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Air carrier medium large transport altitude deviation overshot during climb due to improper use of autoflt system.
| Attributes | |
| ACN | 113722 |
| Time | |
| Date | 198906 |
| Day | Sun |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : mei |
| State Reference | MS |
| Altitude | msl bound lower : 27000 msl bound upper : 28500 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zme artcc : zfw |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other |
| Flight Phase | climbout : intermediate altitude cruise other |
| Route In Use | enroute airway : j22 |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : instrument pilot : flight engineer pilot : commercial pilot : atp |
| Experience | flight time last 90 days : 230 flight time total : 19000 flight time type : 2000 |
| ASRS Report | 113722 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| ASRS Report | 113723 |
| Events | |
| Anomaly | altitude deviation : overshoot non adherence : clearance |
| Independent Detector | 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:
On climb to 270 and leaving 26.5, ZME gave pilot discretion to 240. The aircraft had gone to altitude capture when the first officer select 240 on altitude reminder. This disarmed the altitude capture and the aircraft continued to climb at approximately 300 RPM. There was no altitude warning and this altitude bust went unnoticed by myself or the first officer due to the slight route of climb, and the fact that we both were looking at the WX radar for buildups in the area. At 28.5, ZME asked our altitude and I replied, 28.5 and started an immediate descent to 270. ZME said no problem, and that there was no conflict. This problem could have been alleviated during certification, if the FAA had required the manufacturer to put the logic into the computer so as not to allow the aircraft to climb above the last assigned altitude when a lower is selected before reaching your cruise altitude. This has and is a design flaw, and should be corrected.
Original NASA ASRS Text
Title: ACR MLG ALT DEVIATION OVERSHOT DURING CLIMB DUE TO IMPROPER USE OF AUTOFLT SYSTEM.
Narrative: ON CLB TO 270 AND LEAVING 26.5, ZME GAVE PLT DISCRETION TO 240. THE ACFT HAD GONE TO ALT CAPTURE WHEN THE F/O SELECT 240 ON ALT REMINDER. THIS DISARMED THE ALT CAPTURE AND THE ACFT CONTINUED TO CLIMB AT APPROX 300 RPM. THERE WAS NO ALT WARNING AND THIS ALT BUST WENT UNNOTICED BY MYSELF OR THE F/O DUE TO THE SLIGHT RTE OF CLIMB, AND THE FACT THAT WE BOTH WERE LOOKING AT THE WX RADAR FOR BUILDUPS IN THE AREA. AT 28.5, ZME ASKED OUR ALT AND I REPLIED, 28.5 AND STARTED AN IMMEDIATE DSCNT TO 270. ZME SAID NO PROBLEM, AND THAT THERE WAS NO CONFLICT. THIS PROBLEM COULD HAVE BEEN ALLEVIATED DURING CERTIFICATION, IF THE FAA HAD REQUIRED THE MANUFACTURER TO PUT THE LOGIC INTO THE COMPUTER SO AS NOT TO ALLOW THE ACFT TO CLIMB ABOVE THE LAST ASSIGNED ALT WHEN A LOWER IS SELECTED BEFORE REACHING YOUR CRUISE ALT. THIS HAS AND IS A DESIGN FLAW, AND SHOULD BE CORRECTED.
Data retrieved from NASA's ASRS site as of August 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.