|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||atc facility : gpt|
|Altitude||msl bound lower : 4000|
msl bound upper : 4000
|Controlling Facilities||tower : ssf|
|Operator||general aviation : instructional|
|Make Model Name||Small Aircraft, Low Wing, 1 Eng, Fixed Gear|
|Flight Phase||cruise other|
|Route In Use||enroute airway : v114|
|Function||instruction : instructor|
|Qualification||pilot : commercial|
pilot : cfi
|Experience||flight time last 90 days : 130|
flight time total : 1900
|Function||instruction : trainee|
|Qualification||pilot : student|
|Anomaly||aircraft equipment problem : critical|
non adherence : clearance
other spatial deviation
|Independent Detector||other controllera|
|Resolutory Action||controller : issued new clearance|
|Air Traffic Incident||Pilot Deviation|
Instrument student and cfii departed hks on an instrument cross country training flight with marginal VFR conditions at hks and IFR conditions at gpt, the first destination of the flight. The aircraft had recently been certified for IFR, but there were no recorded VOR checks so one navigation radio was checked against the other prior to entering IMC. The check revealed no bearing error. The flight clearance was direct to the first NAVAID and this was accomplished west/O apparent problem though it was noted that it took a large cut to keep the VOR needles centered. This was attributed to the winds. The second leg of the flight was via a victor arwy composed to 2 radials from different VOR's. The outbnd radial of one should have intercepted the inbound radial of the other, but this never occurred. Again the winds were blamed. Shortly thereafter center transferred control to gpt approach and the landing was accomplished via radar vectors on a routine basis. During the return flight, gpt approach advised that we were 5 mi west of V114 which was the 342 degree right from gpt. The VOR's, however, indicated that we were east of this radial. The DME was in agreement with ATC, so the remainder of the flight was conducted using the DME radial readout. It is my belief that both VOR's were approximately 20 degrees off. This could mean that we were as much as 10 mi off course west/O knowing it. This casts doubt on the option of verifying the VOR's by testing one system against the other when the accuracy of at least one receiver has not been firmly established. I will not do this again.
Original NASA ASRS Text
Title: SMA FLEW 5 MILES WEST OF V114.
Narrative: INSTRUMENT STUDENT AND CFII DEPARTED HKS ON AN INSTRUMENT CROSS COUNTRY TRNING FLT WITH MARGINAL VFR CONDITIONS AT HKS AND IFR CONDITIONS AT GPT, THE FIRST DEST OF THE FLT. THE ACFT HAD RECENTLY BEEN CERTIFIED FOR IFR, BUT THERE WERE NO RECORDED VOR CHKS SO ONE NAV RADIO WAS CHKED AGAINST THE OTHER PRIOR TO ENTERING IMC. THE CHK REVEALED NO BEARING ERROR. THE FLT CLRNC WAS DIRECT TO THE FIRST NAVAID AND THIS WAS ACCOMPLISHED W/O APPARENT PROB THOUGH IT WAS NOTED THAT IT TOOK A LARGE CUT TO KEEP THE VOR NEEDLES CENTERED. THIS WAS ATTRIBUTED TO THE WINDS. THE SECOND LEG OF THE FLT WAS VIA A VICTOR ARWY COMPOSED TO 2 RADIALS FROM DIFFERENT VOR'S. THE OUTBND RADIAL OF ONE SHOULD HAVE INTERCEPTED THE INBND RADIAL OF THE OTHER, BUT THIS NEVER OCCURRED. AGAIN THE WINDS WERE BLAMED. SHORTLY THEREAFTER CENTER TRANSFERRED CTL TO GPT APCH AND THE LNDG WAS ACCOMPLISHED VIA RADAR VECTORS ON A ROUTINE BASIS. DURING THE RETURN FLT, GPT APCH ADVISED THAT WE WERE 5 MI W OF V114 WHICH WAS THE 342 DEG R FROM GPT. THE VOR'S, HOWEVER, INDICATED THAT WE WERE E OF THIS RADIAL. THE DME WAS IN AGREEMENT WITH ATC, SO THE REMAINDER OF THE FLT WAS CONDUCTED USING THE DME RADIAL READOUT. IT IS MY BELIEF THAT BOTH VOR'S WERE APPROX 20 DEGS OFF. THIS COULD MEAN THAT WE WERE AS MUCH AS 10 MI OFF COURSE W/O KNOWING IT. THIS CASTS DOUBT ON THE OPTION OF VERIFYING THE VOR'S BY TESTING ONE SYS AGAINST THE OTHER WHEN THE ACCURACY OF AT LEAST ONE RECEIVER HAS NOT BEEN FIRMLY ESTABLISHED. I WILL NOT DO THIS AGAIN.
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.