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An air carrier medium large transport had multiple aircraft equipment problems #1 compass system inoperative, #2 compass system very slow to slew, and failure flags on both system inoperative.
| Attributes | |
| ACN | 358099 |
| Time | |
| Date | 199701 |
| Day | Fri |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : ord |
| State Reference | IL |
| Altitude | msl bound lower : 5000 msl bound upper : 5000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zau tracon : ord |
| Operator | common carrier : air carrier |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | climbout : intermediate altitude |
| Route In Use | departure other enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : instrument pilot : commercial pilot : atp |
| Experience | flight time last 90 days : 270 flight time total : 17000 flight time type : 2600 |
| ASRS Report | 358099 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Events | |
| Anomaly | aircraft equipment problem : less severe other spatial deviation |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance flight crew : overcame equipment problem other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
Departing ord during busy time. Assigned heading for radar vectors everything in cockpit appears normal. Ord departure asks us what heading we are flying. We were assigned 205 degrees and both compass system showed that. Departure control advised us that we were tracking something far different (about 250 degrees). The first officer and I crosschecked each other's compasses, HSI and RMI. They all agreed and no warning flags or failure lights were in view. We checked the standby compass and it showed about 240 degrees, which agreed with the controller's information and not with our 2 compasses. We advised departure control of our navigation problem and requested a gyro-out turn to the heading he needed. After accomplishing this, we troubleshot the system. We determined that the #2 compass system was very slow to slew, but after wings level, it did become reasonably accurate (about 8-10 degree error). The #1 compass system was inoperative. The flags and failure lights on both system were inoperative. The standby system was ok. We advised ZAU of our limited navigation capabilities. The WX at iah was VFR. We continued to iah with gyro out headings. We had a good standby and the #2 compass error was a known quantity. Uneventful landing.
Original NASA ASRS Text
Title: AN ACR MLG HAD MULTIPLE ACFT EQUIP PROBS #1 COMPASS SYS INOP, #2 COMPASS SYS VERY SLOW TO SLEW, AND FAILURE FLAGS ON BOTH SYS INOP.
Narrative: DEPARTING ORD DURING BUSY TIME. ASSIGNED HDG FOR RADAR VECTORS EVERYTHING IN COCKPIT APPEARS NORMAL. ORD DEP ASKS US WHAT HDG WE ARE FLYING. WE WERE ASSIGNED 205 DEGS AND BOTH COMPASS SYS SHOWED THAT. DEP CTL ADVISED US THAT WE WERE TRACKING SOMETHING FAR DIFFERENT (ABOUT 250 DEGS). THE FO AND I XCHKED EACH OTHER'S COMPASSES, HSI AND RMI. THEY ALL AGREED AND NO WARNING FLAGS OR FAILURE LIGHTS WERE IN VIEW. WE CHKED THE STANDBY COMPASS AND IT SHOWED ABOUT 240 DEGS, WHICH AGREED WITH THE CTLR'S INFO AND NOT WITH OUR 2 COMPASSES. WE ADVISED DEP CTL OF OUR NAV PROB AND REQUESTED A GYRO-OUT TURN TO THE HDG HE NEEDED. AFTER ACCOMPLISHING THIS, WE TROUBLESHOT THE SYS. WE DETERMINED THAT THE #2 COMPASS SYS WAS VERY SLOW TO SLEW, BUT AFTER WINGS LEVEL, IT DID BECOME REASONABLY ACCURATE (ABOUT 8-10 DEG ERROR). THE #1 COMPASS SYS WAS INOP. THE FLAGS AND FAILURE LIGHTS ON BOTH SYS WERE INOP. THE STANDBY SYS WAS OK. WE ADVISED ZAU OF OUR LIMITED NAV CAPABILITIES. THE WX AT IAH WAS VFR. WE CONTINUED TO IAH WITH GYRO OUT HDGS. WE HAD A GOOD STANDBY AND THE #2 COMPASS ERROR WAS A KNOWN QUANTITY. UNEVENTFUL LNDG.
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.