 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Flight crew of cpr turbo propeller in cruise at FL280 lost primary flight control instruments. Reverted to needle ball and airspeed with wet free compass for flight control and heading.
| Attributes | |
| ACN | 193815 |
| Time | |
| Date | 199111 |
| Day | Tue |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : cgt |
| State Reference | IL |
| Altitude | msl bound lower : 27500 msl bound upper : 28500 |
| Environment | |
| Flight Conditions | IMC VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zau |
| Operator | general aviation : corporate |
| Make Model Name | Small Transport, Low Wing, 2 Turboprop Eng |
| Navigation In Use | Other Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : commercial pilot : instrument pilot : atp pilot : cfi |
| Experience | flight time last 90 days : 100 flight time total : 11000 flight time type : 800 |
| ASRS Report | 193815 |
| Person 2 | |
| Affiliation | Other |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial |
| Events | |
| Anomaly | aircraft equipment problem : critical altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other spatial deviation |
| Independent Detector | other controllera other flight crewa |
| Resolutory Action | flight crew : returned to intended course or assigned course flight crew : regained aircraft control |
| Consequence | Other Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
Corporate flight with 6 passenger at FL280 my copilot said look at my attitude indicator. The air driven gyro was flopping from 30 degree bank either side and 30 degree pitch in both directions. Having EFIS on the left side of the cockpit and (2) turn and slip indicators we didn't concern ourselves with the loss of 1 attitude gyro. When approximately 100 mi south of cgt we were cleared direct to cgt direct to brave intersection direct to ues. As the copilot looked up the coordinates for brave I programmed for cgt, but was unable to do so. The RNAV gave funny looking indications and erased the previous way point. About that time I noticed that the autoplt was not maintaining the assigned heading and we were in a bank to the left or turning left. The center controller asked where we were going. I told my copilot we apparently had lost the slaved heading indicators and to go to free slave, while we were doing so and trying to maintain heading my altitude varied 500 ft either side of assigned FL280. The copilot told me we had a 35 degree split in heading indicators, I tried to maintain wings level with the pilots EFIS attitude indicator but noticed the turn needle and compass kept turning. I instructed the copilot to fly using his turn and slip indicator but he too varied in altitude by 500-800 ft. I told him I would now take it using my turn and slip if he would monitor compass (magnetic) and altitude at that time he stated that the compass system was on free gyro but my attitude indicator had failed. We were able to regain complete control of altitude and heading by using needle ball and free gyro compass. Our maintenance department replaced copilot's attitude indicator (mechanical). Pilot's attitude indicator (AC) and pilot's (dc pwred compass indicator) at no time did we have any fail flags on any system.
Original NASA ASRS Text
Title: FLC OF CPR TURBO PROP IN CRUISE AT FL280 LOST PRIMARY FLT CTL INSTS. REVERTED TO NEEDLE BALL AND AIRSPD WITH WET FREE COMPASS FOR FLT CTL AND HDG.
Narrative: CORPORATE FLT WITH 6 PAX AT FL280 MY COPLT SAID LOOK AT MY ATTITUDE INDICATOR. THE AIR DRIVEN GYRO WAS FLOPPING FROM 30 DEG BANK EITHER SIDE AND 30 DEG PITCH IN BOTH DIRECTIONS. HAVING EFIS ON THE L SIDE OF THE COCKPIT AND (2) TURN AND SLIP INDICATORS WE DIDN'T CONCERN OURSELVES WITH THE LOSS OF 1 ATTITUDE GYRO. WHEN APPROX 100 MI S OF CGT WE WERE CLRED DIRECT TO CGT DIRECT TO BRAVE INTXN DIRECT TO UES. AS THE COPLT LOOKED UP THE COORDINATES FOR BRAVE I PROGRAMMED FOR CGT, BUT WAS UNABLE TO DO SO. THE RNAV GAVE FUNNY LOOKING INDICATIONS AND ERASED THE PREVIOUS WAY POINT. ABOUT THAT TIME I NOTICED THAT THE AUTOPLT WAS NOT MAINTAINING THE ASSIGNED HDG AND WE WERE IN A BANK TO THE L OR TURNING L. THE CENTER CTLR ASKED WHERE WE WERE GOING. I TOLD MY COPLT WE APPARENTLY HAD LOST THE SLAVED HDG INDICATORS AND TO GO TO FREE SLAVE, WHILE WE WERE DOING SO AND TRYING TO MAINTAIN HDG MY ALT VARIED 500 FT EITHER SIDE OF ASSIGNED FL280. THE COPLT TOLD ME WE HAD A 35 DEG SPLIT IN HDG INDICATORS, I TRIED TO MAINTAIN WINGS LEVEL WITH THE PLTS EFIS ATTITUDE INDICATOR BUT NOTICED THE TURN NEEDLE AND COMPASS KEPT TURNING. I INSTRUCTED THE COPLT TO FLY USING HIS TURN AND SLIP INDICATOR BUT HE TOO VARIED IN ALT BY 500-800 FT. I TOLD HIM I WOULD NOW TAKE IT USING MY TURN AND SLIP IF HE WOULD MONITOR COMPASS (MAG) AND ALT AT THAT TIME HE STATED THAT THE COMPASS SYS WAS ON FREE GYRO BUT MY ATTITUDE INDICATOR HAD FAILED. WE WERE ABLE TO REGAIN COMPLETE CTL OF ALT AND HDG BY USING NEEDLE BALL AND FREE GYRO COMPASS. OUR MAINT DEPT REPLACED COPLT'S ATTITUDE INDICATOR (MECHANICAL). PLT'S ATTITUDE INDICATOR (AC) AND PLT'S (DC PWRED COMPASS INDICATOR) AT NO TIME DID WE HAVE ANY FAIL FLAGS ON ANY SYS.
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.