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An avionics instrument qualified technician reports that unmodified static inverters in B767-300's that contain a carbon composition resistor on the logic board have been unable to sustain the high current and high heat application; resulting in resistor burning; damage to capacitors; and cabin smoke.
| Attributes | |
| ACN | 846988 |
| Time | |
| Date | 200908 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | B767-300 and 300 ER |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Parked |
| Component | |
| Aircraft Component | Inverter |
| Person 1 | |
| Function | Technician |
| Qualification | Maintenance Powerplant Maintenance Airframe |
| Events | |
| Anomaly | Aircraft Equipment Problem Critical |
Narrative:
Pre-modification avionic instrument static inverters should be campaigned (identified); to have the R170 mod completed immediately. As technicians; we routinely and easily complete this modification in our shop when unmodified units come in. However; there are still many unmodified units in our fleet; which continue to be an issue. Specifically; unmodified units hold a carbon composition resistor on the logic board which have been unable to sustain the high current application and as a result; burn up the resistor; blow surrounding capacitors and in some cases have been a cause of significant smoke within the cabin and possible fire or sparks within the actual unit. The latest incident occurred july 2009. There have been other incidents.
Original NASA ASRS Text
Title: An Avionics Instrument Qualified Technician reports that unmodified static inverters in B767-300's that contain a carbon composition resistor on the logic board have been unable to sustain the high current and high heat application; resulting in resistor burning; damage to capacitors; and cabin smoke.
Narrative: Pre-Modification Avionic Instrument Static Inverters should be campaigned (identified); to have the R170 mod completed immediately. As technicians; we routinely and easily complete this modification in our shop when unmodified units come in. However; there are still many unmodified units in our fleet; which continue to be an issue. Specifically; unmodified units hold a carbon composition resistor on the logic board which have been unable to sustain the high current application and as a result; burn up the resistor; blow surrounding capacitors and in some cases have been a cause of significant smoke within the cabin and possible fire or sparks within the actual unit. The latest incident occurred July 2009. There have been other incidents.
Data retrieved from NASA's ASRS site as of April 2012 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.