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MD269 helicopter pilot failed to assure that the transponder was turned on during flight under class B outer ring. He noticed the lack of the green light blinking and recycled the on and off switch to the on position.
| Attributes | |
| ACN | 531020 |
| Time | |
| Date | 200111 |
| Day | Thu |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : hwd.airport |
| State Reference | CA |
| Altitude | msl bound lower : 500 msl bound upper : 700 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tower : hwd.tower |
| Operator | general aviation : personal |
| Make Model Name | Helicopter |
| Operating Under FAR Part | Part 91 |
| Flight Phase | climbout : takeoff cruise : level |
| Flight Plan | None |
| Person 1 | |
| Affiliation | other |
| Function | flight crew : single pilot |
| Qualification | pilot : commercial |
| Experience | flight time last 90 days : 20 flight time total : 970 flight time type : 120 |
| ASRS Report | 531020 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : local |
| Events | |
| Anomaly | aircraft equipment problem : less severe non adherence : far non adherence other |
| Independent Detector | aircraft equipment other aircraft equipment : transponder op ind light other flight crewa |
| Resolutory Action | none taken : detected after the fact other |
| Supplementary | |
| Problem Areas | Aircraft Airspace Structure Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
Narrative:
At approximately XA00 on nov/xa/01, I departed hwd destined for rhv. The flight was conducted in a helicopter at 500-700 ft MSL. Approximately abeam sonol pass, I noticed that the 'reply' light on the radar transponder was not flashing. The transponder on/off/mode switch may have been set between the 'on' and the 'altitude' position (1/2 way between the switch detents). I cycled the switch to the 'off' and back to the 'altitude' position, and the 'reply' light began flashing. I may have been operating inside the sfo mode C veil for approximately 10 mins without an active transponder or without replying with mode C altitude data. My route of flight was under the class B airspace segments, and at no time did I enter class B airspace. Suggestions for prevention: the only positive indication that a transponder is operating is the flashing 'reply' light. Since helicopters often operate at low altitude, it is consequently common that the light isn't flashing even though the transponder is operating normally. Use of the 'test' function isn't practical due to the need to continually 'hand fly' most helicopters. There should be some other indication that a transponder is operating the 'reply' light and the mode switch position.
Original NASA ASRS Text
Title: MD269 HELI PLT FAILED TO ASSURE THAT THE XPONDER WAS TURNED ON DURING FLT UNDER CLASS B OUTER RING. HE NOTICED THE LACK OF THE GREEN LIGHT BLINKING AND RECYCLED THE ON AND OFF SWITCH TO THE ON POS.
Narrative: AT APPROX XA00 ON NOV/XA/01, I DEPARTED HWD DESTINED FOR RHV. THE FLT WAS CONDUCTED IN A HELI AT 500-700 FT MSL. APPROX ABEAM SONOL PASS, I NOTICED THAT THE 'REPLY' LIGHT ON THE RADAR XPONDER WAS NOT FLASHING. THE XPONDER ON/OFF/MODE SWITCH MAY HAVE BEEN SET BTWN THE 'ON' AND THE 'ALT' POS (1/2 WAY BTWN THE SWITCH DETENTS). I CYCLED THE SWITCH TO THE 'OFF' AND BACK TO THE 'ALT' POS, AND THE 'REPLY' LIGHT BEGAN FLASHING. I MAY HAVE BEEN OPERATING INSIDE THE SFO MODE C VEIL FOR APPROX 10 MINS WITHOUT AN ACTIVE XPONDER OR WITHOUT REPLYING WITH MODE C ALT DATA. MY RTE OF FLT WAS UNDER THE CLASS B AIRSPACE SEGMENTS, AND AT NO TIME DID I ENTER CLASS B AIRSPACE. SUGGESTIONS FOR PREVENTION: THE ONLY POSITIVE INDICATION THAT A XPONDER IS OPERATING IS THE FLASHING 'REPLY' LIGHT. SINCE HELIS OFTEN OPERATE AT LOW ALT, IT IS CONSEQUENTLY COMMON THAT THE LIGHT ISN'T FLASHING EVEN THOUGH THE XPONDER IS OPERATING NORMALLY. USE OF THE 'TEST' FUNCTION ISN'T PRACTICAL DUE TO THE NEED TO CONTINUALLY 'HAND FLY' MOST HELIS. THERE SHOULD BE SOME OTHER INDICATION THAT A XPONDER IS OPERATING THE 'REPLY' LIGHT AND THE MODE SWITCH POS.
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.