Robinson R22
Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument
Flight Crew Last 90 Days 100; Flight Crew Total 580; Flight Crew Type 540
Communication Breakdown; Situational Awareness; Confusion
ATC Issue All Types; Conflict NMAC
General None Reported / Taken
Airport; Procedure; Human Factors
Helicopter crossed both runways at the runway intersection at 700 feet while an airplane was taking off from Runway 13. The helicopter did not see the airplane on a convergent route. The airplane did an evasive [maneuver] to the right to avoid the helicopter. Helicopter and airplane were not on the same radio frequency (Tower for the airplane; [seperate] helicopter traffic pattern frequency for the helicopter).The initial clearance to the helicopter was to cross Runway 13 at A5 but because this clearance was not usual and clear enough in the mind of the copter crew; a second request; more precise had been made and immediately approved by Tower. The new clearance was to cross both runways at 700 feet which is common for a crossing at the runways intersection. The Tower did not read it this way and was still thinking that the helicopter would comply with the initial clearance. The helicopter read back and climbed toward the runway intersection. After having a conversation with Tower it appears that miscommunication led to this situation. To avoid this situation again being on the same frequency can improve situational awareness. The frequency could be changed to the traffic pattern frequency while in the pattern. Using more precise vocabulary like runway intersection or remain south until past traffic will reduce the risk of miscommunication.
A helicopter and an aircraft suffered an NMAC as the helo crossed the runway on one of which the airplane was taking off.