BE1900 flight experiences course deviation due to dual directional gyro failure.

Attributes
ACN	614756
Time
Date	200404
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	navaid : eyw.vortac
State Reference	FL
Altitude	msl single value : 17000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zma.artcc
Operator	common carrier : air carrier
Make Model Name	Beech 1900
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 2000 flight time type : 1400
ASRS Report	614756
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : less severe non adherence : clearance other spatial deviation
Independent Detector	other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance flight crew : overcame equipment problem
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

En route to eyw, crew experienced dual directional gyro failure. Heading and course information became unreliable. The above-mentioned failures were reported to ATC. The crew believes the aircraft was 25-30 degrees off course because of this failure. The deviation occurred because the crew was xchking information from both the captain and first officer sides to try and determine which was accurate. When it was determined that both were not accurate, the crew reported these failures (directional gyro) to ATC and received a revised radar vector. In addition, the crew used the magnetic compass so this revised radar vector would be maintained. Conditions for the entire flight were VMC. This maintenance failure was recorded and full repairs were made the next day.

Original NASA ASRS Text

Title: BE1900 FLT EXPERIENCES COURSE DEV DUE TO DUAL DIRECTIONAL GYRO FAILURE.

Narrative: ENRTE TO EYW, CREW EXPERIENCED DUAL DIRECTIONAL GYRO FAILURE. HDG AND COURSE INFO BECAME UNRELIABLE. THE ABOVE-MENTIONED FAILURES WERE RPTED TO ATC. THE CREW BELIEVES THE ACFT WAS 25-30 DEGS OFF COURSE BECAUSE OF THIS FAILURE. THE DEV OCCURRED BECAUSE THE CREW WAS XCHKING INFO FROM BOTH THE CAPT AND FO SIDES TO TRY AND DETERMINE WHICH WAS ACCURATE. WHEN IT WAS DETERMINED THAT BOTH WERE NOT ACCURATE, THE CREW RPTED THESE FAILURES (DIRECTIONAL GYRO) TO ATC AND RECEIVED A REVISED RADAR VECTOR. IN ADDITION, THE CREW USED THE MAGNETIC COMPASS SO THIS REVISED RADAR VECTOR WOULD BE MAINTAINED. CONDITIONS FOR THE ENTIRE FLT WERE VMC. THIS MAINT FAILURE WAS RECORDED AND FULL REPAIRS WERE MADE THE NEXT DAY.

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.