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Captain of a DC9-30 return land after experiencing unusual aircraft control pressure and autoplt reaction during climb at high altitude resulting in a return land.
| Attributes | |
| ACN | 425553 |
| Time | |
| Date | 199901 |
| Day | Wed |
| Local Time Of Day | 0001 To 0600 |
| Place | |
| Locale Reference | atc facility : mem |
| State Reference | TN |
| Altitude | msl bound lower : 29000 msl bound upper : 29000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Dawn |
| Aircraft 1 | |
| Controlling Facilities | artcc : zme tracon : sts |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | climbout : intermediate altitude |
| Route In Use | enroute airway : zme |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 90 flight time total : 11500 flight time type : 6000 |
| ASRS Report | 425553 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial |
| Events | |
| Anomaly | aircraft equipment problem : critical other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
The flight controls required an unusual amount of pressure and input to make turns. When the autoplt was engaged, it would (without pilot input) make sharp turns up to 30 degrees bank. We were experiencing some turbulence associated with a front with thunderstorms ahead. We decided the most prudent action was a return to mem to have the flight controls inspected. Callback conversation with reporter revealed the following information: reporter stated that the aircraft was a DC9-30 and that he had over 6000 hours in that type of aircraft so when he noticed that the aircraft control pressure was unusually stiff, and the autoplt was overreacting in turns, he decided to return land. The aircraft was in maintenance for some time. The reporter learned that the entire control system was taken apart, examined for conformity and wear and reassembled. It was then flight tested and put on the line where there has been no further difficulty with the aircraft reported. Company maintenance did not indicate that any unusual problem was found.
Original NASA ASRS Text
Title: CAPT OF A DC9-30 RETURN LAND AFTER EXPERIENCING UNUSUAL ACFT CTL PRESSURE AND AUTOPLT REACTION DURING CLB AT HIGH ALT RESULTING IN A RETURN LAND.
Narrative: THE FLT CTLS REQUIRED AN UNUSUAL AMOUNT OF PRESSURE AND INPUT TO MAKE TURNS. WHEN THE AUTOPLT WAS ENGAGED, IT WOULD (WITHOUT PLT INPUT) MAKE SHARP TURNS UP TO 30 DEGS BANK. WE WERE EXPERIENCING SOME TURB ASSOCIATED WITH A FRONT WITH TSTMS AHEAD. WE DECIDED THE MOST PRUDENT ACTION WAS A RETURN TO MEM TO HAVE THE FLT CTLS INSPECTED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT THE ACFT WAS A DC9-30 AND THAT HE HAD OVER 6000 HRS IN THAT TYPE OF ACFT SO WHEN HE NOTICED THAT THE ACFT CTL PRESSURE WAS UNUSUALLY STIFF, AND THE AUTOPLT WAS OVERREACTING IN TURNS, HE DECIDED TO RETURN LAND. THE ACFT WAS IN MAINT FOR SOME TIME. THE RPTR LEARNED THAT THE ENTIRE CTL SYS WAS TAKEN APART, EXAMINED FOR CONFORMITY AND WEAR AND REASSEMBLED. IT WAS THEN FLT TESTED AND PUT ON THE LINE WHERE THERE HAS BEEN NO FURTHER DIFFICULTY WITH THE ACFT RPTED. COMPANY MAINT DID NOT INDICATE THAT ANY UNUSUAL PROB WAS FOUND.
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.