<< >> NASA ASRS Report 1005432, April 2012

A ce-750 flight crew reported ahrs heading information was invalid on the lga whitestone climb. Dg fast slave did not work; and all navigation information was inaccurate until the ahrs corrected itself at cruise altitude.

Attributes
ACN	1005432
Time
Date	201204
Local Time Of Day	1201-1800
Place
Locale Reference	LGA.Airport
State Reference	NY
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Citation X (C750)
Operating Under FAR Part	Part 91
Flight Phase	Takeoff
Component
Aircraft Component	Compass (HSI/ETC)
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 100 Flight Crew Total 10000 Flight Crew Type 3000
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

During lga 4 whitestone climb departure it became immediately apparent that ahrs headings had both malfunctioned and were 30-45 degrees off from each other. Navigation information was extremely unreliable. Dg fast slave did not work on either ahrs and autopilot could not be used. Magnetic compass was only immediate heading source. When ATC cleared us on a heading it was way off due to map error. Lrp and hvq VOR's were given but again displayed info was erroneous and direct course could not be flown even with green needles. Finally at higher altitudes and in smooth air; magnetic compass settled down enough to steer a reasonably accurate heading. No TCAS alerts were received.

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Original NASA ASRS Text

Title: A CE-750 flight crew reported AHRS heading information was invalid on the LGA Whitestone climb. DG fast slave did not work; and all navigation information was inaccurate until the AHRS corrected itself at cruise altitude.

Narrative: During LGA 4 Whitestone Climb departure it became immediately apparent that AHRS headings had both malfunctioned and were 30-45 degrees off from each other. NAV information was extremely unreliable. DG fast slave did not work on either AHRS and autopilot could not be used. Magnetic compass was only immediate heading source. When ATC cleared us on a heading it was way off due to map error. LRP and HVQ VOR's were given but again displayed info was erroneous and direct course could not be flown even with green needles. Finally at higher altitudes and in smooth air; magnetic compass settled down enough to steer a reasonably accurate heading. No TCAS alerts were received.

Data retrieved from NASA's ASRS site as of July 2013 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.