 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
An at-72 flight crew experienced two momentary losses of most flight instruments and the autopilot when landing lights were turned off.
| Attributes | |
| ACN | 940702 |
| Time | |
| Date | 201103 |
| Local Time Of Day | 1201-1800 |
| Aircraft 1 | |
| Make Model Name | ATR 72 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Cruise |
| Flight Plan | VFR |
| Component | |
| Aircraft Component | Electrical Power |
| Person 1 | |
| Function | Captain Pilot Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Person 2 | |
| Function | First Officer Pilot Not Flying |
| Qualification | Flight Crew Commercial |
| Events | |
| Anomaly | Aircraft Equipment Problem Critical Deviation - Procedural MEL Deviation - Procedural Maintenance |
Narrative:
After reaching our cruising altitude I turned off the landing lights as part of the cruise checklist and simultaneously we lost all of our primary flight instruments for a few seconds. All four EFIS screens went black. We lost both air data computer's to include both altimeters; airspeed indicators; and had digital horizontal dashes on the tat; sat; TAS panel. Also; as an associated condition; the auto pilot kicked off; the adu went to standby and the afcs invalid message appeared on the adu.everything returned to normal shortly after we were able to reset everything and turn the autopilot back on. We continued the flight to dfw as everything had returned to normal. The flight attendants did not notice anything out of the ordinary. Later in the flight; after discussing what we saw; I inadvertently recreated the exact same thing when I selected the landing lights to the off position again. In range we contacted maintenance and they met us at the gate to check the landing lights before shut down. I was later advised the maintenance corrective action for this write-up was to MEL a landing light that was found inoperative at our arrival time.I would feel more comfortable if maintenance had taken some action to correct the electrical problem; or at least determined why the landing light switches can affect the flight instruments in a way that is not covered in our systems knowledge.
Original NASA ASRS Text
Title: An AT-72 flight crew experienced two momentary losses of most flight instruments and the autopilot when landing lights were turned off.
Narrative: After reaching our cruising altitude I turned off the landing lights as part of the cruise checklist and simultaneously we lost all of our primary flight instruments for a few seconds. All four EFIS screens went black. We lost both ADC's to include both altimeters; airspeed indicators; and had digital horizontal dashes on the TAT; SAT; TAS panel. Also; as an associated condition; the auto pilot kicked off; the ADU went to standby and the AFCS Invalid message appeared on the ADU.Everything returned to normal shortly after we were able to reset everything and turn the autopilot back on. We continued the flight to DFW as everything had returned to normal. The flight attendants did not notice anything out of the ordinary. Later in the flight; after discussing what we saw; I inadvertently recreated the exact same thing when I selected the landing lights to the off position again. In range we contacted Maintenance and they met us at the gate to check the landing lights before shut down. I was later advised the maintenance corrective action for this write-up was to MEL a landing light that was found inoperative at our arrival time.I would feel more comfortable if Maintenance had taken some action to correct the electrical problem; or at least determined why the landing light switches can affect the flight instruments in a way that is not covered in our systems knowledge.
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.