When the input to their ehsi heading data switched from magnetic to true the flight crew of a CL60 h...

Attributes
ACN	975449
Time
Date	201110
Local Time Of Day	1201-1800
Place
Locale Reference	TEB.Airport
State Reference	NJ
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Challenger CL600
Operating Under FAR Part	Part 91
Flight Phase	Initial Climb
Route In Use	SID RUUDY 2
Flight Plan	IFR
Component
Aircraft Component	Compass (HSI/ETC)
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 3000 Flight Crew Type 600
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Deviation - Track / Heading All Types

Narrative:

[We] took off from teb runway 24 with assigned clearance of ruudy 2 RNAV departure. Initial heading 240 degrees was flown as depicted on the SID. Upon hand off to ny departure; a clearance of 10;000 ft was given. At this point; the pilot flying experienced a flight director failure which was caused by the heading source supplying the ehsi automatically switching (failing) to true north source vs magnetic north. The distraction in the cockpit to this anomaly as well as determining correct heading information makes if difficult to recall if we were given an ATC direction to maintain heading 240 or not. The initial heading of 240 degrees was maintained beyond the depicted RNAV course of 260 degrees to wentz. A frequency change was given and the new controller queried the heading we were flying and then requested an immediate turn to 330 degrees. The controller asked if we were assigned the ruudy 2 departure and then asked us to please pay careful attention next time. There were no TCAS alerts at any time during the flight. A post-flight debriefing between the captain and first officer was completed. It was inconclusive as to whether we were given the 240 degrees heading assignment or not. The heading source failure was reported to maintenance; and additional procedures will be implemented in order to prevent such an occurrence from happening again.

Original NASA ASRS Text

Title: When the input to their EHSI heading data switched from Magnetic to True the flight crew of a CL60 had difficulty maintaining the required flight track parameters of the RUUDY RNAV SID from TEB.

Narrative: [We] took off from TEB Runway 24 with assigned clearance of RUUDY 2 RNAV departure. Initial heading 240 degrees was flown as depicted on the SID. Upon hand off to NY Departure; a clearance of 10;000 FT was given. At this point; the pilot flying experienced a flight director failure which was caused by the heading source supplying the EHSI automatically switching (failing) to TRUE North source vs Magnetic North. The distraction in the cockpit to this anomaly as well as determining correct heading information makes if difficult to recall if we were given an ATC direction to maintain heading 240 or not. The initial heading of 240 degrees was maintained beyond the depicted RNAV course of 260 degrees to WENTZ. A frequency change was given and the new Controller queried the heading we were flying and then requested an immediate turn to 330 degrees. The Controller asked if we were assigned the RUUDY 2 departure and then asked us to please pay careful attention next time. There were no TCAS alerts at any time during the flight. A post-flight debriefing between the Captain and First Officer was completed. It was inconclusive as to whether we were given the 240 degrees heading assignment or not. The heading source failure was reported to Maintenance; and additional procedures will be implemented in order to prevent such an occurrence from happening again.

Data retrieved from NASA's ASRS site as of April 2012 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.

When the input to their ehsi heading data switched from magnetic to true the flight crew of a CL60 had difficulty maintaining the required flight track parameters of the ruudy RNAV SID from teb.