Background
A pilot, preparing for a flight, received a copy of a NOTAM regarding runway 17/35 at a gliding competition. After reading the NOTAM, the pilot assessed that contacting the competition director prior to the flight would permit the use of the runway. The pilot believed that by calling the director, an arrangement had been made to use runway 17, and since the intended arrival time fell outside the 'critical' hours of 1200 to 1400 specified in the NOTAM, the arrival would not interfere with the competition.
Miscommunication
Neither party specifically discussed runway 17/35 during their conversation. Consequently, a connection was not made that they had different interpretations of the NOTAM. The pilot assumed permission had been granted, but the competition director believed that the pilot needed to contact them on the day of the flight to arrange runway use. The gliding club interpreted the NOTAM as 'closing' the runway to all aircraft during daylight hours, except for gliders and tow aircraft participating in the competition.
Safety Issues
Due to the club's interpretation, ground handlers for the event did not make radio calls before entering the runway strip in preparation for the competition, nor did they carry the radio available in their vehicle. The NOTAM itself was not clear about when permission was needed to use runway 17. An opportunity to alert the pilot of ground activity on the runway was missed: the ground vehicle, equipped with a rotating beacon, was not used near or on the runway because the equipment was located close to the launch site. Additionally, ground personnel lacked a radio to communicate on the Common Traffic Advisory Frequency (CTAF).