A PA28 instructor pilot takes off over a PA30 that had entered the runway during the takeoff roll.

Attributes
ACN	398923
Time
Date	199804
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : laf
State Reference	IN
Altitude	agl bound lower : 0 agl bound upper : 100
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	PA-28 Cherokee Arrow IV
Operating Under FAR Part	Part 91
Flight Phase	climbout : initial climbout : takeoff
Flight Plan	None
Aircraft 2
Make Model Name	PA-30 Twin Comanche
Operating Under FAR Part	Part 91
Flight Phase	ground other : taxi
Person 1
Affiliation	Other
Function	instruction : instructor oversight : pic
Qualification	pilot : cfi pilot : commercial pilot : flight engineer pilot : instrument
Experience	flight time last 90 days : 100 flight time total : 970 flight time type : 100
ASRS Report	398923
Person 2
Affiliation	Other
Function	flight crew : single pilot instruction : trainee
Qualification	pilot : student
Events
Anomaly	conflict : ground critical incursion : runway non adherence : clearance non adherence : far other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted other
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 250 vertical : 100
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was cleared for takeoff on runway 10. While on the takeoff roll, another aircraft taxied onto runway 10. We already had full power and were indicating at least 40-50 KTS. The intersection where the other aircraft was crossing was 4600 ft from the end of the runway where we took off. I determined that it would be safer to continue the takeoff because I knew we would lift off before reaching the other aircraft. If I had decided to abort the takeoff, I believe I would have hit the aircraft before I could come to a stop. After talking with the tower and ground controllers, I discovered that the aircraft had been cleared to taxi to runway 10. He was not cleared to cross runway 10.

Original NASA ASRS Text

Title: A PA28 INSTRUCTOR PLT TAKES OFF OVER A PA30 THAT HAD ENTERED THE RWY DURING THE TKOF ROLL.

Narrative: I WAS CLRED FOR TKOF ON RWY 10. WHILE ON THE TKOF ROLL, ANOTHER ACFT TAXIED ONTO RWY 10. WE ALREADY HAD FULL PWR AND WERE INDICATING AT LEAST 40-50 KTS. THE INTXN WHERE THE OTHER ACFT WAS XING WAS 4600 FT FROM THE END OF THE RWY WHERE WE TOOK OFF. I DETERMINED THAT IT WOULD BE SAFER TO CONTINUE THE TKOF BECAUSE I KNEW WE WOULD LIFT OFF BEFORE REACHING THE OTHER ACFT. IF I HAD DECIDED TO ABORT THE TKOF, I BELIEVE I WOULD HAVE HIT THE ACFT BEFORE I COULD COME TO A STOP. AFTER TALKING WITH THE TWR AND GND CTLRS, I DISCOVERED THAT THE ACFT HAD BEEN CLRED TO TAXI TO RWY 10. HE WAS NOT CLRED TO CROSS RWY 10.

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.