Aircraft equipment problem. Navigation equipment. First officer's HSI (heading) error and omega erro...

Attributes
ACN	330161
Time
Date	199603
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : n90
State Reference	NY
Aircraft 1
Controlling Facilities	artcc : n90
Operator	common carrier : air carrier
Make Model Name	DC-10 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	330161
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe other anomaly other other spatial deviation
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	controller : issued new clearance flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Location: jfk north america and sfo. Departure jfk mar/xx/96 flight xx, D10 jfk to sfo. Copilot flying. Copilot's directional gyroscope showed 060 degrees. Heading assigned by departure control. While captain's directional gyroscope, HSI, showed 100 degrees, captain checked whisky compass and confirmed captain's compass correct. Reset, quick align on first officer directional gyroscope and corrected heading 40 degree left to 060 degrees. ATC noted correction. Captain advised ATC of problem and that it appeared corrected. Flight continued in cruise the #2 omega flying autoplt gave a xtrack error of 4 mi and wind read out different from #1 omega of 100 KTS. Omegas precision update over the next VOR and appeared normal for an hour, then we saw HSI compass difference of 30 degrees. No one checked wrong against whisky compass and after realign would only function in the directional gyroscope mode. Continued flight with #1 in directional gyroscope, #2 in navigation and crosschecked both against whisky compass every 5 mins, then #2 omega diverged excessively from #1. We advised ATC of necessity to navigation by VOR due unreliable omegas. Continued to sfo by xchking #1 and #2 directional gyroscope against the whisky compass. On approach sfo units precessing so rapidly we asked for and received radar vectors for visual at sfo at this time all navigation except NDB unreliable. Entered all in logbook. Need follow up information please. I am very much interested in cause or causes these navigation unit failures. Flight safe but track maintenance was difficult and workload very high.

Original NASA ASRS Text

Title: ACFT EQUIP PROB. NAV EQUIP. FO'S HSI (HDG) ERROR AND OMEGA ERROR. ONLY RELIABLE NAVAID IN ACFT AT DEST WAS NDB. MULTIPLE HDG NAV PROBS.

Narrative: LOCATION: JFK NORTH AMERICA AND SFO. DEP JFK MAR/XX/96 FLT XX, D10 JFK TO SFO. COPLT FLYING. COPLT'S DIRECTIONAL GYROSCOPE SHOWED 060 DEGS. HDG ASSIGNED BY DEP CTL. WHILE CAPT'S DIRECTIONAL GYROSCOPE, HSI, SHOWED 100 DEGS, CAPT CHKED WHISKY COMPASS AND CONFIRMED CAPT'S COMPASS CORRECT. RESET, QUICK ALIGN ON FO DIRECTIONAL GYROSCOPE AND CORRECTED HDG 40 DEG L TO 060 DEGS. ATC NOTED CORRECTION. CAPT ADVISED ATC OF PROB AND THAT IT APPEARED CORRECTED. FLT CONTINUED IN CRUISE THE #2 OMEGA FLYING AUTOPLT GAVE A XTRACK ERROR OF 4 MI AND WIND READ OUT DIFFERENT FROM #1 OMEGA OF 100 KTS. OMEGAS PRECISION UPDATE OVER THE NEXT VOR AND APPEARED NORMAL FOR AN HR, THEN WE SAW HSI COMPASS DIFFERENCE OF 30 DEGS. NO ONE CHKED WRONG AGAINST WHISKY COMPASS AND AFTER REALIGN WOULD ONLY FUNCTION IN THE DIRECTIONAL GYROSCOPE MODE. CONTINUED FLT WITH #1 IN DIRECTIONAL GYROSCOPE, #2 IN NAV AND XCHKED BOTH AGAINST WHISKY COMPASS EVERY 5 MINS, THEN #2 OMEGA DIVERGED EXCESSIVELY FROM #1. WE ADVISED ATC OF NECESSITY TO NAV BY VOR DUE UNRELIABLE OMEGAS. CONTINUED TO SFO BY XCHKING #1 AND #2 DIRECTIONAL GYROSCOPE AGAINST THE WHISKY COMPASS. ON APCH SFO UNITS PRECESSING SO RAPIDLY WE ASKED FOR AND RECEIVED RADAR VECTORS FOR VISUAL AT SFO AT THIS TIME ALL NAV EXCEPT NDB UNRELIABLE. ENTERED ALL IN LOGBOOK. NEED FOLLOW UP INFO PLEASE. I AM VERY MUCH INTERESTED IN CAUSE OR CAUSES THESE NAV UNIT FAILURES. FLT SAFE BUT TRACK MAINT WAS DIFFICULT AND WORKLOAD VERY HIGH.

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.

Aircraft equipment problem. Navigation equipment. First officer's HSI (heading) error and omega error. Only reliable NAVAID in aircraft at destination was NDB. Multiple heading navigation problems.