Narrative:

I was operating out of grand canyon west airport in a bell 206 longranger. This aircraft is equipped with dual VHF radios. This feature allows the pilot of the aircraft to monitor both grand canyon west frequency 122.9 and the canyon sector frequency 121.95. I was trying to depart the airport helipad which is located at the north end of the field. A second operator also was operating 2 helicopters flying tours to the bottom of the canyon from the same location. One of the helicopters had already departed and was assumed at the bottom of the canyon, the second helicopter was located on the helipad east of my position. This aircraft was loaded with passenger and was preparing to depart to the bottom of the canyon. I tried several times to contact him on both 122.9 and 121.95 with no response on either radio. This was witnessed by my director of operations, who was seated in the copilot's seat of my aircraft monitoring the radios as well. After several attempts to contact helicopter to advise them of my departure and I did not receive any response I assumed that he was on a separate frequency talking with the helicopter which had already departed. I decided to wait for his departure and to follow, rather than depart without communication with him. Immediately after his departure I announced on 122.9 in the blind that I was departing behind helicopter to the bottom of the canyon. What was not known at the time was that second helicopter was returning from the bottom of the canyon. He was on short final behind me. At no time to this day did I see the second aircraft, however, after my departure I did hear him talking to his sister ship stating that I had departed in front of him. This transmission was heard over the sector frequency 121.95 on my #1 VHF radio. It was later determined once I returned to the helipad at grand canyon west that the #2 VHF radio was intermittent. I discovered this while flipping frequencys between radios, and finally talking between ships on the ground before departing again. After returning to the south rim of the grand canyon, I reported the incident to my chief pilot and filed a flight irregularity and hazard report with him. The report is on file at company.

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Original NASA ASRS Text

Title: SIGHTSEEING HELI OPS AT GRAND CANYON ARPT HAVE PROB WITH NO COM AND 1 HELI DEPARTING AS 1 IS LNDG.

Narrative: I WAS OPERATING OUT OF GRAND CANYON WEST ARPT IN A BELL 206 LONGRANGER. THIS ACFT IS EQUIPPED WITH DUAL VHF RADIOS. THIS FEATURE ALLOWS THE PLT OF THE ACFT TO MONITOR BOTH GRAND CANYON WEST FREQ 122.9 AND THE CANYON SECTOR FREQ 121.95. I WAS TRYING TO DEPART THE ARPT HELIPAD WHICH IS LOCATED AT THE N END OF THE FIELD. A SECOND OPERATOR ALSO WAS OPERATING 2 HELIS FLYING TOURS TO THE BOTTOM OF THE CANYON FROM THE SAME LOCATION. ONE OF THE HELIS HAD ALREADY DEPARTED AND WAS ASSUMED AT THE BOTTOM OF THE CANYON, THE SECOND HELI WAS LOCATED ON THE HELIPAD E OF MY POS. THIS ACFT WAS LOADED WITH PAX AND WAS PREPARING TO DEPART TO THE BOTTOM OF THE CANYON. I TRIED SEVERAL TIMES TO CONTACT HIM ON BOTH 122.9 AND 121.95 WITH NO RESPONSE ON EITHER RADIO. THIS WAS WITNESSED BY MY DIRECTOR OF OPS, WHO WAS SEATED IN THE COPLT'S SEAT OF MY ACFT MONITORING THE RADIOS AS WELL. AFTER SEVERAL ATTEMPTS TO CONTACT HELI TO ADVISE THEM OF MY DEP AND I DID NOT RECEIVE ANY RESPONSE I ASSUMED THAT HE WAS ON A SEPARATE FREQ TALKING WITH THE HELI WHICH HAD ALREADY DEPARTED. I DECIDED TO WAIT FOR HIS DEP AND TO FOLLOW, RATHER THAN DEPART WITHOUT COM WITH HIM. IMMEDIATELY AFTER HIS DEP I ANNOUNCED ON 122.9 IN THE BLIND THAT I WAS DEPARTING BEHIND HELI TO THE BOTTOM OF THE CANYON. WHAT WAS NOT KNOWN AT THE TIME WAS THAT SECOND HELI WAS RETURNING FROM THE BOTTOM OF THE CANYON. HE WAS ON SHORT FINAL BEHIND ME. AT NO TIME TO THIS DAY DID I SEE THE SECOND ACFT, HOWEVER, AFTER MY DEP I DID HEAR HIM TALKING TO HIS SISTER SHIP STATING THAT I HAD DEPARTED IN FRONT OF HIM. THIS XMISSION WAS HEARD OVER THE SECTOR FREQ 121.95 ON MY #1 VHF RADIO. IT WAS LATER DETERMINED ONCE I RETURNED TO THE HELIPAD AT GRAND CANYON WEST THAT THE #2 VHF RADIO WAS INTERMITTENT. I DISCOVERED THIS WHILE FLIPPING FREQS BTWN RADIOS, AND FINALLY TALKING BTWN SHIPS ON THE GND BEFORE DEPARTING AGAIN. AFTER RETURNING TO THE SOUTH RIM OF THE GRAND CANYON, I RPTED THE INCIDENT TO MY CHIEF PLT AND FILED A FLT IRREGULARITY AND HAZARD RPT WITH HIM. THE RPT IS ON FILE AT COMPANY.

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.