely. Although there were no injuries,there was damage to the aircraft and to infrastructure at the Melbourne airport as the aircraft overran in march 2009.The aircraft A340-500, A6-ERG, was damaged as a result. An incorrect weight of 100 tones was keyed in.

Pic from ATSB Report
 In its report the ATSB said: "Previous investigations into similar data entry error and tail-strike occurrences have highlighted the inability of flight crew to conduct a 'rule of thumb' or reasonableness check of speeds when moving between aircraft types.”


Also the report goes on about mixed fleet flying:
"An unintended consequence of mixed fleet flying appears to be a reduction in a flight crew's ability to build a model in long-term memory to facilitate recognition of 'orders of magnitude', or a 'rule of thumb', in respect of take-off performance data."
 The above could have implications on the mixed fleet flying of A320/A330, A330/A340, etc.

Airbus has said that it plans additional development to include functions checking that the aircraft has sufficient runway length to conduct a safe take-off, the ATSB added.

In the history of  aviation, there have been well over 20 such incidents in the past 2 decades or so, involving the human errors in insertion, computation and cross check of data amongst crew  leading to such incidents.
Pic from ATSB report
Will increased automation help in any way to curb the errors of crew in containing this???
A valid viewpoint stems from FAA that such systems, given “all of their inherent complexity”, would be “more problematical than reliance on adequate airmanship”.

What is the way forward in addressing these input  and computation errors and enhance safety??

Airmanship and Procedures
Crew workload is immense during pre-flight when this activity of speed/weight computation takes place. Crew procedures by way of cross checking the data for accuracy and computation, is essential, and coupled with good habit forming and procedural compliance is the way forward.

For crew cross check to be effective, each crew member shall calculate the speeds and thrust settings independently and then cross check to see if there are any differences.
Standard Operating Procedures need to lay emphasis on the same.

Details from loadsheet need to be independently noted by each crew, to avoid any consensus which could lead to an error.

Fortifying crew procedures, cross check of data derived, aircraft systems enhancement  to avoid wrong data insertion and increased thrust in training on this front, will help enhance safety and avoid inevitable tail strikes.

Remember, a wrong keying of numbers on your calculator, will not lead to safety implications, as opposed to wrong keying of numbers on the flight management system.
Procedural  Cross Check  and Compliance, Effective Training and Pre-flight Time Management are the need of the hour.

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