A B737 flight crew departing las was advised by tower after takeoff they departed without clearance;...

Attributes
ACN	811324
Time
Date	200811
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : las.airport
State Reference	NV
Altitude	agl single value : 1500
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tower : las.tower tracon : zzz.tracon
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	climbout : takeoff
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 183
ASRS Report	811324
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 144 flight time type : 1800
ASRS Report	811321
Events
Anomaly	conflict : airborne less severe
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance

Narrative:

We taxied out to runway 7L for an A8 intersection departure. Company was holding short and as we neared the runway; tower cleared him for takeoff. We continued to taxi and just as we got to the hold short; tower cleared us for takeoff. We got airborne and tower asked us if we had a visual on our company. He then said that we had not received clearance to take off. We said that we had and I stated that; 'you can check the tapes.' we maintained visual with company and switched to departure. The rest of the flight was uneventful. While taxiing in; ground advised that mccarran tower wanted us to call them. I phoned the tower supervisor and he had checked the tapes and told us that we did in fact have clearance for takeoff. He said that no further action was necessary for us. However; I informed him that we would be submitting a safety report. He then asked for my name and I replied that he could call company operations if he needed that information. That seemed to end the conversation. Slow down when issuing clrncs! If you are trying to make up for the massive delays out of the airport by rushing to improve your departure rate at night; then it could lead to a mistake.

Original NASA ASRS Text

Title: A B737 FLIGHT CREW DEPARTING LAS WAS ADVISED BY TOWER AFTER TAKEOFF THEY DEPARTED WITHOUT CLEARANCE; BUT A CHECK OF THE TAPES VERIFIED THEY WERE IN FACT CLEARED FOR TAKEOFF.

Narrative: WE TAXIED OUT TO RWY 7L FOR AN A8 INTXN DEP. COMPANY WAS HOLDING SHORT AND AS WE NEARED THE RWY; TWR CLRED HIM FOR TKOF. WE CONTINUED TO TAXI AND JUST AS WE GOT TO THE HOLD SHORT; TWR CLRED US FOR TKOF. WE GOT AIRBORNE AND TWR ASKED US IF WE HAD A VISUAL ON OUR COMPANY. HE THEN SAID THAT WE HAD NOT RECEIVED CLRNC TO TAKE OFF. WE SAID THAT WE HAD AND I STATED THAT; 'YOU CAN CHK THE TAPES.' WE MAINTAINED VISUAL WITH COMPANY AND SWITCHED TO DEP. THE REST OF THE FLT WAS UNEVENTFUL. WHILE TAXIING IN; GND ADVISED THAT MCCARRAN TWR WANTED US TO CALL THEM. I PHONED THE TWR SUPVR AND HE HAD CHKED THE TAPES AND TOLD US THAT WE DID IN FACT HAVE CLRNC FOR TKOF. HE SAID THAT NO FURTHER ACTION WAS NECESSARY FOR US. HOWEVER; I INFORMED HIM THAT WE WOULD BE SUBMITTING A SAFETY RPT. HE THEN ASKED FOR MY NAME AND I REPLIED THAT HE COULD CALL COMPANY OPS IF HE NEEDED THAT INFO. THAT SEEMED TO END THE CONVERSATION. SLOW DOWN WHEN ISSUING CLRNCS! IF YOU ARE TRYING TO MAKE UP FOR THE MASSIVE DELAYS OUT OF THE ARPT BY RUSHING TO IMPROVE YOUR DEP RATE AT NIGHT; THEN IT COULD LEAD TO A MISTAKE.

Data retrieved from NASA's ASRS site as of May 2009 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.

A B737 flight crew departing las was advised by tower after takeoff they departed without clearance; but a check of the tapes verified they were in fact cleared for takeoff.