The lga magnetic disturbance caused a track deviation.

Attributes
ACN	279474
Time
Date	199408
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : lga
State Reference	NY
Altitude	agl bound lower : 0 agl bound upper : 2000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : n90 tower : lga artcc : zan
Operator	common carrier : air carrier
Make Model Name	MD-88
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	climbout : takeoff climbout : initial ground : holding
Route In Use	departure other departure sid : sid enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 90 flight time total : 4700 flight time type : 1000
ASRS Report	279474
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : less severe non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other controllera other flight crewa other other : unspecified cockpit
Resolutory Action	controller : issued new clearance flight crew : became reoriented
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation
Situations
Airport	other physical facility

Narrative:

We were cleared into position and hold, runway 13 at lga, with the added instruction, 'be ready for immediate.' there was an approaching aircraft on final. My RMI read approximately runway heading. However, my nd display showed 030. Confident of the WX and thinking I had one good heading system and not wanting to cause a missed approach, we took off. Shortly after liftoff, I glanced at the first officer's nd, and was surprised to see that I did not agree with my RMI. Tower had, just prior to brake release, directed a turn after takeoff to 090, although we had been originally cleared the whitestone climb and briefed the same (a right turn to 175). I realized at this point that our headings were not indicating correctly, and in the confusion we inadvertently made a right turn to 090 on the first officer's nd. Approach control then began to give us vectors to the left, which we attempted to follow by using the system of mirrors to view the magnetic compass. This did not work extremely well, but kept us in the generally correct direction. This problem was caused by the over-sensitivity of the heading system to the metal in the runway at lga. It was aggravated by the fact that we approached the runway on the closest parallel taxiway, and we experienced an approximately 20 min delay waiting for takeoff. The MD88 should be equipped with a magneto compass which is much more easily accessible and useable.

Original NASA ASRS Text

Title: THE LGA MAGNETIC DISTURBANCE CAUSED A TRACK DEV.

Narrative: WE WERE CLRED INTO POS AND HOLD, RWY 13 AT LGA, WITH THE ADDED INSTRUCTION, 'BE READY FOR IMMEDIATE.' THERE WAS AN APCHING ACFT ON FINAL. MY RMI READ APPROX RWY HDG. HOWEVER, MY ND DISPLAY SHOWED 030. CONFIDENT OF THE WX AND THINKING I HAD ONE GOOD HDG SYS AND NOT WANTING TO CAUSE A MISSED APCH, WE TOOK OFF. SHORTLY AFTER LIFTOFF, I GLANCED AT THE FO'S ND, AND WAS SURPRISED TO SEE THAT I DID NOT AGREE WITH MY RMI. TWR HAD, JUST PRIOR TO BRAKE RELEASE, DIRECTED A TURN AFTER TKOF TO 090, ALTHOUGH WE HAD BEEN ORIGINALLY CLRED THE WHITESTONE CLB AND BRIEFED THE SAME (A R TURN TO 175). I REALIZED AT THIS POINT THAT OUR HDGS WERE NOT INDICATING CORRECTLY, AND IN THE CONFUSION WE INADVERTENTLY MADE A R TURN TO 090 ON THE FO'S ND. APCH CTL THEN BEGAN TO GIVE US VECTORS TO THE L, WHICH WE ATTEMPTED TO FOLLOW BY USING THE SYS OF MIRRORS TO VIEW THE MAGNETIC COMPASS. THIS DID NOT WORK EXTREMELY WELL, BUT KEPT US IN THE GENERALLY CORRECT DIRECTION. THIS PROB WAS CAUSED BY THE OVER-SENSITIVITY OF THE HDG SYS TO THE METAL IN THE RWY AT LGA. IT WAS AGGRAVATED BY THE FACT THAT WE APCHED THE RWY ON THE CLOSEST PARALLEL TXWY, AND WE EXPERIENCED AN APPROX 20 MIN DELAY WAITING FOR TKOF. THE MD88 SHOULD BE EQUIPPED WITH A MAGNETO COMPASS WHICH IS MUCH MORE EASILY ACCESSIBLE AND USEABLE.

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.