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1、Ready to begin,Failure Modes,David L. Andra, Jr. Science and Operations Officer WFO Norman, Oklahoma,Failure Mode:,The manner in which a system fails.,Examples,Technology - WSR-88D klystron fails preventing access to critical data. Conceptual Forecaster fails to recognize small storm as mini-superce
2、ll. Organizational Absence of well defined job roles and mission priorities leads to failure in SA.,Failure Mode and Effects Analysis,A technique employed by engineers to improve system performance.,Failure Mode and Effects Analysis,1. Define failure mode. 2. Identify cause of failure. 3. Identify e
3、ffects of failure. 4. Corrective action.,An Example,Failure mode: Conceptual Cause: Failed to identify mini-SC Mini-SC characteristics not understood by forecaster Effects: Injuries and loss of life Correction: Training for staff on mini-SC structure and evolution,Strategy to Improve,Try to eliminat
4、e the failure mode. Minimize the severity of the failure. Reduce the occurrence of the failure mode. Improve the detection.,Other Considerations,Some failures are more preventable than others!,Examples,Relatively easy to prevent: Failure mode: Conceptual Cause: Classic SC not recognized Forecaster o
5、nly uses 0.5 deg R product Effect: Loss of life, feature on Dateline Correction: Training, etc.,Examples,Nearly impossible to prevent: Failure mode: Technological Cause: mini-SC at long range and embedded stratiform pcpn, night, sparse population. Brief tornado. Effect: mobile home destroyed with lo
6、ss of life. Correction: maybe better VCPs or new radar?,Ten Recent Disasters (since 1989),Complete Embarrassment,AOG,By Failure Mode,Failure Mode and Effects Analysis (FMEA) is only a tool to identify potential or actual points of failure and identify corrective action.,A Case Analysis,A nearly unwa
7、rned tornado in OKC metro area WFO Norman October 22, 2000,Surface 00Z,00Z OUN Raob,00Z OUN Hodograph,Considerations,Tornado day before Midday AC “NO SVR” Tornado watch by early evening,Dayshift held over “just in case” New staff member stopped by Initially one warning forecaster,What happened,5 tor
8、nadoes in CWA One F1, remainder rated F0 F1 occurred in relatively dense population area No significant injuries No significant lead time,Several storms of concern,Tornado warnings SE & NW,About 30 minutes later,Interesting signature W of RDA,Tornado at cursor,F1 tornado occurring,Was this a failure
9、?,Could have had more lead time!,Failure Mode and Effects Analysis,1. Define failure mode. 2. Identify cause of failure. 3. Identify effects of failure. 4. Corrective action.,Analysis,Failure mode: Organizational Cause: Failed to identify mini-SC tornado threat Ambiguity in staffing caused breakdown in lines of responsibility Effects: Not too much, could have been worse! Correction: Re-emphasize intra-staff coordination and strengthen structure of duties,Questions and comments?,
