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SR22 pilot makes two gars when autoplt fails to couple with GS. Altitude deviation occurs on second go around as pilot attempts to resolve roll trim issue.
| Attributes | |
| ACN | 764111 |
| Time | |
| Date | 200711 |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : ads.airport |
| State Reference | TX |
| Altitude | msl single value : 2000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Dusk |
| Aircraft 1 | |
| Controlling Facilities | tracon : d10.tracon |
| Operator | general aviation : personal |
| Make Model Name | SR22 |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | ils localizer & glide slope : 33 |
| Flight Phase | landing : go around landing : missed approach |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | other |
| Function | flight crew : single pilot |
| Qualification | pilot : private pilot : instrument |
| Experience | flight time last 90 days : 18 flight time total : 360 flight time type : 160 |
| ASRS Report | 764111 |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : overshoot inflight encounter : weather non adherence : clearance non adherence : published procedure |
| Independent Detector | other flight crewa |
| Resolutory Action | controller : issued advisory flight crew : overcame equipment problem flight crew : overrode automation |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance Weather Aircraft |
| Primary Problem | Aircraft |
Narrative:
Cleared for ILS runway 33 approach; on autoplt (stgc 55X) capable of flying a GS. Autoplt did not capture GS. Overflew runway in IMC; declared missed approach. Vectored back around; set up same approach. Double-verified GNS 430 and autoplt settings were correct for coupled ILS approach. Failed to capture GS. Expected this; disconnected autoplt to fly approach manually. Aircraft banked sharply to left when autoplt disconnected. Trim switch did not appear to correct the bank. Flew localizer with considerable pressure on stick to maintain wings level. Broke out of overcast over end of runway; but too high/fast to safely land. Declared second missed approach. Attempted to deal with trim issue; overflew assigned altitude. Got aircraft trimmed with several seconds on the trim switch. Unknown why aircraft was so badly out of trim when autoplt engaged. Flew third approach manually and landed. ATC vectors to final were very close to FAF. My guess is that autoplt did not have adequate time to stabilize before intercepting the GS. I did not attempt to manually engage GS -- I was distraction by unexpected autoplt operation and trim issue.
Original NASA ASRS Text
Title: SR22 PLT MAKES TWO GARS WHEN AUTOPLT FAILS TO COUPLE WITH GS. ALT DEV OCCURS ON SECOND GAR AS PLT ATTEMPTS TO RESOLVE ROLL TRIM ISSUE.
Narrative: CLRED FOR ILS RWY 33 APCH; ON AUTOPLT (STGC 55X) CAPABLE OF FLYING A GS. AUTOPLT DID NOT CAPTURE GS. OVERFLEW RWY IN IMC; DECLARED MISSED APCH. VECTORED BACK AROUND; SET UP SAME APCH. DOUBLE-VERIFIED GNS 430 AND AUTOPLT SETTINGS WERE CORRECT FOR COUPLED ILS APCH. FAILED TO CAPTURE GS. EXPECTED THIS; DISCONNECTED AUTOPLT TO FLY APCH MANUALLY. ACFT BANKED SHARPLY TO L WHEN AUTOPLT DISCONNECTED. TRIM SWITCH DID NOT APPEAR TO CORRECT THE BANK. FLEW LOC WITH CONSIDERABLE PRESSURE ON STICK TO MAINTAIN WINGS LEVEL. BROKE OUT OF OVCST OVER END OF RWY; BUT TOO HIGH/FAST TO SAFELY LAND. DECLARED SECOND MISSED APCH. ATTEMPTED TO DEAL WITH TRIM ISSUE; OVERFLEW ASSIGNED ALT. GOT ACFT TRIMMED WITH SEVERAL SECONDS ON THE TRIM SWITCH. UNKNOWN WHY ACFT WAS SO BADLY OUT OF TRIM WHEN AUTOPLT ENGAGED. FLEW THIRD APCH MANUALLY AND LANDED. ATC VECTORS TO FINAL WERE VERY CLOSE TO FAF. MY GUESS IS THAT AUTOPLT DID NOT HAVE ADEQUATE TIME TO STABILIZE BEFORE INTERCEPTING THE GS. I DID NOT ATTEMPT TO MANUALLY ENGAGE GS -- I WAS DISTR BY UNEXPECTED AUTOPLT OP AND TRIM ISSUE.
Data retrieved from NASA's ASRS site as of January 2009 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.