Crew of a cpr lear 31A misread the gso triad 2 SID which resulted in a track deviation.

Attributes
ACN	438176
Time
Date	199905
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : gso.tracon
State Reference	NC
Altitude	msl single value : 5000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : gso.tracon
Operator	general aviation : corporate
Make Model Name	Learjet 31
Operating Under FAR Part	Part 91
Flight Phase	climbout : initial
Route In Use	departure sid : gso.triad 2
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 800 flight time total : 12000 flight time type : 100
ASRS Report	438176
Person 2
Affiliation	government : faa
Function	controller : departure
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : less severe non adherence : clearance other spatial deviation
Independent Detector	other controllera other flight crewa
Resolutory Action	aircraft : automation overrode flight crew controller : issued advisory flight crew : overcame equipment problem flight crew : became reoriented
Supplementary
Problem Areas	ATC Human Performance Chart Or Publication Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation
Situations
Airport	procedure or policy : gso.airport
Airspace Structure	class d : gso.d
Chart	airport : gso.airport sid : triad 2

Narrative:

On departure, FMS GPS dropped out causing some type of data entry error. FMS wouldn't respond correctly. Changing to VOR caused momentary lack of knowledge of immediate position. Clearance on departure was triad 2 departure, but no transition was given. Controller cleared us to a transition intersection and by the time we recognized the name so we could proceed, we were evidently in someone else's airspace where we shouldn't have been. We asked for an initial heading to go to this transition intersection but we were not given a heading. We were just cleared to jan VOR on course. When we were told to proceed to the transition intersection, we advised the controller we were having trouble navigating, which he must have realized because he asked us for our heading. If we had been given the transition with the SID it would have been easier to transition back to VOR navigation when our FMS was responding improperly. The SID called for vector to the radial. It would have been better if the controller would have given us a heading when he realized we weren't navigating properly. We usually back up the FMS with a VOR but we weren't given a transition to set up with.

Original NASA ASRS Text

Title: CREW OF A CPR LEAR 31A MISREAD THE GSO TRIAD 2 SID WHICH RESULTED IN A TRACK DEV.

Narrative: ON DEP, FMS GPS DROPPED OUT CAUSING SOME TYPE OF DATA ENTRY ERROR. FMS WOULDN'T RESPOND CORRECTLY. CHANGING TO VOR CAUSED MOMENTARY LACK OF KNOWLEDGE OF IMMEDIATE POS. CLRNC ON DEP WAS TRIAD 2 DEP, BUT NO TRANSITION WAS GIVEN. CTLR CLRED US TO A TRANSITION INTXN AND BY THE TIME WE RECOGNIZED THE NAME SO WE COULD PROCEED, WE WERE EVIDENTLY IN SOMEONE ELSE'S AIRSPACE WHERE WE SHOULDN'T HAVE BEEN. WE ASKED FOR AN INITIAL HDG TO GO TO THIS TRANSITION INTXN BUT WE WERE NOT GIVEN A HDG. WE WERE JUST CLRED TO JAN VOR ON COURSE. WHEN WE WERE TOLD TO PROCEED TO THE TRANSITION INTXN, WE ADVISED THE CTLR WE WERE HAVING TROUBLE NAVING, WHICH HE MUST HAVE REALIZED BECAUSE HE ASKED US FOR OUR HDG. IF WE HAD BEEN GIVEN THE TRANSITION WITH THE SID IT WOULD HAVE BEEN EASIER TO TRANSITION BACK TO VOR NAV WHEN OUR FMS WAS RESPONDING IMPROPERLY. THE SID CALLED FOR VECTOR TO THE RADIAL. IT WOULD HAVE BEEN BETTER IF THE CTLR WOULD HAVE GIVEN US A HDG WHEN HE REALIZED WE WEREN'T NAVING PROPERLY. WE USUALLY BACK UP THE FMS WITH A VOR BUT WE WEREN'T GIVEN A TRANSITION TO SET UP WITH.

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.