Narrative:

ATC facility: mdw tower, chicago departure. Location: runway 4R mdw after takeoff. First officer takeoff mdw runway 4R night departure. Tower cleared us for takeoff and I heard heading 025 degrees, selected 025 degrees in heading select. Our clearance was the midway 4 departure, which states if your assigned heading is clockwise from 360 degrees to 080 degree turn, heading 100 degrees after takeoff until 2400 ft. Briefed captain of my intentions to comply with departure procedure since assigned 025 degree heading. After takeoff, I started a turn to 100 degrees, but tower instructed turn left heading 250 degrees. That was my first clue to a possible readback error. Immediately started left turn to 250 degrees when departure asked if we were in the turn and mentioned the restr to remain south of dpa 096 degree radial. Onboard navaids indicated we remained south of dpa 096 degree radial. I would like to make a recommendation: please reformat the midway 4 departure page. I suggest we insert in bold letters 'all runways' above the instructions to remain within 4 DME. In a dark cockpit it is easy to associate this instruction with the text associated with runway 13L/C/right, runway 22L/right, runway 3L/C/right. Supplemental information from acn 429463: we were supposed to be heading 250 degrees. First officer read back 025 degrees upon takeoff clearance, and tower did not catch the error. I was busy looking down final for runway 4L since a plane was on short final and I wanted to make sure he was landing on the left, not runway 4R, where we were.

Google
 

Original NASA ASRS Text

Title: FLC OF A FOKKER 100 MISHEARS THE DEP CLRNC AND STARTS TURN IN THE WRONG DIRECTION AFTER TKOF. CTLR SEES THE ERROR AND GIVES THEM AN ALERT TO TURN TO THE CORRECT HDG.

Narrative: ATC FACILITY: MDW TWR, CHICAGO DEP. LOCATION: RWY 4R MDW AFTER TKOF. FO TKOF MDW RWY 4R NIGHT DEP. TWR CLRED US FOR TKOF AND I HEARD HDG 025 DEGS, SELECTED 025 DEGS IN HDG SELECT. OUR CLRNC WAS THE MIDWAY 4 DEP, WHICH STATES IF YOUR ASSIGNED HDG IS CLOCKWISE FROM 360 DEGS TO 080 DEG TURN, HDG 100 DEGS AFTER TKOF UNTIL 2400 FT. BRIEFED CAPT OF MY INTENTIONS TO COMPLY WITH DEP PROC SINCE ASSIGNED 025 DEG HDG. AFTER TKOF, I STARTED A TURN TO 100 DEGS, BUT TWR INSTRUCTED TURN L HDG 250 DEGS. THAT WAS MY FIRST CLUE TO A POSSIBLE READBACK ERROR. IMMEDIATELY STARTED L TURN TO 250 DEGS WHEN DEP ASKED IF WE WERE IN THE TURN AND MENTIONED THE RESTR TO REMAIN S OF DPA 096 DEG RADIAL. ONBOARD NAVAIDS INDICATED WE REMAINED S OF DPA 096 DEG RADIAL. I WOULD LIKE TO MAKE A RECOMMENDATION: PLEASE REFORMAT THE MIDWAY 4 DEP PAGE. I SUGGEST WE INSERT IN BOLD LETTERS 'ALL RWYS' ABOVE THE INSTRUCTIONS TO REMAIN WITHIN 4 DME. IN A DARK COCKPIT IT IS EASY TO ASSOCIATE THIS INSTRUCTION WITH THE TEXT ASSOCIATED WITH RWY 13L/C/R, RWY 22L/R, RWY 3L/C/R. SUPPLEMENTAL INFO FROM ACN 429463: WE WERE SUPPOSED TO BE HDG 250 DEGS. FO READ BACK 025 DEGS UPON TKOF CLRNC, AND TWR DID NOT CATCH THE ERROR. I WAS BUSY LOOKING DOWN FINAL FOR RWY 4L SINCE A PLANE WAS ON SHORT FINAL AND I WANTED TO MAKE SURE HE WAS LNDG ON THE L, NOT RWY 4R, WHERE WE WERE.

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.