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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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Medium large transport excursion from assigned altitude due to switching autoplts while making a route change.
| Attributes | |
| ACN | 267989 |
| Time | |
| Date | 199404 |
| Day | Sat |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : swl |
| State Reference | MD |
| Altitude | msl bound lower : 32600 msl bound upper : 33000 |
| Environment | |
| Flight Conditions | Marginal |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdc |
| Operator | common carrier : air carrier |
| Make Model Name | MD-80 Series (DC-9-80) Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : flight engineer pilot : commercial pilot : cfi pilot : atp |
| Experience | flight time last 90 days : 210 flight time total : 6500 flight time type : 3400 |
| ASRS Report | 267989 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : clearance |
| Independent Detector | atc equipment other atc equipment : unspecified other controllera |
| Resolutory Action | flight crew : returned to intended course or assigned course other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
While at FL330 en route to pvd and 80 mi southwest of swl, we were cleared direct to pvd. The first officer (myself) was flying. The (navigation aid) was track changed, but since it only couples to the #1 autoplt it was disconnected from my side #2 to the #1 autoplt. After approximately 1 min the vertical rate dropped down 500 FPM. I rolled the vertical rate wheel up, but nothing happened. Center said he showed us at 32600. We finally realized the autoplt never engaged when switched to the #1 side. I re-engaged it and leveled at 33000 ft with no conflict. Since the (manufacturer's aid) does not couple on both autoplts, greater attention must be observed after switching to prevent this again.
Original NASA ASRS Text
Title: MLG EXCURSION FROM ASSIGNED ALT DUE TO SWITCHING AUTOPLTS WHILE MAKING A RTE CHANGE.
Narrative: WHILE AT FL330 ENRTE TO PVD AND 80 MI SW OF SWL, WE WERE CLRED DIRECT TO PVD. THE FO (MYSELF) WAS FLYING. THE (NAV AID) WAS TRACK CHANGED, BUT SINCE IT ONLY COUPLES TO THE #1 AUTOPLT IT WAS DISCONNECTED FROM MY SIDE #2 TO THE #1 AUTOPLT. AFTER APPROX 1 MIN THE VERT RATE DROPPED DOWN 500 FPM. I ROLLED THE VERT RATE WHEEL UP, BUT NOTHING HAPPENED. CTR SAID HE SHOWED US AT 32600. WE FINALLY REALIZED THE AUTOPLT NEVER ENGAGED WHEN SWITCHED TO THE #1 SIDE. I RE-ENGAGED IT AND LEVELED AT 33000 FT WITH NO CONFLICT. SINCE THE (MANUFACTURER'S AID) DOES NOT COUPLE ON BOTH AUTOPLTS, GREATER ATTN MUST BE OBSERVED AFTER SWITCHING TO PREVENT THIS AGAIN.
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.