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ATR72 on approach runway 17R was unable to trim aileron. Cleared to fly a pattern to determine flight characteristics of the aircraft at lower speed and rudder inputs. Found aircraft flew ok and made a successful landing. Maintenance found trim switch bad.
| Attributes | |
| ACN | 376099 |
| Time | |
| Date | 199707 |
| Day | Thu |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : hrl |
| State Reference | TX |
| Altitude | agl bound lower : 4000 agl bound upper : 4000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : hrl |
| Operator | common carrier : air carrier |
| Make Model Name | ATR 72 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other |
| Flight Phase | descent : approach descent other landing other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp pilot : instrument |
| Experience | flight time last 90 days : 250 flight time total : 13500 flight time type : 1325 |
| ASRS Report | 376099 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial |
| Events | |
| Anomaly | aircraft equipment problem : critical |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | flight crew : overcame equipment problem |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
We had been cruising at FL210 on our flight from flo to hrl. We accumulated some rime ice on our descent approximately 80 NM north of hrl. We were cleared for the ILS runway 17R into hrl approximately 12 NM out. My first officer disconnected the autoplt after the adu gave us a trim indication. He started complaining about a heavy left wing. We tried to trim the left wing up, but no response. The aileron trim had frozen and trim switch was inoperative. We requested to fly a pattern, so we could check out and observe the aircraft's responses to lower speeds and different rudder trim inputs. After we confirmed our control of the aircraft, we landed safely. Maintenance was called and they replaced the aileron trim switch. Callback conversation with reporter revealed the following information: reporter advised has been on the aircraft 1 1/2 yrs and has never had this problem before. Is not aware it has been a problem. Company has taken no special action on the event. Does not believe icing had anything to do with the failure of the aileron trim system. After a landing and checking the system, was able to get the trim to move one time and then it failed again. Maintenance replaced the faulty switch. Advised the aircraft must be flown using the trim constantly.
Original NASA ASRS Text
Title: ATR72 ON APCH RWY 17R WAS UNABLE TO TRIM AILERON. CLRED TO FLY A PATTERN TO DETERMINE FLT CHARACTERISTICS OF THE ACFT AT LOWER SPD AND RUDDER INPUTS. FOUND ACFT FLEW OK AND MADE A SUCCESSFUL LNDG. MAINT FOUND TRIM SWITCH BAD.
Narrative: WE HAD BEEN CRUISING AT FL210 ON OUR FLT FROM FLO TO HRL. WE ACCUMULATED SOME RIME ICE ON OUR DSCNT APPROX 80 NM N OF HRL. WE WERE CLRED FOR THE ILS RWY 17R INTO HRL APPROX 12 NM OUT. MY FO DISCONNECTED THE AUTOPLT AFTER THE ADU GAVE US A TRIM INDICATION. HE STARTED COMPLAINING ABOUT A HVY L WING. WE TRIED TO TRIM THE L WING UP, BUT NO RESPONSE. THE AILERON TRIM HAD FROZEN AND TRIM SWITCH WAS INOP. WE REQUESTED TO FLY A PATTERN, SO WE COULD CHK OUT AND OBSERVE THE ACFT'S RESPONSES TO LOWER SPDS AND DIFFERENT RUDDER TRIM INPUTS. AFTER WE CONFIRMED OUR CTL OF THE ACFT, WE LANDED SAFELY. MAINT WAS CALLED AND THEY REPLACED THE AILERON TRIM SWITCH. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR ADVISED HAS BEEN ON THE ACFT 1 1/2 YRS AND HAS NEVER HAD THIS PROB BEFORE. IS NOT AWARE IT HAS BEEN A PROB. COMPANY HAS TAKEN NO SPECIAL ACTION ON THE EVENT. DOES NOT BELIEVE ICING HAD ANYTHING TO DO WITH THE FAILURE OF THE AILERON TRIM SYS. AFTER A LNDG AND CHKING THE SYS, WAS ABLE TO GET THE TRIM TO MOVE ONE TIME AND THEN IT FAILED AGAIN. MAINT REPLACED THE FAULTY SWITCH. ADVISED THE ACFT MUST BE FLOWN USING THE TRIM CONSTANTLY.
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.