Narrative:

On mar/xa/99, at approximately XA00, our air carrier flight between mdw and ewr was issued the following takeoff/departure clearance from mdw tower on runway 31C. 'Fly the mdw 4 departure, turn right heading 090 degrees, cleared for takeoff.' the midway 4 departure for runway 31C narrative states, 'climb on runway heading until 1300 ft before turning on course. Complete initially assigned turn within 4 DME of mdw, maintain 3000 ft or assigned lower altitude.' with the mxt localizer 109.9 tuned to provide DME information, we made a normal takeoff on runway 31C, climbed on runway heading until 1300 ft, then commenced a right turn to a 090 degree heading, and climbed to 3000 ft as assigned at clean maneuvering airspeed. Upon check-in with ord departure, the controller told us to turn further right to heading 120 degrees. He stated we had exceeded the 4 DME turn completion requirement of the mdw 4 departure. The following information is noteworthy. At no time did the mxt localizer provide DME information. Had the DME been working properly, you should note we departed runway 31C and were issued a departure which required us to fly runway heading until 1300 ft then commence a right turn to 090 degrees, a 140 degree turn. In this case after climbing to 1300 ft runway heading which is approximately 2 mi, we would have to complete a 140 degree turn in the remaining 2 DME which is beyond the normal turn capabilities of the B737-300 at 30 degree bank and 210 KIAS. In summary, I recommend that a clarification be made as to the mdw 4 departure turn requirements. If the intent still is to have aircraft reach 1300 ft prior to turning the turn radius must be realistic or amount of turn reduced.

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Original NASA ASRS Text

Title: AN ACR B737-300 FLC EXCEEDED THE 4 MI LIMIT FOR THEIR TURN COMPLETION ON THE MDW 4 DEP.

Narrative: ON MAR/XA/99, AT APPROX XA00, OUR ACR FLT BTWN MDW AND EWR WAS ISSUED THE FOLLOWING TKOF/DEP CLRNC FROM MDW TWR ON RWY 31C. 'FLY THE MDW 4 DEP, TURN R HDG 090 DEGS, CLRED FOR TKOF.' THE MIDWAY 4 DEP FOR RWY 31C NARRATIVE STATES, 'CLB ON RWY HDG UNTIL 1300 FT BEFORE TURNING ON COURSE. COMPLETE INITIALLY ASSIGNED TURN WITHIN 4 DME OF MDW, MAINTAIN 3000 FT OR ASSIGNED LOWER ALT.' WITH THE MXT LOC 109.9 TUNED TO PROVIDE DME INFO, WE MADE A NORMAL TKOF ON RWY 31C, CLBED ON RWY HDG UNTIL 1300 FT, THEN COMMENCED A R TURN TO A 090 DEG HDG, AND CLBED TO 3000 FT AS ASSIGNED AT CLEAN MANEUVERING AIRSPD. UPON CHK-IN WITH ORD DEP, THE CTLR TOLD US TO TURN FURTHER R TO HDG 120 DEGS. HE STATED WE HAD EXCEEDED THE 4 DME TURN COMPLETION REQUIREMENT OF THE MDW 4 DEP. THE FOLLOWING INFO IS NOTEWORTHY. AT NO TIME DID THE MXT LOC PROVIDE DME INFO. HAD THE DME BEEN WORKING PROPERLY, YOU SHOULD NOTE WE DEPARTED RWY 31C AND WERE ISSUED A DEP WHICH REQUIRED US TO FLY RWY HDG UNTIL 1300 FT THEN COMMENCE A R TURN TO 090 DEGS, A 140 DEG TURN. IN THIS CASE AFTER CLBING TO 1300 FT RWY HDG WHICH IS APPROX 2 MI, WE WOULD HAVE TO COMPLETE A 140 DEG TURN IN THE REMAINING 2 DME WHICH IS BEYOND THE NORMAL TURN CAPABILITIES OF THE B737-300 AT 30 DEG BANK AND 210 KIAS. IN SUMMARY, I RECOMMEND THAT A CLARIFICATION BE MADE AS TO THE MDW 4 DEP TURN REQUIREMENTS. IF THE INTENT STILL IS TO HAVE ACFT REACH 1300 FT PRIOR TO TURNING THE TURN RADIUS MUST BE REALISTIC OR AMOUNT OF TURN REDUCED.

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.