Aircraft cleared for takeoff, wrong aircraft downfield starts takeoff roll. Pilot deviation.

Attributes
ACN	201017
Time
Date	199202
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : ont
State Reference	CA
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
Navigation In Use	Other Other
Flight Phase	climbout : takeoff ground other : taxi
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Small Transport, Low Wing, 2 Recip Eng
Flight Phase	climbout : takeoff other
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 220 flight time total : 5000 flight time type : 500
ASRS Report	201017
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	incursion : runway non adherence : published procedure non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While talking to ont tower prior to takeoff there was confusion between our aircraft and an small transport Y with a very similar call sign. We were cleared to cross 8L and hold short of 8R at taxiway 20. While holding short the tower say 'air carrier X, cleared for takeoff.' I responded 'air carrier X cleared for takeoff on 8R.' there was no correction by the tower until we were almost lined up with runway heading, at which time I heard the tower say 'air carrier X cancel takeoff clearance.' since we were already on the runway, I said 'roger air carrier X is position and hold, cancelling clearance.' at that time I noticed the small transport Y half way down the runway facing toward us. The tower then said 'you are not cleared position and hold.' at this point it became confusing whether tower was talking to us or the small transport Y as I heard the other aircraft responding to calls I believed were meant for us. As we started to maneuver off the runway, the small transport Y taxied clear of the runway, and tower cleared us for takeoff on 8R. I could not differentiate any difference in 'call signs' from tower xmissions between our aircraft and that of the other aircraft. Apparently the tower had trouble telling the difference as well since immediate corrections did not follow our xmissions and response to tower calls. I was not aware of the existence of the other aircraft until we took the runway in preparation for takeoff.

Original NASA ASRS Text

Title: ACFT CLRED FOR TKOF, WRONG ACFT DOWNFIELD STARTS TKOF ROLL. PLTDEV.

Narrative: WHILE TALKING TO ONT TWR PRIOR TO TKOF THERE WAS CONFUSION BTWN OUR ACFT AND AN SMT Y WITH A VERY SIMILAR CALL SIGN. WE WERE CLRED TO CROSS 8L AND HOLD SHORT OF 8R AT TAXIWAY 20. WHILE HOLDING SHORT THE TWR SAY 'ACR X, CLRED FOR TKOF.' I RESPONDED 'ACR X CLRED FOR TKOF ON 8R.' THERE WAS NO CORRECTION BY THE TWR UNTIL WE WERE ALMOST LINED UP WITH RWY HDG, AT WHICH TIME I HEARD THE TWR SAY 'ACR X CANCEL TKOF CLRNC.' SINCE WE WERE ALREADY ON THE RWY, I SAID 'ROGER ACR X IS POS AND HOLD, CANCELLING CLRNC.' AT THAT TIME I NOTICED THE SMT Y HALF WAY DOWN THE RWY FACING TOWARD US. THE TWR THEN SAID 'YOU ARE NOT CLRED POS AND HOLD.' AT THIS POINT IT BECAME CONFUSING WHETHER TWR WAS TALKING TO US OR THE SMT Y AS I HEARD THE OTHER ACFT RESPONDING TO CALLS I BELIEVED WERE MEANT FOR US. AS WE STARTED TO MANEUVER OFF THE RWY, THE SMT Y TAXIED CLR OF THE RWY, AND TWR CLRED US FOR TKOF ON 8R. I COULD NOT DIFFERENTIATE ANY DIFFERENCE IN 'CALL SIGNS' FROM TWR XMISSIONS BTWN OUR ACFT AND THAT OF THE OTHER ACFT. APPARENTLY THE TWR HAD TROUBLE TELLING THE DIFFERENCE AS WELL SINCE IMMEDIATE CORRECTIONS DID NOT FOLLOW OUR XMISSIONS AND RESPONSE TO TWR CALLS. I WAS NOT AWARE OF THE EXISTENCE OF THE OTHER ACFT UNTIL WE TOOK THE RWY IN PREPARATION FOR TKOF.

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.