Narrative:

After pushback and engine start we noticed our primary flight displays indicated 'WX on,' and the radar display indicated 'predictive windshear on.' this indicated that the predictive windshear system was active and the WX radar was on, looking for windshear and irradiating the pushback crew. I pulled the WX radar circuit breaker and investigated. Our pilot's reference manual says the predictive windshear system is on when both engines are running and the transponder is on. In this case the transponder was set to 'altitude off.' this switch position is one click from 'standby' which is where the switch should have been. The inbound crew must have left it in 'altitude off' and we did not notice, despite a thorough preflight check. The switch is small and has 6 position making it easy to misset. The predictive windshear system is new to the fleet and our training for its use included only a change to the pilot's reference manual. No changes were made to our normal procedures or checklists. There needs to be a 'warning' in our normal procedures that says 'warning, if the transponder is on and both engines are running, the WX radar is on.' there needs to be bulletin issued to insure every crew understands that the transponder switch is very important and if left in the wrong position can hurt people. Callback conversation with reporter revealed the following information: reporter stated that he had reported and discussed this problem with his company with regard to the possibility of the flight crew's not understanding that the WX radar automatically comes on when the engines are started and the transponder switch is not set on off, or standby position. He was advised that the company was disseminating an alert notice via their flight crew bulletin. He also advised that the full operation procedure is covered in their aircraft operations manual but the subject is not covered in the aircraft preflight checklist due to the abbreviated form of the checklist format.

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Original NASA ASRS Text

Title: FLC OF AN MD88 NOTED THAT THE 'WX ON' AND RADAR DISPLAYED PREDICTIVE WINDSHEAR ON AFTER PUSHBACK AND ENG START RESULTING IN IRRADIATING THE PUSH BACK GND CREW. THE XPONDER SWITCH WAS FOUND TO BE IN THE 'ALT OFF POS' INSTEAD OF 'STANDBY.'

Narrative: AFTER PUSHBACK AND ENG START WE NOTICED OUR PRIMARY FLT DISPLAYS INDICATED 'WX ON,' AND THE RADAR DISPLAY INDICATED 'PREDICTIVE WINDSHEAR ON.' THIS INDICATED THAT THE PREDICTIVE WINDSHEAR SYS WAS ACTIVE AND THE WX RADAR WAS ON, LOOKING FOR WINDSHEAR AND IRRADIATING THE PUSHBACK CREW. I PULLED THE WX RADAR CIRCUIT BREAKER AND INVESTIGATED. OUR PLT'S REF MANUAL SAYS THE PREDICTIVE WINDSHEAR SYS IS ON WHEN BOTH ENGS ARE RUNNING AND THE XPONDER IS ON. IN THIS CASE THE XPONDER WAS SET TO 'ALT OFF.' THIS SWITCH POS IS ONE CLICK FROM 'STANDBY' WHICH IS WHERE THE SWITCH SHOULD HAVE BEEN. THE INBOUND CREW MUST HAVE LEFT IT IN 'ALT OFF' AND WE DID NOT NOTICE, DESPITE A THOROUGH PREFLT CHK. THE SWITCH IS SMALL AND HAS 6 POS MAKING IT EASY TO MISSET. THE PREDICTIVE WINDSHEAR SYS IS NEW TO THE FLEET AND OUR TRAINING FOR ITS USE INCLUDED ONLY A CHANGE TO THE PLT'S REF MANUAL. NO CHANGES WERE MADE TO OUR NORMAL PROCS OR CHKLISTS. THERE NEEDS TO BE A 'WARNING' IN OUR NORMAL PROCS THAT SAYS 'WARNING, IF THE XPONDER IS ON AND BOTH ENGS ARE RUNNING, THE WX RADAR IS ON.' THERE NEEDS TO BE BULLETIN ISSUED TO INSURE EVERY CREW UNDERSTANDS THAT THE XPONDER SWITCH IS VERY IMPORTANT AND IF LEFT IN THE WRONG POS CAN HURT PEOPLE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT HE HAD RPTED AND DISCUSSED THIS PROB WITH HIS COMPANY WITH REGARD TO THE POSSIBILITY OF THE FLC'S NOT UNDERSTANDING THAT THE WX RADAR AUTOMATICALLY COMES ON WHEN THE ENGS ARE STARTED AND THE XPONDER SWITCH IS NOT SET ON OFF, OR STANDBY POS. HE WAS ADVISED THAT THE COMPANY WAS DISSEMINATING AN ALERT NOTICE VIA THEIR FLC BULLETIN. HE ALSO ADVISED THAT THE FULL OP PROC IS COVERED IN THEIR ACFT OPS MANUAL BUT THE SUBJECT IS NOT COVERED IN THE ACFT PREFLT CHKLIST DUE TO THE ABBREVIATED FORM OF THE CHKLIST FORMAT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.