Potential conflict as air carrier started takeoff from threshold while small aircraft aircraft start...

Attributes
ACN	95791
Time
Date	198810
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : mdw
State Reference	IL
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : takeoff other
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	climbout : takeoff ground other : taxi
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 8500 flight time type : 3500
ASRS Report	95791
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	conflict : ground less severe incursion : runway non adherence : required legal separation
Independent Detector	other flight crewa
Resolutory Action	flight crew : rejected takeoff
Consequence	Other
Miss Distance	horizontal : 2000 vertical : 0
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	Pilot Deviation Operational Error other

Narrative:

We were cleared into position on runway 31L at mdw. There was an small aircraft Y about 1000' ahead of us on a taxiway to our left. Tower cleared either us or small aircraft Y for takeoff. Our call number was geg and small aircraft Y's was gfg (I think). I'm not sure whether small aircraft Y or I received the takeoff clearance. Tower's transmission were broken. We added the power and started to roll, then small aircraft Y rolled onto the runway ahead of us and took off, so we stopped and taxied back. We again were cleared for takeoff and left west/O incident. The problem here is, we think we received the takeoff clearance and we read back the takeoff clearance including our call sign and tower did not correct us. Maybe small aircraft Y took our clearance or we took his, I don't know. Our radio techniques were perfect. This was just a combination of errors by ATC, us or small aircraft pilot. Human errors. Callback conversation with reporter revealed the following: reporter has not heard any more about incident from FAA and does not believe there was any reports or complaints filed by any of the parties involved. Still not sure if small aircraft accepted takeoff clearance meant for air carrier or vice versa. Air carrier was at small aircraft 5 O'clock position when clearance issued. Small aircraft Y was on n-s taxiway. Air carrier X only moved about 100' on runway when they stopped and turned around. Tower did not say anything to either aircraft reference takeoff west/O clearance.

Original NASA ASRS Text

Title: POTENTIAL CONFLICT AS ACR STARTED TKOF FROM THRESHOLD WHILE SMA ACFT STARTED TKOF FROM INTERSECTION FURTHER DOWN THE SAME RWY. ACR SAW SMA AND ABORTED TKOF EASILY. PLT DEVIATION AND OR OPERATIONAL ERROR.

Narrative: WE WERE CLRED INTO POS ON RWY 31L AT MDW. THERE WAS AN SMA Y ABOUT 1000' AHEAD OF US ON A TXWY TO OUR LEFT. TWR CLRED EITHER US OR SMA Y FOR TKOF. OUR CALL NUMBER WAS GEG AND SMA Y'S WAS GFG (I THINK). I'M NOT SURE WHETHER SMA Y OR I RECEIVED THE TKOF CLRNC. TWR'S XMISSION WERE BROKEN. WE ADDED THE PWR AND STARTED TO ROLL, THEN SMA Y ROLLED ONTO THE RWY AHEAD OF US AND TOOK OFF, SO WE STOPPED AND TAXIED BACK. WE AGAIN WERE CLRED FOR TKOF AND LEFT W/O INCIDENT. THE PROB HERE IS, WE THINK WE RECEIVED THE TKOF CLRNC AND WE READ BACK THE TKOF CLRNC INCLUDING OUR CALL SIGN AND TWR DID NOT CORRECT US. MAYBE SMA Y TOOK OUR CLRNC OR WE TOOK HIS, I DON'T KNOW. OUR RADIO TECHNIQUES WERE PERFECT. THIS WAS JUST A COMBINATION OF ERRORS BY ATC, US OR SMA PLT. HUMAN ERRORS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR HAS NOT HEARD ANY MORE ABOUT INCIDENT FROM FAA AND DOES NOT BELIEVE THERE WAS ANY RPTS OR COMPLAINTS FILED BY ANY OF THE PARTIES INVOLVED. STILL NOT SURE IF SMA ACCEPTED TKOF CLRNC MEANT FOR ACR OR VICE VERSA. ACR WAS AT SMA 5 O'CLOCK POS WHEN CLRNC ISSUED. SMA Y WAS ON N-S TXWY. ACR X ONLY MOVED ABOUT 100' ON RWY WHEN THEY STOPPED AND TURNED AROUND. TWR DID NOT SAY ANYTHING TO EITHER ACFT REF TKOF W/O CLRNC.

Data retrieved from NASA's ASRS site as of August 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.

Potential conflict as air carrier started takeoff from threshold while small aircraft aircraft started takeoff from intersection further down the same runway. Air carrier saw small aircraft and aborted takeoff easily. Pilot deviation and or operational error.