Heading track deviation due to aircraft equipment problem operating procedures.

Attributes
ACN	223830
Time
Date	199210
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : lga
State Reference	NY
Altitude	msl bound lower : 5000 msl bound upper : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : n90
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	climbout : intermediate altitude cruise other
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 : commercial pilot : flight engineer pilot : instrument pilot : atp
Experience	flight time last 90 days : 200 flight time total : 13500 flight time type : 11500
ASRS Report	223830
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : cfi pilot : instrument
Experience	flight time last 90 days : 240 flight time total : 9000 flight time type : 200
ASRS Report	224027
Events
Anomaly	aircraft equipment problem : less severe non adherence : clearance other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance flight crew : overcame equipment problem flight crew : returned to intended course or assigned course
Consequence	Other
Miss Distance	horizontal : 12000 vertical : 1200
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

When lined up on runway 13 at lga, we switched both compasses from magnetic mode to directional gyroscope mode and aligned compasses with the magnetic heading of the runway (134 degrees) (due to steel pilings under runway). After takeoff we followed the normal noise abatement procedures and accomplished the published whitestone climb procedures. We were given a clearance to climb to 15000 ft, and subsequently a left turn to 290 degrees. At this time, and climbing out of 5000 ft, we returned the compasses to the magnetic mode, and rolled out on a 290 degree heading. During the climb we noticed we were converging with other climbing traffic and asked departure about it. We were asked our heading and told to level at 10000 ft. It was then we discovered our magnetic compasses differed from the standby compass by about 40 degrees. Departure gave us gyroscope failure turns until we were able to return our magnetic compasses to normal. Supplemental information from acn 224027: if we had been IMC without CAT ii, only controller vigilance could prevent conflict/collision had conditions (aircraft proximity and flight profile) led us closer.

Original NASA ASRS Text

Title: HDG TRACK DEV DUE TO ACFT EQUIP PROBLEM OPERATING PROCS.

Narrative: WHEN LINED UP ON RWY 13 AT LGA, WE SWITCHED BOTH COMPASSES FROM MAGNETIC MODE TO DIRECTIONAL GYROSCOPE MODE AND ALIGNED COMPASSES WITH THE MAGNETIC HDG OF THE RWY (134 DEGS) (DUE TO STEEL PILINGS UNDER RWY). AFTER TKOF WE FOLLOWED THE NORMAL NOISE ABATEMENT PROCS AND ACCOMPLISHED THE PUBLISHED WHITESTONE CLB PROCS. WE WERE GIVEN A CLRNC TO CLB TO 15000 FT, AND SUBSEQUENTLY A L TURN TO 290 DEGS. AT THIS TIME, AND CLBING OUT OF 5000 FT, WE RETURNED THE COMPASSES TO THE MAGNETIC MODE, AND ROLLED OUT ON A 290 DEG HDG. DURING THE CLB WE NOTICED WE WERE CONVERGING WITH OTHER CLBING TFC AND ASKED DEP ABOUT IT. WE WERE ASKED OUR HDG AND TOLD TO LEVEL AT 10000 FT. IT WAS THEN WE DISCOVERED OUR MAGNETIC COMPASSES DIFFERED FROM THE STANDBY COMPASS BY ABOUT 40 DEGS. DEP GAVE US GYROSCOPE FAILURE TURNS UNTIL WE WERE ABLE TO RETURN OUR MAGNETIC COMPASSES TO NORMAL. SUPPLEMENTAL INFO FROM ACN 224027: IF WE HAD BEEN IMC WITHOUT CAT II, ONLY CTLR VIGILANCE COULD PREVENT CONFLICT/COLLISION HAD CONDITIONS (ACFT PROX AND FLT PROFILE) LED US CLOSER.

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.