Heading track deviation on overwater route using NDB VOR.

Attributes
ACN	205408
Time
Date	199203
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : vuh
State Reference	TX
Altitude	msl bound lower : 31000 msl bound upper : 31000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Navigation In Use	other ndb
Flight Phase	cruise other
Route In Use	enroute : other oceanic enroute : atlantic enroute : direct enroute airway : a766
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : atp pilot : commercial pilot : flight engineer
Experience	flight time last 90 days : 150 flight time total : 6700 flight time type : 285
ASRS Report	205408
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : instrument pilot : atp
Events
Anomaly	non adherence : clearance other spatial deviation
Independent Detector	other controllera other flight crewa
Resolutory Action	controller : issued new clearance flight crew : became reoriented flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation
Situations
Navigational Aid	Unspecified

Narrative:

En route from cancun, mexico, to dfw on A766, we were established on the airway. About 200 mi from cun our navigational aids (ADF and VOR) would not receive a good signal for reliable navigation. We continued on a course that all 3 crew members agreed would keep us on course. When we arrived in houston's airspace our ADF was indicating on course with a fairly weak identify and some excessive needle movement. Houston center then advised the crew that we were 47 NM to the west of A766. I immediately turned about 30 degrees to the right to get back on course. All indications on our ADF appeared to be on course. As we got closer to galveston our vors picked up hou showing we were slightly left of course.

Original NASA ASRS Text

Title: HDG TRACK DEV ON OVERWATER RTE USING NDB VOR.

Narrative: ENRTE FROM CANCUN, MEXICO, TO DFW ON A766, WE WERE ESTABLISHED ON THE AIRWAY. ABOUT 200 MI FROM CUN OUR NAVIGATIONAL AIDS (ADF AND VOR) WOULD NOT RECEIVE A GOOD SIGNAL FOR RELIABLE NAV. WE CONTINUED ON A COURSE THAT ALL 3 CREW MEMBERS AGREED WOULD KEEP US ON COURSE. WHEN WE ARRIVED IN HOUSTON'S AIRSPACE OUR ADF WAS INDICATING ON COURSE WITH A FAIRLY WEAK IDENT AND SOME EXCESSIVE NEEDLE MOVEMENT. HOUSTON CTR THEN ADVISED THE CREW THAT WE WERE 47 NM TO THE W OF A766. I IMMEDIATELY TURNED ABOUT 30 DEGS TO THE R TO GET BACK ON COURSE. ALL INDICATIONS ON OUR ADF APPEARED TO BE ON COURSE. AS WE GOT CLOSER TO GALVESTON OUR VORS PICKED UP HOU SHOWING WE WERE SLIGHTLY L OF COURSE.

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.