Small aircraft misinterpreted instructions and began takeoff roll while another aircraft was landing...

Attributes
ACN	123704
Time
Date	198909
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : hlg
State Reference	WV
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc
Operator	general aviation : personal
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	climbout : takeoff other
Flight Plan	None
Aircraft 2
Operator	other
Make Model Name	Helicopter
Flight Phase	landing other
Flight Plan	VFR
Person 1
Affiliation	government : faa
Function	controller : local
Qualification	controller : non radar
ASRS Report	123704
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Wind was calm, and I was using runway 21 for departures and runway 34 for arrs/traffic pattern work. I was working ground and local positions combined. An army guard small aircraft Y was in right traffic for runway 34. The pilot of small aircraft X called from main ramp for taxi instructions. I taxied him to runway 21. While at the hold line he requested permission to operate south of the airport for aerial photography. I approved this request, after which he requested traffic advisories. I 'roger'ed' this request as I watched small aircraft Y touching down on runway 34. As the helicopter was departing I noticed that small aircraft X was taxiing onto runway 21 and appeared to be starting his takeoff roll. I took immediate action to abort this takeoff, and the pilot stopped. He said he thought he had been cleared, although I never cleared him. Apparently he mistook my approval of his request as a clearance for takeoff as well. From my point of view it seemed clear that an incident with the helicopter could have taken place at midfield.

Original NASA ASRS Text

Title: SMA MISINTERPRETED INSTRUCTIONS AND BEGAN TKOF ROLL WHILE ANOTHER ACFT WAS LNDG ON A CROSSING RWY.

Narrative: WIND WAS CALM, AND I WAS USING RWY 21 FOR DEPS AND RWY 34 FOR ARRS/TFC PATTERN WORK. I WAS WORKING GND AND LCL POSITIONS COMBINED. AN ARMY GUARD SMA Y WAS IN RIGHT TFC FOR RWY 34. THE PLT OF SMA X CALLED FROM MAIN RAMP FOR TAXI INSTRUCTIONS. I TAXIED HIM TO RWY 21. WHILE AT THE HOLD LINE HE REQUESTED PERMISSION TO OPERATE SOUTH OF THE ARPT FOR AERIAL PHOTOGRAPHY. I APPROVED THIS REQUEST, AFTER WHICH HE REQUESTED TFC ADVISORIES. I 'ROGER'ED' THIS REQUEST AS I WATCHED SMA Y TOUCHING DOWN ON RWY 34. AS THE HELI WAS DEPARTING I NOTICED THAT SMA X WAS TAXIING ONTO RWY 21 AND APPEARED TO BE STARTING HIS TKOF ROLL. I TOOK IMMEDIATE ACTION TO ABORT THIS TKOF, AND THE PLT STOPPED. HE SAID HE THOUGHT HE HAD BEEN CLRED, ALTHOUGH I NEVER CLRED HIM. APPARENTLY HE MISTOOK MY APPROVAL OF HIS REQUEST AS A CLRNC FOR TKOF AS WELL. FROM MY POINT OF VIEW IT SEEMED CLEAR THAT AN INCIDENT WITH THE HELI COULD HAVE TAKEN PLACE AT MIDFIELD.

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.

Small aircraft misinterpreted instructions and began takeoff roll while another aircraft was landing on a crossing runway.