Heading deviation and potential conflict for commuter aircraft at mdw.

Attributes
ACN	156579
Time
Date	199009
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : mdw
State Reference	IL
Altitude	msl bound lower : 4000 msl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ord tower : rdu
Operator	common carrier : air carrier
Make Model Name	Small Transport
Flight Phase	descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 2400 flight time type : 500
ASRS Report	156579
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation non adherence : clearance other spatial deviation
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were being given approach vectors by chicago approach to mdw airport. We were flying a heading of 240 when approach instructed us to turn left to 110 degree and keep the turn tight. As PNF I read back the heading as 110 degree. The PIC, and PF, initiated a turn to 180 degree an indicated that that was the heading he understood the controller to give. While discussing this discrepancy the controller inquired as to our heading, and my reply was 180 degree. The controller then repeated the 110 degree heading at which time we initiated the turn as instructed. At this time a possible traffic conflict did exist with an air carrier medium large transport Y that we had in sight at 12 O'clock. I don't feel qualified to specify a horizontal or vertical sep in that it would only be a guess, but it was not dangerously close in my opinion. I feel the PIC in question should pay more attention to cockpit duties and be more willing to accept the fact that he is not always right. In addition anytime there is any question what so even about ATC instructions it should be resolved immediately by requesting ATC repeat or clarify the instructions in question.

Original NASA ASRS Text

Title: HEADING DEVIATION AND POTENTIAL CONFLICT FOR COMMUTER ACFT AT MDW.

Narrative: WE WERE BEING GIVEN APCH VECTORS BY CHICAGO APCH TO MDW ARPT. WE WERE FLYING A HDG OF 240 WHEN APCH INSTRUCTED US TO TURN L TO 110 DEG AND KEEP THE TURN TIGHT. AS PNF I READ BACK THE HDG AS 110 DEG. THE PIC, AND PF, INITIATED A TURN TO 180 DEG AN INDICATED THAT THAT WAS THE HDG HE UNDERSTOOD THE CTLR TO GIVE. WHILE DISCUSSING THIS DISCREPANCY THE CTLR INQUIRED AS TO OUR HDG, AND MY REPLY WAS 180 DEG. THE CTLR THEN REPEATED THE 110 DEG HDG AT WHICH TIME WE INITIATED THE TURN AS INSTRUCTED. AT THIS TIME A POSSIBLE TFC CONFLICT DID EXIST WITH AN ACR MLG Y THAT WE HAD IN SIGHT AT 12 O'CLOCK. I DON'T FEEL QUALIFIED TO SPECIFY A HORIZ OR VERT SEP IN THAT IT WOULD ONLY BE A GUESS, BUT IT WAS NOT DANGEROUSLY CLOSE IN MY OPINION. I FEEL THE PIC IN QUESTION SHOULD PAY MORE ATTN TO COCKPIT DUTIES AND BE MORE WILLING TO ACCEPT THE FACT THAT HE IS NOT ALWAYS RIGHT. IN ADDITION ANYTIME THERE IS ANY QUESTION WHAT SO EVEN ABOUT ATC INSTRUCTIONS IT SHOULD BE RESOLVED IMMEDIATELY BY REQUESTING ATC REPEAT OR CLARIFY THE INSTRUCTIONS IN QUESTION.

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.