2 company aircraft, 1 departing and 1 arriving, were assigned the same flight number.

Attributes
ACN	491954
Time
Date	200011
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : las.airport
State Reference	NV
Altitude	msl single value : 4800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : las.tower
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Navigation In Use	other Other
Flight Phase	descent : approach
Route In Use	approach : visual
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tower : las.tower
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	climbout : takeoff
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	other personnel oversight : coordinator
Qualification	other
Experience	flight time total : 4000
ASRS Report	491954
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 9000 flight time type : 700
ASRS Report	491160
Events
Anomaly	non adherence : company policies non adherence : published procedure
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted none taken : detected after the fact other
Supplementary
Problem Areas	Weather Company
Primary Problem	Company

Narrative:

Flight XXX departs from lax, arrives las, and continues to mdw. Due to a restrictive MEL item, an aircraft change was scheduled in las. Both flts were to operate on time. The aircraft that was to operate from lake to las was delayed on a prior leg, resulting in a late arrival into lax. This carried over to a late departure for XXX from lax to las. The late departure from lax was further complicated by a minor mechanical issue that took approximately 20 mins to resolve. As the 2 segments of flight XXX were operating on different aircraft, and were originally planned to operate on time, I did not notice that the 2 aircraft may be in the air at the same time. The second segment of XXX (las-mdw) operated on time, and departed las as XXX was arriving from lax. The aircraft departing and arriving both had call sign XXX and were simultaneously handled by las tower. No conflict occurred. I believe this was the result of a very challenging WX day that resulted in this oversight -- task saturation.

Original NASA ASRS Text

Title: 2 COMPANY ACFT, 1 DEPARTING AND 1 ARRIVING, WERE ASSIGNED THE SAME FLT NUMBER.

Narrative: FLT XXX DEPARTS FROM LAX, ARRIVES LAS, AND CONTINUES TO MDW. DUE TO A RESTRICTIVE MEL ITEM, AN ACFT CHANGE WAS SCHEDULED IN LAS. BOTH FLTS WERE TO OPERATE ON TIME. THE ACFT THAT WAS TO OPERATE FROM LAKE TO LAS WAS DELAYED ON A PRIOR LEG, RESULTING IN A LATE ARR INTO LAX. THIS CARRIED OVER TO A LATE DEP FOR XXX FROM LAX TO LAS. THE LATE DEP FROM LAX WAS FURTHER COMPLICATED BY A MINOR MECHANICAL ISSUE THAT TOOK APPROX 20 MINS TO RESOLVE. AS THE 2 SEGMENTS OF FLT XXX WERE OPERATING ON DIFFERENT ACFT, AND WERE ORIGINALLY PLANNED TO OPERATE ON TIME, I DID NOT NOTICE THAT THE 2 ACFT MAY BE IN THE AIR AT THE SAME TIME. THE SECOND SEGMENT OF XXX (LAS-MDW) OPERATED ON TIME, AND DEPARTED LAS AS XXX WAS ARRIVING FROM LAX. THE ACFT DEPARTING AND ARRIVING BOTH HAD CALL SIGN XXX AND WERE SIMULTANEOUSLY HANDLED BY LAS TWR. NO CONFLICT OCCURRED. I BELIEVE THIS WAS THE RESULT OF A VERY CHALLENGING WX DAY THAT RESULTED IN THIS OVERSIGHT -- TASK SATURATION.

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.