Pilot of a BE33 taxies aircraft without clearance. 'Thought' he heard his call sign several times bu...

Attributes
ACN	364467
Time
Date	199703
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : fll
State Reference	FL
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, Retractable Gear
Flight Phase	ground : holding ground other : taxi
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Transport, Low Wing, 2 Recip Eng
Flight Phase	climbout : takeoff ground : holding ground other : taxi
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : atp
Experience	flight time last 90 days : 10 flight time total : 5400 flight time type : 450
ASRS Report	364467
Person 2
Affiliation	Other
Function	observation : passenger
Qualification	other other : other
Events
Anomaly	non adherence : clearance non adherence : published procedure non adherence : far 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

Narrative:

Prior to taxi from the xyz FBO at ft lauderdale international airport, I had obtained the ATIS information and my IFR clearance from clearance delivery. While still parked short of the northern east/west taxiway, I made several unsuccessful calls to the ground controller. Upon making one last call on the very busy frequency, I heard, 'ddef, taxi to runway 27L.' I began my taxi toward runway 27, but then realized that it wasn't runway 27L that I desired, as they were using both runways 27R/left for departures. I stopped on the northern taxiway and made several more calls to the ground controller to confirm that I had permission to continue to 'runway 27R.' I believed I heard the ground controller say, 'ddef affirmative.' what I now believe occurred was that another aircraft began his taxi from another FBO on the south side of the airport, from another FBO also with the word 'zfbo' in its name. The call sign of that aircraft was the very similar, 'ddep.' because of the similar sounding call signs, the tendency for both the controller and I to use contractions, there was a total misunderstanding of the instructions and to whom they were issued. 'Ddef and ddep' sound too much alike when the engine is running. The frequency is very busy and a very chatty passenger is trying to engage me in conversation on the intercom. Yes, I was using excellent quality headsets, but this miscom still occurred to a very senior and experienced pilot. I really wasn't aware of the total misunderstanding until I had reached the hold short point of runway 27R and had switched to the tower (local) controller for takeoff clearance when I had to wait for that individual 'clear' a king air 'ddep' for takeoff on runway 27L!! It was at that point that I had that sinking feeling that I had, most likely, taxied out without clearance. In this instance, there were no other ground conflicts with other aircraft, just a clear case of, 'hearing what you expect to hear, not what is actually said!' and I thought it couldn't happen to me!!

Original NASA ASRS Text

Title: PLT OF A BE33 TAXIES ACFT WITHOUT CLRNC. 'THOUGHT' HE HEARD HIS CALL SIGN SEVERAL TIMES BUT WAS DISTRACTED BY A PAX IN THE R SEAT WHO WAS TALKING AND ARPT HAD LOTS OF TFC. PLT ASSOCIATED TAXI CLRNC FROM A SIMILAR SOUNDING BUT DIFFERENT FBO.

Narrative: PRIOR TO TAXI FROM THE XYZ FBO AT FT LAUDERDALE INTL ARPT, I HAD OBTAINED THE ATIS INFO AND MY IFR CLRNC FROM CLRNC DELIVERY. WHILE STILL PARKED SHORT OF THE NORTHERN E/W TXWY, I MADE SEVERAL UNSUCCESSFUL CALLS TO THE GND CTLR. UPON MAKING ONE LAST CALL ON THE VERY BUSY FREQ, I HEARD, 'DDEF, TAXI TO RWY 27L.' I BEGAN MY TAXI TOWARD RWY 27, BUT THEN REALIZED THAT IT WASN'T RWY 27L THAT I DESIRED, AS THEY WERE USING BOTH RWYS 27R/L FOR DEPS. I STOPPED ON THE NORTHERN TXWY AND MADE SEVERAL MORE CALLS TO THE GND CTLR TO CONFIRM THAT I HAD PERMISSION TO CONTINUE TO 'RWY 27R.' I BELIEVED I HEARD THE GND CTLR SAY, 'DDEF AFFIRMATIVE.' WHAT I NOW BELIEVE OCCURRED WAS THAT ANOTHER ACFT BEGAN HIS TAXI FROM ANOTHER FBO ON THE S SIDE OF THE ARPT, FROM ANOTHER FBO ALSO WITH THE WORD 'ZFBO' IN ITS NAME. THE CALL SIGN OF THAT ACFT WAS THE VERY SIMILAR, 'DDEP.' BECAUSE OF THE SIMILAR SOUNDING CALL SIGNS, THE TENDENCY FOR BOTH THE CTLR AND I TO USE CONTRACTIONS, THERE WAS A TOTAL MISUNDERSTANDING OF THE INSTRUCTIONS AND TO WHOM THEY WERE ISSUED. 'DDEF AND DDEP' SOUND TOO MUCH ALIKE WHEN THE ENG IS RUNNING. THE FREQ IS VERY BUSY AND A VERY CHATTY PAX IS TRYING TO ENGAGE ME IN CONVERSATION ON THE INTERCOM. YES, I WAS USING EXCELLENT QUALITY HEADSETS, BUT THIS MISCOM STILL OCCURRED TO A VERY SENIOR AND EXPERIENCED PLT. I REALLY WASN'T AWARE OF THE TOTAL MISUNDERSTANDING UNTIL I HAD REACHED THE HOLD SHORT POINT OF RWY 27R AND HAD SWITCHED TO THE TWR (LCL) CTLR FOR TKOF CLRNC WHEN I HAD TO WAIT FOR THAT INDIVIDUAL 'CLR' A KING AIR 'DDEP' FOR TKOF ON RWY 27L!! IT WAS AT THAT POINT THAT I HAD THAT SINKING FEELING THAT I HAD, MOST LIKELY, TAXIED OUT WITHOUT CLRNC. IN THIS INSTANCE, THERE WERE NO OTHER GND CONFLICTS WITH OTHER ACFT, JUST A CLR CASE OF, 'HEARING WHAT YOU EXPECT TO HEAR, NOT WHAT IS ACTUALLY SAID!' AND I THOUGHT IT COULDN'T HAPPEN TO 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.

Pilot of a BE33 taxies aircraft without clearance. 'Thought' he heard his call sign several times but was distracted by a passenger in the right seat who was talking and airport had lots of traffic. Pilot associated taxi clearance from a similar sounding but different FBO.