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L1011 descending to 13000 ft using IAS mode of autoplt at idle power overshoots altitude by 250 ft account high descent rate. No comment from controller after altitude regained.
| Attributes | |
| ACN | 353690 |
| Time | |
| Date | 199611 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : atl |
| State Reference | GA |
| Altitude | msl bound lower : 12750 msl bound upper : 13000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : atl |
| Operator | common carrier : air carrier |
| Make Model Name | L-1011 Tri-Star All Series |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other |
| Flight Phase | descent other |
| Route In Use | arrival star : star |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 200 flight time total : 17000 flight time type : 3000 |
| ASRS Report | 353690 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Events | |
| Anomaly | altitude deviation : overshoot non adherence : clearance non adherence : far |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : returned to intended course or assigned course |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Descending to 13000 ft using the IAS mode at idle power, altitude arm was indicated, but at idle power the descent rate was approximately 2000 FPM and the altitude at leveloff was -250 ft (12750 ft). We climbed back to 13000 ft and no conflict and no comment from the controller. The IAS mode on the L1011 at idle power sometimes has trouble leveling off because of the descent rate. I will use the vertical speed mode at a less rate when close to altitude.
Original NASA ASRS Text
Title: L1011 DSNDING TO 13000 FT USING IAS MODE OF AUTOPLT AT IDLE PWR OVERSHOOTS ALT BY 250 FT ACCOUNT HIGH DSCNT RATE. NO COMMENT FROM CTLR AFTER ALT REGAINED.
Narrative: DSNDING TO 13000 FT USING THE IAS MODE AT IDLE PWR, ALT ARM WAS INDICATED, BUT AT IDLE PWR THE DSCNT RATE WAS APPROX 2000 FPM AND THE ALT AT LEVELOFF WAS -250 FT (12750 FT). WE CLBED BACK TO 13000 FT AND NO CONFLICT AND NO COMMENT FROM THE CTLR. THE IAS MODE ON THE L1011 AT IDLE PWR SOMETIMES HAS TROUBLE LEVELING OFF BECAUSE OF THE DSCNT RATE. I WILL USE THE VERT SPD MODE AT A LESS RATE WHEN CLOSE TO ALT.
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.