Medium large transport crew had track deviation.

Attributes
ACN	463070
Time
Date	200002
Day	Wed
Local Time Of Day	1801 To 2400
Place
State Reference	NY
Altitude	msl single value : 19000
Environment
Light	Night
Aircraft 1
Controlling Facilities	artcc : zbw.artcc
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level descent : intermediate altitude
Route In Use	enroute airway : ns.airway
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : multi engine
Experience	flight time last 90 days : 270 flight time total : 8000 flight time type : 270
ASRS Report	463070
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe non adherence : published procedure non adherence : company policies non adherence : clearance other spatial deviation
Independent Detector	other controllera
Resolutory Action	controller : issued alert none taken : detected after the fact
Consequence	other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Approaching dpk VOR, ATC advised us of 7 mi error in LNAV. While LNAV showing us at dpk, copilot had switched raw data to mad VOR and did not notice error. Upon notification of navigation error, PF had slowed down to 250 KTS in anticipation of descent and to access situation. ATC complained on slow down and we continued on. Landing uneventful. LNAV malfunction reported to maintenance and recorded.

Original NASA ASRS Text

Title: MLG CREW HAD TRACK DEV.

Narrative: APCHING DPK VOR, ATC ADVISED US OF 7 MI ERROR IN LNAV. WHILE LNAV SHOWING US AT DPK, COPLT HAD SWITCHED RAW DATA TO MAD VOR AND DID NOT NOTICE ERROR. UPON NOTIFICATION OF NAV ERROR, PF HAD SLOWED DOWN TO 250 KTS IN ANTICIPATION OF DSCNT AND TO ACCESS SIT. ATC COMPLAINED ON SLOW DOWN AND WE CONTINUED ON. LNDG UNEVENTFUL. LNAV MALFUNCTION RPTED TO MAINT AND RECORDED.

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.