Small aircraft cleared position and hold. ATC uses wrong north# to clear for immediate takeoff. On s...

Attributes
ACN	152058
Time
Date	199007
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : fcm
State Reference	MN
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	climbout : takeoff ground : holding
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : cfi pilot : commercial
Experience	flight time last 90 days : 100 flight time total : 1000 flight time type : 500
ASRS Report	152058
Person 2
Affiliation	government : faa
Function	controller : local
Qualification	controller : non radar
Events
Anomaly	other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	none taken : unable none taken : insufficient time
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other
Situations
Airport	procedure or policy : unspecified

Narrative:

I was cleared to taxi into position and hold on runway 18 at fcm. The controller was very busy with numerous arrs and departures and had tried to clear me into position a few mins before. I declined that clearance because my access to the runway was blocked by another aircraft, aircraft Y. Tower then cleared aircraft Y into position and shortly after for departure. Tower then cleared me into position and hold, which I acknowledged and complied. While in position on runway 18, numerous other xmissions from and to other aircraft and the tower took place. Tower then gave an north# that was not mine, and clearance for immediate takeoff as another aircraft was on final for 18. This other aircraft was still holding short on the opp side of 18, from which I had entered the runway. I tried to tell tower that I was in position from my previous clearance and asked for a clarification if I was clear for takeoff. I got no reply from tower and heard numerous xmissions from other arriving aircraft all stepping on one another. Again tried to ask for clarification, but when I quit transmitting all I heard was 'cleared for immediate takeoff,' and the controller's voice was raised and seemed urgent. I was further advised, 'traffic on short final.' the other aircraft that the tower had given, mistakenly, the takeoff clearance to was still holding short, so I assumed tower had realized the error and wanted me to takeoff from my position on the runway. Also, the directions for after takeoff turns were what I had expected based on my departure direction of travel. After lifting off and complying with the right turn to my departure heading, I heard tower talk to the other aircraft asking who had just departed. I radioed tower and explained that I was the only one in position as previously cleared, and because of radio traffic after my request for clarification, thought the 'immediate departure' clearance was for me.

Original NASA ASRS Text

Title: SMA CLEARED POSITION AND HOLD. ATC USES WRONG N# TO CLEAR FOR IMMEDIATE TKOF. ON SECOND SUCH CALL REPORTER TAKES OFF. UNABLE COMMUNICATE WITH TWR DUE TO FREQ CONGESTION.

Narrative: I WAS CLRED TO TAXI INTO POS AND HOLD ON RWY 18 AT FCM. THE CTLR WAS VERY BUSY WITH NUMEROUS ARRS AND DEPS AND HAD TRIED TO CLR ME INTO POS A FEW MINS BEFORE. I DECLINED THAT CLRNC BECAUSE MY ACCESS TO THE RWY WAS BLOCKED BY ANOTHER ACFT, ACFT Y. TWR THEN CLRED ACFT Y INTO POS AND SHORTLY AFTER FOR DEP. TWR THEN CLRED ME INTO POS AND HOLD, WHICH I ACKNOWLEDGED AND COMPLIED. WHILE IN POS ON RWY 18, NUMEROUS OTHER XMISSIONS FROM AND TO OTHER ACFT AND THE TWR TOOK PLACE. TWR THEN GAVE AN N# THAT WAS NOT MINE, AND CLRNC FOR IMMEDIATE TKOF AS ANOTHER ACFT WAS ON FINAL FOR 18. THIS OTHER ACFT WAS STILL HOLDING SHORT ON THE OPP SIDE OF 18, FROM WHICH I HAD ENTERED THE RWY. I TRIED TO TELL TWR THAT I WAS IN POS FROM MY PREVIOUS CLRNC AND ASKED FOR A CLARIFICATION IF I WAS CLR FOR TKOF. I GOT NO REPLY FROM TWR AND HEARD NUMEROUS XMISSIONS FROM OTHER ARRIVING ACFT ALL STEPPING ON ONE ANOTHER. AGAIN TRIED TO ASK FOR CLARIFICATION, BUT WHEN I QUIT XMITTING ALL I HEARD WAS 'CLRED FOR IMMEDIATE TKOF,' AND THE CTLR'S VOICE WAS RAISED AND SEEMED URGENT. I WAS FURTHER ADVISED, 'TFC ON SHORT FINAL.' THE OTHER ACFT THAT THE TWR HAD GIVEN, MISTAKENLY, THE TKOF CLRNC TO WAS STILL HOLDING SHORT, SO I ASSUMED TWR HAD REALIZED THE ERROR AND WANTED ME TO TKOF FROM MY POS ON THE RWY. ALSO, THE DIRECTIONS FOR AFTER TKOF TURNS WERE WHAT I HAD EXPECTED BASED ON MY DEP DIRECTION OF TRAVEL. AFTER LIFTING OFF AND COMPLYING WITH THE RIGHT TURN TO MY DEP HDG, I HEARD TWR TALK TO THE OTHER ACFT ASKING WHO HAD JUST DEPARTED. I RADIOED TWR AND EXPLAINED THAT I WAS THE ONLY ONE IN POS AS PREVIOUSLY CLRED, AND BECAUSE OF RADIO TFC AFTER MY REQUEST FOR CLARIFICATION, THOUGHT THE 'IMMEDIATE DEP' CLRNC WAS FOR ME.

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.

Small aircraft cleared position and hold. ATC uses wrong north# to clear for immediate takeoff. On second such call reporter takes off. Unable communicate with tower due to frequency congestion.