Narrative:

Was at hum airport performing instrument and nonstandard flight training with 2 company pilots. Taxied aircraft into FBO to pick up an earlier dropped off pilot upon completion of this training. ATC was using tower frequency for both tower and ground control. I asked pilot at the controls to call for departure. Tower gave him the following clearance 'cleared to runway 36.' as pilot started to cross the runway holding position markings, he was questioned if he had clearance to taxi onto the runway. Tower was then called for takeoff, but after the markings were crossed. There was no other traffic and takeoff clearance was received. Upon arrival at home base, I reviewed with the pilot the aim procedures concerning ATC 'taxi to' clrncs. Specifically, aim 4-3-18 paragraph 5. It was noted that ATC should not use the word 'cleared' in conjunction with authority/authorized for aircraft to taxi. The use of the word 'cleared' is what confused the pilot at the controls.

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Original NASA ASRS Text

Title: S76 PLT HAD A RWY INCURSION AFTER THE COMBINED ATCT LCL GND CTLR 'CLRED' HIM TO RWY 36 AT HUM.

Narrative: WAS AT HUM ARPT PERFORMING INST AND NONSTANDARD FLT TRAINING WITH 2 COMPANY PLTS. TAXIED ACFT INTO FBO TO PICK UP AN EARLIER DROPPED OFF PLT UPON COMPLETION OF THIS TRAINING. ATC WAS USING TWR FREQ FOR BOTH TWR AND GND CTL. I ASKED PLT AT THE CTLS TO CALL FOR DEP. TWR GAVE HIM THE FOLLOWING CLRNC 'CLRED TO RWY 36.' AS PLT STARTED TO CROSS THE RWY HOLDING POS MARKINGS, HE WAS QUESTIONED IF HE HAD CLRNC TO TAXI ONTO THE RWY. TWR WAS THEN CALLED FOR TKOF, BUT AFTER THE MARKINGS WERE CROSSED. THERE WAS NO OTHER TFC AND TKOF CLRNC WAS RECEIVED. UPON ARR AT HOME BASE, I REVIEWED WITH THE PLT THE AIM PROCS CONCERNING ATC 'TAXI TO' CLRNCS. SPECIFICALLY, AIM 4-3-18 PARAGRAPH 5. IT WAS NOTED THAT ATC SHOULD NOT USE THE WORD 'CLRED' IN CONJUNCTION WITH AUTH FOR ACFT TO TAXI. THE USE OF THE WORD 'CLRED' IS WHAT CONFUSED THE PLT AT THE CTLS.

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.