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B737-ng captain reported his IRS navigation system showed significant position errors in the area of the 'bermuda triangle.'
| Attributes | |
| ACN | 1359953 |
| Time | |
| Date | 201605 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | ZMA.ARTCC |
| State Reference | FL |
| Environment | |
| Flight Conditions | Mixed |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | B737 Next Generation Undifferentiated |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Climb |
| Route In Use | Oceanic |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | INS / IRS / IRU |
| Person 1 | |
| Function | Captain |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Last 90 Days 217 Flight Crew Type 11000 |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe |
Narrative:
This report is not meant as a joke. Following an uneventful flight to sju; on the return flight (with the same aircraft) we received several 'verifypos: IRS-IRS' (inertial reference system) scratch pad messages. Checking position shift page three/three; we confirmed that our IRS position errors were significant. During this flight; the left IRS position error varied from two to five NM; the right IRS error varied from three to eleven NM. This did not cause any operational problems because our anp stayed below 0.07 with very tight GPS and radio cross tuning accuracy. This defect was recorded in the aircraft logbook at [destination]. I did not think much more about it until I got home and my wife asked 'any issues today flying thru the bermuda triangle?' I never thought about such a coincidence during the flight; but we were within the southern edge of that area. If anyone is seriously tracking empirical data on navigation errors in that area; please pass on this report. I wonder if (company) has any data on other navigational issues between conus and sju; mdpc or mynn? I have never seen such IRS accuracy errors in 22 years of operating this aircraft.if anyone is seriously tracking navigation anomalies within the 'bermuda triangle'; please forward this report.
Original NASA ASRS Text
Title: B737-NG Captain reported his IRS navigation system showed significant position errors in the area of the 'Bermuda Triangle.'
Narrative: This report is NOT meant as a joke. Following an uneventful flight to SJU; on the return flight (with the same aircraft) we received several 'VERIFYPOS: IRS-IRS' (Inertial Reference System) scratch pad messages. Checking POS SHIFT page three/three; we confirmed that our IRS position errors were significant. During this flight; the L IRS position error varied from two to five NM; the R IRS error varied from three to eleven NM. This did not cause any operational problems because our ANP stayed below 0.07 with very tight GPS and RADIO cross tuning accuracy. This defect was recorded in the aircraft logbook at [destination]. I did not think much more about it until I got home and my wife asked 'Any issues today flying thru the Bermuda Triangle?' I never thought about such a coincidence during the flight; but we were within the southern edge of that area. If anyone is seriously tracking empirical data on navigation errors in that area; please pass on this report. I wonder if (Company) has any data on other navigational issues between CONUS and SJU; MDPC or MYNN? I have never seen such IRS accuracy errors in 22 years of operating this aircraft.If anyone is seriously tracking navigation anomalies within the 'Bermuda Triangle'; please forward this report.
Data retrieved from NASA's ASRS site 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.