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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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A descending MD90 descends below the altitude crossing as designated for kayoh intersection when the FMS malfunctions and distracts the crew from their descent procedure.
| Attributes | |
| ACN | 402690 |
| Time | |
| Date | 199805 |
| Day | Sat |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : sli airport : sna |
| State Reference | CA |
| Altitude | msl bound lower : 5900 msl bound upper : 7000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : lax |
| Operator | common carrier : air carrier |
| Make Model Name | MD-90 Series (DC-9-90) Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | descent other |
| Route In Use | arrival other arrival star : star |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp pilot : flight engineer |
| Experience | flight time last 90 days : 20 flight time total : 3500 flight time type : 800 |
| ASRS Report | 402690 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 45 flight time total : 14000 flight time type : 3500 |
| ASRS Report | 402691 |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : crossing restriction not met altitude deviation : overshoot non adherence : published procedure non adherence : clearance other anomaly other |
| Independent Detector | other controllera other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : became reoriented |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | Pilot Deviation |
Narrative:
We were cleared to cross kayoh at 7000 ft and proceed via eastside 3 arrival. The captain was using a VNAV descent setup for the eastside 3 FMS STAR and verified by both pilots. During our descent to 7000 ft the captain noticed a map failure and attempted to update the aircraft position. I noticed our navigation displays showed the route as a dashing blue line instead of the normal pink route line. The autoplt remained on in the 'heading hold' mode and vertical speed. Since the FMS was set up for the STAR the captain had reset the digital flight guidance computer altitude to 3300 ft for 'snake intersection.' I attempted to regain our arrival since we were on an 'FMS STAR' with no NAVAID backups. After reactivating the route and executing, the navigation display showed a normal display. The captain re-engaged navigation and attempted to re-engage VNAV. The FMS displayed 'no vertical navigation' and 'no performance data.' as I was entering the performance data the autoplt again switched to 'heading hold and vertical speed' mode. At this time ATC radioed about our altitude approximately 5900 ft MSL. The captain immediately disconnected the autoplt and started a climb to 7000 ft MSL. ATC asked if we were VMC, which we were, and cleared us to proceed visually, maintaining terrain clearance at 5000 ft or above. The rest of the flight was uneventful. To prevent recurrence I'll notify ATC immediately with equipment failures. Ensure someone is flying the airplane while the other pilot corrects the malfunction. Provide a better back up for the PF. Supplemental information from acn 402691: I then noticed the autoplt had again gone to 'heading hold' and was still in 'vertical speed' descent and I was 1200 ft or 1300 ft below 7000 ft and 2 or 3 mi east of kayoh. I kicked off the autoplt and started a climb back up to 7000 ft when socal called and said we were cleared to descend and then said we were too low and to climb back to...then he asked if we were VFR. To prevent a recurrence, I'll set the altitude window for the bottom altitude at each waypoint on the STAR.
Original NASA ASRS Text
Title: A DSNDING MD90 DSNDS BELOW THE ALT XING AS DESIGNATED FOR KAYOH INTXN WHEN THE FMS MALFUNCTIONS AND DISTRACTS THE CREW FROM THEIR DSCNT PROC.
Narrative: WE WERE CLRED TO CROSS KAYOH AT 7000 FT AND PROCEED VIA EASTSIDE 3 ARR. THE CAPT WAS USING A VNAV DSCNT SETUP FOR THE EASTSIDE 3 FMS STAR AND VERIFIED BY BOTH PLTS. DURING OUR DSCNT TO 7000 FT THE CAPT NOTICED A MAP FAILURE AND ATTEMPTED TO UPDATE THE ACFT POS. I NOTICED OUR NAV DISPLAYS SHOWED THE RTE AS A DASHING BLUE LINE INSTEAD OF THE NORMAL PINK RTE LINE. THE AUTOPLT REMAINED ON IN THE 'HEADING HOLD' MODE AND VERT SPD. SINCE THE FMS WAS SET UP FOR THE STAR THE CAPT HAD RESET THE DIGITAL FLT GUIDANCE COMPUTER ALT TO 3300 FT FOR 'SNAKE INTXN.' I ATTEMPTED TO REGAIN OUR ARR SINCE WE WERE ON AN 'FMS STAR' WITH NO NAVAID BACKUPS. AFTER REACTIVATING THE RTE AND EXECUTING, THE NAV DISPLAY SHOWED A NORMAL DISPLAY. THE CAPT RE-ENGAGED NAV AND ATTEMPTED TO RE-ENGAGE VNAV. THE FMS DISPLAYED 'NO VERT NAV' AND 'NO PERFORMANCE DATA.' AS I WAS ENTERING THE PERFORMANCE DATA THE AUTOPLT AGAIN SWITCHED TO 'HEADING HOLD AND VERT SPD' MODE. AT THIS TIME ATC RADIOED ABOUT OUR ALT APPROX 5900 FT MSL. THE CAPT IMMEDIATELY DISCONNECTED THE AUTOPLT AND STARTED A CLB TO 7000 FT MSL. ATC ASKED IF WE WERE VMC, WHICH WE WERE, AND CLRED US TO PROCEED VISUALLY, MAINTAINING TERRAIN CLRNC AT 5000 FT OR ABOVE. THE REST OF THE FLT WAS UNEVENTFUL. TO PREVENT RECURRENCE I'LL NOTIFY ATC IMMEDIATELY WITH EQUIP FAILURES. ENSURE SOMEONE IS FLYING THE AIRPLANE WHILE THE OTHER PLT CORRECTS THE MALFUNCTION. PROVIDE A BETTER BACK UP FOR THE PF. SUPPLEMENTAL INFO FROM ACN 402691: I THEN NOTICED THE AUTOPLT HAD AGAIN GONE TO 'HEADING HOLD' AND WAS STILL IN 'VERT SPD' DSCNT AND I WAS 1200 FT OR 1300 FT BELOW 7000 FT AND 2 OR 3 MI E OF KAYOH. I KICKED OFF THE AUTOPLT AND STARTED A CLB BACK UP TO 7000 FT WHEN SOCAL CALLED AND SAID WE WERE CLRED TO DSND AND THEN SAID WE WERE TOO LOW AND TO CLB BACK TO...THEN HE ASKED IF WE WERE VFR. TO PREVENT A RECURRENCE, I'LL SET THE ALT WINDOW FOR THE BOTTOM ALT AT EACH WAYPOINT ON THE STAR.
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.