Narrative:

This general concern is not applicable to only one flight. I would conservatively say that at least 80% of the time at asde-X capable airports that the transponder is not being turned off upon reaching the J line on taxi in and is sometimes turned on too soon on the pushback. The pilot handbook is the same for the -300/500 and the -700; when in fact the systems operate differently. The -700 requires oil pressure; transponder on and thrust lever angle of at least 53 degrees to activate the predictive windshear; while on the -300/500; all that is needed is oil pressure and transponder on. When the pws is active; the radar is energized. On taxi in at asde-X airports; I have witnessed the transponder left on most every time when pulling into the gate. I now make it practice to check it and make sure the first officer has turned it off. Most every time it is still left on. I always inform the first officer's that the procedure in the fom about turning the transponder off at the J line is to ensure that the radar is not emitting energy. Of the ones that I have talked to; at least 30 or more; none realized that the radar stayed energized on the classic fleet. I have seen the first officer turn the transponder on at gate prior to pushback (at least it was in a -700) at an asde-X airport. I think that it is imperative that a read before fly be put out regarding this so that we can preclude possible injury to ground personnel from excessive radar energy. Next; the pilot handbook and fom should reflect the differences in the systems and a reason for turning it on in the after start flow and off prior to entering the safety zone on taxi in. The pilot handbook gives great guidance on other issues that may be comfort related; but needs to have this safety issue addressed in a stronger manner. In researching this I was in contact with an instructor at our flight training center. He confirmed for me the operations of the pws systems and their difference in the classic vs -700 fleets.

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Original NASA ASRS Text

Title: A B737 PLT DISCUSSES B737-300/500/700 RADAR EMISSIONS IN A CLOSE PROXIMITY TO GND PERSONNEL AT ASDE ARPTS WHEN THE ACFT'S XPONDERS ARE NOT IN STANDBY.

Narrative: THIS GENERAL CONCERN IS NOT APPLICABLE TO ONLY ONE FLT. I WOULD CONSERVATIVELY SAY THAT AT LEAST 80% OF THE TIME AT ASDE-X CAPABLE ARPTS THAT THE XPONDER IS NOT BEING TURNED OFF UPON REACHING THE J LINE ON TAXI IN AND IS SOMETIMES TURNED ON TOO SOON ON THE PUSHBACK. THE PLT HANDBOOK IS THE SAME FOR THE -300/500 AND THE -700; WHEN IN FACT THE SYSTEMS OPERATE DIFFERENTLY. THE -700 REQUIRES OIL PRESSURE; XPONDER ON AND THRUST LEVER ANGLE OF AT LEAST 53 DEGS TO ACTIVATE THE PREDICTIVE WINDSHEAR; WHILE ON THE -300/500; ALL THAT IS NEEDED IS OIL PRESSURE AND XPONDER ON. WHEN THE PWS IS ACTIVE; THE RADAR IS ENERGIZED. ON TAXI IN AT ASDE-X ARPTS; I HAVE WITNESSED THE XPONDER LEFT ON MOST EVERY TIME WHEN PULLING INTO THE GATE. I NOW MAKE IT PRACTICE TO CHK IT AND MAKE SURE THE FO HAS TURNED IT OFF. MOST EVERY TIME IT IS STILL LEFT ON. I ALWAYS INFORM THE FO'S THAT THE PROC IN THE FOM ABOUT TURNING THE XPONDER OFF AT THE J LINE IS TO ENSURE THAT THE RADAR IS NOT EMITTING ENERGY. OF THE ONES THAT I HAVE TALKED TO; AT LEAST 30 OR MORE; NONE REALIZED THAT THE RADAR STAYED ENERGIZED ON THE CLASSIC FLEET. I HAVE SEEN THE FO TURN THE XPONDER ON AT GATE PRIOR TO PUSHBACK (AT LEAST IT WAS IN A -700) AT AN ASDE-X ARPT. I THINK THAT IT IS IMPERATIVE THAT A READ BEFORE FLY BE PUT OUT REGARDING THIS SO THAT WE CAN PRECLUDE POSSIBLE INJURY TO GND PERSONNEL FROM EXCESSIVE RADAR ENERGY. NEXT; THE PLT HANDBOOK AND FOM SHOULD REFLECT THE DIFFERENCES IN THE SYSTEMS AND A REASON FOR TURNING IT ON IN THE AFTER START FLOW AND OFF PRIOR TO ENTERING THE SAFETY ZONE ON TAXI IN. THE PLT HANDBOOK GIVES GREAT GUIDANCE ON OTHER ISSUES THAT MAY BE COMFORT RELATED; BUT NEEDS TO HAVE THIS SAFETY ISSUE ADDRESSED IN A STRONGER MANNER. IN RESEARCHING THIS I WAS IN CONTACT WITH AN INSTRUCTOR AT OUR FLT TRAINING CTR. HE CONFIRMED FOR ME THE OPERATIONS OF THE PWS SYSTEMS AND THEIR DIFFERENCE IN THE CLASSIC VS -700 FLEETS.

Data retrieved from NASA's ASRS site as of January 2009 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.