L188 flight crew notices 11 degree difference in heading when changing vors on a 256 mi route of the...

Attributes
ACN	359200
Time
Date	199701
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : zid
State Reference	IN
Altitude	msl bound lower : 22000 msl bound upper : 22000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid
Operator	common carrier : air carrier
Make Model Name	Electra L-188
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 120 flight time total : 2680 flight time type : 620
ASRS Report	359200
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	other anomaly other other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Navigational Facility
Air Traffic Incident	other

Narrative:

At changeover point on J80 between air and vhp (wbound) there is an 11 degree difference in radials between vors. When I switched VOR frequency and radial selector on RMI, I observed position to be north of the airway. I corrected south and my navigation showed me centered on the airway (085 degree radial vhp). Mins later, ATC informed me I was off airway. I received a vector to correct. Flight proceeded without further incident. To correct this in the future, J80 should be examined to see if the radials are correctly aligned. 11 degree difference between vors on an airway seems excessive. Controller mentioned 'this happens all the time.' callback conversation with reporter revealed the following information: reporter states he has not followed up with information to company. He was quite concerned that the FAA was pursuing the incident. He feels strongly that the airway needs to be improved since the controller indicated this happens all the time. They changed at exactly the half way point. There is always some slight difference when switching vors, but this needle was off center enough to make them change the heading drastically until centered.

Original NASA ASRS Text

Title: L188 FLC NOTICES 11 DEG DIFFERENCE IN HDG WHEN CHANGING VORS ON A 256 MI RTE OF THE AIRWAY. THIS CAUSES HDG DEV AND CTLR INTERVENES.

Narrative: AT CHANGEOVER POINT ON J80 BTWN AIR AND VHP (WBOUND) THERE IS AN 11 DEG DIFFERENCE IN RADIALS BTWN VORS. WHEN I SWITCHED VOR FREQ AND RADIAL SELECTOR ON RMI, I OBSERVED POS TO BE N OF THE AIRWAY. I CORRECTED S AND MY NAV SHOWED ME CTRED ON THE AIRWAY (085 DEG RADIAL VHP). MINS LATER, ATC INFORMED ME I WAS OFF AIRWAY. I RECEIVED A VECTOR TO CORRECT. FLT PROCEEDED WITHOUT FURTHER INCIDENT. TO CORRECT THIS IN THE FUTURE, J80 SHOULD BE EXAMINED TO SEE IF THE RADIALS ARE CORRECTLY ALIGNED. 11 DEG DIFFERENCE BTWN VORS ON AN AIRWAY SEEMS EXCESSIVE. CTLR MENTIONED 'THIS HAPPENS ALL THE TIME.' CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES HE HAS NOT FOLLOWED UP WITH INFO TO COMPANY. HE WAS QUITE CONCERNED THAT THE FAA WAS PURSUING THE INCIDENT. HE FEELS STRONGLY THAT THE AIRWAY NEEDS TO BE IMPROVED SINCE THE CTLR INDICATED THIS HAPPENS ALL THE TIME. THEY CHANGED AT EXACTLY THE HALF WAY POINT. THERE IS ALWAYS SOME SLIGHT DIFFERENCE WHEN SWITCHING VORS, BUT THIS NEEDLE WAS OFF CTR ENOUGH TO MAKE THEM CHANGE THE HDG DRASTICALLY UNTIL CTRED.

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.

L188 flight crew notices 11 degree difference in heading when changing vors on a 256 mi route of the airway. This causes heading deviation and controller intervenes.