Narrative:

On expedited departure from midway (mdw); runway 4R; cleared for left turn to a heading of 260 degrees; maintain 3000 ft. Text for takeoff runways 4L/right: (reads) northbound departures assigned heading 360 degrees (cw) through 080 degrees; turn right climb on heading 100 degrees until leaving 2400. Thence via vector to assigned route. DME equipped aircraft: complete initially assigned turn within 4 DME of midway. Maintain 3000 ft or assigned lower altitude. Expect clearance to requested altitude 10 mins after departure. Since we were not assigned a heading from 360 degrees (cw) through 080 degrees; we departed with best noise abatement climb for 3000 ft MSL; and began a 25 degree to 30 degree left bank at 2200 ft and an airspeed of 200 KTS to stay within 4 mi restr; assuming that would otherwise conflict with O'hare traffic; should we not complete our left turn within the prescribed 4 mile limits. Approach called asking about our altitude and if we were turning at that time. We acknowledged that we were out of 2300 ft and commencing our left turn. We continued around to our assigned heading; staying within 3 DME of midway; but apparently approach seemed to imply that we somehow had misinterped the departure somehow. I am still confused as to what alternate interpretation of this published procedure he seemed concerned about? The procedure's wording; I confess is somewhat difficult to initially understand; but the controller's clearance seemed to be quite specific. I would suggest producing a clearer phrasing of these departure procedures to help us eliminate this apparent confusion; and avoid any hazardous conflicts with O'hare traffic. Callback conversation with reporter revealed the following information: reporter stated that the departure procedure only references a procedure for aircraft heading 360 degrees through 080 degrees. Since there is no exclusion for other departure headings the reporter believes that any assigned heading outside of that window should turn to the assigned heading. The written procedural text should be specific for aircraft outside the 360 degrees to 080 degrees and state that a turn should be made when able to the assigned heading; maintain 3000 ft. The reporter stated that part of the confusion was also due to the fact that while on the runway holding for takeoff; ATC changed from the cicero two to the midway four. The crew then felt they did not have sufficient time to thoroughly understand the departure; adding an element of self doubt to the encounter with ATC.

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Original NASA ASRS Text

Title: A LR35 PILOT ON THE MDW FOUR DEP WAS ASSIGNED HDG 260 DEGS AFTER TKOF. DURING TURN ATC QUESTIONED PLT; MAKING HIM UNCERTAIN ABOUT THE CORRECT PROCEDURE.

Narrative: ON EXPEDITED DEP FROM MIDWAY (MDW); RWY 4R; CLRED FOR L TURN TO A HDG OF 260 DEGS; MAINTAIN 3000 FT. TEXT FOR TKOF RWYS 4L/R: (READS) NBOUND DEPS ASSIGNED HDG 360 DEGS (CW) THROUGH 080 DEGS; TURN R CLB ON HDG 100 DEGS UNTIL LEAVING 2400. THENCE VIA VECTOR TO ASSIGNED RTE. DME EQUIPPED ACFT: COMPLETE INITIALLY ASSIGNED TURN WITHIN 4 DME OF MIDWAY. MAINTAIN 3000 FT OR ASSIGNED LOWER ALT. EXPECT CLRNC TO REQUESTED ALT 10 MINS AFTER DEP. SINCE WE WERE NOT ASSIGNED A HDG FROM 360 DEGS (CW) THROUGH 080 DEGS; WE DEPARTED WITH BEST NOISE ABATEMENT CLB FOR 3000 FT MSL; AND BEGAN A 25 DEG TO 30 DEG L BANK AT 2200 FT AND AN AIRSPD OF 200 KTS TO STAY WITHIN 4 MI RESTR; ASSUMING THAT WOULD OTHERWISE CONFLICT WITH O'HARE TFC; SHOULD WE NOT COMPLETE OUR L TURN WITHIN THE PRESCRIBED 4 MILE LIMITS. APCH CALLED ASKING ABOUT OUR ALT AND IF WE WERE TURNING AT THAT TIME. WE ACKNOWLEDGED THAT WE WERE OUT OF 2300 FT AND COMMENCING OUR L TURN. WE CONTINUED AROUND TO OUR ASSIGNED HDG; STAYING WITHIN 3 DME OF MIDWAY; BUT APPARENTLY APCH SEEMED TO IMPLY THAT WE SOMEHOW HAD MISINTERPED THE DEP SOMEHOW. I AM STILL CONFUSED AS TO WHAT ALTERNATE INTERP OF THIS PUBLISHED PROC HE SEEMED CONCERNED ABOUT? THE PROC'S WORDING; I CONFESS IS SOMEWHAT DIFFICULT TO INITIALLY UNDERSTAND; BUT THE CTLR'S CLRNC SEEMED TO BE QUITE SPECIFIC. I WOULD SUGGEST PRODUCING A CLEARER PHRASING OF THESE DEP PROCS TO HELP US ELIMINATE THIS APPARENT CONFUSION; AND AVOID ANY HAZARDOUS CONFLICTS WITH O'HARE TFC. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THAT THE DEPARTURE PROCEDURE ONLY REFERENCES A PROCEDURE FOR ACFT HDG 360 DEGS THROUGH 080 DEGS. SINCE THERE IS NO EXCLUSION FOR OTHER DEPARTURE HDGS THE REPORTER BELIEVES THAT ANY ASSIGNED HDG OUTSIDE OF THAT WINDOW SHOULD TURN TO THE ASSIGNED HDG. THE WRITTEN PROCEDURAL TEXT SHOULD BE SPECIFIC FOR ACFT OUTSIDE THE 360 DEGS TO 080 DEGS AND STATE THAT A TURN SHOULD BE MADE WHEN ABLE TO THE ASSIGNED HDG; MAINTAIN 3000 FT. THE REPORTER STATED THAT PART OF THE CONFUSION WAS ALSO DUE TO THE FACT THAT WHILE ON THE RWY HOLDING FOR TKOF; ATC CHANGED FROM THE CICERO TWO TO THE MIDWAY FOUR. THE CREW THEN FELT THEY DID NOT HAVE SUFFICIENT TIME TO THOROUGHLY UNDERSTAND THE DEP; ADDING AN ELEMENT OF SELF DOUBT TO THE ENCOUNTER WITH ATC.

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.