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Malfunctioning directional gyro inputting invalid data to GPS and associated mfd results in track deviation for pilot of high performance homebuilt.
| Attributes | |
| ACN | 637857 |
| Time | |
| Date | 200411 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | navaid : fod.vortac |
| State Reference | IA |
| Altitude | msl single value : 15000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zmp.artcc |
| Operator | general aviation : personal |
| Make Model Name | Small Aircraft |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | other |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | other |
| Function | flight crew : single pilot |
| Qualification | pilot : private pilot : instrument |
| Experience | flight time last 90 days : 10 flight time total : 1100 flight time type : 10 |
| ASRS Report | 637857 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Events | |
| Anomaly | aircraft equipment problem : critical other spatial deviation |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued advisory controller : issued new clearance controller : provided flight assist |
| Consequence | other |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance Aircraft |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
First indication of problem. Garmin 430 wind direction arrow and speed showed abnormal speed -- up to 195 KT winds aloft. Center informed aircraft was left of course. Garmin 430 moving map and mfd avidyne maps were showing different directions on display. Determined the kcs 55 degree HSI heading was not correct. Used the wet compass and vectors from center to continue on to cps in VFR conditions. The gyro was found to be defective. Gyro was not allowed to spin up fully and every time a turn was made the gyro would lag. The electric gyro feeds information to the 'diga-data' (shadin), garmin 430 and avidyne mfd and to autoplt. There was no flag on the gyro to indicate a problem and the avidyne information took bad information and displayed the moving map in the wrong position. Need a better understanding on interconnected system and how they relate to each other. ATC did a good job in providing vectors to my destination and handled the situation very professionally.
Original NASA ASRS Text
Title: MALFUNCTIONING DIRECTIONAL GYRO INPUTTING INVALID DATA TO GPS AND ASSOCIATED MFD RESULTS IN TRACK DEV FOR PLT OF HIGH PERFORMANCE HOMEBUILT.
Narrative: FIRST INDICATION OF PROB. GARMIN 430 WIND DIRECTION ARROW AND SPD SHOWED ABNORMAL SPD -- UP TO 195 KT WINDS ALOFT. CTR INFORMED ACFT WAS L OF COURSE. GARMIN 430 MOVING MAP AND MFD AVIDYNE MAPS WERE SHOWING DIFFERENT DIRECTIONS ON DISPLAY. DETERMINED THE KCS 55 DEG HSI HDG WAS NOT CORRECT. USED THE WET COMPASS AND VECTORS FROM CTR TO CONTINUE ON TO CPS IN VFR CONDITIONS. THE GYRO WAS FOUND TO BE DEFECTIVE. GYRO WAS NOT ALLOWED TO SPIN UP FULLY AND EVERY TIME A TURN WAS MADE THE GYRO WOULD LAG. THE ELECTRIC GYRO FEEDS INFO TO THE 'DIGA-DATA' (SHADIN), GARMIN 430 AND AVIDYNE MFD AND TO AUTOPLT. THERE WAS NO FLAG ON THE GYRO TO INDICATE A PROB AND THE AVIDYNE INFO TOOK BAD INFO AND DISPLAYED THE MOVING MAP IN THE WRONG POS. NEED A BETTER UNDERSTANDING ON INTERCONNECTED SYS AND HOW THEY RELATE TO EACH OTHER. ATC DID A GOOD JOB IN PROVIDING VECTORS TO MY DEST AND HANDLED THE SIT VERY PROFESSIONALLY.
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.