Pilot of a beech baron, BE55, on an IFR flight after an annual inspection of the aircraft, found tha...

Attributes
ACN	410824
Time
Date	199808
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : dny
State Reference	NY
Altitude	msl bound lower : 8000 msl bound upper : 8000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zbw
Operator	general aviation : personal
Make Model Name	Baron 55/Cochise
Operating Under FAR Part	other : unknown
Flight Phase	cruise other
Route In Use	enroute airway : v449
Flight Plan	IFR
Person 1
Affiliation	Other
Function	oversight : pic
Qualification	pilot : commercial
Experience	flight time last 90 days : 35 flight time total : 5500 flight time type : 35
ASRS Report	410824
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : less severe non adherence : clearance other anomaly other spatial deviation
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa
Resolutory Action	flight crew : regained aircraft control flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

Plane had just come out of annual. Most switches on panel were off or in different position (this should not be since there was a master avionics switch). The slave button for the slaved gyroscope compass was out. There seemed to be a discrepancy between the magnetic and slaved gyroscope, approximately 30-50 degrees. I considered that this might be a necessary heading correction (for winds aloft) to stay on a GPS victor airway course (autoplt) while in the navigation position. After watching through several victor airways (V489 and V449) with changes in heading from 180 degrees to 250 degrees (and since it was good VFR) I decided to disengage the slave button and to immediately re-engage it to see if this would align the compasses. I did not disengage the autoplt during this so that proper altitude would be maintained. The plane immediately started turning to the left as the gyroscope compass went out of control. I tried to resolve this by focusing on the magnetic compass but it was swinging too wildly to use it. The plane turned close to 180 degrees before the compasses stabilized and then I put the autoplt on the heading bug to try to get back on course. At this time ZBW asked me what was going on since I seemed to be heading in an opposite direction. I explained the autoplt slaved gyroscope compass problem and they offered me direct to dny and said they would monitor my track to help me if necessary. Shortly thereafter we both agreed that the tracking was good although there was still a discrepancy in the compass. A solution would have been to place the autoplt in the heading mode before disengaging the slaved gyroscope but I didn't realize the slaved gyroscope would spin to the left. The plane was returned to FBO yesterday and they said perhaps the wrong screws were used in the vicinity of the magnetic compass and were going to test the gyroscope compass on a compass rose and hopefully the compasses will show the same headings. I also would not have done this unless it was good VFR but perhaps I should have taken the plane up on a separate flight to test this.

Original NASA ASRS Text

Title: PLT OF A BEECH BARON, BE55, ON AN IFR FLT AFTER AN ANNUAL INSPECTION OF THE ACFT, FOUND THAT THE DIRECTIONAL GYROSCOPE WOULD NOT STAY IN THE SLAVED MODE RESULTING IN ATC INTERVENTION TO VECTOR THE RPTR TO TURN AROUND AND INTERCEPT FLT PLAN ROUTING.

Narrative: PLANE HAD JUST COME OUT OF ANNUAL. MOST SWITCHES ON PANEL WERE OFF OR IN DIFFERENT POS (THIS SHOULD NOT BE SINCE THERE WAS A MASTER AVIONICS SWITCH). THE SLAVE BUTTON FOR THE SLAVED GYROSCOPE COMPASS WAS OUT. THERE SEEMED TO BE A DISCREPANCY BTWN THE MAGNETIC AND SLAVED GYROSCOPE, APPROX 30-50 DEGS. I CONSIDERED THAT THIS MIGHT BE A NECESSARY HEADING CORRECTION (FOR WINDS ALOFT) TO STAY ON A GPS VICTOR AIRWAY COURSE (AUTOPLT) WHILE IN THE NAV POS. AFTER WATCHING THROUGH SEVERAL VICTOR AIRWAYS (V489 AND V449) WITH CHANGES IN HEADING FROM 180 DEGS TO 250 DEGS (AND SINCE IT WAS GOOD VFR) I DECIDED TO DISENGAGE THE SLAVE BUTTON AND TO IMMEDIATELY RE-ENGAGE IT TO SEE IF THIS WOULD ALIGN THE COMPASSES. I DID NOT DISENGAGE THE AUTOPLT DURING THIS SO THAT PROPER ALT WOULD BE MAINTAINED. THE PLANE IMMEDIATELY STARTED TURNING TO THE L AS THE GYROSCOPE COMPASS WENT OUT OF CTL. I TRIED TO RESOLVE THIS BY FOCUSING ON THE MAGNETIC COMPASS BUT IT WAS SWINGING TOO WILDLY TO USE IT. THE PLANE TURNED CLOSE TO 180 DEGS BEFORE THE COMPASSES STABILIZED AND THEN I PUT THE AUTOPLT ON THE HEADING BUG TO TRY TO GET BACK ON COURSE. AT THIS TIME ZBW ASKED ME WHAT WAS GOING ON SINCE I SEEMED TO BE HEADING IN AN OPPOSITE DIRECTION. I EXPLAINED THE AUTOPLT SLAVED GYROSCOPE COMPASS PROB AND THEY OFFERED ME DIRECT TO DNY AND SAID THEY WOULD MONITOR MY TRACK TO HELP ME IF NECESSARY. SHORTLY THEREAFTER WE BOTH AGREED THAT THE TRACKING WAS GOOD ALTHOUGH THERE WAS STILL A DISCREPANCY IN THE COMPASS. A SOLUTION WOULD HAVE BEEN TO PLACE THE AUTOPLT IN THE HEADING MODE BEFORE DISENGAGING THE SLAVED GYROSCOPE BUT I DIDN'T REALIZE THE SLAVED GYROSCOPE WOULD SPIN TO THE L. THE PLANE WAS RETURNED TO FBO YESTERDAY AND THEY SAID PERHAPS THE WRONG SCREWS WERE USED IN THE VICINITY OF THE MAGNETIC COMPASS AND WERE GOING TO TEST THE GYROSCOPE COMPASS ON A COMPASS ROSE AND HOPEFULLY THE COMPASSES WILL SHOW THE SAME HEADINGS. I ALSO WOULD NOT HAVE DONE THIS UNLESS IT WAS GOOD VFR BUT PERHAPS I SHOULD HAVE TAKEN THE PLANE UP ON A SEPARATE FLT TO TEST THIS.

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.

Pilot of a beech baron, BE55, on an IFR flight after an annual inspection of the aircraft, found that the directional gyroscope would not stay in the slaved mode resulting in ATC intervention to vector the reporter to turn around and intercept flight plan routing.