Air carrier flight crew deviated from SID procedure. Controller intervened.

Attributes
ACN	311150
Time
Date	199507
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : mdw
State Reference	IL
Altitude	msl bound lower : 2500 msl bound upper : 2500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ord tower : mdw tower : dpa
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	climbout : initial
Route In Use	departure other departure sid : sid
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : instrument pilot : flight engineer
Experience	flight time last 90 days : 125 flight time total : 5000 flight time type : 1800
ASRS Report	311150
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 125 flight time total : 10000 flight time type : 8000
ASRS Report	311155
Events
Anomaly	non adherence : clearance non adherence : published procedure other spatial deviation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

When taking off from midway airport, chicago on runway 31C, tower controller asked if we had started our turn to comply with the midway 4 departure. Before we could respond he issued a turn to a 090 degree heading. We started this turn maintaining a 4.5 DME radius from midway. The controller emphasized that we needed to comply with the midway 4 restrs. Both pilots did not hear any assigned heading during takeoff clearance, only a clearance to takeoff on runway 31C. Midway 4 departure says 'complete initially assigned turn within 4 DME.' to the best of our knowledge we were not assigned a turn until the controller called us at approximately 3 DME and only repeated 'cleared for takeoff runway 31C' during takeoff clearance.

Original NASA ASRS Text

Title: ACR FLC DEVIATED FROM SID PROC. CTLR INTERVENED.

Narrative: WHEN TAKING OFF FROM MIDWAY ARPT, CHICAGO ON RWY 31C, TWR CTLR ASKED IF WE HAD STARTED OUR TURN TO COMPLY WITH THE MIDWAY 4 DEP. BEFORE WE COULD RESPOND HE ISSUED A TURN TO A 090 DEG HDG. WE STARTED THIS TURN MAINTAINING A 4.5 DME RADIUS FROM MIDWAY. THE CTLR EMPHASIZED THAT WE NEEDED TO COMPLY WITH THE MIDWAY 4 RESTRS. BOTH PLTS DID NOT HEAR ANY ASSIGNED HDG DURING TKOF CLRNC, ONLY A CLRNC TO TKOF ON RWY 31C. MIDWAY 4 DEP SAYS 'COMPLETE INITIALLY ASSIGNED TURN WITHIN 4 DME.' TO THE BEST OF OUR KNOWLEDGE WE WERE NOT ASSIGNED A TURN UNTIL THE CTLR CALLED US AT APPROX 3 DME AND ONLY REPEATED 'CLRED FOR TKOF RWY 31C' DURING TKOF CLRNC.

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.