Mlt with faulty VOR broke out 1 NM left of center line on a VOR approach to oqu. Aircraft continued ...

Attributes
ACN	91413
Time
Date	198807
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : oqu
State Reference	RI
Altitude	msl bound lower : 700 msl bound upper : 2000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : oqu
Operator	other
Make Model Name	Medium Large Transport
Flight Phase	descent : approach landing other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	government : military
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : military
Experience	flight time last 90 days : 180 flight time total : 2000 flight time type : 1150
ASRS Report	91413
Person 2
Affiliation	government : military
Function	oversight : pic
Qualification	pilot : military
Events
Anomaly	aircraft equipment problem : critical non adherence : published procedure other spatial deviation other spatial deviation
Independent Detector	other controllera other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Cleared VOR runway 34 approach. The PNF contacted quonset tower at the final approach fix. Tower stated that approach control advised that we were about 1/4 mi left of course. We verified our instrument indications, which showed at most 1/2 degree left of course. I immediately increased my wind correction and regained centerline. We continued the approach and broke out of IMC conditions at 700' MSL. We were approximately 1 mi left of course, with the course deviation indicator still centered on course. Tower issued a low altitude alert as we maneuvered for landing and we acknowledged that we were VMC with the runway in sight. After landing, tower stated that approach control wanted to know if we ever were established on final approach course. We replied in the affirmative. We departed for andrews AFB (nsf). Prior to taking the runway we asked tower if anyone else using the VOR approach had experienced any problems. Tower stated that we were the only aircraft to have any problems and we should have our equipment checked. We crosschecked our VOR-1 information with the TACAN and did not show any appreciable difference. On our final leg from andrews AFB (nsf) to selfridge angb (mtl) we were asked by washington (possibly cleveland) center if we showed ourselves on course. We replied that we did and center requested our heading. After we responded they stated that we were 7 mi off course. We were then issued radar vectors direct when able. We informed center that we had had trouble with the VOR-1 receiver. The VOR-2 agreed with the position given by center. We utilized VOR-2 TACAN for navigation for the remainder of the flight. I briefed the approach to quonset state to the PNF, but failed to recognize that he selected VOR-1 instead of the normal VOR-2 for his course information. With both of us on VOR-1, we had no xchk. Had I recognized this, we would have determined the VOR-1 to be unreliable at the time tower indicated that we were off course. After experiencing the problems on final at quonset state, we should have utilized only TACAN and VOR-2 for the remaining flts.

Original NASA ASRS Text

Title: MLT WITH FAULTY VOR BROKE OUT 1 NM LEFT OF CENTER LINE ON A VOR APCH TO OQU. ACFT CONTINUED 2 MORE FLTS BEFORE THE FLT CREW RECOGNIZED THE PROBLEM.

Narrative: CLRED VOR RWY 34 APCH. THE PNF CONTACTED QUONSET TWR AT THE FINAL APCH FIX. TWR STATED THAT APCH CTL ADVISED THAT WE WERE ABOUT 1/4 MI LEFT OF COURSE. WE VERIFIED OUR INSTRUMENT INDICATIONS, WHICH SHOWED AT MOST 1/2 DEG LEFT OF COURSE. I IMMEDIATELY INCREASED MY WIND CORRECTION AND REGAINED CENTERLINE. WE CONTINUED THE APCH AND BROKE OUT OF IMC CONDITIONS AT 700' MSL. WE WERE APPROX 1 MI LEFT OF COURSE, WITH THE COURSE DEVIATION INDICATOR STILL CENTERED ON COURSE. TWR ISSUED A LOW ALT ALERT AS WE MANEUVERED FOR LNDG AND WE ACKNOWLEDGED THAT WE WERE VMC WITH THE RWY IN SIGHT. AFTER LNDG, TWR STATED THAT APCH CTL WANTED TO KNOW IF WE EVER WERE ESTABLISHED ON FINAL APCH COURSE. WE REPLIED IN THE AFFIRMATIVE. WE DEPARTED FOR ANDREWS AFB (NSF). PRIOR TO TAKING THE RWY WE ASKED TWR IF ANYONE ELSE USING THE VOR APCH HAD EXPERIENCED ANY PROBS. TWR STATED THAT WE WERE THE ONLY ACFT TO HAVE ANY PROBS AND WE SHOULD HAVE OUR EQUIP CHKED. WE XCHKED OUR VOR-1 INFO WITH THE TACAN AND DID NOT SHOW ANY APPRECIABLE DIFFERENCE. ON OUR FINAL LEG FROM ANDREWS AFB (NSF) TO SELFRIDGE ANGB (MTL) WE WERE ASKED BY WASHINGTON (POSSIBLY CLEVELAND) CENTER IF WE SHOWED OURSELVES ON COURSE. WE REPLIED THAT WE DID AND CENTER REQUESTED OUR HDG. AFTER WE RESPONDED THEY STATED THAT WE WERE 7 MI OFF COURSE. WE WERE THEN ISSUED RADAR VECTORS DIRECT WHEN ABLE. WE INFORMED CENTER THAT WE HAD HAD TROUBLE WITH THE VOR-1 RECEIVER. THE VOR-2 AGREED WITH THE POS GIVEN BY CENTER. WE UTILIZED VOR-2 TACAN FOR NAV FOR THE REMAINDER OF THE FLT. I BRIEFED THE APCH TO QUONSET STATE TO THE PNF, BUT FAILED TO RECOGNIZE THAT HE SELECTED VOR-1 INSTEAD OF THE NORMAL VOR-2 FOR HIS COURSE INFO. WITH BOTH OF US ON VOR-1, WE HAD NO XCHK. HAD I RECOGNIZED THIS, WE WOULD HAVE DETERMINED THE VOR-1 TO BE UNRELIABLE AT THE TIME TWR INDICATED THAT WE WERE OFF COURSE. AFTER EXPERIENCING THE PROBS ON FINAL AT QUONSET STATE, WE SHOULD HAVE UTILIZED ONLY TACAN AND VOR-2 FOR THE REMAINING FLTS.

Data retrieved from NASA's ASRS site as of August 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.

Mlt with faulty VOR broke out 1 NM left of center line on a VOR approach to oqu. Aircraft continued 2 more flts before the flight crew recognized the problem.