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An air carrier MD82 flight crew got off course on a SID, in part, because of a malfunction in their #1 VOR receiver. The alert departure controller gave them vectors back on course.
| Attributes | |
| ACN | 398729 |
| Time | |
| Date | 199804 |
| Day | Mon |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : pdx |
| State Reference | OR |
| Altitude | msl bound lower : 27 msl bound upper : 6000 |
| Environment | |
| Flight Conditions | Mixed |
| Light | Dawn |
| Aircraft 1 | |
| Controlling Facilities | tracon : pdx |
| Operator | common carrier : air carrier |
| Make Model Name | MD-82 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other |
| Flight Phase | climbout : initial climbout : intermediate altitude |
| Route In Use | departure other departure sid : sid enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp pilot : commercial pilot : instrument pilot : flight engineer |
| Experience | flight time last 90 days : 85 flight time total : 15000 flight time type : 1000 |
| ASRS Report | 398729 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp pilot : commercial pilot : instrument |
| Experience | flight time last 90 days : 150 flight time total : 6000 flight time type : 2000 |
| ASRS Report | 398730 |
| Events | |
| Anomaly | aircraft equipment problem : less severe non adherence : clearance non adherence : far non adherence : published procedure other anomaly other other spatial deviation |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance flight crew : returned to intended course or assigned course other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation other |
Narrative:
#1 VOR (with #1 digital flight guidance system selected to #1 position) failed almost immediately after takeoff. There were no flags/failure indications and VOR continued to identify and give accurate DME indications. The failure caused an overfly of an assigned departure radial (river 6 departure). Departure control corrected our track and gave us a vector to a subsequent fix. At that time we had a chance to tune several VOR stations with both radios. #1 VOR and #2 VOR consistently disagreed by approximately 30 degrees. A later power down (pulling and resetting respective circuit breaker for the #1 VOR) brought it back to complete agreement with #2 VOR and no further problems were noted. Problem was entered in aircraft maintenance log. I do not know the conclusion of the maintenance checks. In thinking this over, a better way to do this departure would be to have both VOR, on the same frequency. (#2 was tuned to the next fix.) while this would necessitate some quick retuning in order to set up the next fix, it would do a good job of pointing out a failure like the one we had. Also, thanks to the pdx departure controller for closely monitoring our track.
Original NASA ASRS Text
Title: AN ACR MD82 FLC GOT OFF COURSE ON A SID, IN PART, BECAUSE OF A MALFUNCTION IN THEIR #1 VOR RECEIVER. THE ALERT DEP CTLR GAVE THEM VECTORS BACK ON COURSE.
Narrative: #1 VOR (WITH #1 DIGITAL FLT GUIDANCE SYS SELECTED TO #1 POS) FAILED ALMOST IMMEDIATELY AFTER TKOF. THERE WERE NO FLAGS/FAILURE INDICATIONS AND VOR CONTINUED TO IDENT AND GIVE ACCURATE DME INDICATIONS. THE FAILURE CAUSED AN OVERFLY OF AN ASSIGNED DEP RADIAL (RIVER 6 DEP). DEP CTL CORRECTED OUR TRACK AND GAVE US A VECTOR TO A SUBSEQUENT FIX. AT THAT TIME WE HAD A CHANCE TO TUNE SEVERAL VOR STATIONS WITH BOTH RADIOS. #1 VOR AND #2 VOR CONSISTENTLY DISAGREED BY APPROX 30 DEGS. A LATER PWR DOWN (PULLING AND RESETTING RESPECTIVE CIRCUIT BREAKER FOR THE #1 VOR) BROUGHT IT BACK TO COMPLETE AGREEMENT WITH #2 VOR AND NO FURTHER PROBS WERE NOTED. PROB WAS ENTERED IN ACFT MAINT LOG. I DO NOT KNOW THE CONCLUSION OF THE MAINT CHKS. IN THINKING THIS OVER, A BETTER WAY TO DO THIS DEP WOULD BE TO HAVE BOTH VOR, ON THE SAME FREQ. (#2 WAS TUNED TO THE NEXT FIX.) WHILE THIS WOULD NECESSITATE SOME QUICK RETUNING IN ORDER TO SET UP THE NEXT FIX, IT WOULD DO A GOOD JOB OF POINTING OUT A FAILURE LIKE THE ONE WE HAD. ALSO, THANKS TO THE PDX DEP CTLR FOR CLOSELY MONITORING OUR TRACK.
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.