EMS helicopter departs without clearance.

Attributes
ACN	272947
Time
Date	199406
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz
State Reference	US
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : zzz
Operator	common carrier : air taxi
Make Model Name	Helicopter
Operating Under FAR Part	Part 135
Flight Phase	climbout : takeoff descent : holding ground : holding
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : atp
Experience	flight time last 90 days : 50 flight time total : 5000 flight time type : 20
ASRS Report	272947
Person 2
Affiliation	government : faa
Function	controller : local
Qualification	controller : non radar
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation other
Situations
ATC Facility	procedure or policy : unspecified

Narrative:

While departing on an EMS flight (helicopter) and pursuant to a LOA with control tower, a request for an EMS departure was made on tower frequency 118.20. After the request was made the controller directed this pilot to ground control stating 'I'm too busy to handle you now, go to ground control' assuming that ground control was taking up the slack for tower, and upon receiving a clearance from ground out of class C airspace. I departed on the EMS flight northbound from taxiway C, spot X. My aircraft did not come in conflict with any other aircraft, but the departure was made without tower authorization. In my opinion the deviation from the LOA with my company and tower controller, contributed to the confusion of this pilot and caused him to believe that ground control was being authority/authorized by tower to clear my aircraft for takeoff. And this entire event would not have occurred had the tower controller not deviated from the original procedure of calling tower on EMS flts. This procedure had been in effect for 3 yrs with no incident.

Original NASA ASRS Text

Title: EMS HELI DEPARTS WITHOUT CLRNC.

Narrative: WHILE DEPARTING ON AN EMS FLT (HELI) AND PURSUANT TO A LOA WITH CTL TWR, A REQUEST FOR AN EMS DEP WAS MADE ON TWR FREQ 118.20. AFTER THE REQUEST WAS MADE THE CTLR DIRECTED THIS PLT TO GND CTL STATING 'I'M TOO BUSY TO HANDLE YOU NOW, GO TO GND CTL' ASSUMING THAT GND CTL WAS TAKING UP THE SLACK FOR TWR, AND UPON RECEIVING A CLRNC FROM GND OUT OF CLASS C AIRSPACE. I DEPARTED ON THE EMS FLT NBOUND FROM TXWY C, SPOT X. MY ACFT DID NOT COME IN CONFLICT WITH ANY OTHER ACFT, BUT THE DEP WAS MADE WITHOUT TWR AUTHORIZATION. IN MY OPINION THE DEV FROM THE LOA WITH MY COMPANY AND TWR CTLR, CONTRIBUTED TO THE CONFUSION OF THIS PLT AND CAUSED HIM TO BELIEVE THAT GND CTL WAS BEING AUTH BY TWR TO CLR MY ACFT FOR TKOF. AND THIS ENTIRE EVENT WOULD NOT HAVE OCCURRED HAD THE TWR CTLR NOT DEVIATED FROM THE ORIGINAL PROC OF CALLING TWR ON EMS FLTS. THIS PROC HAD BEEN IN EFFECT FOR 3 YRS WITH NO INCIDENT.

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.