Air carrier pilot departing dtw on the MAARS1 SID experienced a track deviation.

Attributes
ACN	756887
Time
Date	200710
Local Time Of Day	1801 To 2400
Place
Locale Reference	navaid : aco.vor
State Reference	OH
Altitude	msl single value : 31000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zob.artcc
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level
Route In Use	departure sid : maars
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 210 flight time total : 18000 flight time type : 5500
ASRS Report	756887
Person 2
Affiliation	government : faa
Function	controller : radar
Events
Anomaly	non adherence : published procedure non adherence : clearance other spatial deviation
Independent Detector	other controllera
Resolutory Action	none taken : detected after the fact
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Chart Or Publication Flight Crew Human Performance
Primary Problem	Ambiguous

Narrative:

Climbing out 31000 ft on the MAARS1 departure out of dtw. After maars intersection; we thought we had been cleared dir aco. Cleveland center called and told us that we were about 20 miles off course; and were we going direct aco. We said we were. We were later told to give cleveland center a call. The supervisor told me that we had not been cleared maars direct to aco; but should have remained on the MAARS1 departure; which goes maars to sheap to aco.

Original NASA ASRS Text

Title: ACR PILOT DEPARTING DTW ON THE MAARS1 SID EXPERIENCED A TRACK DEV.

Narrative: CLIMBING OUT 31000 FT ON THE MAARS1 DEPARTURE OUT OF DTW. AFTER MAARS INTERSECTION; WE THOUGHT WE HAD BEEN CLEARED DIR ACO. CLEVELAND CENTER CALLED AND TOLD US THAT WE WERE ABOUT 20 MILES OFF COURSE; AND WERE WE GOING DIRECT ACO. WE SAID WE WERE. WE WERE LATER TOLD TO GIVE CLEVELAND CENTER A CALL. THE SUPERVISOR TOLD ME THAT WE HAD NOT BEEN CLEARED MAARS DIRECT TO ACO; BUT SHOULD HAVE REMAINED ON THE MAARS1 DEPARTURE; WHICH GOES MAARS TO SHEAP TO ACO.

Data retrieved from NASA's ASRS site as of January 2009 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.