Flight Crew Commercial; Flight Crew Rotorcraft
Flight Crew Last 90 Days 10; Flight Crew Total 350; Flight Crew Type 150
Situational Awareness
Airspace Violation All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert
Human Factors
The PIC (non-flying) pilot for the leg was on board the running helicopter so we could cool the interior for a passenger leg; I (SIC-flying) had just escorted the passenger to the awaiting aircraft for the trip. I strapped into the helicopter and proceeded to do the final checklist items prior to take off from a non-movement area when the PIC called ready for takeoff. The controller told us to proceed to the intersection V/B in the movement area; however we thought it safer to depart from the non-movement area due to personnel and equipment between us and the intersection. The PIC asked for an amended clearance and told them that we would not 'hit anything' on our departure; [but we were] told to standby. During this period; several aircraft were also receiving ATC instructions on the frequency as several [aircraft were] departing at close intervals. Through the radio chatter; over the intercom the PIC told me we were cleared to go; I queried him and said 'I didn't hear them tell us departure from the non-movement area is at our own risk; cleared for take-off' and his reply was 'you won't hear that here'! At his insistence; I proceeded with the take-off; flying a direct course to [our destination]. He immediately contacted departure control with our altitude and on course heading which was met with 'who is checking in'; I knew then we had taken off without a clearance. After some initial vectoring we were cleared on course and prior to the hand off were told of the possible deviation and given a number to call.I should have insisted on clarification; however was hesitant due to his experience and my relatively low time against the demeanor of the Captain and the need to meet our passenger's itinerary. Our normal protocol is everyone should be clear on ATC instructions however this one fell through the cracks.
Called tower to get departure instruction VFR helicopter flight. I requested on Ground frequency to depart from the non-movement area. We were told to contact Departure. (later surmised this was for another aircraft with the same last three [call sign]; broadcast on the local frequency and ground.)The Tower was on a single frequency and we were transmitting on Ground. We picked up to a hover in the non-movement area and intended to call the Tower on the local frequency to check our departure status. The Tower then asked for our departure direction and desired course. I responded with takeoff into the wind 300 then 040 to [our destination]. I took this to mean that departure was approved; knowing as usual that this is at our own risk.We then departed squawking the assigned code from our VFR clearance issued by the Tower and called Departure only to discover that they were not expecting us. We were issued vectors; complied; handed off to another sector and then were advised to make a phone call back to Tower after landing.I made the phone call and talked to the controller in charge. It was pointed out that we were not issued 'departure from the north ramp will be at your own risk.' With both Ground and local frequencies in use; my transmissions and others were partially blocked as well as some Tower conversations. This led to the misunderstanding of contact Departure and our premature takeoff lacking the above phraseology.
Helicopter flight crew reported taking off without clearance due to communication confusion in the cockpit.